text: #
  #   Parse tree nodes for expressions
  #
  
  from __future__ import absolute_import
  
  import cython
  cython.declare(error=object, warning=object, warn_once=object, InternalError=object,
                 CompileError=object, UtilityCode=object, TempitaUtilityCode=object,
                 StringEncoding=object, operator=object, local_errors=object, report_error=object,
                 Naming=object, Nodes=object, PyrexTypes=object, py_object_type=object,
                 list_type=object, tuple_type=object, set_type=object, dict_type=object,
                 unicode_type=object, str_type=object, bytes_type=object, type_type=object,
                 Builtin=object, Symtab=object, Utils=object, find_coercion_error=object,
                 debug_disposal_code=object, debug_temp_alloc=object, debug_coercion=object,
                 bytearray_type=object, slice_type=object, _py_int_types=object,
                 IS_PYTHON3=cython.bint)
  
  import re
  import sys
  import copy
  import os.path
  import operator
  
  from .Errors import (
      error, warning, InternalError, CompileError, report_error, local_errors,
      CannotSpecialize)
  from .Code import UtilityCode, TempitaUtilityCode
  from . import StringEncoding
  from . import Naming
  from . import Nodes
  from .Nodes import Node, utility_code_for_imports, SingleAssignmentNode, PassStatNode
  from . import PyrexTypes
  from .PyrexTypes import py_object_type, c_long_type, typecast, error_type, \
      unspecified_type
  from . import TypeSlots
  from .Builtin import list_type, tuple_type, set_type, dict_type, type_type, \
       unicode_type, str_type, bytes_type, bytearray_type, basestring_type, slice_type
  from . import Builtin
  from . import Symtab
  from .. import Utils
  from .Annotate import AnnotationItem
  from . import Future
  from ..Debugging import print_call_chain
  from .DebugFlags import debug_disposal_code, debug_temp_alloc, \
      debug_coercion
  from .Pythran import (to_pythran, is_pythran_supported_type, is_pythran_supported_operation_type,
       is_pythran_expr, pythran_func_type, pythran_binop_type, pythran_unaryop_type, has_np_pythran,
       pythran_indexing_code, pythran_indexing_type, is_pythran_supported_node_or_none, pythran_type,
       pythran_is_numpy_func_supported, pythran_get_func_include_file, pythran_functor)
  from .PyrexTypes import PythranExpr
  
  try:
      from __builtin__ import basestring
  except ImportError:
      # Python 3
      basestring = str
      any_string_type = (bytes, str)
  else:
      # Python 2
      any_string_type = (bytes, unicode)
  
  
  if sys.version_info[0] >= 3:
      IS_PYTHON3 = True
      _py_int_types = int
  else:
      IS_PYTHON3 = False
      _py_int_types = (int, long)
  
  
  class NotConstant(object):
      _obj = None
  
      def __new__(cls):
          if NotConstant._obj is None:
              NotConstant._obj = super(NotConstant, cls).__new__(cls)
  
          return NotConstant._obj
  
      def __repr__(self):
          return "<NOT CONSTANT>"
  
  not_a_constant = NotConstant()
  constant_value_not_set = object()
  
  # error messages when coercing from key[0] to key[1]
  coercion_error_dict = {
      # string related errors
      (unicode_type, str_type): ("Cannot convert Unicode string to 'str' implicitly."
                                 " This is not portable and requires explicit encoding."),
      (unicode_type, bytes_type): "Cannot convert Unicode string to 'bytes' implicitly, encoding required.",
      (unicode_type, PyrexTypes.c_char_ptr_type): "Unicode objects only support coercion to Py_UNICODE*.",
      (unicode_type, PyrexTypes.c_const_char_ptr_type): "Unicode objects only support coercion to Py_UNICODE*.",
      (unicode_type, PyrexTypes.c_uchar_ptr_type): "Unicode objects only support coercion to Py_UNICODE*.",
      (unicode_type, PyrexTypes.c_const_uchar_ptr_type): "Unicode objects only support coercion to Py_UNICODE*.",
      (bytes_type, unicode_type): "Cannot convert 'bytes' object to unicode implicitly, decoding required",
      (bytes_type, str_type): "Cannot convert 'bytes' object to str implicitly. This is not portable to Py3.",
      (bytes_type, basestring_type): ("Cannot convert 'bytes' object to basestring implicitly."
                                      " This is not portable to Py3."),
      (bytes_type, PyrexTypes.c_py_unicode_ptr_type): "Cannot convert 'bytes' object to Py_UNICODE*, use 'unicode'.",
      (bytes_type, PyrexTypes.c_const_py_unicode_ptr_type): (
          "Cannot convert 'bytes' object to Py_UNICODE*, use 'unicode'."),
      (basestring_type, bytes_type): "Cannot convert 'basestring' object to bytes implicitly. This is not portable.",
      (str_type, unicode_type): ("str objects do not support coercion to unicode,"
                                 " use a unicode string literal instead (u'')"),
      (str_type, bytes_type): "Cannot convert 'str' to 'bytes' implicitly. This is not portable.",
      (str_type, PyrexTypes.c_char_ptr_type): "'str' objects do not support coercion to C types (use 'bytes'?).",
      (str_type, PyrexTypes.c_const_char_ptr_type): "'str' objects do not support coercion to C types (use 'bytes'?).",
      (str_type, PyrexTypes.c_uchar_ptr_type): "'str' objects do not support coercion to C types (use 'bytes'?).",
      (str_type, PyrexTypes.c_const_uchar_ptr_type): "'str' objects do not support coercion to C types (use 'bytes'?).",
      (str_type, PyrexTypes.c_py_unicode_ptr_type): "'str' objects do not support coercion to C types (use 'unicode'?).",
      (str_type, PyrexTypes.c_const_py_unicode_ptr_type): (
          "'str' objects do not support coercion to C types (use 'unicode'?)."),
      (PyrexTypes.c_char_ptr_type, unicode_type): "Cannot convert 'char*' to unicode implicitly, decoding required",
      (PyrexTypes.c_const_char_ptr_type, unicode_type): (
          "Cannot convert 'char*' to unicode implicitly, decoding required"),
      (PyrexTypes.c_uchar_ptr_type, unicode_type): "Cannot convert 'char*' to unicode implicitly, decoding required",
      (PyrexTypes.c_const_uchar_ptr_type, unicode_type): (
          "Cannot convert 'char*' to unicode implicitly, decoding required"),
  }
  
  def find_coercion_error(type_tuple, default, env):
      err = coercion_error_dict.get(type_tuple)
      if err is None:
          return default
      elif (env.directives['c_string_encoding'] and
                any(t in type_tuple for t in (PyrexTypes.c_char_ptr_type, PyrexTypes.c_uchar_ptr_type,
                                              PyrexTypes.c_const_char_ptr_type, PyrexTypes.c_const_uchar_ptr_type))):
          if type_tuple[1].is_pyobject:
              return default
          elif env.directives['c_string_encoding'] in ('ascii', 'default'):
              return default
          else:
              return "'%s' objects do not support coercion to C types with non-ascii or non-default c_string_encoding" % type_tuple[0].name
      else:
          return err
  
  
  def default_str_type(env):
      return {
          'bytes': bytes_type,
          'bytearray': bytearray_type,
          'str': str_type,
          'unicode': unicode_type
      }.get(env.directives['c_string_type'])
  
  
  def check_negative_indices(*nodes):
      """
      Raise a warning on nodes that are known to have negative numeric values.
      Used to find (potential) bugs inside of "wraparound=False" sections.
      """
      for node in nodes:
          if node is None or (
                  not isinstance(node.constant_result, _py_int_types) and
                  not isinstance(node.constant_result, float)):
              continue
          if node.constant_result < 0:
              warning(node.pos,
                      "the result of using negative indices inside of "
                      "code sections marked as 'wraparound=False' is "
                      "undefined", level=1)
  
  
  def infer_sequence_item_type(env, seq_node, index_node=None, seq_type=None):
      if not seq_node.is_sequence_constructor:
          if seq_type is None:
              seq_type = seq_node.infer_type(env)
          if seq_type is tuple_type:
              # tuples are immutable => we can safely follow assignments
              if seq_node.cf_state and len(seq_node.cf_state) == 1:
                  try:
                      seq_node = seq_node.cf_state[0].rhs
                  except AttributeError:
                      pass
      if seq_node is not None and seq_node.is_sequence_constructor:
          if index_node is not None and index_node.has_constant_result():
              try:
                  item = seq_node.args[index_node.constant_result]
              except (ValueError, TypeError, IndexError):
                  pass
              else:
                  return item.infer_type(env)
          # if we're lucky, all items have the same type
          item_types = {item.infer_type(env) for item in seq_node.args}
          if len(item_types) == 1:
              return item_types.pop()
      return None
  
  
  def make_dedup_key(outer_type, item_nodes):
      """
      Recursively generate a deduplication key from a sequence of values.
      Includes Cython node types to work around the fact that (1, 2.0) == (1.0, 2), for example.
  
      @param outer_type: The type of the outer container.
      @param item_nodes: A sequence of constant nodes that will be traversed recursively.
      @return: A tuple that can be used as a dict key for deduplication.
      """
      item_keys = [
          (py_object_type, None, type(None)) if node is None
          # For sequences and their "mult_factor", see TupleNode.
          else make_dedup_key(node.type, [node.mult_factor if node.is_literal else None] + node.args) if node.is_sequence_constructor
          else make_dedup_key(node.type, (node.start, node.stop, node.step)) if node.is_slice
          # For constants, look at the Python value type if we don't know the concrete Cython type.
          else (node.type, node.constant_result,
                type(node.constant_result) if node.type is py_object_type else None) if node.has_constant_result()
          else None  # something we cannot handle => short-circuit below
          for node in item_nodes
      ]
      if None in item_keys:
          return None
      return outer_type, tuple(item_keys)
  
  
  # Returns a block of code to translate the exception,
  # plus a boolean indicating whether to check for Python exceptions.
  def get_exception_handler(exception_value):
      if exception_value is None:
          return "__Pyx_CppExn2PyErr();", False
      elif (exception_value.type == PyrexTypes.c_char_type
            and exception_value.value == '*'):
          return "__Pyx_CppExn2PyErr();", True
      elif exception_value.type.is_pyobject:
          return (
              'try { throw; } catch(const std::exception& exn) {'
              'PyErr_SetString(%s, exn.what());'
              '} catch(...) { PyErr_SetNone(%s); }' % (
                  exception_value.entry.cname,
                  exception_value.entry.cname),
              False)
      else:
          return (
              '%s(); if (!PyErr_Occurred())'
              'PyErr_SetString(PyExc_RuntimeError, '
              '"Error converting c++ exception.");' % (
                  exception_value.entry.cname),
              False)
  
  
  def maybe_check_py_error(code, check_py_exception, pos, nogil):
      if check_py_exception:
          if nogil:
              code.putln(code.error_goto_if("__Pyx_ErrOccurredWithGIL()", pos))
          else:
              code.putln(code.error_goto_if("PyErr_Occurred()", pos))
  
  
  def translate_cpp_exception(code, pos, inside, py_result, exception_value, nogil):
      raise_py_exception, check_py_exception = get_exception_handler(exception_value)
      code.putln("try {")
      code.putln("%s" % inside)
      if py_result:
          code.putln(code.error_goto_if_null(py_result, pos))
      maybe_check_py_error(code, check_py_exception, pos, nogil)
      code.putln("} catch(...) {")
      if nogil:
          code.put_ensure_gil(declare_gilstate=True)
      code.putln(raise_py_exception)
      if nogil:
          code.put_release_ensured_gil()
      code.putln(code.error_goto(pos))
      code.putln("}")
  
  
  # Used to handle the case where an lvalue expression and an overloaded assignment
  # both have an exception declaration.
  def translate_double_cpp_exception(code, pos, lhs_type, lhs_code, rhs_code, lhs_exc_val, assign_exc_val, nogil):
      handle_lhs_exc, lhc_check_py_exc = get_exception_handler(lhs_exc_val)
      handle_assignment_exc, assignment_check_py_exc = get_exception_handler(assign_exc_val)
      code.putln("try {")
      code.putln(lhs_type.declaration_code("__pyx_local_lvalue = %s;" % lhs_code))
      maybe_check_py_error(code, lhc_check_py_exc, pos, nogil)
      code.putln("try {")
      code.putln("__pyx_local_lvalue = %s;" % rhs_code)
      maybe_check_py_error(code, assignment_check_py_exc, pos, nogil)
      # Catch any exception from the overloaded assignment.
      code.putln("} catch(...) {")
      if nogil:
          code.put_ensure_gil(declare_gilstate=True)
      code.putln(handle_assignment_exc)
      if nogil:
          code.put_release_ensured_gil()
      code.putln(code.error_goto(pos))
      code.putln("}")
      # Catch any exception from evaluating lhs.
      code.putln("} catch(...) {")
      if nogil:
          code.put_ensure_gil(declare_gilstate=True)
      code.putln(handle_lhs_exc)
      if nogil:
          code.put_release_ensured_gil()
      code.putln(code.error_goto(pos))
      code.putln('}')
  
  
  class ExprNode(Node):
      #  subexprs     [string]     Class var holding names of subexpr node attrs
      #  type         PyrexType    Type of the result
      #  result_code  string       Code fragment
      #  result_ctype string       C type of result_code if different from type
      #  is_temp      boolean      Result is in a temporary variable
      #  is_sequence_constructor
      #               boolean      Is a list or tuple constructor expression
      #  is_starred   boolean      Is a starred expression (e.g. '*a')
      #  saved_subexpr_nodes
      #               [ExprNode or [ExprNode or None] or None]
      #                            Cached result of subexpr_nodes()
      #  use_managed_ref boolean   use ref-counted temps/assignments/etc.
      #  result_is_used  boolean   indicates that the result will be dropped and the
      #  is_numpy_attribute   boolean   Is a Numpy module attribute
      #                            result_code/temp_result can safely be set to None
      #  annotation   ExprNode or None    PEP526 annotation for names or expressions
  
      result_ctype = None
      type = None
      annotation = None
      temp_code = None
      old_temp = None  # error checker for multiple frees etc.
      use_managed_ref = True  # can be set by optimisation transforms
      result_is_used = True
      is_numpy_attribute = False
  
      #  The Analyse Expressions phase for expressions is split
      #  into two sub-phases:
      #
      #    Analyse Types
      #      Determines the result type of the expression based
      #      on the types of its sub-expressions, and inserts
      #      coercion nodes into the expression tree where needed.
      #      Marks nodes which will need to have temporary variables
      #      allocated.
      #
      #    Allocate Temps
      #      Allocates temporary variables where needed, and fills
      #      in the result_code field of each node.
      #
      #  ExprNode provides some convenience routines which
      #  perform both of the above phases. These should only
      #  be called from statement nodes, and only when no
      #  coercion nodes need to be added around the expression
      #  being analysed. In that case, the above two phases
      #  should be invoked separately.
      #
      #  Framework code in ExprNode provides much of the common
      #  processing for the various phases. It makes use of the
      #  'subexprs' class attribute of ExprNodes, which should
      #  contain a list of the names of attributes which can
      #  hold sub-nodes or sequences of sub-nodes.
      #
      #  The framework makes use of a number of abstract methods.
      #  Their responsibilities are as follows.
      #
      #    Declaration Analysis phase
      #
      #      analyse_target_declaration
      #        Called during the Analyse Declarations phase to analyse
      #        the LHS of an assignment or argument of a del statement.
      #        Nodes which cannot be the LHS of an assignment need not
      #        implement it.
      #
      #    Expression Analysis phase
      #
      #      analyse_types
      #        - Call analyse_types on all sub-expressions.
      #        - Check operand types, and wrap coercion nodes around
      #          sub-expressions where needed.
      #        - Set the type of this node.
      #        - If a temporary variable will be required for the
      #          result, set the is_temp flag of this node.
      #
      #      analyse_target_types
      #        Called during the Analyse Types phase to analyse
      #        the LHS of an assignment or argument of a del
      #        statement. Similar responsibilities to analyse_types.
      #
      #      target_code
      #        Called by the default implementation of allocate_target_temps.
      #        Should return a C lvalue for assigning to the node. The default
      #        implementation calls calculate_result_code.
      #
      #      check_const
      #        - Check that this node and its subnodes form a
      #          legal constant expression. If so, do nothing,
      #          otherwise call not_const.
      #
      #        The default implementation of check_const
      #        assumes that the expression is not constant.
      #
      #      check_const_addr
      #        - Same as check_const, except check that the
      #          expression is a C lvalue whose address is
      #          constant. Otherwise, call addr_not_const.
      #
      #        The default implementation of calc_const_addr
      #        assumes that the expression is not a constant
      #        lvalue.
      #
      #   Code Generation phase
      #
      #      generate_evaluation_code
      #        - Call generate_evaluation_code for sub-expressions.
      #        - Perform the functions of generate_result_code
      #          (see below).
      #        - If result is temporary, call generate_disposal_code
      #          on all sub-expressions.
      #
      #        A default implementation of generate_evaluation_code
      #        is provided which uses the following abstract methods:
      #
      #          generate_result_code
      #            - Generate any C statements necessary to calculate
      #              the result of this node from the results of its
      #              sub-expressions.
      #
      #          calculate_result_code
      #            - Should return a C code fragment evaluating to the
      #              result. This is only called when the result is not
      #              a temporary.
      #
      #      generate_assignment_code
      #        Called on the LHS of an assignment.
      #        - Call generate_evaluation_code for sub-expressions.
      #        - Generate code to perform the assignment.
      #        - If the assignment absorbed a reference, call
      #          generate_post_assignment_code on the RHS,
      #          otherwise call generate_disposal_code on it.
      #
      #      generate_deletion_code
      #        Called on an argument of a del statement.
      #        - Call generate_evaluation_code for sub-expressions.
      #        - Generate code to perform the deletion.
      #        - Call generate_disposal_code on all sub-expressions.
      #
      #
  
      is_sequence_constructor = False
      is_dict_literal = False
      is_set_literal = False
      is_string_literal = False
      is_attribute = False
      is_subscript = False
      is_slice = False
  
      is_buffer_access = False
      is_memview_index = False
      is_memview_slice = False
      is_memview_broadcast = False
      is_memview_copy_assignment = False
  
      saved_subexpr_nodes = None
      is_temp = False
      has_temp_moved = False  # if True then attempting to do anything but free the temp is invalid
      is_target = False
      is_starred = False
  
      constant_result = constant_value_not_set
  
      child_attrs = property(fget=operator.attrgetter('subexprs'))
  
      def analyse_annotations(self, env):
          pass
  
      def not_implemented(self, method_name):
          print_call_chain(method_name, "not implemented")
          raise InternalError(
              "%s.%s not implemented" % (self.__class__.__name__, method_name))
  
      def is_lvalue(self):
          return 0
  
      def is_addressable(self):
          return self.is_lvalue() and not self.type.is_memoryviewslice
  
      def is_ephemeral(self):
          #  An ephemeral node is one whose result is in
          #  a Python temporary and we suspect there are no
          #  other references to it. Certain operations are
          #  disallowed on such values, since they are
          #  likely to result in a dangling pointer.
          return self.type.is_pyobject and self.is_temp
  
      def subexpr_nodes(self):
          #  Extract a list of subexpression nodes based
          #  on the contents of the subexprs class attribute.
          nodes = []
          for name in self.subexprs:
              item = getattr(self, name)
              if item is not None:
                  if type(item) is list:
                      nodes.extend(item)
                  else:
                      nodes.append(item)
          return nodes
  
      def result(self):
          if self.is_temp:
              #if not self.temp_code:
              #    pos = (os.path.basename(self.pos[0].get_description()),) + self.pos[1:] if self.pos else '(?)'
              #    raise RuntimeError("temp result name not set in %s at %r" % (
              #        self.__class__.__name__, pos))
              return self.temp_code
          else:
              return self.calculate_result_code()
  
      def _make_move_result_rhs(self, result, optional=False):
          if optional and not (self.is_temp and self.type.is_cpp_class and not self.type.is_reference):
              return result
          self.has_temp_moved = True
          return "{}({})".format("__PYX_STD_MOVE_IF_SUPPORTED" if optional else "std::move", result)
  
      def move_result_rhs(self):
          return self._make_move_result_rhs(self.result(), optional=True)
  
      def move_result_rhs_as(self, type):
          result = self.result_as(type)
          if not (type.is_reference or type.needs_refcounting):
              requires_move = type.is_rvalue_reference and self.is_temp
              result = self._make_move_result_rhs(result, optional=not requires_move)
          return result
  
      def pythran_result(self, type_=None):
          if is_pythran_supported_node_or_none(self):
              return to_pythran(self)
  
          assert(type_ is not None)
          return to_pythran(self, type_)
  
      def is_c_result_required(self):
          """
          Subtypes may return False here if result temp allocation can be skipped.
          """
          return True
  
      def result_as(self, type = None):
          #  Return the result code cast to the specified C type.
          if (self.is_temp and self.type.is_pyobject and
                  type != py_object_type):
              # Allocated temporaries are always PyObject *, which may not
              # reflect the actual type (e.g. an extension type)
              return typecast(type, py_object_type, self.result())
          return typecast(type, self.ctype(), self.result())
  
      def py_result(self):
          #  Return the result code cast to PyObject *.
          return self.result_as(py_object_type)
  
      def ctype(self):
          #  Return the native C type of the result (i.e. the
          #  C type of the result_code expression).
          return self.result_ctype or self.type
  
      def get_constant_c_result_code(self):
          # Return the constant value of this node as a result code
          # string, or None if the node is not constant.  This method
          # can be called when the constant result code is required
          # before the code generation phase.
          #
          # The return value is a string that can represent a simple C
          # value, a constant C name or a constant C expression.  If the
          # node type depends on Python code, this must return None.
          return None
  
      def calculate_constant_result(self):
          # Calculate the constant compile time result value of this
          # expression and store it in ``self.constant_result``.  Does
          # nothing by default, thus leaving ``self.constant_result``
          # unknown.  If valid, the result can be an arbitrary Python
          # value.
          #
          # This must only be called when it is assured that all
          # sub-expressions have a valid constant_result value.  The
          # ConstantFolding transform will do this.
          pass
  
      def has_constant_result(self):
          return self.constant_result is not constant_value_not_set and \
                 self.constant_result is not not_a_constant
  
      def compile_time_value(self, denv):
          #  Return value of compile-time expression, or report error.
          error(self.pos, "Invalid compile-time expression")
  
      def compile_time_value_error(self, e):
          error(self.pos, "Error in compile-time expression: %s: %s" % (
              e.__class__.__name__, e))
  
      # ------------- Declaration Analysis ----------------
  
      def analyse_target_declaration(self, env):
          error(self.pos, "Cannot assign to or delete this")
  
      # ------------- Expression Analysis ----------------
  
      def analyse_const_expression(self, env):
          #  Called during the analyse_declarations phase of a
          #  constant expression. Analyses the expression's type,
          #  checks whether it is a legal const expression,
          #  and determines its value.
          node = self.analyse_types(env)
          node.check_const()
          return node
  
      def analyse_expressions(self, env):
          #  Convenience routine performing both the Type
          #  Analysis and Temp Allocation phases for a whole
          #  expression.
          return self.analyse_types(env)
  
      def analyse_target_expression(self, env, rhs):
          #  Convenience routine performing both the Type
          #  Analysis and Temp Allocation phases for the LHS of
          #  an assignment.
          return self.analyse_target_types(env)
  
      def analyse_boolean_expression(self, env):
          #  Analyse expression and coerce to a boolean.
          node = self.analyse_types(env)
          bool = node.coerce_to_boolean(env)
          return bool
  
      def analyse_temp_boolean_expression(self, env):
          #  Analyse boolean expression and coerce result into
          #  a temporary. This is used when a branch is to be
          #  performed on the result and we won't have an
          #  opportunity to ensure disposal code is executed
          #  afterwards. By forcing the result into a temporary,
          #  we ensure that all disposal has been done by the
          #  time we get the result.
          node = self.analyse_types(env)
          return node.coerce_to_boolean(env).coerce_to_simple(env)
  
      # --------------- Type Inference -----------------
  
      def type_dependencies(self, env):
          # Returns the list of entries whose types must be determined
          # before the type of self can be inferred.
          if getattr(self, 'type', None) is not None:
              return ()
          return sum([node.type_dependencies(env) for node in self.subexpr_nodes()], ())
  
      def infer_type(self, env):
          # Attempt to deduce the type of self.
          # Differs from analyse_types as it avoids unnecessary
          # analysis of subexpressions, but can assume everything
          # in self.type_dependencies() has been resolved.
          type = getattr(self, 'type', None)
          if type is not None:
              return type
          entry = getattr(self, 'entry', None)
          if entry is not None:
              return entry.type
          self.not_implemented("infer_type")
  
      def nonlocally_immutable(self):
          # Returns whether this variable is a safe reference, i.e.
          # can't be modified as part of globals or closures.
          return self.is_literal or self.is_temp or self.type.is_array or self.type.is_cfunction
  
      def inferable_item_node(self, index=0):
          """
          Return a node that represents the (type) result of an indexing operation,
          e.g. for tuple unpacking or iteration.
          """
          return IndexNode(self.pos, base=self, index=IntNode(
              self.pos, value=str(index), constant_result=index, type=PyrexTypes.c_py_ssize_t_type))
  
      # --------------- Type Analysis ------------------
  
      def analyse_as_module(self, env):
          # If this node can be interpreted as a reference to a
          # cimported module, return its scope, else None.
          return None
  
      def analyse_as_type(self, env):
          # If this node can be interpreted as a reference to a
          # type, return that type, else None.
          return None
  
      def analyse_as_specialized_type(self, env):
          type = self.analyse_as_type(env)
          if type and type.is_fused and env.fused_to_specific:
              # while it would be nice to test "if entry.type in env.fused_to_specific"
              # rather than try/catch this doesn't work reliably (mainly for nested fused types)
              try:
                  return type.specialize(env.fused_to_specific)
              except KeyError:
                  pass
          if type and type.is_fused:
              error(self.pos, "Type is not specific")
          return type
  
      def analyse_as_extension_type(self, env):
          # If this node can be interpreted as a reference to an
          # extension type or builtin type, return its type, else None.
          return None
  
      def analyse_types(self, env):
          self.not_implemented("analyse_types")
  
      def analyse_target_types(self, env):
          return self.analyse_types(env)
  
      def nogil_check(self, env):
          # By default, any expression based on Python objects is
          # prevented in nogil environments.  Subtypes must override
          # this if they can work without the GIL.
          if self.type and self.type.is_pyobject:
              self.gil_error()
  
      def gil_assignment_check(self, env):
          if env.nogil and self.type.is_pyobject:
              error(self.pos, "Assignment of Python object not allowed without gil")
  
      def check_const(self):
          self.not_const()
          return False
  
      def not_const(self):
          error(self.pos, "Not allowed in a constant expression")
  
      def check_const_addr(self):
          self.addr_not_const()
          return False
  
      def addr_not_const(self):
          error(self.pos, "Address is not constant")
  
      # ----------------- Result Allocation -----------------
  
      def result_in_temp(self):
          #  Return true if result is in a temporary owned by
          #  this node or one of its subexpressions. Overridden
          #  by certain nodes which can share the result of
          #  a subnode.
          return self.is_temp
  
      def target_code(self):
          #  Return code fragment for use as LHS of a C assignment.
          return self.calculate_result_code()
  
      def calculate_result_code(self):
          self.not_implemented("calculate_result_code")
  
  #    def release_target_temp(self, env):
  #        #  Release temporaries used by LHS of an assignment.
  #        self.release_subexpr_temps(env)
  
      def allocate_temp_result(self, code):
          if self.temp_code:
              raise RuntimeError("Temp allocated multiple times in %r: %r" % (self.__class__.__name__, self.pos))
          type = self.type
          if not type.is_void:
              if type.is_pyobject:
                  type = PyrexTypes.py_object_type
              elif not (self.result_is_used or type.is_memoryviewslice or self.is_c_result_required()):
                  self.temp_code = None
                  return
              self.temp_code = code.funcstate.allocate_temp(
                  type, manage_ref=self.use_managed_ref)
          else:
              self.temp_code = None
  
      def release_temp_result(self, code):
          if not self.temp_code:
              if not self.result_is_used:
                  # not used anyway, so ignore if not set up
                  return
              pos = (os.path.basename(self.pos[0].get_description()),) + self.pos[1:] if self.pos else '(?)'
              if self.old_temp:
                  raise RuntimeError("temp %s released multiple times in %s at %r" % (
                      self.old_temp, self.__class__.__name__, pos))
              else:
                  raise RuntimeError("no temp, but release requested in %s at %r" % (
                      self.__class__.__name__, pos))
          code.funcstate.release_temp(self.temp_code)
          self.old_temp = self.temp_code
          self.temp_code = None
  
      # ---------------- Code Generation -----------------
  
      def make_owned_reference(self, code):
          """
          Make sure we own a reference to result.
          If the result is in a temp, it is already a new reference.
          """
          if not self.result_in_temp():
              code.put_incref(self.result(), self.ctype())
  
      def make_owned_memoryviewslice(self, code):
          """
          Make sure we own the reference to this memoryview slice.
          """
          # TODO ideally this would be shared with "make_owned_reference"
          if not self.result_in_temp():
              code.put_incref_memoryviewslice(self.result(), self.type,
                                              have_gil=not self.in_nogil_context)
  
      def generate_evaluation_code(self, code):
          #  Generate code to evaluate this node and
          #  its sub-expressions, and dispose of any
          #  temporary results of its sub-expressions.
          self.generate_subexpr_evaluation_code(code)
  
          code.mark_pos(self.pos)
          if self.is_temp:
              self.allocate_temp_result(code)
  
          self.generate_result_code(code)
          if self.is_temp and not (self.type.is_string or self.type.is_pyunicode_ptr):
              # If we are temp we do not need to wait until this node is disposed
              # before disposing children.
              self.generate_subexpr_disposal_code(code)
              self.free_subexpr_temps(code)
  
      def generate_subexpr_evaluation_code(self, code):
          for node in self.subexpr_nodes():
              node.generate_evaluation_code(code)
  
      def generate_result_code(self, code):
          self.not_implemented("generate_result_code")
  
      def generate_disposal_code(self, code):
          if self.is_temp:
              if self.type.is_string or self.type.is_pyunicode_ptr:
                  # postponed from self.generate_evaluation_code()
                  self.generate_subexpr_disposal_code(code)
                  self.free_subexpr_temps(code)
              if self.result():
                  code.put_decref_clear(self.result(), self.ctype(),
                                          have_gil=not self.in_nogil_context)
              if self.has_temp_moved:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("MoveIfSupported", "CppSupport.cpp"))
          else:
              # Already done if self.is_temp
              self.generate_subexpr_disposal_code(code)
  
      def generate_subexpr_disposal_code(self, code):
          #  Generate code to dispose of temporary results
          #  of all sub-expressions.
          for node in self.subexpr_nodes():
              node.generate_disposal_code(code)
  
      def generate_post_assignment_code(self, code):
          if self.is_temp:
              if self.type.is_string or self.type.is_pyunicode_ptr:
                  # postponed from self.generate_evaluation_code()
                  self.generate_subexpr_disposal_code(code)
                  self.free_subexpr_temps(code)
              elif self.type.is_pyobject:
                  code.putln("%s = 0;" % self.result())
              elif self.type.is_memoryviewslice:
                  code.putln("%s.memview = NULL;" % self.result())
                  code.putln("%s.data = NULL;" % self.result())
  
              if self.has_temp_moved:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("MoveIfSupported", "CppSupport.cpp"))
          else:
              self.generate_subexpr_disposal_code(code)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          #  Stub method for nodes which are not legal as
          #  the LHS of an assignment. An error will have
          #  been reported earlier.
          pass
  
      def generate_deletion_code(self, code, ignore_nonexisting=False):
          #  Stub method for nodes that are not legal as
          #  the argument of a del statement. An error
          #  will have been reported earlier.
          pass
  
      def free_temps(self, code):
          if self.is_temp:
              if not self.type.is_void:
                  self.release_temp_result(code)
          else:
              self.free_subexpr_temps(code)
  
      def free_subexpr_temps(self, code):
          for sub in self.subexpr_nodes():
              sub.free_temps(code)
  
      def generate_function_definitions(self, env, code):
          pass
  
      # ----Generation of small bits of reference counting --
  
      def generate_decref_set(self, code, rhs):
          code.put_decref_set(self.result(), self.ctype(), rhs)
  
      def generate_xdecref_set(self, code, rhs):
          code.put_xdecref_set(self.result(), self.ctype(), rhs)
  
      def generate_gotref(self, code, handle_null=False,
                          maybe_null_extra_check=True):
          if not (handle_null and self.cf_is_null):
              if (handle_null and self.cf_maybe_null
                      and maybe_null_extra_check):
                  self.generate_xgotref(code)
              else:
                  code.put_gotref(self.result(), self.ctype())
  
      def generate_xgotref(self, code):
          code.put_xgotref(self.result(), self.ctype())
  
      def generate_giveref(self, code):
          code.put_giveref(self.result(), self.ctype())
  
      def generate_xgiveref(self, code):
          code.put_xgiveref(self.result(), self.ctype())
  
      # ---------------- Annotation ---------------------
  
      def annotate(self, code):
          for node in self.subexpr_nodes():
              node.annotate(code)
  
      # ----------------- Coercion ----------------------
  
      def coerce_to(self, dst_type, env):
          #   Coerce the result so that it can be assigned to
          #   something of type dst_type. If processing is necessary,
          #   wraps this node in a coercion node and returns that.
          #   Otherwise, returns this node unchanged.
          #
          #   This method is called during the analyse_expressions
          #   phase of the src_node's processing.
          #
          #   Note that subclasses that override this (especially
          #   ConstNodes) must not (re-)set their own .type attribute
          #   here.  Since expression nodes may turn up in different
          #   places in the tree (e.g. inside of CloneNodes in cascaded
          #   assignments), this method must return a new node instance
          #   if it changes the type.
          #
          src = self
          src_type = self.type
  
          if self.check_for_coercion_error(dst_type, env):
              return self
  
          used_as_reference = dst_type.is_reference
          if used_as_reference and not src_type.is_reference:
              dst_type = dst_type.ref_base_type
  
          if src_type.is_cv_qualified:
              src_type = src_type.cv_base_type
  
          if src_type.is_fused or dst_type.is_fused:
              # See if we are coercing a fused function to a pointer to a
              # specialized function
              if (src_type.is_cfunction and not dst_type.is_fused and
                      dst_type.is_ptr and dst_type.base_type.is_cfunction):
  
                  dst_type = dst_type.base_type
  
                  for signature in src_type.get_all_specialized_function_types():
                      if signature.same_as(dst_type):
                          src.type = signature
                          src.entry = src.type.entry
                          src.entry.used = True
                          return self
  
              if src_type.is_fused:
                  error(self.pos, "Type is not specialized")
              elif src_type.is_null_ptr and dst_type.is_ptr:
                  # NULL can be implicitly cast to any pointer type
                  return self
              else:
                  error(self.pos, "Cannot coerce to a type that is not specialized")
  
              self.type = error_type
              return self
  
          if self.coercion_type is not None:
              # This is purely for error checking purposes!
              node = NameNode(self.pos, name='', type=self.coercion_type)
              node.coerce_to(dst_type, env)
  
          if dst_type.is_memoryviewslice:
              from . import MemoryView
              if not src.type.is_memoryviewslice:
                  if src.type.is_pyobject:
                      src = CoerceToMemViewSliceNode(src, dst_type, env)
                  elif src.type.is_array:
                      src = CythonArrayNode.from_carray(src, env).coerce_to(dst_type, env)
                  elif not src_type.is_error:
                      error(self.pos,
                            "Cannot convert '%s' to memoryviewslice" % (src_type,))
              else:
                  if src.type.writable_needed:
                      dst_type.writable_needed = True
                  if not src.type.conforms_to(dst_type, broadcast=self.is_memview_broadcast,
                                              copying=self.is_memview_copy_assignment):
                      if src.type.dtype.same_as(dst_type.dtype):
                          msg = "Memoryview '%s' not conformable to memoryview '%s'."
                          tup = src.type, dst_type
                      else:
                          msg = "Different base types for memoryviews (%s, %s)"
                          tup = src.type.dtype, dst_type.dtype
  
                      error(self.pos, msg % tup)
  
          elif dst_type.is_pyobject:
              if not src.type.is_pyobject:
                  if dst_type is bytes_type and src.type.is_int:
                      src = CoerceIntToBytesNode(src, env)
                  else:
                      src = CoerceToPyTypeNode(src, env, type=dst_type)
              if not src.type.subtype_of(dst_type):
                  if src.constant_result is not None:
                      src = PyTypeTestNode(src, dst_type, env)
          elif is_pythran_expr(dst_type) and is_pythran_supported_type(src.type):
              # We let the compiler decide whether this is valid
              return src
          elif is_pythran_expr(src.type):
              if is_pythran_supported_type(dst_type):
                  # Match the case were a pythran expr is assigned to a value, or vice versa.
                  # We let the C++ compiler decide whether this is valid or not!
                  return src
              # Else, we need to convert the Pythran expression to a Python object
              src = CoerceToPyTypeNode(src, env, type=dst_type)
          elif src.type.is_pyobject:
              if used_as_reference and dst_type.is_cpp_class:
                  warning(
                      self.pos,
                      "Cannot pass Python object as C++ data structure reference (%s &), will pass by copy." % dst_type)
              src = CoerceFromPyTypeNode(dst_type, src, env)
          elif (dst_type.is_complex
                and src_type != dst_type
                and dst_type.assignable_from(src_type)):
              src = CoerceToComplexNode(src, dst_type, env)
          else:
              # neither src nor dst are py types
              # Added the string comparison, since for c types that
              # is enough, but Cython gets confused when the types are
              # in different pxi files.
              # TODO: Remove this hack and require shared declarations.
              if not (src.type == dst_type or str(src.type) == str(dst_type) or dst_type.assignable_from(src_type)):
                  self.fail_assignment(dst_type)
          return src
  
      def fail_assignment(self, dst_type):
          error(self.pos, "Cannot assign type '%s' to '%s'" % (self.type, dst_type))
  
      def check_for_coercion_error(self, dst_type, env, fail=False, default=None):
          if fail and not default:
              default = "Cannot assign type '%(FROM)s' to '%(TO)s'"
          message = find_coercion_error((self.type, dst_type), default, env)
          if message is not None:
              error(self.pos, message % {'FROM': self.type, 'TO': dst_type})
              return True
          if fail:
              self.fail_assignment(dst_type)
              return True
          return False
  
      def coerce_to_pyobject(self, env):
          return self.coerce_to(PyrexTypes.py_object_type, env)
  
      def coerce_to_boolean(self, env):
          #  Coerce result to something acceptable as
          #  a boolean value.
  
          # if it's constant, calculate the result now
          if self.has_constant_result():
              bool_value = bool(self.constant_result)
              return BoolNode(self.pos, value=bool_value,
                              constant_result=bool_value)
  
          type = self.type
          if type.is_enum or type.is_error:
              return self
          elif type.is_pyobject or type.is_int or type.is_ptr or type.is_float:
              return CoerceToBooleanNode(self, env)
          elif type.is_cpp_class:
              return SimpleCallNode(
                  self.pos,
                  function=AttributeNode(
                      self.pos, obj=self, attribute='operator bool'),
                  args=[]).analyse_types(env)
          elif type.is_ctuple:
              bool_value = len(type.components) == 0
              return BoolNode(self.pos, value=bool_value,
                              constant_result=bool_value)
          else:
              error(self.pos, "Type '%s' not acceptable as a boolean" % type)
              return self
  
      def coerce_to_integer(self, env):
          # If not already some C integer type, coerce to longint.
          if self.type.is_int:
              return self
          else:
              return self.coerce_to(PyrexTypes.c_long_type, env)
  
      def coerce_to_temp(self, env):
          #  Ensure that the result is in a temporary.
          if self.result_in_temp():
              return self
          else:
              return CoerceToTempNode(self, env)
  
      def coerce_to_simple(self, env):
          #  Ensure that the result is simple (see is_simple).
          if self.is_simple():
              return self
          else:
              return self.coerce_to_temp(env)
  
      def is_simple(self):
          #  A node is simple if its result is something that can
          #  be referred to without performing any operations, e.g.
          #  a constant, local var, C global var, struct member
          #  reference, or temporary.
          return self.result_in_temp()
  
      def may_be_none(self):
          if self.type and not (self.type.is_pyobject or
                                self.type.is_memoryviewslice):
              return False
          if self.has_constant_result():
              return self.constant_result is not None
          return True
  
      def as_cython_attribute(self):
          return None
  
      def as_none_safe_node(self, message, error="PyExc_TypeError", format_args=()):
          # Wraps the node in a NoneCheckNode if it is not known to be
          # not-None (e.g. because it is a Python literal).
          if self.may_be_none():
              return NoneCheckNode(self, error, message, format_args)
          else:
              return self
  
      @classmethod
      def from_node(cls, node, **kwargs):
          """Instantiate this node class from another node, properly
          copying over all attributes that one would forget otherwise.
          """
          attributes = "cf_state cf_maybe_null cf_is_null constant_result".split()
          for attr_name in attributes:
              if attr_name in kwargs:
                  continue
              try:
                  value = getattr(node, attr_name)
              except AttributeError:
                  pass
              else:
                  kwargs[attr_name] = value
          return cls(node.pos, **kwargs)
  
  
  class AtomicExprNode(ExprNode):
      #  Abstract base class for expression nodes which have
      #  no sub-expressions.
  
      subexprs = []
  
      # Override to optimize -- we know we have no children
      def generate_subexpr_evaluation_code(self, code):
          pass
      def generate_subexpr_disposal_code(self, code):
          pass
  
  class PyConstNode(AtomicExprNode):
      #  Abstract base class for constant Python values.
  
      is_literal = 1
      type = py_object_type
      nogil_check = None
  
      def is_simple(self):
          return 1
  
      def may_be_none(self):
          return False
  
      def analyse_types(self, env):
          return self
  
      def calculate_result_code(self):
          return self.value
  
      def generate_result_code(self, code):
          pass
  
  
  class NoneNode(PyConstNode):
      #  The constant value None
  
      is_none = 1
      value = "Py_None"
  
      constant_result = None
  
      def compile_time_value(self, denv):
          return None
  
      def may_be_none(self):
          return True
  
      def coerce_to(self, dst_type, env):
          if not (dst_type.is_pyobject or dst_type.is_memoryviewslice or dst_type.is_error):
              # Catch this error early and loudly.
              error(self.pos, "Cannot assign None to %s" % dst_type)
          return super(NoneNode, self).coerce_to(dst_type, env)
  
  
  class EllipsisNode(PyConstNode):
      #  '...' in a subscript list.
  
      value = "Py_Ellipsis"
  
      constant_result = Ellipsis
  
      def compile_time_value(self, denv):
          return Ellipsis
  
  
  class ConstNode(AtomicExprNode):
      # Abstract base type for literal constant nodes.
      #
      # value     string      C code fragment
  
      is_literal = 1
      nogil_check = None
  
      def is_simple(self):
          return 1
  
      def nonlocally_immutable(self):
          return 1
  
      def may_be_none(self):
          return False
  
      def analyse_types(self, env):
          return self  # Types are held in class variables
  
      def check_const(self):
          return True
  
      def get_constant_c_result_code(self):
          return self.calculate_result_code()
  
      def calculate_result_code(self):
          return str(self.value)
  
      def generate_result_code(self, code):
          pass
  
  
  class BoolNode(ConstNode):
      type = PyrexTypes.c_bint_type
      #  The constant value True or False
  
      def calculate_constant_result(self):
          self.constant_result = self.value
  
      def compile_time_value(self, denv):
          return self.value
  
      def calculate_result_code(self):
          if self.type.is_pyobject:
              return 'Py_True' if self.value else 'Py_False'
          else:
              return str(int(self.value))
  
      def coerce_to(self, dst_type, env):
          if dst_type == self.type:
              return self
          if dst_type is py_object_type and self.type is Builtin.bool_type:
              return self
          if dst_type.is_pyobject and self.type.is_int:
              return BoolNode(
                  self.pos, value=self.value,
                  constant_result=self.constant_result,
                  type=Builtin.bool_type)
          if dst_type.is_int and self.type.is_pyobject:
              return BoolNode(
                  self.pos, value=self.value,
                  constant_result=self.constant_result,
                  type=PyrexTypes.c_bint_type)
          return ConstNode.coerce_to(self, dst_type, env)
  
  
  class NullNode(ConstNode):
      type = PyrexTypes.c_null_ptr_type
      value = "NULL"
      constant_result = 0
  
      def get_constant_c_result_code(self):
          return self.value
  
  
  class CharNode(ConstNode):
      type = PyrexTypes.c_char_type
  
      def calculate_constant_result(self):
          self.constant_result = ord(self.value)
  
      def compile_time_value(self, denv):
          return ord(self.value)
  
      def calculate_result_code(self):
          return "'%s'" % StringEncoding.escape_char(self.value)
  
  
  class IntNode(ConstNode):
  
      # unsigned     "" or "U"
      # longness     "" or "L" or "LL"
      # is_c_literal   True/False/None   creator considers this a C integer literal
  
      unsigned = ""
      longness = ""
      is_c_literal = None  # unknown
  
      def __init__(self, pos, **kwds):
          ExprNode.__init__(self, pos, **kwds)
          if 'type' not in kwds:
              self.type = self.find_suitable_type_for_value()
  
      def find_suitable_type_for_value(self):
          if self.constant_result is constant_value_not_set:
              try:
                  self.calculate_constant_result()
              except ValueError:
                  pass
          # we ignore 'is_c_literal = True' and instead map signed 32bit
          # integers as C long values
          if self.is_c_literal or \
                 not self.has_constant_result() or \
                 self.unsigned or self.longness == 'LL':
              # clearly a C literal
              rank = (self.longness == 'LL') and 2 or 1
              suitable_type = PyrexTypes.modifiers_and_name_to_type[not self.unsigned, rank, "int"]
              if self.type:
                  suitable_type = PyrexTypes.widest_numeric_type(suitable_type, self.type)
          else:
              # C literal or Python literal - split at 32bit boundary
              if -2**31 <= self.constant_result < 2**31:
                  if self.type and self.type.is_int:
                      suitable_type = self.type
                  else:
                      suitable_type = PyrexTypes.c_long_type
              else:
                  suitable_type = PyrexTypes.py_object_type
          return suitable_type
  
      def coerce_to(self, dst_type, env):
          if self.type is dst_type:
              return self
          elif dst_type.is_float:
              if self.has_constant_result():
                  return FloatNode(self.pos, value='%d.0' % int(self.constant_result), type=dst_type,
                                   constant_result=float(self.constant_result))
              else:
                  return FloatNode(self.pos, value=self.value, type=dst_type,
                                   constant_result=not_a_constant)
          if dst_type.is_numeric and not dst_type.is_complex:
              node = IntNode(self.pos, value=self.value, constant_result=self.constant_result,
                             type=dst_type, is_c_literal=True,
                             unsigned=self.unsigned, longness=self.longness)
              return node
          elif dst_type.is_pyobject:
              node = IntNode(self.pos, value=self.value, constant_result=self.constant_result,
                             type=PyrexTypes.py_object_type, is_c_literal=False,
                             unsigned=self.unsigned, longness=self.longness)
          else:
              # FIXME: not setting the type here to keep it working with
              # complex numbers. Should they be special cased?
              node = IntNode(self.pos, value=self.value, constant_result=self.constant_result,
                             unsigned=self.unsigned, longness=self.longness)
          # We still need to perform normal coerce_to processing on the
          # result, because we might be coercing to an extension type,
          # in which case a type test node will be needed.
          return ConstNode.coerce_to(node, dst_type, env)
  
      def coerce_to_boolean(self, env):
          return IntNode(
              self.pos, value=self.value,
              constant_result=self.constant_result,
              type=PyrexTypes.c_bint_type,
              unsigned=self.unsigned, longness=self.longness)
  
      def generate_evaluation_code(self, code):
          if self.type.is_pyobject:
              # pre-allocate a Python version of the number
              plain_integer_string = str(Utils.str_to_number(self.value))
              self.result_code = code.get_py_int(plain_integer_string, self.longness)
          else:
              self.result_code = self.get_constant_c_result_code()
  
      def get_constant_c_result_code(self):
          unsigned, longness = self.unsigned, self.longness
          literal = self.value_as_c_integer_string()
          if not (unsigned or longness) and self.type.is_int and literal[0] == '-' and literal[1] != '0':
              # negative decimal literal => guess longness from type to prevent wrap-around
              if self.type.rank >= PyrexTypes.c_longlong_type.rank:
                  longness = 'LL'
              elif self.type.rank >= PyrexTypes.c_long_type.rank:
                  longness = 'L'
          return literal + unsigned + longness
  
      def value_as_c_integer_string(self):
          value = self.value
          if len(value) <= 2:
              # too short to go wrong (and simplifies code below)
              return value
          neg_sign = ''
          if value[0] == '-':
              neg_sign = '-'
              value = value[1:]
          if value[0] == '0':
              literal_type = value[1]  # 0'o' - 0'b' - 0'x'
              # 0x123 hex literals and 0123 octal literals work nicely in C
              # but C-incompatible Py3 oct/bin notations need conversion
              if neg_sign and literal_type in 'oOxX0123456789' and value[2:].isdigit():
                  # negative hex/octal literal => prevent C compiler from using
                  # unsigned integer types by converting to decimal (see C standard 6.4.4.1)
                  value = str(Utils.str_to_number(value))
              elif literal_type in 'oO':
                  value = '0' + value[2:]  # '0o123' => '0123'
              elif literal_type in 'bB':
                  value = str(int(value[2:], 2))
          elif value.isdigit() and not self.unsigned and not self.longness:
              if not neg_sign:
                  # C compilers do not consider unsigned types for decimal literals,
                  # but they do for hex (see C standard 6.4.4.1)
                  value = '0x%X' % int(value)
          return neg_sign + value
  
      def calculate_result_code(self):
          return self.result_code
  
      def calculate_constant_result(self):
          self.constant_result = Utils.str_to_number(self.value)
  
      def compile_time_value(self, denv):
          return Utils.str_to_number(self.value)
  
  class FloatNode(ConstNode):
      type = PyrexTypes.c_double_type
  
      def calculate_constant_result(self):
          self.constant_result = float(self.value)
  
      def compile_time_value(self, denv):
          return float(self.value)
  
      def coerce_to(self, dst_type, env):
          if dst_type.is_pyobject and self.type.is_float:
              return FloatNode(
                  self.pos, value=self.value,
                  constant_result=self.constant_result,
                  type=Builtin.float_type)
          if dst_type.is_float and self.type.is_pyobject:
              return FloatNode(
                  self.pos, value=self.value,
                  constant_result=self.constant_result,
                  type=dst_type)
          return ConstNode.coerce_to(self, dst_type, env)
  
      def calculate_result_code(self):
          return self.result_code
  
      def get_constant_c_result_code(self):
          strval = self.value
          assert isinstance(strval, basestring)
          cmpval = repr(float(strval))
          if cmpval == 'nan':
              return "(Py_HUGE_VAL * 0)"
          elif cmpval == 'inf':
              return "Py_HUGE_VAL"
          elif cmpval == '-inf':
              return "(-Py_HUGE_VAL)"
          else:
              return strval
  
      def generate_evaluation_code(self, code):
          c_value = self.get_constant_c_result_code()
          if self.type.is_pyobject:
              self.result_code = code.get_py_float(self.value, c_value)
          else:
              self.result_code = c_value
  
  
  def _analyse_name_as_type(name, pos, env):
      type = PyrexTypes.parse_basic_type(name)
      if type is not None:
          return type
  
      global_entry = env.global_scope().lookup(name)
      if global_entry and global_entry.is_type and global_entry.type:
          return global_entry.type
  
      from .TreeFragment import TreeFragment
      with local_errors(ignore=True):
          pos = (pos[0], pos[1], pos[2]-7)
          try:
              declaration = TreeFragment(u"sizeof(%s)" % name, name=pos[0].filename, initial_pos=pos)
          except CompileError:
              pass
          else:
              sizeof_node = declaration.root.stats[0].expr
              if isinstance(sizeof_node, SizeofTypeNode):
                  sizeof_node = sizeof_node.analyse_types(env)
                  if isinstance(sizeof_node, SizeofTypeNode):
                      return sizeof_node.arg_type
      return None
  
  
  class BytesNode(ConstNode):
      # A char* or bytes literal
      #
      # value      BytesLiteral
  
      is_string_literal = True
      # start off as Python 'bytes' to support len() in O(1)
      type = bytes_type
  
      def calculate_constant_result(self):
          self.constant_result = self.value
  
      def as_sliced_node(self, start, stop, step=None):
          value = StringEncoding.bytes_literal(self.value[start:stop:step], self.value.encoding)
          return BytesNode(self.pos, value=value, constant_result=value)
  
      def compile_time_value(self, denv):
          return self.value.byteencode()
  
      def analyse_as_type(self, env):
          return _analyse_name_as_type(self.value.decode('ISO8859-1'), self.pos, env)
  
      def can_coerce_to_char_literal(self):
          return len(self.value) == 1
  
      def coerce_to_boolean(self, env):
          # This is special because testing a C char* for truth directly
          # would yield the wrong result.
          bool_value = bool(self.value)
          return BoolNode(self.pos, value=bool_value, constant_result=bool_value)
  
      def coerce_to(self, dst_type, env):
          if self.type == dst_type:
              return self
          if dst_type.is_int:
              if not self.can_coerce_to_char_literal():
                  error(self.pos, "Only single-character string literals can be coerced into ints.")
                  return self
              if dst_type.is_unicode_char:
                  error(self.pos, "Bytes literals cannot coerce to Py_UNICODE/Py_UCS4, use a unicode literal instead.")
                  return self
              return CharNode(self.pos, value=self.value,
                              constant_result=ord(self.value))
  
          node = BytesNode(self.pos, value=self.value, constant_result=self.constant_result)
          if dst_type.is_pyobject:
              if dst_type in (py_object_type, Builtin.bytes_type):
                  node.type = Builtin.bytes_type
              else:
                  self.check_for_coercion_error(dst_type, env, fail=True)
              return node
          elif dst_type in (PyrexTypes.c_char_ptr_type, PyrexTypes.c_const_char_ptr_type):
              node.type = dst_type
              return node
          elif dst_type in (PyrexTypes.c_uchar_ptr_type, PyrexTypes.c_const_uchar_ptr_type, PyrexTypes.c_void_ptr_type):
              node.type = (PyrexTypes.c_const_char_ptr_type if dst_type == PyrexTypes.c_const_uchar_ptr_type
                           else PyrexTypes.c_char_ptr_type)
              return CastNode(node, dst_type)
          elif dst_type.assignable_from(PyrexTypes.c_char_ptr_type):
              # Exclude the case of passing a C string literal into a non-const C++ string.
              if not dst_type.is_cpp_class or dst_type.is_const:
                  node.type = dst_type
                  return node
  
          # We still need to perform normal coerce_to processing on the
          # result, because we might be coercing to an extension type,
          # in which case a type test node will be needed.
          return ConstNode.coerce_to(node, dst_type, env)
  
      def generate_evaluation_code(self, code):
          if self.type.is_pyobject:
              result = code.get_py_string_const(self.value)
          elif self.type.is_const:
              result = code.get_string_const(self.value)
          else:
              # not const => use plain C string literal and cast to mutable type
              literal = self.value.as_c_string_literal()
              # C++ may require a cast
              result = typecast(self.type, PyrexTypes.c_void_ptr_type, literal)
          self.result_code = result
  
      def get_constant_c_result_code(self):
          return None  # FIXME
  
      def calculate_result_code(self):
          return self.result_code
  
  
  class UnicodeNode(ConstNode):
      # A Py_UNICODE* or unicode literal
      #
      # value        EncodedString
      # bytes_value  BytesLiteral    the literal parsed as bytes string
      #                              ('-3' unicode literals only)
  
      is_string_literal = True
      bytes_value = None
      type = unicode_type
  
      def calculate_constant_result(self):
          self.constant_result = self.value
  
      def analyse_as_type(self, env):
          return _analyse_name_as_type(self.value, self.pos, env)
  
      def as_sliced_node(self, start, stop, step=None):
          if StringEncoding.string_contains_surrogates(self.value[:stop]):
              # this is unsafe as it may give different results
              # in different runtimes
              return None
          value = StringEncoding.EncodedString(self.value[start:stop:step])
          value.encoding = self.value.encoding
          if self.bytes_value is not None:
              bytes_value = StringEncoding.bytes_literal(
                  self.bytes_value[start:stop:step], self.bytes_value.encoding)
          else:
              bytes_value = None
          return UnicodeNode(
              self.pos, value=value, bytes_value=bytes_value,
              constant_result=value)
  
      def coerce_to(self, dst_type, env):
          if dst_type is self.type:
              pass
          elif dst_type.is_unicode_char:
              if not self.can_coerce_to_char_literal():
                  error(self.pos,
                        "Only single-character Unicode string literals or "
                        "surrogate pairs can be coerced into Py_UCS4/Py_UNICODE.")
                  return self
              int_value = ord(self.value)
              return IntNode(self.pos, type=dst_type, value=str(int_value),
                             constant_result=int_value)
          elif not dst_type.is_pyobject:
              if dst_type.is_string and self.bytes_value is not None:
                  # special case: '-3' enforced unicode literal used in a
                  # C char* context
                  return BytesNode(self.pos, value=self.bytes_value).coerce_to(dst_type, env)
              if dst_type.is_pyunicode_ptr:
                  return UnicodeNode(self.pos, value=self.value, type=dst_type)
              error(self.pos,
                    "Unicode literals do not support coercion to C types other "
                    "than Py_UNICODE/Py_UCS4 (for characters) or Py_UNICODE* "
                    "(for strings).")
          elif dst_type not in (py_object_type, Builtin.basestring_type):
              self.check_for_coercion_error(dst_type, env, fail=True)
          return self
  
      def can_coerce_to_char_literal(self):
          return len(self.value) == 1
              ## or (len(self.value) == 2
              ##     and (0xD800 <= self.value[0] <= 0xDBFF)
              ##     and (0xDC00 <= self.value[1] <= 0xDFFF))
  
      def coerce_to_boolean(self, env):
          bool_value = bool(self.value)
          return BoolNode(self.pos, value=bool_value, constant_result=bool_value)
  
      def contains_surrogates(self):
          return StringEncoding.string_contains_surrogates(self.value)
  
      def generate_evaluation_code(self, code):
          if self.type.is_pyobject:
              # FIXME: this should go away entirely!
              # Since string_contains_lone_surrogates() returns False for surrogate pairs in Py2/UCS2,
              # Py2 can generate different code from Py3 here.  Let's hope we get away with claiming that
              # the processing of surrogate pairs in code was always ambiguous and lead to different results
              # on P16/32bit Unicode platforms.
              if StringEncoding.string_contains_lone_surrogates(self.value):
                  # lone (unpaired) surrogates are not really portable and cannot be
                  # decoded by the UTF-8 codec in Py3.3
                  self.result_code = code.get_py_const(py_object_type, 'ustring')
                  data_cname = code.get_string_const(
                      StringEncoding.BytesLiteral(self.value.encode('unicode_escape')))
                  const_code = code.get_cached_constants_writer(self.result_code)
                  if const_code is None:
                      return  # already initialised
                  const_code.mark_pos(self.pos)
                  const_code.putln(
                      "%s = PyUnicode_DecodeUnicodeEscape(%s, sizeof(%s) - 1, NULL); %s" % (
                          self.result_code,
                          data_cname,
                          data_cname,
                          const_code.error_goto_if_null(self.result_code, self.pos)))
                  const_code.put_error_if_neg(
                      self.pos, "__Pyx_PyUnicode_READY(%s)" % self.result_code)
              else:
                  self.result_code = code.get_py_string_const(self.value)
          else:
              self.result_code = code.get_pyunicode_ptr_const(self.value)
  
      def calculate_result_code(self):
          return self.result_code
  
      def compile_time_value(self, env):
          return self.value
  
  
  class StringNode(PyConstNode):
      # A Python str object, i.e. a byte string in Python 2.x and a
      # unicode string in Python 3.x
      #
      # value          BytesLiteral (or EncodedString with ASCII content)
      # unicode_value  EncodedString or None
      # is_identifier  boolean
  
      type = str_type
      is_string_literal = True
      is_identifier = None
      unicode_value = None
  
      def calculate_constant_result(self):
          if self.unicode_value is not None:
              # only the Unicode value is portable across Py2/3
              self.constant_result = self.unicode_value
  
      def analyse_as_type(self, env):
          return _analyse_name_as_type(self.unicode_value or self.value.decode('ISO8859-1'), self.pos, env)
  
      def as_sliced_node(self, start, stop, step=None):
          value = type(self.value)(self.value[start:stop:step])
          value.encoding = self.value.encoding
          if self.unicode_value is not None:
              if StringEncoding.string_contains_surrogates(self.unicode_value[:stop]):
                  # this is unsafe as it may give different results in different runtimes
                  return None
              unicode_value = StringEncoding.EncodedString(
                  self.unicode_value[start:stop:step])
          else:
              unicode_value = None
          return StringNode(
              self.pos, value=value, unicode_value=unicode_value,
              constant_result=value, is_identifier=self.is_identifier)
  
      def coerce_to(self, dst_type, env):
          if dst_type is not py_object_type and not str_type.subtype_of(dst_type):
  #            if dst_type is Builtin.bytes_type:
  #                # special case: bytes = 'str literal'
  #                return BytesNode(self.pos, value=self.value)
              if not dst_type.is_pyobject:
                  return BytesNode(self.pos, value=self.value).coerce_to(dst_type, env)
              if dst_type is not Builtin.basestring_type:
                  self.check_for_coercion_error(dst_type, env, fail=True)
          return self
  
      def can_coerce_to_char_literal(self):
          return not self.is_identifier and len(self.value) == 1
  
      def generate_evaluation_code(self, code):
          self.result_code = code.get_py_string_const(
              self.value, identifier=self.is_identifier, is_str=True,
              unicode_value=self.unicode_value)
  
      def get_constant_c_result_code(self):
          return None
  
      def calculate_result_code(self):
          return self.result_code
  
      def compile_time_value(self, env):
          if self.value.is_unicode:
              return self.value
          if not IS_PYTHON3:
              # use plain str/bytes object in Py2
              return self.value.byteencode()
          # in Py3, always return a Unicode string
          if self.unicode_value is not None:
              return self.unicode_value
          return self.value.decode('iso8859-1')
  
  
  class IdentifierStringNode(StringNode):
      # A special str value that represents an identifier (bytes in Py2,
      # unicode in Py3).
      is_identifier = True
  
  
  class ImagNode(AtomicExprNode):
      #  Imaginary number literal
      #
      #  value   string    imaginary part (float value)
  
      type = PyrexTypes.c_double_complex_type
  
      def calculate_constant_result(self):
          self.constant_result = complex(0.0, float(self.value))
  
      def compile_time_value(self, denv):
          return complex(0.0, float(self.value))
  
      def analyse_types(self, env):
          self.type.create_declaration_utility_code(env)
          return self
  
      def may_be_none(self):
          return False
  
      def coerce_to(self, dst_type, env):
          if self.type is dst_type:
              return self
          node = ImagNode(self.pos, value=self.value)
          if dst_type.is_pyobject:
              node.is_temp = 1
              node.type = Builtin.complex_type
          # We still need to perform normal coerce_to processing on the
          # result, because we might be coercing to an extension type,
          # in which case a type test node will be needed.
          return AtomicExprNode.coerce_to(node, dst_type, env)
  
      gil_message = "Constructing complex number"
  
      def calculate_result_code(self):
          if self.type.is_pyobject:
              return self.result()
          else:
              return "%s(0, %r)" % (self.type.from_parts, float(self.value))
  
      def generate_result_code(self, code):
          if self.type.is_pyobject:
              code.putln(
                  "%s = PyComplex_FromDoubles(0.0, %r); %s" % (
                      self.result(),
                      float(self.value),
                      code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
  
  
  class NewExprNode(AtomicExprNode):
  
      # C++ new statement
      #
      # cppclass              node                 c++ class to create
  
      type = None
  
      def infer_type(self, env):
          type = self.cppclass.analyse_as_type(env)
          if type is None or not type.is_cpp_class:
              error(self.pos, "new operator can only be applied to a C++ class")
              self.type = error_type
              return
          self.cpp_check(env)
          constructor = type.get_constructor(self.pos)
          self.class_type = type
          self.entry = constructor
          self.type = constructor.type
          return self.type
  
      def analyse_types(self, env):
          if self.type is None:
              self.infer_type(env)
          return self
  
      def may_be_none(self):
          return False
  
      def generate_result_code(self, code):
          pass
  
      def calculate_result_code(self):
          return "new " + self.class_type.empty_declaration_code()
  
  
  class NameNode(AtomicExprNode):
      #  Reference to a local or global variable name.
      #
      #  name            string    Python name of the variable
      #  entry           Entry     Symbol table entry
      #  type_entry      Entry     For extension type names, the original type entry
      #  cf_is_null      boolean   Is uninitialized before this node
      #  cf_maybe_null   boolean   Maybe uninitialized before this node
      #  allow_null      boolean   Don't raise UnboundLocalError
      #  nogil           boolean   Whether it is used in a nogil context
  
      is_name = True
      is_cython_module = False
      cython_attribute = None
      lhs_of_first_assignment = False  # TODO: remove me
      is_used_as_rvalue = 0
      entry = None
      type_entry = None
      cf_maybe_null = True
      cf_is_null = False
      allow_null = False
      nogil = False
      inferred_type = None
  
      def as_cython_attribute(self):
          return self.cython_attribute
  
      def type_dependencies(self, env):
          if self.entry is None:
              self.entry = env.lookup(self.name)
          if self.entry is not None and self.entry.type.is_unspecified:
              return (self,)
          else:
              return ()
  
      def infer_type(self, env):
          if self.entry is None:
              self.entry = env.lookup(self.name)
          if self.entry is None or self.entry.type is unspecified_type:
              if self.inferred_type is not None:
                  return self.inferred_type
              return py_object_type
          elif (self.entry.type.is_extension_type or self.entry.type.is_builtin_type) and \
                  self.name == self.entry.type.name:
              # Unfortunately the type attribute of type objects
              # is used for the pointer to the type they represent.
              return type_type
          elif self.entry.type.is_cfunction:
              if self.entry.scope.is_builtin_scope:
                  # special case: optimised builtin functions must be treated as Python objects
                  return py_object_type
              else:
                  # special case: referring to a C function must return its pointer
                  return PyrexTypes.CPtrType(self.entry.type)
          else:
              # If entry is inferred as pyobject it's safe to use local
              # NameNode's inferred_type.
              if self.entry.type.is_pyobject and self.inferred_type:
                  # Overflow may happen if integer
                  if not (self.inferred_type.is_int and self.entry.might_overflow):
                      return self.inferred_type
              return self.entry.type
  
      def compile_time_value(self, denv):
          try:
              return denv.lookup(self.name)
          except KeyError:
              error(self.pos, "Compile-time name '%s' not defined" % self.name)
  
      def get_constant_c_result_code(self):
          if not self.entry or self.entry.type.is_pyobject:
              return None
          return self.entry.cname
  
      def coerce_to(self, dst_type, env):
          #  If coercing to a generic pyobject and this is a builtin
          #  C function with a Python equivalent, manufacture a NameNode
          #  referring to the Python builtin.
          #print "NameNode.coerce_to:", self.name, dst_type ###
          if dst_type is py_object_type:
              entry = self.entry
              if entry and entry.is_cfunction:
                  var_entry = entry.as_variable
                  if var_entry:
                      if var_entry.is_builtin and var_entry.is_const:
                          var_entry = env.declare_builtin(var_entry.name, self.pos)
                      node = NameNode(self.pos, name = self.name)
                      node.entry = var_entry
                      node.analyse_rvalue_entry(env)
                      return node
  
          return super(NameNode, self).coerce_to(dst_type, env)
  
      def declare_from_annotation(self, env, as_target=False):
          """Implements PEP 526 annotation typing in a fairly relaxed way.
  
          Annotations are ignored for global variables.
          All other annotations are stored on the entry in the symbol table.
          String literals are allowed and not evaluated.
          The ambiguous Python types 'int' and 'long' are not evaluated - the 'cython.int' form must be used instead.
          """
          name = self.name
          annotation = self.annotation
          entry = self.entry or env.lookup_here(name)
          if not entry:
              # annotations never create global cdef names
              if env.is_module_scope:
                  return
              if (
                  # name: "description" => not a type, but still a declared variable or attribute
                  annotation.expr.is_string_literal
                  # don't do type analysis from annotations if not asked to, but still collect the annotation
                  or not env.directives['annotation_typing']
              ):
                  atype = None
              else:
                  _, atype = annotation.analyse_type_annotation(env)
              if atype is None:
                  atype = unspecified_type if as_target and env.directives['infer_types'] != False else py_object_type
              if atype.is_fused and env.fused_to_specific:
                  try:
                      atype = atype.specialize(env.fused_to_specific)
                  except CannotSpecialize:
                      error(self.pos,
                            "'%s' cannot be specialized since its type is not a fused argument to this function" %
                            self.name)
                      atype = error_type
              if as_target and env.is_c_class_scope and not (atype.is_pyobject or atype.is_error):
                  # TODO: this will need revising slightly if either cdef dataclasses or
                  # annotated cdef attributes are implemented
                  atype = py_object_type
                  warning(annotation.pos, "Annotation ignored since class-level attributes must be Python objects. "
                          "Were you trying to set up an instance attribute?", 2)
              entry = self.entry = env.declare_var(name, atype, self.pos, is_cdef=not as_target)
          # Even if the entry already exists, make sure we're supplying an annotation if we can.
          if annotation and not entry.annotation:
              entry.annotation = annotation
  
      def analyse_as_module(self, env):
          # Try to interpret this as a reference to a cimported module.
          # Returns the module scope, or None.
          entry = self.entry
          if not entry:
              entry = env.lookup(self.name)
          if entry and entry.as_module:
              return entry.as_module
          return None
  
      def analyse_as_type(self, env):
          if self.cython_attribute:
              type = PyrexTypes.parse_basic_type(self.cython_attribute)
          else:
              type = PyrexTypes.parse_basic_type(self.name)
          if type:
              return type
          entry = self.entry
          if not entry:
              entry = env.lookup(self.name)
          if entry and entry.is_type:
              return entry.type
          else:
              return None
  
      def analyse_as_extension_type(self, env):
          # Try to interpret this as a reference to an extension type.
          # Returns the extension type, or None.
          entry = self.entry
          if not entry:
              entry = env.lookup(self.name)
          if entry and entry.is_type:
              if entry.type.is_extension_type or entry.type.is_builtin_type:
                  return entry.type
          return None
  
      def analyse_target_declaration(self, env):
          if not self.entry:
              self.entry = env.lookup_here(self.name)
          if not self.entry and self.annotation is not None:
              # name : type = ...
              self.declare_from_annotation(env, as_target=True)
          if not self.entry:
              if env.directives['warn.undeclared']:
                  warning(self.pos, "implicit declaration of '%s'" % self.name, 1)
              if env.directives['infer_types'] != False:
                  type = unspecified_type
              else:
                  type = py_object_type
              self.entry = env.declare_var(self.name, type, self.pos)
          if self.entry.is_declared_generic:
              self.result_ctype = py_object_type
          if self.entry.as_module:
              # cimported modules namespace can shadow actual variables
              self.entry.is_variable = 1
  
      def analyse_types(self, env):
          self.initialized_check = env.directives['initializedcheck']
          entry = self.entry
          if entry is None:
              entry = env.lookup(self.name)
              if not entry:
                  entry = env.declare_builtin(self.name, self.pos)
                  if entry and entry.is_builtin and entry.is_const:
                      self.is_literal = True
              if not entry:
                  self.type = PyrexTypes.error_type
                  return self
              self.entry = entry
          entry.used = 1
          if entry.type.is_buffer:
              from . import Buffer
              Buffer.used_buffer_aux_vars(entry)
          self.analyse_rvalue_entry(env)
          return self
  
      def analyse_target_types(self, env):
          self.analyse_entry(env, is_target=True)
  
          entry = self.entry
          if entry.is_cfunction and entry.as_variable:
              # FIXME: unify "is_overridable" flags below
              if (entry.is_overridable or entry.type.is_overridable) or not self.is_lvalue() and entry.fused_cfunction:
                  # We need this for assigning to cpdef names and for the fused 'def' TreeFragment
                  entry = self.entry = entry.as_variable
                  self.type = entry.type
  
          if self.type.is_const:
              error(self.pos, "Assignment to const '%s'" % self.name)
          if self.type.is_reference:
              error(self.pos, "Assignment to reference '%s'" % self.name)
          if not self.is_lvalue():
              error(self.pos, "Assignment to non-lvalue '%s'" % self.name)
              self.type = PyrexTypes.error_type
          entry.used = 1
          if entry.type.is_buffer:
              from . import Buffer
              Buffer.used_buffer_aux_vars(entry)
          return self
  
      def analyse_rvalue_entry(self, env):
          #print "NameNode.analyse_rvalue_entry:", self.name ###
          #print "Entry:", self.entry.__dict__ ###
          self.analyse_entry(env)
          entry = self.entry
  
          if entry.is_declared_generic:
              self.result_ctype = py_object_type
  
          if entry.is_pyglobal or entry.is_builtin:
              if entry.is_builtin and entry.is_const:
                  self.is_temp = 0
              else:
                  self.is_temp = 1
  
              self.is_used_as_rvalue = 1
          elif entry.type.is_memoryviewslice:
              self.is_temp = False
              self.is_used_as_rvalue = True
              self.use_managed_ref = True
          return self
  
      def nogil_check(self, env):
          self.nogil = True
          if self.is_used_as_rvalue:
              entry = self.entry
              if entry.is_builtin:
                  if not entry.is_const:  # cached builtins are ok
                      self.gil_error()
              elif entry.is_pyglobal:
                  self.gil_error()
  
      gil_message = "Accessing Python global or builtin"
  
      def analyse_entry(self, env, is_target=False):
          #print "NameNode.analyse_entry:", self.name ###
          self.check_identifier_kind()
          entry = self.entry
          type = entry.type
          if (not is_target and type.is_pyobject and self.inferred_type and
                  self.inferred_type.is_builtin_type):
              # assume that type inference is smarter than the static entry
              type = self.inferred_type
          self.type = type
  
      def check_identifier_kind(self):
          # Check that this is an appropriate kind of name for use in an
          # expression.  Also finds the variable entry associated with
          # an extension type.
          entry = self.entry
          if entry.is_type and entry.type.is_extension_type:
              self.type_entry = entry
          if entry.is_type and (entry.type.is_enum or entry.type.is_cpp_enum):
              py_entry = Symtab.Entry(self.name, None, py_object_type)
              py_entry.is_pyglobal = True
              py_entry.scope = self.entry.scope
              self.entry = py_entry
          elif not (entry.is_const or entry.is_variable or
                    entry.is_builtin or entry.is_cfunction or
                    entry.is_cpp_class):
              if self.entry.as_variable:
                  self.entry = self.entry.as_variable
              elif not self.is_cython_module:
                  error(self.pos, "'%s' is not a constant, variable or function identifier" % self.name)
  
      def is_cimported_module_without_shadow(self, env):
          if self.is_cython_module or self.cython_attribute:
              return False
          entry = self.entry or env.lookup(self.name)
          return entry.as_module and not entry.is_variable
  
      def is_simple(self):
          #  If it's not a C variable, it'll be in a temp.
          return 1
  
      def may_be_none(self):
          if self.cf_state and self.type and (self.type.is_pyobject or
                                              self.type.is_memoryviewslice):
              # guard against infinite recursion on self-dependencies
              if getattr(self, '_none_checking', False):
                  # self-dependency - either this node receives a None
                  # value from *another* node, or it can not reference
                  # None at this point => safe to assume "not None"
                  return False
              self._none_checking = True
              # evaluate control flow state to see if there were any
              # potential None values assigned to the node so far
              may_be_none = False
              for assignment in self.cf_state:
                  if assignment.rhs.may_be_none():
                      may_be_none = True
                      break
              del self._none_checking
              return may_be_none
          return super(NameNode, self).may_be_none()
  
      def nonlocally_immutable(self):
          if ExprNode.nonlocally_immutable(self):
              return True
          entry = self.entry
          if not entry or entry.in_closure:
              return False
          return entry.is_local or entry.is_arg or entry.is_builtin or entry.is_readonly
  
      def calculate_target_results(self, env):
          pass
  
      def check_const(self):
          entry = self.entry
          if entry is not None and not (
                  entry.is_const or
                  entry.is_cfunction or
                  entry.is_builtin or
                  entry.type.is_const):
              self.not_const()
              return False
          return True
  
      def check_const_addr(self):
          entry = self.entry
          if not (entry.is_cglobal or entry.is_cfunction or entry.is_builtin):
              self.addr_not_const()
              return False
          return True
  
      def is_lvalue(self):
          return (
              self.entry.is_variable and
              not self.entry.is_readonly
          ) or (
              self.entry.is_cfunction and
              self.entry.is_overridable
          )
  
      def is_addressable(self):
          return self.entry.is_variable and not self.type.is_memoryviewslice
  
      def is_ephemeral(self):
          #  Name nodes are never ephemeral, even if the
          #  result is in a temporary.
          return 0
  
      def calculate_result_code(self):
          entry = self.entry
          if not entry:
              return "<error>"  # There was an error earlier
          return entry.cname
  
      def generate_result_code(self, code):
          entry = self.entry
          if entry is None:
              return  # There was an error earlier
          if entry.utility_code:
              code.globalstate.use_utility_code(entry.utility_code)
          if entry.is_builtin and entry.is_const:
              return  # Lookup already cached
          elif entry.is_pyclass_attr:
              assert entry.type.is_pyobject, "Python global or builtin not a Python object"
              interned_cname = code.intern_identifier(self.entry.name)
              if entry.is_builtin:
                  namespace = Naming.builtins_cname
              else:  # entry.is_pyglobal
                  namespace = entry.scope.namespace_cname
              if not self.cf_is_null:
                  code.putln(
                      '%s = PyObject_GetItem(%s, %s);' % (
                          self.result(),
                          namespace,
                          interned_cname))
                  code.putln('if (unlikely(!%s)) {' % self.result())
                  code.putln('PyErr_Clear();')
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("GetModuleGlobalName", "ObjectHandling.c"))
              code.putln(
                  '__Pyx_GetModuleGlobalName(%s, %s);' % (
                      self.result(),
                      interned_cname))
              if not self.cf_is_null:
                  code.putln("}")
              code.putln(code.error_goto_if_null(self.result(), self.pos))
              self.generate_gotref(code)
  
          elif entry.is_builtin and not entry.scope.is_module_scope:
              # known builtin
              assert entry.type.is_pyobject, "Python global or builtin not a Python object"
              interned_cname = code.intern_identifier(self.entry.name)
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("GetBuiltinName", "ObjectHandling.c"))
              code.putln(
                  '%s = __Pyx_GetBuiltinName(%s); %s' % (
                  self.result(),
                  interned_cname,
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
  
          elif entry.is_pyglobal or (entry.is_builtin and entry.scope.is_module_scope):
              # name in class body, global name or unknown builtin
              assert entry.type.is_pyobject, "Python global or builtin not a Python object"
              interned_cname = code.intern_identifier(self.entry.name)
              if entry.scope.is_module_scope:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("GetModuleGlobalName", "ObjectHandling.c"))
                  code.putln(
                      '__Pyx_GetModuleGlobalName(%s, %s); %s' % (
                          self.result(),
                          interned_cname,
                          code.error_goto_if_null(self.result(), self.pos)))
              else:
                  # FIXME: is_pyglobal is also used for class namespace
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("GetNameInClass", "ObjectHandling.c"))
                  code.putln(
                      '__Pyx_GetNameInClass(%s, %s, %s); %s' % (
                          self.result(),
                          entry.scope.namespace_cname,
                          interned_cname,
                          code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
  
          elif entry.is_local or entry.in_closure or entry.from_closure or entry.type.is_memoryviewslice:
              # Raise UnboundLocalError for objects and memoryviewslices
              raise_unbound = (
                  (self.cf_maybe_null or self.cf_is_null) and not self.allow_null)
              null_code = entry.type.check_for_null_code(entry.cname)
  
              memslice_check = entry.type.is_memoryviewslice and self.initialized_check
  
              if null_code and raise_unbound and (entry.type.is_pyobject or memslice_check):
                  code.put_error_if_unbound(self.pos, entry, self.in_nogil_context)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          #print "NameNode.generate_assignment_code:", self.name ###
          entry = self.entry
          if entry is None:
              return  # There was an error earlier
  
          if (self.entry.type.is_ptr and isinstance(rhs, ListNode)
                  and not self.lhs_of_first_assignment and not rhs.in_module_scope):
              error(self.pos, "Literal list must be assigned to pointer at time of declaration")
  
          # is_pyglobal seems to be True for module level-globals only.
          # We use this to access class->tp_dict if necessary.
          if entry.is_pyglobal:
              assert entry.type.is_pyobject, "Python global or builtin not a Python object"
              interned_cname = code.intern_identifier(self.entry.name)
              namespace = self.entry.scope.namespace_cname
              if entry.is_member:
                  # if the entry is a member we have to cheat: SetAttr does not work
                  # on types, so we create a descriptor which is then added to tp_dict
                  setter = 'PyDict_SetItem'
                  namespace = '%s->tp_dict' % namespace
              elif entry.scope.is_module_scope:
                  setter = 'PyDict_SetItem'
                  namespace = Naming.moddict_cname
              elif entry.is_pyclass_attr:
                  # Special-case setting __new__
                  n = "SetNewInClass" if self.name == "__new__" else "SetNameInClass"
                  code.globalstate.use_utility_code(UtilityCode.load_cached(n, "ObjectHandling.c"))
                  setter = '__Pyx_' + n
              else:
                  assert False, repr(entry)
              code.put_error_if_neg(
                  self.pos,
                  '%s(%s, %s, %s)' % (
                      setter,
                      namespace,
                      interned_cname,
                      rhs.py_result()))
              if debug_disposal_code:
                  print("NameNode.generate_assignment_code:")
                  print("...generating disposal code for %s" % rhs)
              rhs.generate_disposal_code(code)
              rhs.free_temps(code)
              if entry.is_member:
                  # in Py2.6+, we need to invalidate the method cache
                  code.putln("PyType_Modified(%s);" %
                             entry.scope.parent_type.typeptr_cname)
          else:
              if self.type.is_memoryviewslice:
                  self.generate_acquire_memoryviewslice(rhs, code)
  
              elif self.type.is_buffer:
                  # Generate code for doing the buffer release/acquisition.
                  # This might raise an exception in which case the assignment (done
                  # below) will not happen.
                  #
                  # The reason this is not in a typetest-like node is because the
                  # variables that the acquired buffer info is stored to is allocated
                  # per entry and coupled with it.
                  self.generate_acquire_buffer(rhs, code)
              assigned = False
              if self.type.is_pyobject:
                  #print "NameNode.generate_assignment_code: to", self.name ###
                  #print "...from", rhs ###
                  #print "...LHS type", self.type, "ctype", self.ctype() ###
                  #print "...RHS type", rhs.type, "ctype", rhs.ctype() ###
                  if self.use_managed_ref:
                      rhs.make_owned_reference(code)
                      is_external_ref = entry.is_cglobal or self.entry.in_closure or self.entry.from_closure
                      if is_external_ref:
                          self.generate_gotref(code, handle_null=True)
                      assigned = True
                      if entry.is_cglobal:
                          self.generate_decref_set(code, rhs.result_as(self.ctype()))
                      else:
                          if not self.cf_is_null:
                              if self.cf_maybe_null:
                                  self.generate_xdecref_set(code, rhs.result_as(self.ctype()))
                              else:
                                  self.generate_decref_set(code, rhs.result_as(self.ctype()))
                          else:
                              assigned = False
                      if is_external_ref:
                          rhs.generate_giveref(code)
              if not self.type.is_memoryviewslice:
                  if not assigned:
                      if overloaded_assignment:
                          result = rhs.move_result_rhs()
                          if exception_check == '+':
                              translate_cpp_exception(
                                  code, self.pos,
                                  '%s = %s;' % (self.result(), result),
                                  self.result() if self.type.is_pyobject else None,
                                  exception_value, self.in_nogil_context)
                          else:
                              code.putln('%s = %s;' % (self.result(), result))
                      else:
                          result = rhs.move_result_rhs_as(self.ctype())
  
                          if is_pythran_expr(self.type):
                              code.putln('new (&%s) decltype(%s){%s};' % (self.result(), self.result(), result))
                          elif result != self.result():
                              code.putln('%s = %s;' % (self.result(), result))
                  if debug_disposal_code:
                      print("NameNode.generate_assignment_code:")
                      print("...generating post-assignment code for %s" % rhs)
                  rhs.generate_post_assignment_code(code)
              elif rhs.result_in_temp():
                  rhs.generate_post_assignment_code(code)
  
              rhs.free_temps(code)
  
      def generate_acquire_memoryviewslice(self, rhs, code):
          """
          Slices, coercions from objects, return values etc are new references.
          We have a borrowed reference in case of dst = src
          """
          from . import MemoryView
  
          MemoryView.put_acquire_memoryviewslice(
              lhs_cname=self.result(),
              lhs_type=self.type,
              lhs_pos=self.pos,
              rhs=rhs,
              code=code,
              have_gil=not self.in_nogil_context,
              first_assignment=self.cf_is_null)
  
      def generate_acquire_buffer(self, rhs, code):
          # rhstmp is only used in case the rhs is a complicated expression leading to
          # the object, to avoid repeating the same C expression for every reference
          # to the rhs. It does NOT hold a reference.
          pretty_rhs = isinstance(rhs, NameNode) or rhs.is_temp
          if pretty_rhs:
              rhstmp = rhs.result_as(self.ctype())
          else:
              rhstmp = code.funcstate.allocate_temp(self.entry.type, manage_ref=False)
              code.putln('%s = %s;' % (rhstmp, rhs.result_as(self.ctype())))
  
          from . import Buffer
          Buffer.put_assign_to_buffer(self.result(), rhstmp, self.entry,
                                      is_initialized=not self.lhs_of_first_assignment,
                                      pos=self.pos, code=code)
  
          if not pretty_rhs:
              code.putln("%s = 0;" % rhstmp)
              code.funcstate.release_temp(rhstmp)
  
      def generate_deletion_code(self, code, ignore_nonexisting=False):
          if self.entry is None:
              return  # There was an error earlier
          elif self.entry.is_pyclass_attr:
              namespace = self.entry.scope.namespace_cname
              interned_cname = code.intern_identifier(self.entry.name)
              if ignore_nonexisting:
                  key_error_code = 'PyErr_Clear(); else'
              else:
                  # minor hack: fake a NameError on KeyError
                  key_error_code = (
                      '{ PyErr_Clear(); PyErr_Format(PyExc_NameError, "name \'%%s\' is not defined", "%s"); }' %
                      self.entry.name)
              code.putln(
                  'if (unlikely(PyObject_DelItem(%s, %s) < 0)) {'
                  ' if (likely(PyErr_ExceptionMatches(PyExc_KeyError))) %s'
                  ' %s '
                  '}' % (namespace, interned_cname,
                         key_error_code,
                         code.error_goto(self.pos)))
          elif self.entry.is_pyglobal:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectSetAttrStr", "ObjectHandling.c"))
              interned_cname = code.intern_identifier(self.entry.name)
              del_code = '__Pyx_PyObject_DelAttrStr(%s, %s)' % (
                  Naming.module_cname, interned_cname)
              if ignore_nonexisting:
                  code.putln(
                      'if (unlikely(%s < 0)) {'
                      ' if (likely(PyErr_ExceptionMatches(PyExc_AttributeError))) PyErr_Clear(); else %s '
                      '}' % (del_code, code.error_goto(self.pos)))
              else:
                  code.put_error_if_neg(self.pos, del_code)
          elif self.entry.type.is_pyobject or self.entry.type.is_memoryviewslice:
              if not self.cf_is_null:
                  if self.cf_maybe_null and not ignore_nonexisting:
                      code.put_error_if_unbound(self.pos, self.entry)
  
                  if self.entry.in_closure:
                      # generator
                      self.generate_gotref(code, handle_null=True, maybe_null_extra_check=ignore_nonexisting)
                  if ignore_nonexisting and self.cf_maybe_null:
                      code.put_xdecref_clear(self.result(), self.ctype(),
                                          have_gil=not self.nogil)
                  else:
                      code.put_decref_clear(self.result(), self.ctype(),
                                            have_gil=not self.nogil)
          else:
              error(self.pos, "Deletion of C names not supported")
  
      def annotate(self, code):
          if getattr(self, 'is_called', False):
              pos = (self.pos[0], self.pos[1], self.pos[2] - len(self.name) - 1)
              if self.type.is_pyobject:
                  style, text = 'py_call', 'python function (%s)'
              else:
                  style, text = 'c_call', 'c function (%s)'
              code.annotate(pos, AnnotationItem(style, text % self.type, size=len(self.name)))
  
  class BackquoteNode(ExprNode):
      #  `expr`
      #
      #  arg    ExprNode
  
      type = py_object_type
  
      subexprs = ['arg']
  
      def analyse_types(self, env):
          self.arg = self.arg.analyse_types(env)
          self.arg = self.arg.coerce_to_pyobject(env)
          self.is_temp = 1
          return self
  
      gil_message = "Backquote expression"
  
      def calculate_constant_result(self):
          self.constant_result = repr(self.arg.constant_result)
  
      def generate_result_code(self, code):
          code.putln(
              "%s = PyObject_Repr(%s); %s" % (
                  self.result(),
                  self.arg.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class ImportNode(ExprNode):
      #  Used as part of import statement implementation.
      #  Implements result =
      #    __import__(module_name, globals(), None, name_list, level)
      #
      #  module_name   StringNode            dotted name of module. Empty module
      #                       name means importing the parent package according
      #                       to level
      #  name_list     ListNode or None      list of names to be imported
      #  level         int                   relative import level:
      #                       -1: attempt both relative import and absolute import;
      #                        0: absolute import;
      #                       >0: the number of parent directories to search
      #                           relative to the current module.
      #                     None: decide the level according to language level and
      #                           directives
      #  get_top_level_module   int          true: return top-level module, false: return imported module
      #  module_names           TupleNode    the separate names of the module and submodules, or None
  
      type = py_object_type
      module_names = None
      get_top_level_module = False
      is_temp = True
  
      subexprs = ['module_name', 'name_list', 'module_names']
  
      def analyse_types(self, env):
          if self.level is None:
              # For modules in packages, and without 'absolute_import' enabled, try relative (Py2) import first.
              if env.global_scope().parent_module and (
                      env.directives['py2_import'] or
                      Future.absolute_import not in env.global_scope().context.future_directives):
                  self.level = -1
              else:
                  self.level = 0
          module_name = self.module_name.analyse_types(env)
          self.module_name = module_name.coerce_to_pyobject(env)
          assert self.module_name.is_string_literal
          if self.name_list:
              name_list = self.name_list.analyse_types(env)
              self.name_list = name_list.coerce_to_pyobject(env)
          elif '.' in self.module_name.value:
              self.module_names = TupleNode(self.module_name.pos, args=[
                  IdentifierStringNode(self.module_name.pos, value=part, constant_result=part)
                  for part in map(StringEncoding.EncodedString, self.module_name.value.split('.'))
              ]).analyse_types(env)
          return self
  
      gil_message = "Python import"
  
      def generate_result_code(self, code):
          assert self.module_name.is_string_literal
          module_name = self.module_name.value
  
          if self.level == 0 and not self.name_list and not self.get_top_level_module:
              if self.module_names:
                  assert self.module_names.is_literal  # make sure we create the tuple only once
              code.globalstate.use_utility_code(UtilityCode.load_cached("ImportDottedModule", "ImportExport.c"))
              import_code = "__Pyx_ImportDottedModule(%s, %s)" % (
                  self.module_name.py_result(),
                  self.module_names.py_result() if self.module_names else 'NULL',
              )
          else:
              code.globalstate.use_utility_code(UtilityCode.load_cached("Import", "ImportExport.c"))
              import_code = "__Pyx_Import(%s, %s, %d)" % (
                  self.module_name.py_result(),
                  self.name_list.py_result() if self.name_list else '0',
                  self.level)
  
          if self.level <= 0 and module_name in utility_code_for_imports:
              helper_func, code_name, code_file = utility_code_for_imports[module_name]
              code.globalstate.use_utility_code(UtilityCode.load_cached(code_name, code_file))
              import_code = '%s(%s)' % (helper_func, import_code)
  
          code.putln("%s = %s; %s" % (
              self.result(),
              import_code,
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class IteratorNode(ExprNode):
      #  Used as part of for statement implementation.
      #
      #  Implements result = iter(sequence)
      #
      #  sequence   ExprNode
  
      type = py_object_type
      iter_func_ptr = None
      counter_cname = None
      reversed = False      # currently only used for list/tuple types (see Optimize.py)
      is_async = False
  
      subexprs = ['sequence']
  
      def analyse_types(self, env):
          self.sequence = self.sequence.analyse_types(env)
          if (self.sequence.type.is_array or self.sequence.type.is_ptr) and \
                  not self.sequence.type.is_string:
              # C array iteration will be transformed later on
              self.type = self.sequence.type
          elif self.sequence.type.is_cpp_class:
              return CppIteratorNode(self.pos, sequence=self.sequence).analyse_types(env)
          else:
              self.sequence = self.sequence.coerce_to_pyobject(env)
              if self.sequence.type in (list_type, tuple_type):
                  self.sequence = self.sequence.as_none_safe_node("'NoneType' object is not iterable")
          self.is_temp = 1
          return self
  
      gil_message = "Iterating over Python object"
  
      _func_iternext_type = PyrexTypes.CPtrType(PyrexTypes.CFuncType(
          PyrexTypes.py_object_type, [
              PyrexTypes.CFuncTypeArg("it", PyrexTypes.py_object_type, None),
              ]))
  
      def type_dependencies(self, env):
          return self.sequence.type_dependencies(env)
  
      def infer_type(self, env):
          sequence_type = self.sequence.infer_type(env)
          if sequence_type.is_array or sequence_type.is_ptr:
              return sequence_type
          elif sequence_type.is_cpp_class:
              begin = sequence_type.scope.lookup("begin")
              if begin is not None:
                  return begin.type.return_type
          elif sequence_type.is_pyobject:
              return sequence_type
          return py_object_type
  
      def generate_result_code(self, code):
          sequence_type = self.sequence.type
          if sequence_type.is_cpp_class:
              assert False, "Should have been changed to CppIteratorNode"
          if sequence_type.is_array or sequence_type.is_ptr:
              raise InternalError("for in carray slice not transformed")
  
          is_builtin_sequence = sequence_type in (list_type, tuple_type)
          if not is_builtin_sequence:
              # reversed() not currently optimised (see Optimize.py)
              assert not self.reversed, "internal error: reversed() only implemented for list/tuple objects"
          self.may_be_a_sequence = not sequence_type.is_builtin_type
          if self.may_be_a_sequence:
              code.putln(
                  "if (likely(PyList_CheckExact(%s)) || PyTuple_CheckExact(%s)) {" % (
                      self.sequence.py_result(),
                      self.sequence.py_result()))
  
          if is_builtin_sequence or self.may_be_a_sequence:
              self.counter_cname = code.funcstate.allocate_temp(
                  PyrexTypes.c_py_ssize_t_type, manage_ref=False)
              if self.reversed:
                  if sequence_type is list_type:
                      init_value = 'PyList_GET_SIZE(%s) - 1' % self.result()
                  else:
                      init_value = 'PyTuple_GET_SIZE(%s) - 1' % self.result()
              else:
                  init_value = '0'
              code.putln("%s = %s; __Pyx_INCREF(%s); %s = %s;" % (
                  self.result(),
                  self.sequence.py_result(),
                  self.result(),
                  self.counter_cname,
                  init_value))
          if not is_builtin_sequence:
              self.iter_func_ptr = code.funcstate.allocate_temp(self._func_iternext_type, manage_ref=False)
              if self.may_be_a_sequence:
                  code.putln("%s = NULL;" % self.iter_func_ptr)
                  code.putln("} else {")
                  code.put("%s = -1; " % self.counter_cname)
  
              code.putln("%s = PyObject_GetIter(%s); %s" % (
                  self.result(),
                  self.sequence.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
  
              # PyObject_GetIter() fails if "tp_iternext" is not set, but the check below
              # makes it visible to the C compiler that the pointer really isn't NULL, so that
              # it can distinguish between the special cases and the generic case
              code.putln("%s = __Pyx_PyObject_GetIterNextFunc(%s); %s" % (
                  self.iter_func_ptr, self.py_result(),
                  code.error_goto_if_null(self.iter_func_ptr, self.pos)))
          if self.may_be_a_sequence:
              code.putln("}")
  
      def generate_next_sequence_item(self, test_name, result_name, code):
          assert self.counter_cname, "internal error: counter_cname temp not prepared"
          final_size = 'Py%s_GET_SIZE(%s)' % (test_name, self.py_result())
          if self.sequence.is_sequence_constructor:
              item_count = len(self.sequence.args)
              if self.sequence.mult_factor is None:
                  final_size = item_count
              elif isinstance(self.sequence.mult_factor.constant_result, _py_int_types):
                  final_size = item_count * self.sequence.mult_factor.constant_result
          code.putln("if (%s >= %s) break;" % (self.counter_cname, final_size))
          if self.reversed:
              inc_dec = '--'
          else:
              inc_dec = '++'
          code.putln("#if CYTHON_ASSUME_SAFE_MACROS && !CYTHON_AVOID_BORROWED_REFS")
          code.putln(
              "%s = Py%s_GET_ITEM(%s, %s); __Pyx_INCREF(%s); %s%s; %s" % (
                  result_name,
                  test_name,
                  self.py_result(),
                  self.counter_cname,
                  result_name,
                  self.counter_cname,
                  inc_dec,
                  # use the error label to avoid C compiler warnings if we only use it below
                  code.error_goto_if_neg('0', self.pos)
                  ))
          code.putln("#else")
          code.putln(
              "%s = PySequence_ITEM(%s, %s); %s%s; %s" % (
                  result_name,
                  self.py_result(),
                  self.counter_cname,
                  self.counter_cname,
                  inc_dec,
                  code.error_goto_if_null(result_name, self.pos)))
          code.put_gotref(result_name, py_object_type)
          code.putln("#endif")
  
      def generate_iter_next_result_code(self, result_name, code):
          sequence_type = self.sequence.type
          if self.reversed:
              code.putln("if (%s < 0) break;" % self.counter_cname)
          if sequence_type is list_type:
              self.generate_next_sequence_item('List', result_name, code)
              return
          elif sequence_type is tuple_type:
              self.generate_next_sequence_item('Tuple', result_name, code)
              return
  
          if self.may_be_a_sequence:
              code.putln("if (likely(!%s)) {" % self.iter_func_ptr)
              code.putln("if (likely(PyList_CheckExact(%s))) {" % self.py_result())
              self.generate_next_sequence_item('List', result_name, code)
              code.putln("} else {")
              self.generate_next_sequence_item('Tuple', result_name, code)
              code.putln("}")
              code.put("} else ")
  
          code.putln("{")
          code.putln(
              "%s = %s(%s);" % (
                  result_name,
                  self.iter_func_ptr,
                  self.py_result()))
          code.putln("if (unlikely(!%s)) {" % result_name)
          code.putln("PyObject* exc_type = PyErr_Occurred();")
          code.putln("if (exc_type) {")
          code.putln("if (likely(__Pyx_PyErr_GivenExceptionMatches(exc_type, PyExc_StopIteration))) PyErr_Clear();")
          code.putln("else %s" % code.error_goto(self.pos))
          code.putln("}")
          code.putln("break;")
          code.putln("}")
          code.put_gotref(result_name, py_object_type)
          code.putln("}")
  
      def free_temps(self, code):
          if self.counter_cname:
              code.funcstate.release_temp(self.counter_cname)
          if self.iter_func_ptr:
              code.funcstate.release_temp(self.iter_func_ptr)
              self.iter_func_ptr = None
          ExprNode.free_temps(self, code)
  
  
  class CppIteratorNode(ExprNode):
      # Iteration over a C++ container.
      # Created at the analyse_types stage by IteratorNode
      cpp_sequence_cname = None
      cpp_attribute_op = "."
      is_temp = True
  
      subexprs = ['sequence']
  
      def analyse_types(self, env):
          sequence_type = self.sequence.type
          if sequence_type.is_ptr:
              sequence_type = sequence_type.base_type
          begin = sequence_type.scope.lookup("begin")
          end = sequence_type.scope.lookup("end")
          if (begin is None
                  or not begin.type.is_cfunction
                  or begin.type.args):
              error(self.pos, "missing begin() on %s" % self.sequence.type)
              self.type = error_type
              return self
          if (end is None
                  or not end.type.is_cfunction
                  or end.type.args):
              error(self.pos, "missing end() on %s" % self.sequence.type)
              self.type = error_type
              return self
          iter_type = begin.type.return_type
          if iter_type.is_cpp_class:
              if env.lookup_operator_for_types(
                      self.pos,
                      "!=",
                      [iter_type, end.type.return_type]) is None:
                  error(self.pos, "missing operator!= on result of begin() on %s" % self.sequence.type)
                  self.type = error_type
                  return self
              if env.lookup_operator_for_types(self.pos, '++', [iter_type]) is None:
                  error(self.pos, "missing operator++ on result of begin() on %s" % self.sequence.type)
                  self.type = error_type
                  return self
              if env.lookup_operator_for_types(self.pos, '*', [iter_type]) is None:
                  error(self.pos, "missing operator* on result of begin() on %s" % self.sequence.type)
                  self.type = error_type
                  return self
              self.type = iter_type
          elif iter_type.is_ptr:
              if not (iter_type == end.type.return_type):
                  error(self.pos, "incompatible types for begin() and end()")
              self.type = iter_type
          else:
              error(self.pos, "result type of begin() on %s must be a C++ class or pointer" % self.sequence.type)
              self.type = error_type
          return self
  
      def generate_result_code(self, code):
          sequence_type = self.sequence.type
          # essentially 3 options:
          if self.sequence.is_name or self.sequence.is_attribute:
              # 1) is a name and can be accessed directly;
              #    assigning to it may break the container, but that's the responsibility
              #    of the user
              code.putln("%s = %s%sbegin();" % (self.result(),
                                                  self.sequence.result(),
                                                  self.cpp_attribute_op))
          else:
                  # (while it'd be nice to limit the scope of the loop temp, it's essentially
                  # impossible to do while supporting generators)
                  temp_type = sequence_type
                  if temp_type.is_reference:
                      # 2) Sequence is a reference (often obtained by dereferencing a pointer);
                      #    make the temp a pointer so we are not sensitive to users reassigning
                      #    the pointer than it came from
                      temp_type = PyrexTypes.CPtrType(sequence_type.ref_base_type)
                  if temp_type.is_ptr:
                      self.cpp_attribute_op = "->"
                  # 3) (otherwise) sequence comes from a function call or similar, so we must
                  #    create a temp to store it in
                  self.cpp_sequence_cname = code.funcstate.allocate_temp(temp_type, manage_ref=False)
                  code.putln("%s = %s%s;" % (self.cpp_sequence_cname,
                                             "&" if temp_type.is_ptr else "",
                                             self.sequence.move_result_rhs()))
                  code.putln("%s = %s%sbegin();" % (self.result(), self.cpp_sequence_cname,
                                                    self.cpp_attribute_op))
  
      def generate_iter_next_result_code(self, result_name, code):
          # end call isn't cached to support containers that allow adding while iterating
          # (much as this is usually a bad idea)
          code.putln("if (!(%s != %s%send())) break;" % (
                          self.result(),
                          self.cpp_sequence_cname or self.sequence.result(),
                          self.cpp_attribute_op))
          code.putln("%s = *%s;" % (
                          result_name,
                          self.result()))
          code.putln("++%s;" % self.result())
  
      def free_temps(self, code):
          if self.cpp_sequence_cname:
              code.funcstate.release_temp(self.cpp_sequence_cname)
          # skip over IteratorNode since we don't use any of the temps it does
          ExprNode.free_temps(self, code)
  
  
  class NextNode(AtomicExprNode):
      #  Used as part of for statement implementation.
      #  Implements result = next(iterator)
      #  Created during analyse_types phase.
      #  The iterator is not owned by this node.
      #
      #  iterator   IteratorNode
  
      def __init__(self, iterator):
          AtomicExprNode.__init__(self, iterator.pos)
          self.iterator = iterator
  
      def nogil_check(self, env):
          # ignore - errors (if any) are already handled by IteratorNode
          pass
  
      def type_dependencies(self, env):
          return self.iterator.type_dependencies(env)
  
      def infer_type(self, env, iterator_type=None):
          if iterator_type is None:
              iterator_type = self.iterator.infer_type(env)
          if iterator_type.is_ptr or iterator_type.is_array:
              return iterator_type.base_type
          elif iterator_type.is_cpp_class:
              item_type = env.lookup_operator_for_types(self.pos, "*", [iterator_type]).type.return_type
              if item_type.is_reference:
                  item_type = item_type.ref_base_type
              if item_type.is_cv_qualified:
                  item_type = item_type.cv_base_type
              return item_type
          else:
              # Avoid duplication of complicated logic.
              fake_index_node = IndexNode(
                  self.pos,
                  base=self.iterator.sequence,
                  index=IntNode(self.pos, value='PY_SSIZE_T_MAX',
                                type=PyrexTypes.c_py_ssize_t_type))
              return fake_index_node.infer_type(env)
  
      def analyse_types(self, env):
          self.type = self.infer_type(env, self.iterator.type)
          self.is_temp = 1
          return self
  
      def generate_result_code(self, code):
          self.iterator.generate_iter_next_result_code(self.result(), code)
  
  
  class AsyncIteratorNode(ExprNode):
      #  Used as part of 'async for' statement implementation.
      #
      #  Implements result = sequence.__aiter__()
      #
      #  sequence   ExprNode
  
      subexprs = ['sequence']
  
      is_async = True
      type = py_object_type
      is_temp = 1
  
      def infer_type(self, env):
          return py_object_type
  
      def analyse_types(self, env):
          self.sequence = self.sequence.analyse_types(env)
          if not self.sequence.type.is_pyobject:
              error(self.pos, "async for loops not allowed on C/C++ types")
              self.sequence = self.sequence.coerce_to_pyobject(env)
          return self
  
      def generate_result_code(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("AsyncIter", "Coroutine.c"))
          code.putln("%s = __Pyx_Coroutine_GetAsyncIter(%s); %s" % (
              self.result(),
              self.sequence.py_result(),
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class AsyncNextNode(AtomicExprNode):
      #  Used as part of 'async for' statement implementation.
      #  Implements result = iterator.__anext__()
      #  Created during analyse_types phase.
      #  The iterator is not owned by this node.
      #
      #  iterator   IteratorNode
  
      type = py_object_type
      is_temp = 1
  
      def __init__(self, iterator):
          AtomicExprNode.__init__(self, iterator.pos)
          self.iterator = iterator
  
      def infer_type(self, env):
          return py_object_type
  
      def analyse_types(self, env):
          return self
  
      def generate_result_code(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("AsyncIter", "Coroutine.c"))
          code.putln("%s = __Pyx_Coroutine_AsyncIterNext(%s); %s" % (
              self.result(),
              self.iterator.py_result(),
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class WithExitCallNode(ExprNode):
      # The __exit__() call of a 'with' statement.  Used in both the
      # except and finally clauses.
  
      # with_stat   WithStatNode                the surrounding 'with' statement
      # args        TupleNode or ResultStatNode the exception info tuple
      # await_expr  AwaitExprNode               the await expression of an 'async with' statement
  
      subexprs = ['args', 'await_expr']
      test_if_run = True
      await_expr = None
  
      def analyse_types(self, env):
          self.args = self.args.analyse_types(env)
          if self.await_expr:
              self.await_expr = self.await_expr.analyse_types(env)
          self.type = PyrexTypes.c_bint_type
          self.is_temp = True
          return self
  
      def generate_evaluation_code(self, code):
          if self.test_if_run:
              # call only if it was not already called (and decref-cleared)
              code.putln("if (%s) {" % self.with_stat.exit_var)
  
          self.args.generate_evaluation_code(code)
          result_var = code.funcstate.allocate_temp(py_object_type, manage_ref=False)
  
          code.mark_pos(self.pos)
          code.globalstate.use_utility_code(UtilityCode.load_cached(
              "PyObjectCall", "ObjectHandling.c"))
          code.putln("%s = __Pyx_PyObject_Call(%s, %s, NULL);" % (
              result_var,
              self.with_stat.exit_var,
              self.args.result()))
          code.put_decref_clear(self.with_stat.exit_var, type=py_object_type)
          self.args.generate_disposal_code(code)
          self.args.free_temps(code)
  
          code.putln(code.error_goto_if_null(result_var, self.pos))
          code.put_gotref(result_var, py_object_type)
  
          if self.await_expr:
              # FIXME: result_var temp currently leaks into the closure
              self.await_expr.generate_evaluation_code(code, source_cname=result_var, decref_source=True)
              code.putln("%s = %s;" % (result_var, self.await_expr.py_result()))
              self.await_expr.generate_post_assignment_code(code)
              self.await_expr.free_temps(code)
  
          if self.result_is_used:
              self.allocate_temp_result(code)
              code.putln("%s = __Pyx_PyObject_IsTrue(%s);" % (self.result(), result_var))
          code.put_decref_clear(result_var, type=py_object_type)
          if self.result_is_used:
              code.put_error_if_neg(self.pos, self.result())
          code.funcstate.release_temp(result_var)
          if self.test_if_run:
              code.putln("}")
  
  
  class ExcValueNode(AtomicExprNode):
      #  Node created during analyse_types phase
      #  of an ExceptClauseNode to fetch the current
      #  exception value.
  
      type = py_object_type
  
      def __init__(self, pos):
          ExprNode.__init__(self, pos)
  
      def set_var(self, var):
          self.var = var
  
      def calculate_result_code(self):
          return self.var
  
      def generate_result_code(self, code):
          pass
  
      def analyse_types(self, env):
          return self
  
  
  class TempNode(ExprNode):
      # Node created during analyse_types phase
      # of some nodes to hold a temporary value.
      #
      # Note: One must call "allocate" and "release" on
      # the node during code generation to get/release the temp.
      # This is because the temp result is often used outside of
      # the regular cycle.
  
      subexprs = []
  
      def __init__(self, pos, type, env=None):
          ExprNode.__init__(self, pos)
          self.type = type
          if type.is_pyobject:
              self.result_ctype = py_object_type
          self.is_temp = 1
  
      def analyse_types(self, env):
          return self
  
      def analyse_target_declaration(self, env):
          pass
  
      def generate_result_code(self, code):
          pass
  
      def allocate(self, code):
          self.temp_cname = code.funcstate.allocate_temp(self.type, manage_ref=True)
  
      def release(self, code):
          code.funcstate.release_temp(self.temp_cname)
          self.temp_cname = None
  
      def result(self):
          try:
              return self.temp_cname
          except:
              assert False, "Remember to call allocate/release on TempNode"
              raise
  
      # Do not participate in normal temp alloc/dealloc:
      def allocate_temp_result(self, code):
          pass
  
      def release_temp_result(self, code):
          pass
  
  class PyTempNode(TempNode):
      #  TempNode holding a Python value.
  
      def __init__(self, pos, env):
          TempNode.__init__(self, pos, PyrexTypes.py_object_type, env)
  
  class RawCNameExprNode(ExprNode):
      subexprs = []
  
      def __init__(self, pos, type=None, cname=None):
          ExprNode.__init__(self, pos, type=type)
          if cname is not None:
              self.cname = cname
  
      def analyse_types(self, env):
          return self
  
      def set_cname(self, cname):
          self.cname = cname
  
      def result(self):
          return self.cname
  
      def generate_result_code(self, code):
          pass
  
  
  #-------------------------------------------------------------------
  #
  #  F-strings
  #
  #-------------------------------------------------------------------
  
  
  class JoinedStrNode(ExprNode):
      # F-strings
      #
      # values   [UnicodeNode|FormattedValueNode]   Substrings of the f-string
      #
      type = unicode_type
      is_temp = True
      gil_message = "String concatenation"
  
      subexprs = ['values']
  
      def analyse_types(self, env):
          self.values = [v.analyse_types(env).coerce_to_pyobject(env) for v in self.values]
          return self
  
      def may_be_none(self):
          # PyUnicode_Join() always returns a Unicode string or raises an exception
          return False
  
      def generate_evaluation_code(self, code):
          code.mark_pos(self.pos)
          num_items = len(self.values)
          list_var = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
          ulength_var = code.funcstate.allocate_temp(PyrexTypes.c_py_ssize_t_type, manage_ref=False)
          max_char_var = code.funcstate.allocate_temp(PyrexTypes.c_py_ucs4_type, manage_ref=False)
  
          code.putln('%s = PyTuple_New(%s); %s' % (
              list_var,
              num_items,
              code.error_goto_if_null(list_var, self.pos)))
          code.put_gotref(list_var, py_object_type)
          code.putln("%s = 0;" % ulength_var)
          code.putln("%s = 127;" % max_char_var)  # at least ASCII character range
  
          for i, node in enumerate(self.values):
              node.generate_evaluation_code(code)
              node.make_owned_reference(code)
  
              ulength = "__Pyx_PyUnicode_GET_LENGTH(%s)" % node.py_result()
              max_char_value = "__Pyx_PyUnicode_MAX_CHAR_VALUE(%s)" % node.py_result()
              is_ascii = False
              if isinstance(node, UnicodeNode):
                  try:
                      # most strings will be ASCII or at least Latin-1
                      node.value.encode('iso8859-1')
                      max_char_value = '255'
                      node.value.encode('us-ascii')
                      is_ascii = True
                  except UnicodeEncodeError:
                      if max_char_value != '255':
                          # not ISO8859-1 => check BMP limit
                          max_char = max(map(ord, node.value))
                          if max_char < 0xD800:
                              # BMP-only, no surrogate pairs used
                              max_char_value = '65535'
                              ulength = str(len(node.value))
                          elif max_char >= 65536:
                              # cleary outside of BMP, and not on a 16-bit Unicode system
                              max_char_value = '1114111'
                              ulength = str(len(node.value))
                          else:
                              # not really worth implementing a check for surrogate pairs here
                              # drawback: C code can differ when generating on Py2 with 2-byte Unicode
                              pass
                  else:
                      ulength = str(len(node.value))
              elif isinstance(node, FormattedValueNode) and node.value.type.is_numeric:
                  is_ascii = True  # formatted C numbers are always ASCII
  
              if not is_ascii:
                  code.putln("%s = (%s > %s) ? %s : %s;" % (
                      max_char_var, max_char_value, max_char_var, max_char_value, max_char_var))
              code.putln("%s += %s;" % (ulength_var, ulength))
  
              node.generate_giveref(code)
              code.putln('PyTuple_SET_ITEM(%s, %s, %s);' % (list_var, i, node.py_result()))
              node.generate_post_assignment_code(code)
              node.free_temps(code)
  
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
          code.globalstate.use_utility_code(UtilityCode.load_cached("JoinPyUnicode", "StringTools.c"))
          code.putln('%s = __Pyx_PyUnicode_Join(%s, %d, %s, %s); %s' % (
              self.result(),
              list_var,
              num_items,
              ulength_var,
              max_char_var,
              code.error_goto_if_null(self.py_result(), self.pos)))
          self.generate_gotref(code)
  
          code.put_decref_clear(list_var, py_object_type)
          code.funcstate.release_temp(list_var)
          code.funcstate.release_temp(ulength_var)
          code.funcstate.release_temp(max_char_var)
  
  
  class FormattedValueNode(ExprNode):
      # {}-delimited portions of an f-string
      #
      # value           ExprNode                The expression itself
      # conversion_char str or None             Type conversion (!s, !r, !a, or none, or 'd' for integer conversion)
      # format_spec     JoinedStrNode or None   Format string passed to __format__
      # c_format_spec   str or None             If not None, formatting can be done at the C level
  
      subexprs = ['value', 'format_spec']
  
      type = unicode_type
      is_temp = True
      c_format_spec = None
      gil_message = "String formatting"
  
      find_conversion_func = {
          's': 'PyObject_Unicode',
          'r': 'PyObject_Repr',
          'a': 'PyObject_ASCII',  # NOTE: mapped to PyObject_Repr() in Py2
          'd': '__Pyx_PyNumber_IntOrLong',  # NOTE: internal mapping for '%d' formatting
      }.get
  
      def may_be_none(self):
          # PyObject_Format() always returns a Unicode string or raises an exception
          return False
  
      def analyse_types(self, env):
          self.value = self.value.analyse_types(env)
          if not self.format_spec or self.format_spec.is_string_literal:
              c_format_spec = self.format_spec.value if self.format_spec else self.value.type.default_format_spec
              if self.value.type.can_coerce_to_pystring(env, format_spec=c_format_spec):
                  self.c_format_spec = c_format_spec
  
          if self.format_spec:
              self.format_spec = self.format_spec.analyse_types(env).coerce_to_pyobject(env)
          if self.c_format_spec is None:
              self.value = self.value.coerce_to_pyobject(env)
              if not self.format_spec and (not self.conversion_char or self.conversion_char == 's'):
                  if self.value.type is unicode_type and not self.value.may_be_none():
                      # value is definitely a unicode string and we don't format it any special
                      return self.value
          return self
  
      def generate_result_code(self, code):
          if self.c_format_spec is not None and not self.value.type.is_pyobject:
              convert_func_call = self.value.type.convert_to_pystring(
                  self.value.result(), code, self.c_format_spec)
              code.putln("%s = %s; %s" % (
                  self.result(),
                  convert_func_call,
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
              return
  
          value_result = self.value.py_result()
          value_is_unicode = self.value.type is unicode_type and not self.value.may_be_none()
          if self.format_spec:
              format_func = '__Pyx_PyObject_Format'
              format_spec = self.format_spec.py_result()
          else:
              # common case: expect simple Unicode pass-through if no format spec
              format_func = '__Pyx_PyObject_FormatSimple'
              # passing a Unicode format string in Py2 forces PyObject_Format() to also return a Unicode string
              format_spec = Naming.empty_unicode
  
          conversion_char = self.conversion_char
          if conversion_char == 's' and value_is_unicode:
              # no need to pipe unicode strings through str()
              conversion_char = None
  
          if conversion_char:
              fn = self.find_conversion_func(conversion_char)
              assert fn is not None, "invalid conversion character found: '%s'" % conversion_char
              value_result = '%s(%s)' % (fn, value_result)
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectFormatAndDecref", "StringTools.c"))
              format_func += 'AndDecref'
          elif self.format_spec:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectFormat", "StringTools.c"))
          else:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectFormatSimple", "StringTools.c"))
  
          code.putln("%s = %s(%s, %s); %s" % (
              self.result(),
              format_func,
              value_result,
              format_spec,
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  #-------------------------------------------------------------------
  #
  #  Parallel nodes (cython.parallel.thread(savailable|id))
  #
  #-------------------------------------------------------------------
  
  class ParallelThreadsAvailableNode(AtomicExprNode):
      """
      Note: this is disabled and not a valid directive at this moment
  
      Implements cython.parallel.threadsavailable(). If we are called from the
      sequential part of the application, we need to call omp_get_max_threads(),
      and in the parallel part we can just call omp_get_num_threads()
      """
  
      type = PyrexTypes.c_int_type
  
      def analyse_types(self, env):
          self.is_temp = True
          # env.add_include_file("omp.h")
          return self
  
      def generate_result_code(self, code):
          code.putln("#ifdef _OPENMP")
          code.putln("if (omp_in_parallel()) %s = omp_get_max_threads();" %
                                                              self.temp_code)
          code.putln("else %s = omp_get_num_threads();" % self.temp_code)
          code.putln("#else")
          code.putln("%s = 1;" % self.temp_code)
          code.putln("#endif")
  
      def result(self):
          return self.temp_code
  
  
  class ParallelThreadIdNode(AtomicExprNode):  #, Nodes.ParallelNode):
      """
      Implements cython.parallel.threadid()
      """
  
      type = PyrexTypes.c_int_type
  
      def analyse_types(self, env):
          self.is_temp = True
          # env.add_include_file("omp.h")
          return self
  
      def generate_result_code(self, code):
          code.putln("#ifdef _OPENMP")
          code.putln("%s = omp_get_thread_num();" % self.temp_code)
          code.putln("#else")
          code.putln("%s = 0;" % self.temp_code)
          code.putln("#endif")
  
      def result(self):
          return self.temp_code
  
  
  #-------------------------------------------------------------------
  #
  #  Trailer nodes
  #
  #-------------------------------------------------------------------
  
  
  class _IndexingBaseNode(ExprNode):
      # Base class for indexing nodes.
      #
      # base   ExprNode   the value being indexed
  
      def is_ephemeral(self):
          # in most cases, indexing will return a safe reference to an object in a container,
          # so we consider the result safe if the base object is
          return self.base.is_ephemeral() or self.base.type in (
              basestring_type, str_type, bytes_type, bytearray_type, unicode_type)
  
      def check_const_addr(self):
          return self.base.check_const_addr() and self.index.check_const()
  
      def is_lvalue(self):
          # NOTE: references currently have both is_reference and is_ptr
          # set.  Since pointers and references have different lvalue
          # rules, we must be careful to separate the two.
          if self.type.is_reference:
              if self.type.ref_base_type.is_array:
                  # fixed-sized arrays aren't l-values
                  return False
          elif self.type.is_ptr:
              # non-const pointers can always be reassigned
              return True
          # Just about everything else returned by the index operator
          # can be an lvalue.
          return True
  
  
  class IndexNode(_IndexingBaseNode):
      #  Sequence indexing.
      #
      #  base     ExprNode
      #  index    ExprNode
      #  type_indices  [PyrexType]
      #
      #  is_fused_index boolean   Whether the index is used to specialize a
      #                           c(p)def function
  
      subexprs = ['base', 'index']
      type_indices = None
  
      is_subscript = True
      is_fused_index = False
  
      def calculate_constant_result(self):
          self.constant_result = self.base.constant_result[self.index.constant_result]
  
      def compile_time_value(self, denv):
          base = self.base.compile_time_value(denv)
          index = self.index.compile_time_value(denv)
          try:
              return base[index]
          except Exception as e:
              self.compile_time_value_error(e)
  
      def is_simple(self):
          base = self.base
          return (base.is_simple() and self.index.is_simple()
                  and base.type and (base.type.is_ptr or base.type.is_array))
  
      def may_be_none(self):
          base_type = self.base.type
          if base_type:
              if base_type.is_string:
                  return False
              if isinstance(self.index, SliceNode):
                  # slicing!
                  if base_type in (bytes_type, bytearray_type, str_type, unicode_type,
                                   basestring_type, list_type, tuple_type):
                      return False
          return ExprNode.may_be_none(self)
  
      def analyse_target_declaration(self, env):
          pass
  
      def analyse_as_type(self, env):
          base_type = self.base.analyse_as_type(env)
          if base_type and not base_type.is_pyobject:
              if base_type.is_cpp_class:
                  if isinstance(self.index, TupleNode):
                      template_values = self.index.args
                  else:
                      template_values = [self.index]
                  type_node = Nodes.TemplatedTypeNode(
                      pos=self.pos,
                      positional_args=template_values,
                      keyword_args=None)
                  return type_node.analyse(env, base_type=base_type)
              elif self.index.is_slice or self.index.is_sequence_constructor:
                  # memory view
                  from . import MemoryView
                  env.use_utility_code(MemoryView.view_utility_code)
                  axes = [self.index] if self.index.is_slice else list(self.index.args)
                  return PyrexTypes.MemoryViewSliceType(base_type, MemoryView.get_axes_specs(env, axes))
              else:
                  # C array
                  index = self.index.compile_time_value(env)
                  if index is not None:
                      try:
                          index = int(index)
                      except (ValueError, TypeError):
                          pass
                      else:
                          return PyrexTypes.CArrayType(base_type, index)
                  error(self.pos, "Array size must be a compile time constant")
          return None
  
      def type_dependencies(self, env):
          return self.base.type_dependencies(env) + self.index.type_dependencies(env)
  
      def infer_type(self, env):
          base_type = self.base.infer_type(env)
          if self.index.is_slice:
              # slicing!
              if base_type.is_string:
                  # sliced C strings must coerce to Python
                  return bytes_type
              elif base_type.is_pyunicode_ptr:
                  # sliced Py_UNICODE* strings must coerce to Python
                  return unicode_type
              elif base_type in (unicode_type, bytes_type, str_type,
                                 bytearray_type, list_type, tuple_type):
                  # slicing these returns the same type
                  return base_type
              elif base_type.is_memoryviewslice:
                  return base_type
              else:
                  # TODO: Handle buffers (hopefully without too much redundancy).
                  return py_object_type
  
          index_type = self.index.infer_type(env)
          if index_type and index_type.is_int or isinstance(self.index, IntNode):
              # indexing!
              if base_type is unicode_type:
                  # Py_UCS4 will automatically coerce to a unicode string
                  # if required, so this is safe.  We only infer Py_UCS4
                  # when the index is a C integer type.  Otherwise, we may
                  # need to use normal Python item access, in which case
                  # it's faster to return the one-char unicode string than
                  # to receive it, throw it away, and potentially rebuild it
                  # on a subsequent PyObject coercion.
                  return PyrexTypes.c_py_ucs4_type
              elif base_type is str_type:
                  # always returns str - Py2: bytes, Py3: unicode
                  return base_type
              elif base_type is bytearray_type:
                  return PyrexTypes.c_uchar_type
              elif isinstance(self.base, BytesNode):
                  #if env.global_scope().context.language_level >= 3:
                  #    # inferring 'char' can be made to work in Python 3 mode
                  #    return PyrexTypes.c_char_type
                  # Py2/3 return different types on indexing bytes objects
                  return py_object_type
              elif base_type in (tuple_type, list_type):
                  # if base is a literal, take a look at its values
                  item_type = infer_sequence_item_type(
                      env, self.base, self.index, seq_type=base_type)
                  if item_type is not None:
                      return item_type
              elif base_type.is_ptr or base_type.is_array:
                  return base_type.base_type
              elif base_type.is_ctuple and isinstance(self.index, IntNode):
                  if self.index.has_constant_result():
                      index = self.index.constant_result
                      if index < 0:
                          index += base_type.size
                      if 0 <= index < base_type.size:
                          return base_type.components[index]
              elif base_type.is_memoryviewslice:
                  if base_type.ndim == 0:
                      pass  # probably an error, but definitely don't know what to do - return pyobject for now
                  if base_type.ndim == 1:
                      return base_type.dtype
                  else:
                      return PyrexTypes.MemoryViewSliceType(base_type.dtype, base_type.axes[1:])
  
          if self.index.is_sequence_constructor and base_type.is_memoryviewslice:
              inferred_type = base_type
              for a in self.index.args:
                  if not inferred_type.is_memoryviewslice:
                      break  # something's gone wrong
                  inferred_type = IndexNode(self.pos, base=ExprNode(self.base.pos, type=inferred_type),
                                            index=a).infer_type(env)
              else:
                  return inferred_type
  
          if base_type.is_cpp_class:
              class FakeOperand:
                  def __init__(self, **kwds):
                      self.__dict__.update(kwds)
              operands = [
                  FakeOperand(pos=self.pos, type=base_type),
                  FakeOperand(pos=self.pos, type=index_type),
              ]
              index_func = env.lookup_operator('[]', operands)
              if index_func is not None:
                  return index_func.type.return_type
  
          if is_pythran_expr(base_type) and is_pythran_expr(index_type):
              index_with_type = (self.index, index_type)
              return PythranExpr(pythran_indexing_type(base_type, [index_with_type]))
  
          # may be slicing or indexing, we don't know
          if base_type in (unicode_type, str_type):
              # these types always returns their own type on Python indexing/slicing
              return base_type
          else:
              # TODO: Handle buffers (hopefully without too much redundancy).
              return py_object_type
  
      def analyse_types(self, env):
          return self.analyse_base_and_index_types(env, getting=True)
  
      def analyse_target_types(self, env):
          node = self.analyse_base_and_index_types(env, setting=True)
          if node.type.is_const:
              error(self.pos, "Assignment to const dereference")
          if node is self and not node.is_lvalue():
              error(self.pos, "Assignment to non-lvalue of type '%s'" % node.type)
          return node
  
      def analyse_base_and_index_types(self, env, getting=False, setting=False,
                                       analyse_base=True):
          # Note: This might be cleaned up by having IndexNode
          # parsed in a saner way and only construct the tuple if
          # needed.
          if analyse_base:
              self.base = self.base.analyse_types(env)
  
          if self.base.type.is_error:
              # Do not visit child tree if base is undeclared to avoid confusing
              # error messages
              self.type = PyrexTypes.error_type
              return self
  
          is_slice = self.index.is_slice
          if not env.directives['wraparound']:
              if is_slice:
                  check_negative_indices(self.index.start, self.index.stop)
              else:
                  check_negative_indices(self.index)
  
          # Potentially overflowing index value.
          if not is_slice and isinstance(self.index, IntNode) and Utils.long_literal(self.index.value):
              self.index = self.index.coerce_to_pyobject(env)
  
          is_memslice = self.base.type.is_memoryviewslice
          # Handle the case where base is a literal char* (and we expect a string, not an int)
          if not is_memslice and (isinstance(self.base, BytesNode) or is_slice):
              if self.base.type.is_string or not (self.base.type.is_ptr or self.base.type.is_array):
                  self.base = self.base.coerce_to_pyobject(env)
  
          replacement_node = self.analyse_as_buffer_operation(env, getting)
          if replacement_node is not None:
              return replacement_node
  
          self.nogil = env.nogil
          base_type = self.base.type
  
          if not base_type.is_cfunction:
              self.index = self.index.analyse_types(env)
              self.original_index_type = self.index.type
              if self.original_index_type.is_reference:
                  self.original_index_type = self.original_index_type.ref_base_type
  
              if base_type.is_unicode_char:
                  # we infer Py_UNICODE/Py_UCS4 for unicode strings in some
                  # cases, but indexing must still work for them
                  if setting:
                      warning(self.pos, "cannot assign to Unicode string index", level=1)
                  elif self.index.constant_result in (0, -1):
                      # uchar[0] => uchar
                      return self.base
                  self.base = self.base.coerce_to_pyobject(env)
                  base_type = self.base.type
  
          if base_type.is_pyobject:
              return self.analyse_as_pyobject(env, is_slice, getting, setting)
          elif base_type.is_ptr or base_type.is_array:
              return self.analyse_as_c_array(env, is_slice)
          elif base_type.is_cpp_class:
              return self.analyse_as_cpp(env, setting)
          elif base_type.is_cfunction:
              return self.analyse_as_c_function(env)
          elif base_type.is_ctuple:
              return self.analyse_as_c_tuple(env, getting, setting)
          else:
              error(self.pos,
                    "Attempting to index non-array type '%s'" %
                    base_type)
              self.type = PyrexTypes.error_type
              return self
  
      def analyse_as_pyobject(self, env, is_slice, getting, setting):
          base_type = self.base.type
          if self.index.type.is_unicode_char and base_type is not dict_type:
              # TODO: eventually fold into case below and remove warning, once people have adapted their code
              warning(self.pos,
                      "Item lookup of unicode character codes now always converts to a Unicode string. "
                      "Use an explicit C integer cast to get back the previous integer lookup behaviour.", level=1)
              self.index = self.index.coerce_to_pyobject(env)
              self.is_temp = 1
          elif self.index.type.is_int and base_type is not dict_type:
              if (getting
                      and (base_type in (list_type, tuple_type, bytearray_type))
                      and (not self.index.type.signed
                           or not env.directives['wraparound']
                           or (isinstance(self.index, IntNode) and
                               self.index.has_constant_result() and self.index.constant_result >= 0))
                      and not env.directives['boundscheck']):
                  self.is_temp = 0
              else:
                  self.is_temp = 1
              self.index = self.index.coerce_to(PyrexTypes.c_py_ssize_t_type, env).coerce_to_simple(env)
              self.original_index_type.create_to_py_utility_code(env)
          else:
              self.index = self.index.coerce_to_pyobject(env)
              self.is_temp = 1
  
          if self.index.type.is_int and base_type is unicode_type:
              # Py_UNICODE/Py_UCS4 will automatically coerce to a unicode string
              # if required, so this is fast and safe
              self.type = PyrexTypes.c_py_ucs4_type
          elif self.index.type.is_int and base_type is bytearray_type:
              if setting:
                  self.type = PyrexTypes.c_uchar_type
              else:
                  # not using 'uchar' to enable fast and safe error reporting as '-1'
                  self.type = PyrexTypes.c_int_type
          elif is_slice and base_type in (bytes_type, bytearray_type, str_type, unicode_type, list_type, tuple_type):
              self.type = base_type
          else:
              item_type = None
              if base_type in (list_type, tuple_type) and self.index.type.is_int:
                  item_type = infer_sequence_item_type(
                      env, self.base, self.index, seq_type=base_type)
              if item_type is None:
                  item_type = py_object_type
              self.type = item_type
              if base_type in (list_type, tuple_type, dict_type):
                  # do the None check explicitly (not in a helper) to allow optimising it away
                  self.base = self.base.as_none_safe_node("'NoneType' object is not subscriptable")
  
          self.wrap_in_nonecheck_node(env, getting)
          return self
  
      def analyse_as_c_array(self, env, is_slice):
          base_type = self.base.type
          self.type = base_type.base_type
          if self.type.is_cpp_class:
              self.type = PyrexTypes.CReferenceType(self.type)
          if is_slice:
              self.type = base_type
          elif self.index.type.is_pyobject:
              self.index = self.index.coerce_to(PyrexTypes.c_py_ssize_t_type, env)
          elif not self.index.type.is_int:
              error(self.pos, "Invalid index type '%s'" % self.index.type)
          return self
  
      def analyse_as_cpp(self, env, setting):
          base_type = self.base.type
          function = env.lookup_operator("[]", [self.base, self.index])
          if function is None:
              error(self.pos, "Indexing '%s' not supported for index type '%s'" % (base_type, self.index.type))
              self.type = PyrexTypes.error_type
              self.result_code = "<error>"
              return self
          func_type = function.type
          if func_type.is_ptr:
              func_type = func_type.base_type
          self.exception_check = func_type.exception_check
          self.exception_value = func_type.exception_value
          if self.exception_check:
              if not setting:
                  self.is_temp = True
              if self.exception_value is None:
                  env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
          self.index = self.index.coerce_to(func_type.args[0].type, env)
          self.type = func_type.return_type
          if setting and not func_type.return_type.is_reference:
              error(self.pos, "Can't set non-reference result '%s'" % self.type)
          return self
  
      def analyse_as_c_function(self, env):
          base_type = self.base.type
          if base_type.is_fused:
              self.parse_indexed_fused_cdef(env)
          else:
              self.type_indices = self.parse_index_as_types(env)
              self.index = None  # FIXME: use a dedicated Node class instead of generic IndexNode
              if base_type.templates is None:
                  error(self.pos, "Can only parameterize template functions.")
                  self.type = error_type
              elif self.type_indices is None:
                  # Error recorded earlier.
                  self.type = error_type
              elif len(base_type.templates) != len(self.type_indices):
                  error(self.pos, "Wrong number of template arguments: expected %s, got %s" % (
                          (len(base_type.templates), len(self.type_indices))))
                  self.type = error_type
              else:
                  self.type = base_type.specialize(dict(zip(base_type.templates, self.type_indices)))
          # FIXME: use a dedicated Node class instead of generic IndexNode
          return self
  
      def analyse_as_c_tuple(self, env, getting, setting):
          base_type = self.base.type
          if isinstance(self.index, IntNode) and self.index.has_constant_result():
              index = self.index.constant_result
              if -base_type.size <= index < base_type.size:
                  if index < 0:
                      index += base_type.size
                  self.type = base_type.components[index]
              else:
                  error(self.pos,
                        "Index %s out of bounds for '%s'" %
                        (index, base_type))
                  self.type = PyrexTypes.error_type
              return self
          else:
              self.base = self.base.coerce_to_pyobject(env)
              return self.analyse_base_and_index_types(env, getting=getting, setting=setting, analyse_base=False)
  
      def analyse_as_buffer_operation(self, env, getting):
          """
          Analyse buffer indexing and memoryview indexing/slicing
          """
          if isinstance(self.index, TupleNode):
              indices = self.index.args
          else:
              indices = [self.index]
  
          base = self.base
          base_type = base.type
          replacement_node = None
          if base_type.is_memoryviewslice:
              # memoryviewslice indexing or slicing
              from . import MemoryView
              if base.is_memview_slice:
                  # For memory views, "view[i][j]" is the same as "view[i, j]" => use the latter for speed.
                  merged_indices = base.merged_indices(indices)
                  if merged_indices is not None:
                      base = base.base
                      base_type = base.type
                      indices = merged_indices
              have_slices, indices, newaxes = MemoryView.unellipsify(indices, base_type.ndim)
              if have_slices:
                  replacement_node = MemoryViewSliceNode(self.pos, indices=indices, base=base)
              else:
                  replacement_node = MemoryViewIndexNode(self.pos, indices=indices, base=base)
          elif base_type.is_buffer or base_type.is_pythran_expr:
              if base_type.is_pythran_expr or len(indices) == base_type.ndim:
                  # Buffer indexing
                  is_buffer_access = True
                  indices = [index.analyse_types(env) for index in indices]
                  if base_type.is_pythran_expr:
                      do_replacement = all(
                          index.type.is_int or index.is_slice or index.type.is_pythran_expr
                          for index in indices)
                      if do_replacement:
                          for i,index in enumerate(indices):
                              if index.is_slice:
                                  index = SliceIntNode(index.pos, start=index.start, stop=index.stop, step=index.step)
                                  index = index.analyse_types(env)
                                  indices[i] = index
                  else:
                      do_replacement = all(index.type.is_int for index in indices)
                  if do_replacement:
                      replacement_node = BufferIndexNode(self.pos, indices=indices, base=base)
                      # On cloning, indices is cloned. Otherwise, unpack index into indices.
                      assert not isinstance(self.index, CloneNode)
  
          if replacement_node is not None:
              replacement_node = replacement_node.analyse_types(env, getting)
          return replacement_node
  
      def wrap_in_nonecheck_node(self, env, getting):
          if not env.directives['nonecheck'] or not self.base.may_be_none():
              return
          self.base = self.base.as_none_safe_node("'NoneType' object is not subscriptable")
  
      def parse_index_as_types(self, env, required=True):
          if isinstance(self.index, TupleNode):
              indices = self.index.args
          else:
              indices = [self.index]
          type_indices = []
          for index in indices:
              type_indices.append(index.analyse_as_type(env))
              if type_indices[-1] is None:
                  if required:
                      error(index.pos, "not parsable as a type")
                  return None
          return type_indices
  
      def parse_indexed_fused_cdef(self, env):
          """
          Interpret fused_cdef_func[specific_type1, ...]
  
          Note that if this method is called, we are an indexed cdef function
          with fused argument types, and this IndexNode will be replaced by the
          NameNode with specific entry just after analysis of expressions by
          AnalyseExpressionsTransform.
          """
          self.type = PyrexTypes.error_type
  
          self.is_fused_index = True
  
          base_type = self.base.type
          positions = []
  
          if self.index.is_name or self.index.is_attribute:
              positions.append(self.index.pos)
          elif isinstance(self.index, TupleNode):
              for arg in self.index.args:
                  positions.append(arg.pos)
          specific_types = self.parse_index_as_types(env, required=False)
  
          if specific_types is None:
              self.index = self.index.analyse_types(env)
  
              if not self.base.entry.as_variable:
                  error(self.pos, "Can only index fused functions with types")
              else:
                  # A cpdef function indexed with Python objects
                  self.base.entry = self.entry = self.base.entry.as_variable
                  self.base.type = self.type = self.entry.type
  
                  self.base.is_temp = True
                  self.is_temp = True
  
                  self.entry.used = True
  
              self.is_fused_index = False
              return
  
          for i, type in enumerate(specific_types):
              specific_types[i] = type.specialize_fused(env)
  
          fused_types = base_type.get_fused_types()
          if len(specific_types) > len(fused_types):
              return error(self.pos, "Too many types specified")
          elif len(specific_types) < len(fused_types):
              t = fused_types[len(specific_types)]
              return error(self.pos, "Not enough types specified to specialize "
                                     "the function, %s is still fused" % t)
  
          # See if our index types form valid specializations
          for pos, specific_type, fused_type in zip(positions,
                                                    specific_types,
                                                    fused_types):
              if not any([specific_type.same_as(t) for t in fused_type.types]):
                  return error(pos, "Type not in fused type")
  
              if specific_type is None or specific_type.is_error:
                  return
  
          fused_to_specific = dict(zip(fused_types, specific_types))
          type = base_type.specialize(fused_to_specific)
  
          if type.is_fused:
              # Only partially specific, this is invalid
              error(self.pos,
                    "Index operation makes function only partially specific")
          else:
              # Fully specific, find the signature with the specialized entry
              for signature in self.base.type.get_all_specialized_function_types():
                  if type.same_as(signature):
                      self.type = signature
  
                      if self.base.is_attribute:
                          # Pretend to be a normal attribute, for cdef extension
                          # methods
                          self.entry = signature.entry
                          self.is_attribute = True
                          self.obj = self.base.obj
  
                      self.type.entry.used = True
                      self.base.type = signature
                      self.base.entry = signature.entry
  
                      break
              else:
                  # This is a bug
                  raise InternalError("Couldn't find the right signature")
  
      gil_message = "Indexing Python object"
  
      def calculate_result_code(self):
          if self.base.type in (list_type, tuple_type, bytearray_type):
              if self.base.type is list_type:
                  index_code = "PyList_GET_ITEM(%s, %s)"
              elif self.base.type is tuple_type:
                  index_code = "PyTuple_GET_ITEM(%s, %s)"
              elif self.base.type is bytearray_type:
                  index_code = "((unsigned char)(PyByteArray_AS_STRING(%s)[%s]))"
              else:
                  assert False, "unexpected base type in indexing: %s" % self.base.type
          elif self.base.type.is_cfunction:
              return "%s<%s>" % (
                  self.base.result(),
                  ",".join([param.empty_declaration_code() for param in self.type_indices]))
          elif self.base.type.is_ctuple:
              index = self.index.constant_result
              if index < 0:
                  index += self.base.type.size
              return "%s.f%s" % (self.base.result(), index)
          else:
              if (self.type.is_ptr or self.type.is_array) and self.type == self.base.type:
                  error(self.pos, "Invalid use of pointer slice")
                  return
              index_code = "(%s[%s])"
          return index_code % (self.base.result(), self.index.result())
  
      def extra_index_params(self, code):
          if self.index.type.is_int:
              is_list = self.base.type is list_type
              wraparound = (
                  bool(code.globalstate.directives['wraparound']) and
                  self.original_index_type.signed and
                  not (isinstance(self.index.constant_result, _py_int_types)
                       and self.index.constant_result >= 0))
              boundscheck = bool(code.globalstate.directives['boundscheck'])
              return ", %s, %d, %s, %d, %d, %d" % (
                  self.original_index_type.empty_declaration_code(),
                  self.original_index_type.signed and 1 or 0,
                  self.original_index_type.to_py_function,
                  is_list, wraparound, boundscheck)
          else:
              return ""
  
      def generate_result_code(self, code):
          if not self.is_temp:
              # all handled in self.calculate_result_code()
              return
  
          utility_code = None
          if self.type.is_pyobject:
              error_value = 'NULL'
              if self.index.type.is_int:
                  if self.base.type is list_type:
                      function = "__Pyx_GetItemInt_List"
                  elif self.base.type is tuple_type:
                      function = "__Pyx_GetItemInt_Tuple"
                  else:
                      function = "__Pyx_GetItemInt"
                  utility_code = TempitaUtilityCode.load_cached("GetItemInt", "ObjectHandling.c")
              else:
                  if self.base.type is dict_type:
                      function = "__Pyx_PyDict_GetItem"
                      utility_code = UtilityCode.load_cached("DictGetItem", "ObjectHandling.c")
                  elif self.base.type is py_object_type and self.index.type in (str_type, unicode_type):
                      # obj[str] is probably doing a dict lookup
                      function = "__Pyx_PyObject_Dict_GetItem"
                      utility_code = UtilityCode.load_cached("DictGetItem", "ObjectHandling.c")
                  else:
                      function = "__Pyx_PyObject_GetItem"
                      code.globalstate.use_utility_code(
                          TempitaUtilityCode.load_cached("GetItemInt", "ObjectHandling.c"))
                      utility_code = UtilityCode.load_cached("ObjectGetItem", "ObjectHandling.c")
          elif self.type.is_unicode_char and self.base.type is unicode_type:
              assert self.index.type.is_int
              function = "__Pyx_GetItemInt_Unicode"
              error_value = '(Py_UCS4)-1'
              utility_code = UtilityCode.load_cached("GetItemIntUnicode", "StringTools.c")
          elif self.base.type is bytearray_type:
              assert self.index.type.is_int
              assert self.type.is_int
              function = "__Pyx_GetItemInt_ByteArray"
              error_value = '-1'
              utility_code = UtilityCode.load_cached("GetItemIntByteArray", "StringTools.c")
          elif not (self.base.type.is_cpp_class and self.exception_check):
              assert False, "unexpected type %s and base type %s for indexing" % (
                  self.type, self.base.type)
  
          if utility_code is not None:
              code.globalstate.use_utility_code(utility_code)
  
          if self.index.type.is_int:
              index_code = self.index.result()
          else:
              index_code = self.index.py_result()
  
          if self.base.type.is_cpp_class and self.exception_check:
              translate_cpp_exception(code, self.pos,
                  "%s = %s[%s];" % (self.result(), self.base.result(),
                                    self.index.result()),
                  self.result() if self.type.is_pyobject else None,
                  self.exception_value, self.in_nogil_context)
          else:
              error_check = '!%s' if error_value == 'NULL' else '%%s == %s' % error_value
              code.putln(
                  "%s = %s(%s, %s%s); %s" % (
                      self.result(),
                      function,
                      self.base.py_result(),
                      index_code,
                      self.extra_index_params(code),
                      code.error_goto_if(error_check % self.result(), self.pos)))
          if self.type.is_pyobject:
              self.generate_gotref(code)
  
      def generate_setitem_code(self, value_code, code):
          if self.index.type.is_int:
              if self.base.type is bytearray_type:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("SetItemIntByteArray", "StringTools.c"))
                  function = "__Pyx_SetItemInt_ByteArray"
              else:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("SetItemInt", "ObjectHandling.c"))
                  function = "__Pyx_SetItemInt"
              index_code = self.index.result()
          else:
              index_code = self.index.py_result()
              if self.base.type is dict_type:
                  function = "PyDict_SetItem"
              # It would seem that we could specialized lists/tuples, but that
              # shouldn't happen here.
              # Both PyList_SetItem() and PyTuple_SetItem() take a Py_ssize_t as
              # index instead of an object, and bad conversion here would give
              # the wrong exception. Also, tuples are supposed to be immutable,
              # and raise a TypeError when trying to set their entries
              # (PyTuple_SetItem() is for creating new tuples from scratch).
              else:
                  function = "PyObject_SetItem"
          code.putln(code.error_goto_if_neg(
              "%s(%s, %s, %s%s)" % (
                  function,
                  self.base.py_result(),
                  index_code,
                  value_code,
                  self.extra_index_params(code)),
              self.pos))
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          self.generate_subexpr_evaluation_code(code)
  
          if self.type.is_pyobject:
              self.generate_setitem_code(rhs.py_result(), code)
          elif self.base.type is bytearray_type:
              value_code = self._check_byte_value(code, rhs)
              self.generate_setitem_code(value_code, code)
          elif self.base.type.is_cpp_class and self.exception_check and self.exception_check == '+':
              if overloaded_assignment and exception_check and self.exception_value != exception_value:
                  # Handle the case that both the index operator and the assignment
                  # operator have a c++ exception handler and they are not the same.
                  translate_double_cpp_exception(code, self.pos, self.type,
                      self.result(), rhs.result(), self.exception_value,
                      exception_value, self.in_nogil_context)
              else:
                  # Handle the case that only the index operator has a
                  # c++ exception handler, or that
                  # both exception handlers are the same.
                  translate_cpp_exception(code, self.pos,
                      "%s = %s;" % (self.result(), rhs.result()),
                      self.result() if self.type.is_pyobject else None,
                      self.exception_value, self.in_nogil_context)
          else:
              code.putln(
                  "%s = %s;" % (self.result(), rhs.result()))
  
          self.generate_subexpr_disposal_code(code)
          self.free_subexpr_temps(code)
          rhs.generate_disposal_code(code)
          rhs.free_temps(code)
  
      def _check_byte_value(self, code, rhs):
          # TODO: should we do this generally on downcasts, or just here?
          assert rhs.type.is_int, repr(rhs.type)
          value_code = rhs.result()
          if rhs.has_constant_result():
              if 0 <= rhs.constant_result < 256:
                  return value_code
              needs_cast = True  # make at least the C compiler happy
              warning(rhs.pos,
                      "value outside of range(0, 256)"
                      " when assigning to byte: %s" % rhs.constant_result,
                      level=1)
          else:
              needs_cast = rhs.type != PyrexTypes.c_uchar_type
  
          if not self.nogil:
              conditions = []
              if rhs.is_literal or rhs.type.signed:
                  conditions.append('%s < 0' % value_code)
              if (rhs.is_literal or not
                      (rhs.is_temp and rhs.type in (
                          PyrexTypes.c_uchar_type, PyrexTypes.c_char_type,
                          PyrexTypes.c_schar_type))):
                  conditions.append('%s > 255' % value_code)
              if conditions:
                  code.putln("if (unlikely(%s)) {" % ' || '.join(conditions))
                  code.putln(
                      'PyErr_SetString(PyExc_ValueError,'
                      ' "byte must be in range(0, 256)"); %s' %
                      code.error_goto(self.pos))
                  code.putln("}")
  
          if needs_cast:
              value_code = '((unsigned char)%s)' % value_code
          return value_code
  
      def generate_deletion_code(self, code, ignore_nonexisting=False):
          self.generate_subexpr_evaluation_code(code)
          #if self.type.is_pyobject:
          if self.index.type.is_int:
              function = "__Pyx_DelItemInt"
              index_code = self.index.result()
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("DelItemInt", "ObjectHandling.c"))
          else:
              index_code = self.index.py_result()
              if self.base.type is dict_type:
                  function = "PyDict_DelItem"
              else:
                  function = "PyObject_DelItem"
          code.putln(code.error_goto_if_neg(
              "%s(%s, %s%s)" % (
                  function,
                  self.base.py_result(),
                  index_code,
                  self.extra_index_params(code)),
              self.pos))
          self.generate_subexpr_disposal_code(code)
          self.free_subexpr_temps(code)
  
  
  class BufferIndexNode(_IndexingBaseNode):
      """
      Indexing of buffers and memoryviews. This node is created during type
      analysis from IndexNode and replaces it.
  
      Attributes:
          base - base node being indexed
          indices - list of indexing expressions
      """
  
      subexprs = ['base', 'indices']
  
      is_buffer_access = True
  
      # Whether we're assigning to a buffer (in that case it needs to be writable)
      writable_needed = False
  
      # Any indexing temp variables that we need to clean up.
      index_temps = ()
  
      def analyse_target_types(self, env):
          self.analyse_types(env, getting=False)
  
      def analyse_types(self, env, getting=True):
          """
          Analyse types for buffer indexing only. Overridden by memoryview
          indexing and slicing subclasses
          """
          # self.indices are already analyzed
          if not self.base.is_name and not is_pythran_expr(self.base.type):
              error(self.pos, "Can only index buffer variables")
              self.type = error_type
              return self
  
          if not getting:
              if not self.base.entry.type.writable:
                  error(self.pos, "Writing to readonly buffer")
              else:
                  self.writable_needed = True
                  if self.base.type.is_buffer:
                      self.base.entry.buffer_aux.writable_needed = True
  
          self.none_error_message = "'NoneType' object is not subscriptable"
          self.analyse_buffer_index(env, getting)
          self.wrap_in_nonecheck_node(env)
          return self
  
      def analyse_buffer_index(self, env, getting):
          if is_pythran_expr(self.base.type):
              index_with_type_list = [(idx, idx.type) for idx in self.indices]
              self.type = PythranExpr(pythran_indexing_type(self.base.type, index_with_type_list))
          else:
              self.base = self.base.coerce_to_simple(env)
              self.type = self.base.type.dtype
          self.buffer_type = self.base.type
  
          if getting and (self.type.is_pyobject or self.type.is_pythran_expr):
              self.is_temp = True
  
      def analyse_assignment(self, rhs):
          """
          Called by IndexNode when this node is assigned to,
          with the rhs of the assignment
          """
  
      def wrap_in_nonecheck_node(self, env):
          if not env.directives['nonecheck'] or not self.base.may_be_none():
              return
          self.base = self.base.as_none_safe_node(self.none_error_message)
  
      def nogil_check(self, env):
          if self.is_buffer_access or self.is_memview_index:
              if self.type.is_pyobject:
                  error(self.pos, "Cannot access buffer with object dtype without gil")
                  self.type = error_type
  
      def calculate_result_code(self):
          return "(*%s)" % self.buffer_ptr_code
  
      def buffer_entry(self):
          base = self.base
          if self.base.is_nonecheck:
              base = base.arg
          return base.type.get_entry(base)
  
      def get_index_in_temp(self, code, ivar):
          ret = code.funcstate.allocate_temp(
              PyrexTypes.widest_numeric_type(
                  ivar.type,
                  PyrexTypes.c_ssize_t_type if ivar.type.signed else PyrexTypes.c_size_t_type),
              manage_ref=False)
          code.putln("%s = %s;" % (ret, ivar.result()))
          return ret
  
      def buffer_lookup_code(self, code):
          """
          ndarray[1, 2, 3] and memslice[1, 2, 3]
          """
          if self.in_nogil_context:
              if self.is_buffer_access or self.is_memview_index:
                  if code.globalstate.directives['boundscheck']:
                      warning(self.pos, "Use boundscheck(False) for faster access", level=1)
  
          # Assign indices to temps of at least (s)size_t to allow further index calculations.
          self.index_temps = index_temps = [self.get_index_in_temp(code,ivar) for ivar in self.indices]
  
          # Generate buffer access code using these temps
          from . import Buffer
          buffer_entry = self.buffer_entry()
          if buffer_entry.type.is_buffer:
              negative_indices = buffer_entry.type.negative_indices
          else:
              negative_indices = Buffer.buffer_defaults['negative_indices']
  
          return buffer_entry, Buffer.put_buffer_lookup_code(
              entry=buffer_entry,
              index_signeds=[ivar.type.signed for ivar in self.indices],
              index_cnames=index_temps,
              directives=code.globalstate.directives,
              pos=self.pos, code=code,
              negative_indices=negative_indices,
              in_nogil_context=self.in_nogil_context)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False):
          self.generate_subexpr_evaluation_code(code)
          self.generate_buffer_setitem_code(rhs, code)
          self.generate_subexpr_disposal_code(code)
          self.free_subexpr_temps(code)
          rhs.generate_disposal_code(code)
          rhs.free_temps(code)
  
      def generate_buffer_setitem_code(self, rhs, code, op=""):
          base_type = self.base.type
          if is_pythran_expr(base_type) and is_pythran_supported_type(rhs.type):
              obj = code.funcstate.allocate_temp(PythranExpr(pythran_type(self.base.type)), manage_ref=False)
              # We have got to do this because we have to declare pythran objects
              # at the beginning of the functions.
              # Indeed, Cython uses "goto" statement for error management, and
              # RAII doesn't work with that kind of construction.
              # Moreover, the way Pythran expressions are made is that they don't
              # support move-assignation easily.
              # This, we explicitly destroy then in-place new objects in this
              # case.
              code.putln("__Pyx_call_destructor(%s);" % obj)
              code.putln("new (&%s) decltype(%s){%s};" % (obj, obj, self.base.pythran_result()))
              code.putln("%s%s %s= %s;" % (
                  obj,
                  pythran_indexing_code(self.indices),
                  op,
                  rhs.pythran_result()))
              code.funcstate.release_temp(obj)
              return
  
          # Used from generate_assignment_code and InPlaceAssignmentNode
          buffer_entry, ptrexpr = self.buffer_lookup_code(code)
  
          if self.buffer_type.dtype.is_pyobject:
              # Must manage refcounts. Decref what is already there
              # and incref what we put in.
              ptr = code.funcstate.allocate_temp(buffer_entry.buf_ptr_type,
                                                 manage_ref=False)
              rhs_code = rhs.result()
              code.putln("%s = %s;" % (ptr, ptrexpr))
              code.put_gotref("*%s" % ptr, self.buffer_type.dtype)
              code.putln("__Pyx_INCREF(%s); __Pyx_DECREF(*%s);" % (
                  rhs_code, ptr))
              code.putln("*%s %s= %s;" % (ptr, op, rhs_code))
              code.put_giveref("*%s" % ptr, self.buffer_type.dtype)
              code.funcstate.release_temp(ptr)
          else:
              # Simple case
              code.putln("*%s %s= %s;" % (ptrexpr, op, rhs.result()))
  
      def generate_result_code(self, code):
          if is_pythran_expr(self.base.type):
              res = self.result()
              code.putln("__Pyx_call_destructor(%s);" % res)
              code.putln("new (&%s) decltype(%s){%s%s};" % (
                  res,
                  res,
                  self.base.pythran_result(),
                  pythran_indexing_code(self.indices)))
              return
          buffer_entry, self.buffer_ptr_code = self.buffer_lookup_code(code)
          if self.type.is_pyobject:
              # is_temp is True, so must pull out value and incref it.
              # NOTE: object temporary results for nodes are declared
              #       as PyObject *, so we need a cast
              code.putln("%s = (PyObject *) *%s;" % (self.result(), self.buffer_ptr_code))
              code.putln("__Pyx_INCREF((PyObject*)%s);" % self.result())
  
      def free_subexpr_temps(self, code):
          for temp in self.index_temps:
              code.funcstate.release_temp(temp)
          self.index_temps = ()
          super(BufferIndexNode, self).free_subexpr_temps(code)
  
  
  class MemoryViewIndexNode(BufferIndexNode):
  
      is_memview_index = True
      is_buffer_access = False
      warned_untyped_idx = False
  
      def analyse_types(self, env, getting=True):
          # memoryviewslice indexing or slicing
          from . import MemoryView
  
          self.is_pythran_mode = has_np_pythran(env)
          indices = self.indices
          have_slices, indices, newaxes = MemoryView.unellipsify(indices, self.base.type.ndim)
  
          if not getting:
              self.writable_needed = True
              if self.base.is_name or self.base.is_attribute:
                  self.base.entry.type.writable_needed = True
  
          self.memslice_index = (not newaxes and len(indices) == self.base.type.ndim)
          axes = []
  
          index_type = PyrexTypes.c_py_ssize_t_type
          new_indices = []
  
          if len(indices) - len(newaxes) > self.base.type.ndim:
              self.type = error_type
              error(indices[self.base.type.ndim].pos,
                    "Too many indices specified for type %s" % self.base.type)
              return self
  
          axis_idx = 0
          for i, index in enumerate(indices[:]):
              index = index.analyse_types(env)
              if index.is_none:
                  self.is_memview_slice = True
                  new_indices.append(index)
                  axes.append(('direct', 'strided'))
                  continue
  
              access, packing = self.base.type.axes[axis_idx]
              axis_idx += 1
  
              if index.is_slice:
                  self.is_memview_slice = True
                  if index.step.is_none:
                      axes.append((access, packing))
                  else:
                      axes.append((access, 'strided'))
  
                  # Coerce start, stop and step to temps of the right type
                  for attr in ('start', 'stop', 'step'):
                      value = getattr(index, attr)
                      if not value.is_none:
                          value = value.coerce_to(index_type, env)
                          #value = value.coerce_to_temp(env)
                          setattr(index, attr, value)
                          new_indices.append(value)
  
              elif index.type.is_int or index.type.is_pyobject:
                  if index.type.is_pyobject and not self.warned_untyped_idx:
                      warning(index.pos, "Index should be typed for more efficient access", level=2)
                      MemoryViewIndexNode.warned_untyped_idx = True
  
                  self.is_memview_index = True
                  index = index.coerce_to(index_type, env)
                  indices[i] = index
                  new_indices.append(index)
  
              else:
                  self.type = error_type
                  error(index.pos, "Invalid index for memoryview specified, type %s" % index.type)
                  return self
  
          ### FIXME: replace by MemoryViewSliceNode if is_memview_slice ?
          self.is_memview_index = self.is_memview_index and not self.is_memview_slice
          self.indices = new_indices
          # All indices with all start/stop/step for slices.
          # We need to keep this around.
          self.original_indices = indices
          self.nogil = env.nogil
  
          self.analyse_operation(env, getting, axes)
          self.wrap_in_nonecheck_node(env)
          return self
  
      def analyse_operation(self, env, getting, axes):
          self.none_error_message = "Cannot index None memoryview slice"
          self.analyse_buffer_index(env, getting)
  
      def analyse_broadcast_operation(self, rhs):
          """
          Support broadcasting for slice assignment.
          E.g.
              m_2d[...] = m_1d  # or,
              m_1d[...] = m_2d  # if the leading dimension has extent 1
          """
          if self.type.is_memoryviewslice:
              lhs = self
              if lhs.is_memview_broadcast or rhs.is_memview_broadcast:
                  lhs.is_memview_broadcast = True
                  rhs.is_memview_broadcast = True
  
      def analyse_as_memview_scalar_assignment(self, rhs):
          lhs = self.analyse_assignment(rhs)
          if lhs:
              rhs.is_memview_copy_assignment = lhs.is_memview_copy_assignment
              return lhs
          return self
  
  
  class MemoryViewSliceNode(MemoryViewIndexNode):
  
      is_memview_slice = True
  
      # No-op slicing operation, this node will be replaced
      is_ellipsis_noop = False
      is_memview_scalar_assignment = False
      is_memview_index = False
      is_memview_broadcast = False
  
      def analyse_ellipsis_noop(self, env, getting):
          """Slicing operations needing no evaluation, i.e. m[...] or m[:, :]"""
          ### FIXME: replace directly
          self.is_ellipsis_noop = all(
              index.is_slice and index.start.is_none and index.stop.is_none and index.step.is_none
              for index in self.indices)
  
          if self.is_ellipsis_noop:
              self.type = self.base.type
  
      def analyse_operation(self, env, getting, axes):
          from . import MemoryView
  
          if not getting:
              self.is_memview_broadcast = True
              self.none_error_message = "Cannot assign to None memoryview slice"
          else:
              self.none_error_message = "Cannot slice None memoryview slice"
  
          self.analyse_ellipsis_noop(env, getting)
          if self.is_ellipsis_noop:
              return
  
          self.index = None
          self.is_temp = True
          self.use_managed_ref = True
  
          if not MemoryView.validate_axes(self.pos, axes):
              self.type = error_type
              return
  
          self.type = PyrexTypes.MemoryViewSliceType(self.base.type.dtype, axes)
  
          if not (self.base.is_simple() or self.base.result_in_temp()):
              self.base = self.base.coerce_to_temp(env)
  
      def analyse_assignment(self, rhs):
          if not rhs.type.is_memoryviewslice and (
                  self.type.dtype.assignable_from(rhs.type) or
                  rhs.type.is_pyobject):
              # scalar assignment
              return MemoryCopyScalar(self.pos, self)
          else:
              return MemoryCopySlice(self.pos, self)
  
      def merged_indices(self, indices):
          """Return a new list of indices/slices with 'indices' merged into the current ones
          according to slicing rules.
          Is used to implement "view[i][j]" => "view[i, j]".
          Return None if the indices cannot (easily) be merged at compile time.
          """
          if not indices:
              return None
          # NOTE: Need to evaluate "self.original_indices" here as they might differ from "self.indices".
          new_indices = self.original_indices[:]
          indices = indices[:]
          for i, s in enumerate(self.original_indices):
              if s.is_slice:
                  if s.start.is_none and s.stop.is_none and s.step.is_none:
                      # Full slice found, replace by index.
                      new_indices[i] = indices[0]
                      indices.pop(0)
                      if not indices:
                          return new_indices
                  else:
                      # Found something non-trivial, e.g. a partial slice.
                      return None
              elif not s.type.is_int:
                  # Not a slice, not an integer index => could be anything...
                  return None
          if indices:
              if len(new_indices) + len(indices) > self.base.type.ndim:
                  return None
              new_indices += indices
          return new_indices
  
      def is_simple(self):
          if self.is_ellipsis_noop:
              # TODO: fix SimpleCallNode.is_simple()
              return self.base.is_simple() or self.base.result_in_temp()
  
          return self.result_in_temp()
  
      def calculate_result_code(self):
          """This is called in case this is a no-op slicing node"""
          return self.base.result()
  
      def generate_result_code(self, code):
          if self.is_ellipsis_noop:
              return  ### FIXME: remove
          buffer_entry = self.buffer_entry()
          have_gil = not self.in_nogil_context
  
          # TODO Mark: this is insane, do it better
          have_slices = False
          it = iter(self.indices)
          for index in self.original_indices:
              if index.is_slice:
                  have_slices = True
                  if not index.start.is_none:
                      index.start = next(it)
                  if not index.stop.is_none:
                      index.stop = next(it)
                  if not index.step.is_none:
                      index.step = next(it)
              else:
                  next(it)
  
          assert not list(it)
  
          buffer_entry.generate_buffer_slice_code(
              code, self.original_indices, self.result(), self.type,
              have_gil=have_gil, have_slices=have_slices,
              directives=code.globalstate.directives)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False):
          if self.is_ellipsis_noop:
              self.generate_subexpr_evaluation_code(code)
          else:
              self.generate_evaluation_code(code)
  
          if self.is_memview_scalar_assignment:
              self.generate_memoryviewslice_assign_scalar_code(rhs, code)
          else:
              self.generate_memoryviewslice_setslice_code(rhs, code)
  
          if self.is_ellipsis_noop:
              self.generate_subexpr_disposal_code(code)
          else:
              self.generate_disposal_code(code)
  
          rhs.generate_disposal_code(code)
          rhs.free_temps(code)
  
  
  class MemoryCopyNode(ExprNode):
      """
      Wraps a memoryview slice for slice assignment.
  
          dst: destination mememoryview slice
      """
  
      subexprs = ['dst']
  
      def __init__(self, pos, dst):
          super(MemoryCopyNode, self).__init__(pos)
          self.dst = dst
          self.type = dst.type
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False):
          self.dst.generate_evaluation_code(code)
          self._generate_assignment_code(rhs, code)
          self.dst.generate_disposal_code(code)
          self.dst.free_temps(code)
          rhs.generate_disposal_code(code)
          rhs.free_temps(code)
  
  
  class MemoryCopySlice(MemoryCopyNode):
      """
      Copy the contents of slice src to slice dst. Does not support indirect
      slices.
  
          memslice1[...] = memslice2
          memslice1[:] = memslice2
      """
  
      is_memview_copy_assignment = True
      copy_slice_cname = "__pyx_memoryview_copy_contents"
  
      def _generate_assignment_code(self, src, code):
          dst = self.dst
  
          src.type.assert_direct_dims(src.pos)
          dst.type.assert_direct_dims(dst.pos)
  
          code.putln(code.error_goto_if_neg(
              "%s(%s, %s, %d, %d, %d)" % (self.copy_slice_cname,
                                          src.result(), dst.result(),
                                          src.type.ndim, dst.type.ndim,
                                          dst.type.dtype.is_pyobject),
              dst.pos))
  
  
  class MemoryCopyScalar(MemoryCopyNode):
      """
      Assign a scalar to a slice. dst must be simple, scalar will be assigned
      to a correct type and not just something assignable.
  
          memslice1[...] = 0.0
          memslice1[:] = 0.0
      """
  
      def __init__(self, pos, dst):
          super(MemoryCopyScalar, self).__init__(pos, dst)
          self.type = dst.type.dtype
  
      def _generate_assignment_code(self, scalar, code):
          from . import MemoryView
  
          self.dst.type.assert_direct_dims(self.dst.pos)
  
          dtype = self.dst.type.dtype
          type_decl = dtype.declaration_code("")
          slice_decl = self.dst.type.declaration_code("")
  
          code.begin_block()
          code.putln("%s __pyx_temp_scalar = %s;" % (type_decl, scalar.result()))
          if self.dst.result_in_temp() or self.dst.is_simple():
              dst_temp = self.dst.result()
          else:
              code.putln("%s __pyx_temp_slice = %s;" % (slice_decl, self.dst.result()))
              dst_temp = "__pyx_temp_slice"
  
          force_strided = False
          indices = self.dst.original_indices
          for idx in indices:
              if isinstance(idx, SliceNode) and not (idx.start.is_none and
                                                     idx.stop.is_none and
                                                     idx.step.is_none):
                  force_strided = True
  
          slice_iter_obj = MemoryView.slice_iter(self.dst.type, dst_temp,
                                                 self.dst.type.ndim, code,
                                                 force_strided=force_strided)
          p = slice_iter_obj.start_loops()
  
          if dtype.is_pyobject:
              code.putln("Py_DECREF(*(PyObject **) %s);" % p)
  
          code.putln("*((%s *) %s) = __pyx_temp_scalar;" % (type_decl, p))
  
          if dtype.is_pyobject:
              code.putln("Py_INCREF(__pyx_temp_scalar);")
  
          slice_iter_obj.end_loops()
          code.end_block()
  
  
  class SliceIndexNode(ExprNode):
      #  2-element slice indexing
      #
      #  base      ExprNode
      #  start     ExprNode or None
      #  stop      ExprNode or None
      #  slice     ExprNode or None   constant slice object
  
      subexprs = ['base', 'start', 'stop', 'slice']
  
      slice = None
  
      def infer_type(self, env):
          base_type = self.base.infer_type(env)
          if base_type.is_string or base_type.is_cpp_class:
              return bytes_type
          elif base_type.is_pyunicode_ptr:
              return unicode_type
          elif base_type in (bytes_type, bytearray_type, str_type, unicode_type,
                             basestring_type, list_type, tuple_type):
              return base_type
          elif base_type.is_ptr or base_type.is_array:
              return PyrexTypes.c_array_type(base_type.base_type, None)
          return py_object_type
  
      def inferable_item_node(self, index=0):
          # slicing shouldn't change the result type of the base, but the index might
          if index is not not_a_constant and self.start:
              if self.start.has_constant_result():
                  index += self.start.constant_result
              else:
                  index = not_a_constant
          return self.base.inferable_item_node(index)
  
      def may_be_none(self):
          base_type = self.base.type
          if base_type:
              if base_type.is_string:
                  return False
              if base_type in (bytes_type, str_type, unicode_type,
                               basestring_type, list_type, tuple_type):
                  return False
          return ExprNode.may_be_none(self)
  
      def calculate_constant_result(self):
          if self.start is None:
              start = None
          else:
              start = self.start.constant_result
          if self.stop is None:
              stop = None
          else:
              stop = self.stop.constant_result
          self.constant_result = self.base.constant_result[start:stop]
  
      def compile_time_value(self, denv):
          base = self.base.compile_time_value(denv)
          if self.start is None:
              start = 0
          else:
              start = self.start.compile_time_value(denv)
          if self.stop is None:
              stop = None
          else:
              stop = self.stop.compile_time_value(denv)
          try:
              return base[start:stop]
          except Exception as e:
              self.compile_time_value_error(e)
  
      def analyse_target_declaration(self, env):
          pass
  
      def analyse_target_types(self, env):
          node = self.analyse_types(env, getting=False)
          # when assigning, we must accept any Python type
          if node.type.is_pyobject:
              node.type = py_object_type
          return node
  
      def analyse_types(self, env, getting=True):
          self.base = self.base.analyse_types(env)
  
          if self.base.type.is_buffer or self.base.type.is_pythran_expr or self.base.type.is_memoryviewslice:
              none_node = NoneNode(self.pos)
              index = SliceNode(self.pos,
                                start=self.start or none_node,
                                stop=self.stop or none_node,
                                step=none_node)
              index_node = IndexNode(self.pos, index=index, base=self.base)
              return index_node.analyse_base_and_index_types(
                  env, getting=getting, setting=not getting,
                  analyse_base=False)
  
          if self.start:
              self.start = self.start.analyse_types(env)
          if self.stop:
              self.stop = self.stop.analyse_types(env)
  
          if not env.directives['wraparound']:
              check_negative_indices(self.start, self.stop)
  
          base_type = self.base.type
          if base_type.is_array and not getting:
              # cannot assign directly to C array => try to assign by making a copy
              if not self.start and not self.stop:
                  self.type = base_type
              else:
                  self.type = PyrexTypes.CPtrType(base_type.base_type)
          elif base_type.is_string or base_type.is_cpp_string:
              self.type = default_str_type(env)
          elif base_type.is_pyunicode_ptr:
              self.type = unicode_type
          elif base_type.is_ptr:
              self.type = base_type
          elif base_type.is_array:
              # we need a ptr type here instead of an array type, as
              # array types can result in invalid type casts in the C
              # code
              self.type = PyrexTypes.CPtrType(base_type.base_type)
          else:
              self.base = self.base.coerce_to_pyobject(env)
              self.type = py_object_type
          if base_type.is_builtin_type:
              # slicing builtin types returns something of the same type
              self.type = base_type
              self.base = self.base.as_none_safe_node("'NoneType' object is not subscriptable")
  
          if self.type is py_object_type:
              if (not self.start or self.start.is_literal) and \
                      (not self.stop or self.stop.is_literal):
                  # cache the constant slice object, in case we need it
                  none_node = NoneNode(self.pos)
                  self.slice = SliceNode(
                      self.pos,
                      start=copy.deepcopy(self.start or none_node),
                      stop=copy.deepcopy(self.stop or none_node),
                      step=none_node
                  ).analyse_types(env)
          else:
              c_int = PyrexTypes.c_py_ssize_t_type
  
              def allow_none(node, default_value, env):
                  # Coerce to Py_ssize_t, but allow None as meaning the default slice bound.
                  from .UtilNodes import EvalWithTempExprNode, ResultRefNode
  
                  node_ref = ResultRefNode(node)
                  new_expr = CondExprNode(
                      node.pos,
                      true_val=IntNode(
                          node.pos,
                          type=c_int,
                          value=default_value,
                          constant_result=int(default_value) if default_value.isdigit() else not_a_constant,
                      ),
                      false_val=node_ref.coerce_to(c_int, env),
                      test=PrimaryCmpNode(
                          node.pos,
                          operand1=node_ref,
                          operator='is',
                          operand2=NoneNode(node.pos),
                      ).analyse_types(env)
                  ).analyse_result_type(env)
                  return EvalWithTempExprNode(node_ref, new_expr)
  
              if self.start:
                  if self.start.type.is_pyobject:
                      self.start = allow_none(self.start, '0', env)
                  self.start = self.start.coerce_to(c_int, env)
              if self.stop:
                  if self.stop.type.is_pyobject:
                      self.stop = allow_none(self.stop, 'PY_SSIZE_T_MAX', env)
                  self.stop = self.stop.coerce_to(c_int, env)
          self.is_temp = 1
          return self
  
      def analyse_as_type(self, env):
          base_type = self.base.analyse_as_type(env)
          if base_type and not base_type.is_pyobject:
              if not self.start and not self.stop:
                  # memory view
                  from . import MemoryView
                  env.use_utility_code(MemoryView.view_utility_code)
                  none_node = NoneNode(self.pos)
                  slice_node = SliceNode(
                      self.pos,
                      start=none_node,
                      stop=none_node,
                      step=none_node,
                  )
                  return PyrexTypes.MemoryViewSliceType(
                      base_type, MemoryView.get_axes_specs(env, [slice_node]))
          return None
  
      nogil_check = Node.gil_error
      gil_message = "Slicing Python object"
  
      get_slice_utility_code = TempitaUtilityCode.load(
          "SliceObject", "ObjectHandling.c", context={'access': 'Get'})
  
      set_slice_utility_code = TempitaUtilityCode.load(
          "SliceObject", "ObjectHandling.c", context={'access': 'Set'})
  
      def coerce_to(self, dst_type, env):
          if ((self.base.type.is_string or self.base.type.is_cpp_string)
                  and dst_type in (bytes_type, bytearray_type, str_type, unicode_type)):
              if (dst_type not in (bytes_type, bytearray_type)
                      and not env.directives['c_string_encoding']):
                  error(self.pos,
                      "default encoding required for conversion from '%s' to '%s'" %
                      (self.base.type, dst_type))
              self.type = dst_type
          if dst_type.is_array and self.base.type.is_array:
              if not self.start and not self.stop:
                  # redundant slice building, copy C arrays directly
                  return self.base.coerce_to(dst_type, env)
              # else: check array size if possible
          return super(SliceIndexNode, self).coerce_to(dst_type, env)
  
      def generate_result_code(self, code):
          if not self.type.is_pyobject:
              error(self.pos,
                    "Slicing is not currently supported for '%s'." % self.type)
              return
  
          base_result = self.base.result()
          result = self.result()
          start_code = self.start_code()
          stop_code = self.stop_code()
          if self.base.type.is_string:
              base_result = self.base.result()
              if self.base.type not in (PyrexTypes.c_char_ptr_type, PyrexTypes.c_const_char_ptr_type):
                  base_result = '((const char*)%s)' % base_result
              if self.type is bytearray_type:
                  type_name = 'ByteArray'
              else:
                  type_name = self.type.name.title()
              if self.stop is None:
                  code.putln(
                      "%s = __Pyx_Py%s_FromString(%s + %s); %s" % (
                          result,
                          type_name,
                          base_result,
                          start_code,
                          code.error_goto_if_null(result, self.pos)))
              else:
                  code.putln(
                      "%s = __Pyx_Py%s_FromStringAndSize(%s + %s, %s - %s); %s" % (
                          result,
                          type_name,
                          base_result,
                          start_code,
                          stop_code,
                          start_code,
                          code.error_goto_if_null(result, self.pos)))
          elif self.base.type.is_pyunicode_ptr:
              base_result = self.base.result()
              if self.base.type != PyrexTypes.c_py_unicode_ptr_type:
                  base_result = '((const Py_UNICODE*)%s)' % base_result
              if self.stop is None:
                  code.putln(
                      "%s = __Pyx_PyUnicode_FromUnicode(%s + %s); %s" % (
                          result,
                          base_result,
                          start_code,
                          code.error_goto_if_null(result, self.pos)))
              else:
                  code.putln(
                      "%s = __Pyx_PyUnicode_FromUnicodeAndLength(%s + %s, %s - %s); %s" % (
                          result,
                          base_result,
                          start_code,
                          stop_code,
                          start_code,
                          code.error_goto_if_null(result, self.pos)))
  
          elif self.base.type is unicode_type:
              code.globalstate.use_utility_code(
                            UtilityCode.load_cached("PyUnicode_Substring", "StringTools.c"))
              code.putln(
                  "%s = __Pyx_PyUnicode_Substring(%s, %s, %s); %s" % (
                      result,
                      base_result,
                      start_code,
                      stop_code,
                      code.error_goto_if_null(result, self.pos)))
          elif self.type is py_object_type:
              code.globalstate.use_utility_code(self.get_slice_utility_code)
              (has_c_start, has_c_stop, c_start, c_stop,
               py_start, py_stop, py_slice) = self.get_slice_config()
              code.putln(
                  "%s = __Pyx_PyObject_GetSlice(%s, %s, %s, %s, %s, %s, %d, %d, %d); %s" % (
                      result,
                      self.base.py_result(),
                      c_start, c_stop,
                      py_start, py_stop, py_slice,
                      has_c_start, has_c_stop,
                      bool(code.globalstate.directives['wraparound']),
                      code.error_goto_if_null(result, self.pos)))
          else:
              if self.base.type is list_type:
                  code.globalstate.use_utility_code(
                      TempitaUtilityCode.load_cached("SliceTupleAndList", "ObjectHandling.c"))
                  cfunc = '__Pyx_PyList_GetSlice'
              elif self.base.type is tuple_type:
                  code.globalstate.use_utility_code(
                      TempitaUtilityCode.load_cached("SliceTupleAndList", "ObjectHandling.c"))
                  cfunc = '__Pyx_PyTuple_GetSlice'
              else:
                  cfunc = 'PySequence_GetSlice'
              code.putln(
                  "%s = %s(%s, %s, %s); %s" % (
                      result,
                      cfunc,
                      self.base.py_result(),
                      start_code,
                      stop_code,
                      code.error_goto_if_null(result, self.pos)))
          self.generate_gotref(code)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          self.generate_subexpr_evaluation_code(code)
          if self.type.is_pyobject:
              code.globalstate.use_utility_code(self.set_slice_utility_code)
              has_c_start, has_c_stop, c_start, c_stop, py_start, py_stop, py_slice = self.get_slice_config()
              code.put_error_if_neg(self.pos,
                  "__Pyx_PyObject_SetSlice(%s, %s, %s, %s, %s, %s, %s, %d, %d, %d)" % (
                      self.base.py_result(),
                      rhs.py_result(),
                      c_start, c_stop,
                      py_start, py_stop, py_slice,
                      has_c_start, has_c_stop,
                      bool(code.globalstate.directives['wraparound'])))
          else:
              start_offset = self.start_code() if self.start else '0'
              if rhs.type.is_array:
                  array_length = rhs.type.size
                  self.generate_slice_guard_code(code, array_length)
              else:
                  array_length = '%s - %s' % (self.stop_code(), start_offset)
  
              code.globalstate.use_utility_code(UtilityCode.load_cached("IncludeStringH", "StringTools.c"))
              code.putln("memcpy(&(%s[%s]), %s, sizeof(%s[0]) * (%s));" % (
                  self.base.result(), start_offset,
                  rhs.result(),
                  self.base.result(), array_length
              ))
  
          self.generate_subexpr_disposal_code(code)
          self.free_subexpr_temps(code)
          rhs.generate_disposal_code(code)
          rhs.free_temps(code)
  
      def generate_deletion_code(self, code, ignore_nonexisting=False):
          if not self.base.type.is_pyobject:
              error(self.pos,
                    "Deleting slices is only supported for Python types, not '%s'." % self.type)
              return
          self.generate_subexpr_evaluation_code(code)
          code.globalstate.use_utility_code(self.set_slice_utility_code)
          (has_c_start, has_c_stop, c_start, c_stop,
           py_start, py_stop, py_slice) = self.get_slice_config()
          code.put_error_if_neg(self.pos,
              "__Pyx_PyObject_DelSlice(%s, %s, %s, %s, %s, %s, %d, %d, %d)" % (
                  self.base.py_result(),
                  c_start, c_stop,
                  py_start, py_stop, py_slice,
                  has_c_start, has_c_stop,
                  bool(code.globalstate.directives['wraparound'])))
          self.generate_subexpr_disposal_code(code)
          self.free_subexpr_temps(code)
  
      def get_slice_config(self):
          has_c_start, c_start, py_start = False, '0', 'NULL'
          if self.start:
              has_c_start = not self.start.type.is_pyobject
              if has_c_start:
                  c_start = self.start.result()
              else:
                  py_start = '&%s' % self.start.py_result()
          has_c_stop, c_stop, py_stop = False, '0', 'NULL'
          if self.stop:
              has_c_stop = not self.stop.type.is_pyobject
              if has_c_stop:
                  c_stop = self.stop.result()
              else:
                  py_stop = '&%s' % self.stop.py_result()
          py_slice = self.slice and '&%s' % self.slice.py_result() or 'NULL'
          return (has_c_start, has_c_stop, c_start, c_stop,
                  py_start, py_stop, py_slice)
  
      def generate_slice_guard_code(self, code, target_size):
          if not self.base.type.is_array:
              return
          slice_size = self.base.type.size
          try:
              total_length = slice_size = int(slice_size)
          except ValueError:
              total_length = None
  
          start = stop = None
          if self.stop:
              stop = self.stop.result()
              try:
                  stop = int(stop)
                  if stop < 0:
                      if total_length is None:
                          slice_size = '%s + %d' % (slice_size, stop)
                      else:
                          slice_size += stop
                  else:
                      slice_size = stop
                  stop = None
              except ValueError:
                  pass
  
          if self.start:
              start = self.start.result()
              try:
                  start = int(start)
                  if start < 0:
                      if total_length is None:
                          start = '%s + %d' % (self.base.type.size, start)
                      else:
                          start += total_length
                  if isinstance(slice_size, _py_int_types):
                      slice_size -= start
                  else:
                      slice_size = '%s - (%s)' % (slice_size, start)
                  start = None
              except ValueError:
                  pass
  
          runtime_check = None
          compile_time_check = False
          try:
              int_target_size = int(target_size)
          except ValueError:
              int_target_size = None
          else:
              compile_time_check = isinstance(slice_size, _py_int_types)
  
          if compile_time_check and slice_size < 0:
              if int_target_size > 0:
                  error(self.pos, "Assignment to empty slice.")
          elif compile_time_check and start is None and stop is None:
              # we know the exact slice length
              if int_target_size != slice_size:
                  error(self.pos, "Assignment to slice of wrong length, expected %s, got %s" % (
                        slice_size, target_size))
          elif start is not None:
              if stop is None:
                  stop = slice_size
              runtime_check = "(%s)-(%s)" % (stop, start)
          elif stop is not None:
              runtime_check = stop
          else:
              runtime_check = slice_size
  
          if runtime_check:
              code.putln("if (unlikely((%s) != (%s))) {" % (runtime_check, target_size))
              code.putln(
                  'PyErr_Format(PyExc_ValueError, "Assignment to slice of wrong length,'
                  ' expected %%" CYTHON_FORMAT_SSIZE_T "d, got %%" CYTHON_FORMAT_SSIZE_T "d",'
                  ' (Py_ssize_t)(%s), (Py_ssize_t)(%s));' % (
                      target_size, runtime_check))
              code.putln(code.error_goto(self.pos))
              code.putln("}")
  
      def start_code(self):
          if self.start:
              return self.start.result()
          else:
              return "0"
  
      def stop_code(self):
          if self.stop:
              return self.stop.result()
          elif self.base.type.is_array:
              return self.base.type.size
          else:
              return "PY_SSIZE_T_MAX"
  
      def calculate_result_code(self):
          # self.result() is not used, but this method must exist
          return "<unused>"
  
  
  class SliceNode(ExprNode):
      #  start:stop:step in subscript list
      #
      #  start     ExprNode
      #  stop      ExprNode
      #  step      ExprNode
  
      subexprs = ['start', 'stop', 'step']
      is_slice = True
      type = slice_type
      is_temp = 1
  
      def calculate_constant_result(self):
          self.constant_result = slice(
              self.start.constant_result,
              self.stop.constant_result,
              self.step.constant_result)
  
      def compile_time_value(self, denv):
          start = self.start.compile_time_value(denv)
          stop = self.stop.compile_time_value(denv)
          step = self.step.compile_time_value(denv)
          try:
              return slice(start, stop, step)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def may_be_none(self):
          return False
  
      def analyse_types(self, env):
          start = self.start.analyse_types(env)
          stop = self.stop.analyse_types(env)
          step = self.step.analyse_types(env)
          self.start = start.coerce_to_pyobject(env)
          self.stop = stop.coerce_to_pyobject(env)
          self.step = step.coerce_to_pyobject(env)
          if self.start.is_literal and self.stop.is_literal and self.step.is_literal:
              self.is_literal = True
              self.is_temp = False
          return self
  
      gil_message = "Constructing Python slice object"
  
      def calculate_result_code(self):
          return self.result_code
  
      def generate_result_code(self, code):
          if self.is_literal:
              dedup_key = make_dedup_key(self.type, (self,))
              self.result_code = code.get_py_const(py_object_type, 'slice', cleanup_level=2, dedup_key=dedup_key)
              code = code.get_cached_constants_writer(self.result_code)
              if code is None:
                  return  # already initialised
              code.mark_pos(self.pos)
  
          code.putln(
              "%s = PySlice_New(%s, %s, %s); %s" % (
                  self.result(),
                  self.start.py_result(),
                  self.stop.py_result(),
                  self.step.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
          if self.is_literal:
              self.generate_giveref(code)
  
  class SliceIntNode(SliceNode):
      #  start:stop:step in subscript list
      # This is just a node to hold start,stop and step nodes that can be
      # converted to integers. This does not generate a slice python object.
      #
      #  start     ExprNode
      #  stop      ExprNode
      #  step      ExprNode
  
      is_temp = 0
  
      def calculate_constant_result(self):
          self.constant_result = slice(
              self.start.constant_result,
              self.stop.constant_result,
              self.step.constant_result)
  
      def compile_time_value(self, denv):
          start = self.start.compile_time_value(denv)
          stop = self.stop.compile_time_value(denv)
          step = self.step.compile_time_value(denv)
          try:
              return slice(start, stop, step)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def may_be_none(self):
          return False
  
      def analyse_types(self, env):
          self.start = self.start.analyse_types(env)
          self.stop = self.stop.analyse_types(env)
          self.step = self.step.analyse_types(env)
  
          if not self.start.is_none:
              self.start = self.start.coerce_to_integer(env)
          if not self.stop.is_none:
              self.stop = self.stop.coerce_to_integer(env)
          if not self.step.is_none:
              self.step = self.step.coerce_to_integer(env)
  
          if self.start.is_literal and self.stop.is_literal and self.step.is_literal:
              self.is_literal = True
              self.is_temp = False
          return self
  
      def calculate_result_code(self):
          pass
  
      def generate_result_code(self, code):
          for a in self.start,self.stop,self.step:
              if isinstance(a, CloneNode):
                  a.arg.result()
  
  
  class CallNode(ExprNode):
  
      # allow overriding the default 'may_be_none' behaviour
      may_return_none = None
  
      def infer_type(self, env):
          # TODO(robertwb): Reduce redundancy with analyse_types.
          function = self.function
          func_type = function.infer_type(env)
          if isinstance(function, NewExprNode):
              # note: needs call to infer_type() above
              return PyrexTypes.CPtrType(function.class_type)
          if func_type is py_object_type:
              # function might have lied for safety => try to find better type
              entry = getattr(function, 'entry', None)
              if entry is not None:
                  func_type = entry.type or func_type
          if func_type.is_ptr:
              func_type = func_type.base_type
          if func_type.is_cfunction:
              if getattr(self.function, 'entry', None) and hasattr(self, 'args'):
                  alternatives = self.function.entry.all_alternatives()
                  arg_types = [arg.infer_type(env) for arg in self.args]
                  func_entry = PyrexTypes.best_match(arg_types, alternatives)
                  if func_entry:
                      func_type = func_entry.type
                      if func_type.is_ptr:
                          func_type = func_type.base_type
                      return func_type.return_type
              return func_type.return_type
          elif func_type is type_type:
              if function.is_name and function.entry and function.entry.type:
                  result_type = function.entry.type
                  if result_type.is_extension_type:
                      return result_type
                  elif result_type.is_builtin_type:
                      if function.entry.name == 'float':
                          return PyrexTypes.c_double_type
                      elif function.entry.name in Builtin.types_that_construct_their_instance:
                          return result_type
          func_type = self.function.analyse_as_type(env)
          if func_type and (func_type.is_struct_or_union or func_type.is_cpp_class):
              return func_type
          return py_object_type
  
      def type_dependencies(self, env):
          # TODO: Update when Danilo's C++ code merged in to handle the
          # the case of function overloading.
          return self.function.type_dependencies(env)
  
      def is_simple(self):
          # C function calls could be considered simple, but they may
          # have side-effects that may hit when multiple operations must
          # be effected in order, e.g. when constructing the argument
          # sequence for a function call or comparing values.
          return False
  
      def may_be_none(self):
          if self.may_return_none is not None:
              return self.may_return_none
          func_type = self.function.type
          if func_type is type_type and self.function.is_name:
              entry = self.function.entry
              if entry.type.is_extension_type:
                  return False
              if (entry.type.is_builtin_type and
                      entry.name in Builtin.types_that_construct_their_instance):
                  return False
          return ExprNode.may_be_none(self)
  
      def set_py_result_type(self, function, func_type=None):
          if func_type is None:
              func_type = function.type
          if func_type is Builtin.type_type and (
                  function.is_name and
                  function.entry and
                  function.entry.is_builtin and
                  function.entry.name in Builtin.types_that_construct_their_instance):
              # calling a builtin type that returns a specific object type
              if function.entry.name == 'float':
                  # the following will come true later on in a transform
                  self.type = PyrexTypes.c_double_type
                  self.result_ctype = PyrexTypes.c_double_type
              else:
                  self.type = Builtin.builtin_types[function.entry.name]
                  self.result_ctype = py_object_type
              self.may_return_none = False
          elif function.is_name and function.type_entry:
              # We are calling an extension type constructor.  As long as we do not
              # support __new__(), the result type is clear
              self.type = function.type_entry.type
              self.result_ctype = py_object_type
              self.may_return_none = False
          else:
              self.type = py_object_type
  
      def analyse_as_type_constructor(self, env):
          type = self.function.analyse_as_type(env)
          if type and type.is_struct_or_union:
              args, kwds = self.explicit_args_kwds()
              items = []
              for arg, member in zip(args, type.scope.var_entries):
                  items.append(DictItemNode(pos=arg.pos, key=StringNode(pos=arg.pos, value=member.name), value=arg))
              if kwds:
                  items += kwds.key_value_pairs
              self.key_value_pairs = items
              self.__class__ = DictNode
              self.analyse_types(env)    # FIXME
              self.coerce_to(type, env)
              return True
          elif type and type.is_cpp_class:
              self.args = [ arg.analyse_types(env) for arg in self.args ]
              constructor = type.scope.lookup("<init>")
              if not constructor:
                  error(self.function.pos, "no constructor found for C++  type '%s'" % self.function.name)
                  self.type = error_type
                  return self
              self.function = RawCNameExprNode(self.function.pos, constructor.type)
              self.function.entry = constructor
              self.function.set_cname(type.empty_declaration_code())
              self.analyse_c_function_call(env)
              self.type = type
              return True
  
      def is_lvalue(self):
          return self.type.is_reference
  
      def nogil_check(self, env):
          func_type = self.function_type()
          if func_type.is_pyobject:
              self.gil_error()
          elif not func_type.is_error and not getattr(func_type, 'nogil', False):
              self.gil_error()
  
      gil_message = "Calling gil-requiring function"
  
  
  class SimpleCallNode(CallNode):
      #  Function call without keyword, * or ** args.
      #
      #  function       ExprNode
      #  args           [ExprNode]
      #  arg_tuple      ExprNode or None     used internally
      #  self           ExprNode or None     used internally
      #  coerced_self   ExprNode or None     used internally
      #  wrapper_call   bool                 used internally
      #  has_optional_args   bool            used internally
      #  nogil          bool                 used internally
  
      subexprs = ['self', 'coerced_self', 'function', 'args', 'arg_tuple']
  
      self = None
      coerced_self = None
      arg_tuple = None
      wrapper_call = False
      has_optional_args = False
      nogil = False
      analysed = False
      overflowcheck = False
  
      def compile_time_value(self, denv):
          function = self.function.compile_time_value(denv)
          args = [arg.compile_time_value(denv) for arg in self.args]
          try:
              return function(*args)
          except Exception as e:
              self.compile_time_value_error(e)
  
      @classmethod
      def for_cproperty(cls, pos, obj, entry):
          # Create a call node for C property access.
          property_scope = entry.scope
          getter_entry = property_scope.lookup_here(entry.name)
          assert getter_entry, "Getter not found in scope %s: %s" % (property_scope, property_scope.entries)
          function = NameNode(pos, name=entry.name, entry=getter_entry, type=getter_entry.type)
          node = cls(pos, function=function, args=[obj])
          return node
  
      def analyse_as_type(self, env):
          attr = self.function.as_cython_attribute()
          if attr == 'pointer':
              if len(self.args) != 1:
                  error(self.args.pos, "only one type allowed.")
              else:
                  type = self.args[0].analyse_as_type(env)
                  if not type:
                      error(self.args[0].pos, "Unknown type")
                  else:
                      return PyrexTypes.CPtrType(type)
          elif attr == 'typeof':
              if len(self.args) != 1:
                  error(self.args.pos, "only one type allowed.")
              operand = self.args[0].analyse_types(env)
              return operand.type
  
      def explicit_args_kwds(self):
          return self.args, None
  
      def analyse_types(self, env):
          if self.analyse_as_type_constructor(env):
              return self
          if self.analysed:
              return self
          self.analysed = True
          self.function.is_called = 1
          self.function = self.function.analyse_types(env)
          function = self.function
  
          if function.is_attribute and function.entry and function.entry.is_cmethod:
              # Take ownership of the object from which the attribute
              # was obtained, because we need to pass it as 'self'.
              self.self = function.obj
              function.obj = CloneNode(self.self)
  
          func_type = self.function_type()
          self.is_numpy_call_with_exprs = False
          if (has_np_pythran(env) and function.is_numpy_attribute and
                  pythran_is_numpy_func_supported(function)):
              has_pythran_args = True
              self.arg_tuple = TupleNode(self.pos, args = self.args)
              self.arg_tuple = self.arg_tuple.analyse_types(env)
              for arg in self.arg_tuple.args:
                  has_pythran_args &= is_pythran_supported_node_or_none(arg)
              self.is_numpy_call_with_exprs = bool(has_pythran_args)
          if self.is_numpy_call_with_exprs:
              env.add_include_file(pythran_get_func_include_file(function))
              return NumPyMethodCallNode.from_node(
                  self,
                  function_cname=pythran_functor(function),
                  arg_tuple=self.arg_tuple,
                  type=PythranExpr(pythran_func_type(function, self.arg_tuple.args)),
              )
          elif func_type.is_pyobject:
              self.arg_tuple = TupleNode(self.pos, args = self.args)
              self.arg_tuple = self.arg_tuple.analyse_types(env).coerce_to_pyobject(env)
              self.args = None
              self.set_py_result_type(function, func_type)
              self.is_temp = 1
          else:
              self.args = [ arg.analyse_types(env) for arg in self.args ]
              self.analyse_c_function_call(env)
              if func_type.exception_check == '+':
                  self.is_temp = True
  
          return self
  
      def function_type(self):
          # Return the type of the function being called, coercing a function
          # pointer to a function if necessary. If the function has fused
          # arguments, return the specific type.
          func_type = self.function.type
  
          if func_type.is_ptr:
              func_type = func_type.base_type
  
          return func_type
  
      def analyse_c_function_call(self, env):
          func_type = self.function.type
          if func_type is error_type:
              self.type = error_type
              return
  
          if func_type.is_cfunction and func_type.is_static_method:
              if self.self and self.self.type.is_extension_type:
                  # To support this we'd need to pass self to determine whether
                  # it was overloaded in Python space (possibly via a Cython
                  # superclass turning a cdef method into a cpdef one).
                  error(self.pos, "Cannot call a static method on an instance variable.")
              args = self.args
          elif self.self:
              args = [self.self] + self.args
          else:
              args = self.args
  
          if func_type.is_cpp_class:
              overloaded_entry = self.function.type.scope.lookup("operator()")
              if overloaded_entry is None:
                  self.type = PyrexTypes.error_type
                  self.result_code = "<error>"
                  return
          elif hasattr(self.function, 'entry'):
              overloaded_entry = self.function.entry
          elif self.function.is_subscript and self.function.is_fused_index:
              overloaded_entry = self.function.type.entry
          else:
              overloaded_entry = None
  
          if overloaded_entry:
              if self.function.type.is_fused:
                  functypes = self.function.type.get_all_specialized_function_types()
                  alternatives = [f.entry for f in functypes]
              else:
                  alternatives = overloaded_entry.all_alternatives()
  
              # For any argument/parameter pair A/P, if P is a forwarding reference,
              # use lvalue-reference-to-A for deduction in place of A when the
              # function call argument is an lvalue. See:
              # https://en.cppreference.com/w/cpp/language/template_argument_deduction#Deduction_from_a_function_call
              arg_types = [arg.type for arg in args]
              if func_type.is_cfunction:
                  for i, formal_arg in enumerate(func_type.args):
                      if formal_arg.is_forwarding_reference():
                          if self.args[i].is_lvalue():
                              arg_types[i] = PyrexTypes.c_ref_type(arg_types[i])
  
              entry = PyrexTypes.best_match(arg_types, alternatives, self.pos, env, args)
  
              if not entry:
                  self.type = PyrexTypes.error_type
                  self.result_code = "<error>"
                  return
  
              entry.used = True
              if not func_type.is_cpp_class:
                  self.function.entry = entry
              self.function.type = entry.type
              func_type = self.function_type()
          else:
              entry = None
              func_type = self.function_type()
              if not func_type.is_cfunction:
                  error(self.pos, "Calling non-function type '%s'" % func_type)
                  self.type = PyrexTypes.error_type
                  self.result_code = "<error>"
                  return
  
          # Check no. of args
          max_nargs = len(func_type.args)
          expected_nargs = max_nargs - func_type.optional_arg_count
          actual_nargs = len(args)
          if func_type.optional_arg_count and expected_nargs != actual_nargs:
              self.has_optional_args = 1
              self.is_temp = 1
  
          # check 'self' argument
          if entry and entry.is_cmethod and func_type.args and not func_type.is_static_method:
              formal_arg = func_type.args[0]
              arg = args[0]
              if formal_arg.not_none:
                  if self.self:
                      self.self = self.self.as_none_safe_node(
                          "'NoneType' object has no attribute '%{0}s'".format('.30' if len(entry.name) <= 30 else ''),
                          error='PyExc_AttributeError',
                          format_args=[entry.name])
                  else:
                      # unbound method
                      arg = arg.as_none_safe_node(
                          "descriptor '%s' requires a '%s' object but received a 'NoneType'",
                          format_args=[entry.name, formal_arg.type.name])
              if self.self:
                  if formal_arg.accept_builtin_subtypes:
                      arg = CMethodSelfCloneNode(self.self)
                  else:
                      arg = CloneNode(self.self)
                  arg = self.coerced_self = arg.coerce_to(formal_arg.type, env)
              elif formal_arg.type.is_builtin_type:
                  # special case: unbound methods of builtins accept subtypes
                  arg = arg.coerce_to(formal_arg.type, env)
                  if arg.type.is_builtin_type and isinstance(arg, PyTypeTestNode):
                      arg.exact_builtin_type = False
              args[0] = arg
  
          # Coerce arguments
          some_args_in_temps = False
          for i in range(min(max_nargs, actual_nargs)):
              formal_arg = func_type.args[i]
              formal_type = formal_arg.type
              arg = args[i].coerce_to(formal_type, env)
              if formal_arg.not_none:
                  # C methods must do the None checks at *call* time
                  arg = arg.as_none_safe_node(
                      "cannot pass None into a C function argument that is declared 'not None'")
              if arg.is_temp:
                  if i > 0:
                      # first argument in temp doesn't impact subsequent arguments
                      some_args_in_temps = True
              elif arg.type.is_pyobject and not env.nogil:
                  if i == 0 and self.self is not None:
                      # a method's cloned "self" argument is ok
                      pass
                  elif arg.nonlocally_immutable():
                      # plain local variables are ok
                      pass
                  else:
                      # we do not safely own the argument's reference,
                      # but we must make sure it cannot be collected
                      # before we return from the function, so we create
                      # an owned temp reference to it
                      if i > 0:  # first argument doesn't matter
                          some_args_in_temps = True
                      arg = arg.coerce_to_temp(env)
              args[i] = arg
  
          # handle additional varargs parameters
          for i in range(max_nargs, actual_nargs):
              arg = args[i]
              if arg.type.is_pyobject:
                  if arg.type is str_type:
                      arg_ctype = PyrexTypes.c_char_ptr_type
                  else:
                      arg_ctype = arg.type.default_coerced_ctype()
                  if arg_ctype is None:
                      error(self.args[i].pos,
                            "Python object cannot be passed as a varargs parameter")
                  else:
                      args[i] = arg = arg.coerce_to(arg_ctype, env)
              if arg.is_temp and i > 0:
                  some_args_in_temps = True
  
          if some_args_in_temps:
              # if some args are temps and others are not, they may get
              # constructed in the wrong order (temps first) => make
              # sure they are either all temps or all not temps (except
              # for the last argument, which is evaluated last in any
              # case)
              for i in range(actual_nargs-1):
                  if i == 0 and self.self is not None:
                      continue  # self is ok
                  arg = args[i]
                  if arg.nonlocally_immutable():
                      # locals, C functions, unassignable types are safe.
                      pass
                  elif arg.type.is_cpp_class:
                      # Assignment has side effects, avoid.
                      pass
                  elif env.nogil and arg.type.is_pyobject:
                      # can't copy a Python reference into a temp in nogil
                      # env (this is safe: a construction would fail in
                      # nogil anyway)
                      pass
                  else:
                      #self.args[i] = arg.coerce_to_temp(env)
                      # instead: issue a warning
                      if i > 0 or i == 1 and self.self is not None:  # skip first arg
                          warning(arg.pos, "Argument evaluation order in C function call is undefined and may not be as expected", 0)
                          break
  
          self.args[:] = args
  
          # Calc result type and code fragment
          if isinstance(self.function, NewExprNode):
              self.type = PyrexTypes.CPtrType(self.function.class_type)
          else:
              self.type = func_type.return_type
  
          if self.function.is_name or self.function.is_attribute:
              func_entry = self.function.entry
              if func_entry and (func_entry.utility_code or func_entry.utility_code_definition):
                  self.is_temp = 1  # currently doesn't work for self.calculate_result_code()
  
          if self.type.is_pyobject:
              self.result_ctype = py_object_type
              self.is_temp = 1
          elif func_type.exception_value is not None or func_type.exception_check:
              self.is_temp = 1
          elif self.type.is_memoryviewslice:
              self.is_temp = 1
              # func_type.exception_check = True
  
          if self.is_temp and self.type.is_reference:
              self.type = PyrexTypes.CFakeReferenceType(self.type.ref_base_type)
  
          # Called in 'nogil' context?
          self.nogil = env.nogil
          if (self.nogil and
                  func_type.exception_check and
                  func_type.exception_check != '+'):
              env.use_utility_code(pyerr_occurred_withgil_utility_code)
          # C++ exception handler
          if func_type.exception_check == '+':
              if func_type.exception_value is None:
                  env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
  
          self.overflowcheck = env.directives['overflowcheck']
  
      def calculate_result_code(self):
          return self.c_call_code()
  
      def c_call_code(self):
          func_type = self.function_type()
          if self.type is PyrexTypes.error_type or not func_type.is_cfunction:
              return "<error>"
          formal_args = func_type.args
          arg_list_code = []
          args = list(zip(formal_args, self.args))
          max_nargs = len(func_type.args)
          expected_nargs = max_nargs - func_type.optional_arg_count
          actual_nargs = len(self.args)
          for formal_arg, actual_arg in args[:expected_nargs]:
              arg_code = actual_arg.move_result_rhs_as(formal_arg.type)
              arg_list_code.append(arg_code)
  
          if func_type.is_overridable:
              arg_list_code.append(str(int(self.wrapper_call or self.function.entry.is_unbound_cmethod)))
  
          if func_type.optional_arg_count:
              if expected_nargs == actual_nargs:
                  optional_args = 'NULL'
              else:
                  optional_args = "&%s" % self.opt_arg_struct
              arg_list_code.append(optional_args)
  
          for actual_arg in self.args[len(formal_args):]:
              arg_list_code.append(actual_arg.move_result_rhs())
  
          result = "%s(%s)" % (self.function.result(), ', '.join(arg_list_code))
          return result
  
      def is_c_result_required(self):
          func_type = self.function_type()
          if not func_type.exception_value or func_type.exception_check == '+':
              return False  # skip allocation of unused result temp
          return True
  
      def generate_evaluation_code(self, code):
          function = self.function
          if function.is_name or function.is_attribute:
              code.globalstate.use_entry_utility_code(function.entry)
  
          abs_function_cnames = ('abs', 'labs', '__Pyx_abs_longlong')
          is_signed_int = self.type.is_int and self.type.signed
          if self.overflowcheck and is_signed_int and function.result() in abs_function_cnames:
              code.globalstate.use_utility_code(UtilityCode.load_cached("Common", "Overflow.c"))
              code.putln('if (unlikely(%s == __PYX_MIN(%s))) {\
                  PyErr_SetString(PyExc_OverflowError,\
                                  "Trying to take the absolute value of the most negative integer is not defined."); %s; }' % (
                              self.args[0].result(),
                              self.args[0].type.empty_declaration_code(),
                              code.error_goto(self.pos)))
  
          if not function.type.is_pyobject or len(self.arg_tuple.args) > 1 or (
                  self.arg_tuple.args and self.arg_tuple.is_literal):
              super(SimpleCallNode, self).generate_evaluation_code(code)
              return
  
          # Special case 0-args and try to avoid explicit tuple creation for Python calls with 1 arg.
          arg = self.arg_tuple.args[0] if self.arg_tuple.args else None
          subexprs = (self.self, self.coerced_self, function, arg)
          for subexpr in subexprs:
              if subexpr is not None:
                  subexpr.generate_evaluation_code(code)
  
          code.mark_pos(self.pos)
          assert self.is_temp
          self.allocate_temp_result(code)
  
          if arg is None:
              code.globalstate.use_utility_code(UtilityCode.load_cached(
                  "PyObjectCallNoArg", "ObjectHandling.c"))
              code.putln(
                  "%s = __Pyx_PyObject_CallNoArg(%s); %s" % (
                      self.result(),
                      function.py_result(),
                      code.error_goto_if_null(self.result(), self.pos)))
          else:
              code.globalstate.use_utility_code(UtilityCode.load_cached(
                  "PyObjectCallOneArg", "ObjectHandling.c"))
              code.putln(
                  "%s = __Pyx_PyObject_CallOneArg(%s, %s); %s" % (
                      self.result(),
                      function.py_result(),
                      arg.py_result(),
                      code.error_goto_if_null(self.result(), self.pos)))
  
          self.generate_gotref(code)
  
          for subexpr in subexprs:
              if subexpr is not None:
                  subexpr.generate_disposal_code(code)
                  subexpr.free_temps(code)
  
      def generate_result_code(self, code):
          func_type = self.function_type()
          if func_type.is_pyobject:
              arg_code = self.arg_tuple.py_result()
              code.globalstate.use_utility_code(UtilityCode.load_cached(
                  "PyObjectCall", "ObjectHandling.c"))
              code.putln(
                  "%s = __Pyx_PyObject_Call(%s, %s, NULL); %s" % (
                      self.result(),
                      self.function.py_result(),
                      arg_code,
                      code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
          elif func_type.is_cfunction:
              if self.has_optional_args:
                  actual_nargs = len(self.args)
                  expected_nargs = len(func_type.args) - func_type.optional_arg_count
                  self.opt_arg_struct = code.funcstate.allocate_temp(
                      func_type.op_arg_struct.base_type, manage_ref=True)
                  code.putln("%s.%s = %s;" % (
                          self.opt_arg_struct,
                          Naming.pyrex_prefix + "n",
                          len(self.args) - expected_nargs))
                  args = list(zip(func_type.args, self.args))
                  for formal_arg, actual_arg in args[expected_nargs:actual_nargs]:
                      code.putln("%s.%s = %s;" % (
                              self.opt_arg_struct,
                              func_type.opt_arg_cname(formal_arg.name),
                              actual_arg.result_as(formal_arg.type)))
              exc_checks = []
              if self.type.is_pyobject and self.is_temp:
                  exc_checks.append("!%s" % self.result())
              elif self.type.is_memoryviewslice:
                  assert self.is_temp
                  exc_checks.append(self.type.error_condition(self.result()))
              elif func_type.exception_check != '+':
                  exc_val = func_type.exception_value
                  exc_check = func_type.exception_check
                  if exc_val is not None:
                      exc_checks.append("%s == %s" % (self.result(), func_type.return_type.cast_code(exc_val)))
                  if exc_check:
                      if self.nogil:
                          exc_checks.append("__Pyx_ErrOccurredWithGIL()")
                      else:
                          exc_checks.append("PyErr_Occurred()")
              if self.is_temp or exc_checks:
                  rhs = self.c_call_code()
                  if self.result():
                      lhs = "%s = " % self.result()
                      if self.is_temp and self.type.is_pyobject:
                          #return_type = self.type # func_type.return_type
                          #print "SimpleCallNode.generate_result_code: casting", rhs, \
                          #    "from", return_type, "to pyobject" ###
                          rhs = typecast(py_object_type, self.type, rhs)
                  else:
                      lhs = ""
                  if func_type.exception_check == '+':
                      translate_cpp_exception(code, self.pos, '%s%s;' % (lhs, rhs),
                                              self.result() if self.type.is_pyobject else None,
                                              func_type.exception_value, self.nogil)
                  else:
                      if exc_checks:
                          goto_error = code.error_goto_if(" && ".join(exc_checks), self.pos)
                      else:
                          goto_error = ""
                      code.putln("%s%s; %s" % (lhs, rhs, goto_error))
                  if self.type.is_pyobject and self.result():
                      self.generate_gotref(code)
              if self.has_optional_args:
                  code.funcstate.release_temp(self.opt_arg_struct)
  
  
  class NumPyMethodCallNode(ExprNode):
      # Pythran call to a NumPy function or method.
      #
      # function_cname  string      the function/method to call
      # arg_tuple       TupleNode   the arguments as an args tuple
  
      subexprs = ['arg_tuple']
      is_temp = True
      may_return_none = True
  
      def generate_evaluation_code(self, code):
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
  
          assert self.arg_tuple.mult_factor is None
          args = self.arg_tuple.args
          for arg in args:
              arg.generate_evaluation_code(code)
  
          code.putln("// function evaluation code for numpy function")
          code.putln("__Pyx_call_destructor(%s);" % self.result())
          code.putln("new (&%s) decltype(%s){%s{}(%s)};" % (
              self.result(),
              self.result(),
              self.function_cname,
              ", ".join(a.pythran_result() for a in args)))
  
  
  class PyMethodCallNode(SimpleCallNode):
      # Specialised call to a (potential) PyMethodObject with non-constant argument tuple.
      # Allows the self argument to be injected directly instead of repacking a tuple for it.
      #
      # function    ExprNode      the function/method object to call
      # arg_tuple   TupleNode     the arguments for the args tuple
  
      subexprs = ['function', 'arg_tuple']
      is_temp = True
  
      def generate_evaluation_code(self, code):
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
  
          self.function.generate_evaluation_code(code)
          assert self.arg_tuple.mult_factor is None
          args = self.arg_tuple.args
          for arg in args:
              arg.generate_evaluation_code(code)
  
          # make sure function is in temp so that we can replace the reference below if it's a method
          reuse_function_temp = self.function.is_temp
          if reuse_function_temp:
              function = self.function.result()
          else:
              function = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
              self.function.make_owned_reference(code)
              code.put("%s = %s; " % (function, self.function.py_result()))
              self.function.generate_disposal_code(code)
              self.function.free_temps(code)
  
          self_arg = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
          code.putln("%s = NULL;" % self_arg)
          arg_offset_cname = code.funcstate.allocate_temp(PyrexTypes.c_int_type, manage_ref=False)
          code.putln("%s = 0;" % arg_offset_cname)
  
          def attribute_is_likely_method(attr):
              obj = attr.obj
              if obj.is_name and obj.entry.is_pyglobal:
                  return False  # more likely to be a function
              return True
  
          if self.function.is_attribute:
              likely_method = 'likely' if attribute_is_likely_method(self.function) else 'unlikely'
          elif self.function.is_name and self.function.cf_state:
              # not an attribute itself, but might have been assigned from one (e.g. bound method)
              for assignment in self.function.cf_state:
                  value = assignment.rhs
                  if value and value.is_attribute and value.obj.type and value.obj.type.is_pyobject:
                      if attribute_is_likely_method(value):
                          likely_method = 'likely'
                          break
              else:
                  likely_method = 'unlikely'
          else:
              likely_method = 'unlikely'
  
          code.putln("if (CYTHON_UNPACK_METHODS && %s(PyMethod_Check(%s))) {" % (likely_method, function))
          code.putln("%s = PyMethod_GET_SELF(%s);" % (self_arg, function))
          # the following is always true in Py3 (kept only for safety),
          # but is false for unbound methods in Py2
          code.putln("if (likely(%s)) {" % self_arg)
          code.putln("PyObject* function = PyMethod_GET_FUNCTION(%s);" % function)
          code.put_incref(self_arg, py_object_type)
          code.put_incref("function", py_object_type)
          # free method object as early to possible to enable reuse from CPython's freelist
          code.put_decref_set(function, py_object_type, "function")
          code.putln("%s = 1;" % arg_offset_cname)
          code.putln("}")
          code.putln("}")
  
          # actually call the function
          code.globalstate.use_utility_code(
              UtilityCode.load_cached("PyObjectFastCall", "ObjectHandling.c"))
  
          code.putln("{")
          code.putln("PyObject *__pyx_callargs[%d] = {%s, %s};" % (
              len(args)+1,
              self_arg,
              ', '.join(arg.py_result() for arg in args)))
          code.putln("%s = __Pyx_PyObject_FastCall(%s, __pyx_callargs+1-%s, %d+%s);" % (
              self.result(),
              function,
              arg_offset_cname,
              len(args),
              arg_offset_cname))
  
          code.put_xdecref_clear(self_arg, py_object_type)
          code.funcstate.release_temp(self_arg)
          code.funcstate.release_temp(arg_offset_cname)
          for arg in args:
              arg.generate_disposal_code(code)
              arg.free_temps(code)
          code.putln(code.error_goto_if_null(self.result(), self.pos))
          self.generate_gotref(code)
  
          if reuse_function_temp:
              self.function.generate_disposal_code(code)
              self.function.free_temps(code)
          else:
              code.put_decref_clear(function, py_object_type)
              code.funcstate.release_temp(function)
          code.putln("}")
  
  
  class InlinedDefNodeCallNode(CallNode):
      #  Inline call to defnode
      #
      #  function       PyCFunctionNode
      #  function_name  NameNode
      #  args           [ExprNode]
  
      subexprs = ['args', 'function_name']
      is_temp = 1
      type = py_object_type
      function = None
      function_name = None
  
      def can_be_inlined(self):
          func_type= self.function.def_node
          if func_type.star_arg or func_type.starstar_arg:
              return False
          if len(func_type.args) != len(self.args):
              return False
          if func_type.num_kwonly_args:
              return False  # actually wrong number of arguments
          return True
  
      def analyse_types(self, env):
          self.function_name = self.function_name.analyse_types(env)
  
          self.args = [ arg.analyse_types(env) for arg in self.args ]
          func_type = self.function.def_node
          actual_nargs = len(self.args)
  
          # Coerce arguments
          some_args_in_temps = False
          for i in range(actual_nargs):
              formal_type = func_type.args[i].type
              arg = self.args[i].coerce_to(formal_type, env)
              if arg.is_temp:
                  if i > 0:
                      # first argument in temp doesn't impact subsequent arguments
                      some_args_in_temps = True
              elif arg.type.is_pyobject and not env.nogil:
                  if arg.nonlocally_immutable():
                      # plain local variables are ok
                      pass
                  else:
                      # we do not safely own the argument's reference,
                      # but we must make sure it cannot be collected
                      # before we return from the function, so we create
                      # an owned temp reference to it
                      if i > 0:  # first argument doesn't matter
                          some_args_in_temps = True
                      arg = arg.coerce_to_temp(env)
              self.args[i] = arg
  
          if some_args_in_temps:
              # if some args are temps and others are not, they may get
              # constructed in the wrong order (temps first) => make
              # sure they are either all temps or all not temps (except
              # for the last argument, which is evaluated last in any
              # case)
              for i in range(actual_nargs-1):
                  arg = self.args[i]
                  if arg.nonlocally_immutable():
                      # locals, C functions, unassignable types are safe.
                      pass
                  elif arg.type.is_cpp_class:
                      # Assignment has side effects, avoid.
                      pass
                  elif env.nogil and arg.type.is_pyobject:
                      # can't copy a Python reference into a temp in nogil
                      # env (this is safe: a construction would fail in
                      # nogil anyway)
                      pass
                  else:
                      #self.args[i] = arg.coerce_to_temp(env)
                      # instead: issue a warning
                      if i > 0:
                          warning(arg.pos, "Argument evaluation order in C function call is undefined and may not be as expected", 0)
                          break
          return self
  
      def generate_result_code(self, code):
          arg_code = [self.function_name.py_result()]
          func_type = self.function.def_node
          for arg, proto_arg in zip(self.args, func_type.args):
              if arg.type.is_pyobject:
                  arg_code.append(arg.result_as(proto_arg.type))
              else:
                  arg_code.append(arg.result())
          arg_code = ', '.join(arg_code)
          code.putln(
              "%s = %s(%s); %s" % (
                  self.result(),
                  self.function.def_node.entry.pyfunc_cname,
                  arg_code,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class PythonCapiFunctionNode(ExprNode):
      subexprs = []
  
      def __init__(self, pos, py_name, cname, func_type, utility_code = None):
          ExprNode.__init__(self, pos, name=py_name, cname=cname,
                            type=func_type, utility_code=utility_code)
  
      def analyse_types(self, env):
          return self
  
      def generate_result_code(self, code):
          if self.utility_code:
              code.globalstate.use_utility_code(self.utility_code)
  
      def calculate_result_code(self):
          return self.cname
  
  
  class PythonCapiCallNode(SimpleCallNode):
      # Python C-API Function call (only created in transforms)
  
      # By default, we assume that the call never returns None, as this
      # is true for most C-API functions in CPython.  If this does not
      # apply to a call, set the following to True (or None to inherit
      # the default behaviour).
      may_return_none = False
  
      def __init__(self, pos, function_name, func_type,
                   utility_code = None, py_name=None, **kwargs):
          self.type = func_type.return_type
          self.result_ctype = self.type
          self.function = PythonCapiFunctionNode(
              pos, py_name, function_name, func_type,
              utility_code = utility_code)
          # call this last so that we can override the constructed
          # attributes above with explicit keyword arguments if required
          SimpleCallNode.__init__(self, pos, **kwargs)
  
  
  class CachedBuiltinMethodCallNode(CallNode):
      # Python call to a method of a known Python builtin (only created in transforms)
  
      subexprs = ['obj', 'args']
      is_temp = True
  
      def __init__(self, call_node, obj, method_name, args):
          super(CachedBuiltinMethodCallNode, self).__init__(
              call_node.pos,
              obj=obj, method_name=method_name, args=args,
              may_return_none=call_node.may_return_none,
              type=call_node.type)
  
      def may_be_none(self):
          if self.may_return_none is not None:
              return self.may_return_none
          return ExprNode.may_be_none(self)
  
      def generate_result_code(self, code):
          type_cname = self.obj.type.cname
          obj_cname = self.obj.py_result()
          args = [arg.py_result() for arg in self.args]
          call_code = code.globalstate.cached_unbound_method_call_code(
              obj_cname, type_cname, self.method_name, args)
          code.putln("%s = %s; %s" % (
              self.result(), call_code,
              code.error_goto_if_null(self.result(), self.pos)
          ))
          self.generate_gotref(code)
  
  
  class GeneralCallNode(CallNode):
      #  General Python function call, including keyword,
      #  * and ** arguments.
      #
      #  function         ExprNode
      #  positional_args  ExprNode          Tuple of positional arguments
      #  keyword_args     ExprNode or None  Dict of keyword arguments
  
      type = py_object_type
  
      subexprs = ['function', 'positional_args', 'keyword_args']
  
      nogil_check = Node.gil_error
  
      def compile_time_value(self, denv):
          function = self.function.compile_time_value(denv)
          positional_args = self.positional_args.compile_time_value(denv)
          keyword_args = self.keyword_args.compile_time_value(denv)
          try:
              return function(*positional_args, **keyword_args)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def explicit_args_kwds(self):
          if (self.keyword_args and not self.keyword_args.is_dict_literal or
                  not self.positional_args.is_sequence_constructor):
              raise CompileError(self.pos,
                  'Compile-time keyword arguments must be explicit.')
          return self.positional_args.args, self.keyword_args
  
      def analyse_types(self, env):
          if self.analyse_as_type_constructor(env):
              return self
          self.function = self.function.analyse_types(env)
          if not self.function.type.is_pyobject:
              if self.function.type.is_error:
                  self.type = error_type
                  return self
              if hasattr(self.function, 'entry'):
                  node = self.map_to_simple_call_node()
                  if node is not None and node is not self:
                      return node.analyse_types(env)
                  elif self.function.entry.as_variable:
                      self.function = self.function.coerce_to_pyobject(env)
                  elif node is self:
                      error(self.pos,
                            "Non-trivial keyword arguments and starred "
                            "arguments not allowed in cdef functions.")
                  else:
                      # error was already reported
                      pass
              else:
                  self.function = self.function.coerce_to_pyobject(env)
          if self.keyword_args:
              self.keyword_args = self.keyword_args.analyse_types(env)
          self.positional_args = self.positional_args.analyse_types(env)
          self.positional_args = \
              self.positional_args.coerce_to_pyobject(env)
          self.set_py_result_type(self.function)
          self.is_temp = 1
          return self
  
      def map_to_simple_call_node(self):
          """
          Tries to map keyword arguments to declared positional arguments.
          Returns self to try a Python call, None to report an error
          or a SimpleCallNode if the mapping succeeds.
          """
          if not isinstance(self.positional_args, TupleNode):
              # has starred argument
              return self
          if not self.keyword_args.is_dict_literal:
              # keywords come from arbitrary expression => nothing to do here
              return self
          function = self.function
          entry = getattr(function, 'entry', None)
          if not entry:
              return self
          function_type = entry.type
          if function_type.is_ptr:
              function_type = function_type.base_type
          if not function_type.is_cfunction:
              return self
  
          pos_args = self.positional_args.args
          kwargs = self.keyword_args
          declared_args = function_type.args
          if entry.is_cmethod:
              declared_args = declared_args[1:]  # skip 'self'
  
          if len(pos_args) > len(declared_args):
              error(self.pos, "function call got too many positional arguments, "
                              "expected %d, got %s" % (len(declared_args),
                                                       len(pos_args)))
              return None
  
          matched_args = {
              arg.name for arg in declared_args[:len(pos_args)]
              if arg.name
          }
          unmatched_args = declared_args[len(pos_args):]
          matched_kwargs_count = 0
          args = list(pos_args)
  
          # check for duplicate keywords
          seen = set(matched_args)
          has_errors = False
          for arg in kwargs.key_value_pairs:
              name = arg.key.value
              if name in seen:
                  error(arg.pos, "argument '%s' passed twice" % name)
                  has_errors = True
                  # continue to report more errors if there are any
              seen.add(name)
  
          # match keywords that are passed in order
          for decl_arg, arg in zip(unmatched_args, kwargs.key_value_pairs):
              name = arg.key.value
              if decl_arg.name == name:
                  matched_args.add(name)
                  matched_kwargs_count += 1
                  args.append(arg.value)
              else:
                  break
  
          # match keyword arguments that are passed out-of-order, but keep
          # the evaluation of non-simple arguments in order by moving them
          # into temps
          from .UtilNodes import EvalWithTempExprNode, LetRefNode
          temps = []
          if len(kwargs.key_value_pairs) > matched_kwargs_count:
              unmatched_args = declared_args[len(args):]
              keywords = dict([ (arg.key.value, (i+len(pos_args), arg))
                                for i, arg in enumerate(kwargs.key_value_pairs) ])
              first_missing_keyword = None
              for decl_arg in unmatched_args:
                  name = decl_arg.name
                  if name not in keywords:
                      # missing keyword argument => either done or error
                      if not first_missing_keyword:
                          first_missing_keyword = name
                      continue
                  elif first_missing_keyword:
                      if entry.as_variable:
                          # we might be able to convert the function to a Python
                          # object, which then allows full calling semantics
                          # with default values in gaps - currently, we only
                          # support optional arguments at the end
                          return self
                      # wasn't the last keyword => gaps are not supported
                      error(self.pos, "C function call is missing "
                                      "argument '%s'" % first_missing_keyword)
                      return None
                  pos, arg = keywords[name]
                  matched_args.add(name)
                  matched_kwargs_count += 1
                  if arg.value.is_simple():
                      args.append(arg.value)
                  else:
                      temp = LetRefNode(arg.value)
                      assert temp.is_simple()
                      args.append(temp)
                      temps.append((pos, temp))
  
              if temps:
                  # may have to move preceding non-simple args into temps
                  final_args = []
                  new_temps = []
                  first_temp_arg = temps[0][-1]
                  for arg_value in args:
                      if arg_value is first_temp_arg:
                          break  # done
                      if arg_value.is_simple():
                          final_args.append(arg_value)
                      else:
                          temp = LetRefNode(arg_value)
                          new_temps.append(temp)
                          final_args.append(temp)
                  if new_temps:
                      args = final_args
                  temps = new_temps + [ arg for i,arg in sorted(temps) ]
  
          # check for unexpected keywords
          for arg in kwargs.key_value_pairs:
              name = arg.key.value
              if name not in matched_args:
                  has_errors = True
                  error(arg.pos,
                        "C function got unexpected keyword argument '%s'" %
                        name)
  
          if has_errors:
              # error was reported already
              return None
  
          # all keywords mapped to positional arguments
          # if we are missing arguments, SimpleCallNode will figure it out
          node = SimpleCallNode(self.pos, function=function, args=args)
          for temp in temps[::-1]:
              node = EvalWithTempExprNode(temp, node)
          return node
  
      def generate_result_code(self, code):
          if self.type.is_error: return
          if self.keyword_args:
              kwargs = self.keyword_args.py_result()
          else:
              kwargs = 'NULL'
          code.globalstate.use_utility_code(UtilityCode.load_cached(
              "PyObjectCall", "ObjectHandling.c"))
          code.putln(
              "%s = __Pyx_PyObject_Call(%s, %s, %s); %s" % (
                  self.result(),
                  self.function.py_result(),
                  self.positional_args.py_result(),
                  kwargs,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class AsTupleNode(ExprNode):
      #  Convert argument to tuple. Used for normalising
      #  the * argument of a function call.
      #
      #  arg    ExprNode
  
      subexprs = ['arg']
      is_temp = 1
  
      def calculate_constant_result(self):
          self.constant_result = tuple(self.arg.constant_result)
  
      def compile_time_value(self, denv):
          arg = self.arg.compile_time_value(denv)
          try:
              return tuple(arg)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def analyse_types(self, env):
          self.arg = self.arg.analyse_types(env).coerce_to_pyobject(env)
          if self.arg.type is tuple_type:
              return self.arg.as_none_safe_node("'NoneType' object is not iterable")
          self.type = tuple_type
          return self
  
      def may_be_none(self):
          return False
  
      nogil_check = Node.gil_error
      gil_message = "Constructing Python tuple"
  
      def generate_result_code(self, code):
          cfunc = "__Pyx_PySequence_Tuple" if self.arg.type in (py_object_type, tuple_type) else "PySequence_Tuple"
          code.putln(
              "%s = %s(%s); %s" % (
                  self.result(),
                  cfunc, self.arg.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class MergedDictNode(ExprNode):
      #  Helper class for keyword arguments and other merged dicts.
      #
      #  keyword_args      [DictNode or other ExprNode]
  
      subexprs = ['keyword_args']
      is_temp = 1
      type = dict_type
      reject_duplicates = True
  
      def calculate_constant_result(self):
          result = {}
          reject_duplicates = self.reject_duplicates
          for item in self.keyword_args:
              if item.is_dict_literal:
                  # process items in order
                  items = ((key.constant_result, value.constant_result)
                           for key, value in item.key_value_pairs)
              else:
                  items = item.constant_result.iteritems()
  
              for key, value in items:
                  if reject_duplicates and key in result:
                      raise ValueError("duplicate keyword argument found: %s" % key)
                  result[key] = value
  
          self.constant_result = result
  
      def compile_time_value(self, denv):
          result = {}
          reject_duplicates = self.reject_duplicates
          for item in self.keyword_args:
              if item.is_dict_literal:
                  # process items in order
                  items = [(key.compile_time_value(denv), value.compile_time_value(denv))
                           for key, value in item.key_value_pairs]
              else:
                  items = item.compile_time_value(denv).iteritems()
  
              try:
                  for key, value in items:
                      if reject_duplicates and key in result:
                          raise ValueError("duplicate keyword argument found: %s" % key)
                      result[key] = value
              except Exception as e:
                  self.compile_time_value_error(e)
          return result
  
      def type_dependencies(self, env):
          return ()
  
      def infer_type(self, env):
          return dict_type
  
      def analyse_types(self, env):
          self.keyword_args = [
              arg.analyse_types(env).coerce_to_pyobject(env).as_none_safe_node(
                  # FIXME: CPython's error message starts with the runtime function name
                  'argument after ** must be a mapping, not NoneType')
              for arg in self.keyword_args
          ]
  
          return self
  
      def may_be_none(self):
          return False
  
      gil_message = "Constructing Python dict"
  
      def generate_evaluation_code(self, code):
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
  
          args = iter(self.keyword_args)
          item = next(args)
          item.generate_evaluation_code(code)
          if item.type is not dict_type:
              # CPython supports calling functions with non-dicts, so do we
              code.putln('if (likely(PyDict_CheckExact(%s))) {' %
                         item.py_result())
  
          if item.is_dict_literal:
              item.make_owned_reference(code)
              code.putln("%s = %s;" % (self.result(), item.py_result()))
              item.generate_post_assignment_code(code)
          else:
              code.putln("%s = PyDict_Copy(%s); %s" % (
                  self.result(),
                  item.py_result(),
                  code.error_goto_if_null(self.result(), item.pos)))
              self.generate_gotref(code)
              item.generate_disposal_code(code)
  
          if item.type is not dict_type:
              code.putln('} else {')
              code.globalstate.use_utility_code(UtilityCode.load_cached(
                  "PyObjectCallOneArg", "ObjectHandling.c"))
              code.putln("%s = __Pyx_PyObject_CallOneArg((PyObject*)&PyDict_Type, %s); %s" % (
                  self.result(),
                  item.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
              item.generate_disposal_code(code)
              code.putln('}')
          item.free_temps(code)
  
          helpers = set()
          for item in args:
              if item.is_dict_literal:
                  # inline update instead of creating an intermediate dict
                  for arg in item.key_value_pairs:
                      arg.generate_evaluation_code(code)
                      if self.reject_duplicates:
                          code.putln("if (unlikely(PyDict_Contains(%s, %s))) {" % (
                              self.result(),
                              arg.key.py_result()))
                          helpers.add("RaiseDoubleKeywords")
                          # FIXME: find out function name at runtime!
                          code.putln('__Pyx_RaiseDoubleKeywordsError("function", %s); %s' % (
                              arg.key.py_result(),
                              code.error_goto(self.pos)))
                          code.putln("}")
                      code.put_error_if_neg(arg.key.pos, "PyDict_SetItem(%s, %s, %s)" % (
                          self.result(),
                          arg.key.py_result(),
                          arg.value.py_result()))
                      arg.generate_disposal_code(code)
                      arg.free_temps(code)
              else:
                  item.generate_evaluation_code(code)
                  if self.reject_duplicates:
                      # merge mapping into kwdict one by one as we need to check for duplicates
                      helpers.add("MergeKeywords")
                      code.put_error_if_neg(item.pos, "__Pyx_MergeKeywords(%s, %s)" % (
                          self.result(), item.py_result()))
                  else:
                      # simple case, just add all entries
                      helpers.add("RaiseMappingExpected")
                      code.putln("if (unlikely(PyDict_Update(%s, %s) < 0)) {" % (
                          self.result(), item.py_result()))
                      code.putln("if (PyErr_ExceptionMatches(PyExc_AttributeError)) "
                                 "__Pyx_RaiseMappingExpectedError(%s);" % item.py_result())
                      code.putln(code.error_goto(item.pos))
                      code.putln("}")
                  item.generate_disposal_code(code)
                  item.free_temps(code)
  
          for helper in sorted(helpers):
              code.globalstate.use_utility_code(UtilityCode.load_cached(helper, "FunctionArguments.c"))
  
      def annotate(self, code):
          for item in self.keyword_args:
              item.annotate(code)
  
  
  class AttributeNode(ExprNode):
      #  obj.attribute
      #
      #  obj          ExprNode
      #  attribute    string
      #  needs_none_check boolean        Used if obj is an extension type.
      #                                  If set to True, it is known that the type is not None.
      #
      #  Used internally:
      #
      #  is_py_attr           boolean   Is a Python getattr operation
      #  member               string    C name of struct member
      #  is_called            boolean   Function call is being done on result
      #  entry                Entry     Symbol table entry of attribute
  
      is_attribute = 1
      subexprs = ['obj']
  
      type = PyrexTypes.error_type
      entry = None
      is_called = 0
      needs_none_check = True
      is_memslice_transpose = False
      is_special_lookup = False
      is_py_attr = 0
  
      def as_cython_attribute(self):
          if (isinstance(self.obj, NameNode) and
                  self.obj.is_cython_module and not
                  self.attribute == u"parallel"):
              return self.attribute
  
          cy = self.obj.as_cython_attribute()
          if cy:
              return "%s.%s" % (cy, self.attribute)
          return None
  
      def coerce_to(self, dst_type, env):
          #  If coercing to a generic pyobject and this is a cpdef function
          #  we can create the corresponding attribute
          if dst_type is py_object_type:
              entry = self.entry
              if entry and entry.is_cfunction and entry.as_variable:
                  # must be a cpdef function
                  self.is_temp = 1
                  self.entry = entry.as_variable
                  self.analyse_as_python_attribute(env)
                  return self
          return ExprNode.coerce_to(self, dst_type, env)
  
      def calculate_constant_result(self):
          attr = self.attribute
          if attr.startswith("__") and attr.endswith("__"):
              return
          self.constant_result = getattr(self.obj.constant_result, attr)
  
      def compile_time_value(self, denv):
          attr = self.attribute
          if attr.startswith("__") and attr.endswith("__"):
              error(self.pos,
                    "Invalid attribute name '%s' in compile-time expression" % attr)
              return None
          obj = self.obj.compile_time_value(denv)
          try:
              return getattr(obj, attr)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def type_dependencies(self, env):
          return self.obj.type_dependencies(env)
  
      def infer_type(self, env):
          # FIXME: this is way too redundant with analyse_types()
          node = self.analyse_as_cimported_attribute_node(env, target=False)
          if node is not None:
              if node.entry.type and node.entry.type.is_cfunction:
                  # special-case - function converted to pointer
                  return PyrexTypes.CPtrType(node.entry.type)
              else:
                  return node.entry.type
          node = self.analyse_as_type_attribute(env)
          if node is not None:
              return node.entry.type
          obj_type = self.obj.infer_type(env)
          self.analyse_attribute(env, obj_type=obj_type)
          if obj_type.is_builtin_type and self.type.is_cfunction:
              # special case: C-API replacements for C methods of
              # builtin types cannot be inferred as C functions as
              # that would prevent their use as bound methods
              return py_object_type
          elif self.entry and self.entry.is_cmethod:
              # special case: bound methods should not be inferred
              # as their unbound method types
              return py_object_type
          return self.type
  
      def analyse_target_declaration(self, env):
          pass
  
      def analyse_target_types(self, env):
          node = self.analyse_types(env, target = 1)
          if node.type.is_const:
              error(self.pos, "Assignment to const attribute '%s'" % self.attribute)
          if not node.is_lvalue():
              error(self.pos, "Assignment to non-lvalue of type '%s'" % self.type)
          return node
  
      def analyse_types(self, env, target = 0):
          self.initialized_check = env.directives['initializedcheck']
          node = self.analyse_as_cimported_attribute_node(env, target)
          if node is None and not target:
              node = self.analyse_as_type_attribute(env)
          if node is None:
              node = self.analyse_as_ordinary_attribute_node(env, target)
              assert node is not None
          if (node.is_attribute or node.is_name) and node.entry:
              node.entry.used = True
          if node.is_attribute:
              node.wrap_obj_in_nonecheck(env)
          return node
  
      def analyse_as_cimported_attribute_node(self, env, target):
          # Try to interpret this as a reference to an imported
          # C const, type, var or function. If successful, mutates
          # this node into a NameNode and returns 1, otherwise
          # returns 0.
          module_scope = self.obj.analyse_as_module(env)
          if module_scope:
              entry = module_scope.lookup_here(self.attribute)
              if entry and (
                      entry.is_cglobal or entry.is_cfunction
                      or entry.is_type or entry.is_const):
                  return self.as_name_node(env, entry, target)
              if self.is_cimported_module_without_shadow(env):
                  error(self.pos, "cimported module has no attribute '%s'" % self.attribute)
                  return self
          return None
  
      def analyse_as_type_attribute(self, env):
          # Try to interpret this as a reference to an unbound
          # C method of an extension type or builtin type.  If successful,
          # creates a corresponding NameNode and returns it, otherwise
          # returns None.
          if self.obj.is_string_literal:
              return
          type = self.obj.analyse_as_type(env)
          if type:
              if type.is_extension_type or type.is_builtin_type or type.is_cpp_class:
                  entry = type.scope.lookup_here(self.attribute)
                  if entry and (entry.is_cmethod or type.is_cpp_class and entry.type.is_cfunction):
                      if type.is_builtin_type:
                          if not self.is_called:
                              # must handle this as Python object
                              return None
                          ubcm_entry = entry
                      else:
                          # Create a temporary entry describing the C method
                          # as an ordinary function.
                          if entry.func_cname and not hasattr(entry.type, 'op_arg_struct'):
                              cname = entry.func_cname
                              if entry.type.is_static_method or (
                                      env.parent_scope and env.parent_scope.is_cpp_class_scope):
                                  ctype = entry.type
                              elif type.is_cpp_class:
                                  error(self.pos, "%s not a static member of %s" % (entry.name, type))
                                  ctype = PyrexTypes.error_type
                              else:
                                  # Fix self type.
                                  ctype = copy.copy(entry.type)
                                  ctype.args = ctype.args[:]
                                  ctype.args[0] = PyrexTypes.CFuncTypeArg('self', type, 'self', None)
                          else:
                              cname = "%s->%s" % (type.vtabptr_cname, entry.cname)
                              ctype = entry.type
                          ubcm_entry = Symtab.Entry(entry.name, cname, ctype)
                          ubcm_entry.is_cfunction = 1
                          ubcm_entry.func_cname = entry.func_cname
                          ubcm_entry.is_unbound_cmethod = 1
                          ubcm_entry.scope = entry.scope
                      return self.as_name_node(env, ubcm_entry, target=False)
              elif type.is_enum or type.is_cpp_enum:
                  if self.attribute in type.values:
                      for entry in type.entry.enum_values:
                          if entry.name == self.attribute:
                              return self.as_name_node(env, entry, target=False)
                      else:
                          error(self.pos, "%s not a known value of %s" % (self.attribute, type))
                  else:
                      error(self.pos, "%s not a known value of %s" % (self.attribute, type))
          return None
  
      def analyse_as_type(self, env):
          module_scope = self.obj.analyse_as_module(env)
          if module_scope:
              return module_scope.lookup_type(self.attribute)
          if not self.obj.is_string_literal:
              base_type = self.obj.analyse_as_type(env)
              if base_type and getattr(base_type, 'scope', None) is not None:
                  return base_type.scope.lookup_type(self.attribute)
          return None
  
      def analyse_as_extension_type(self, env):
          # Try to interpret this as a reference to an extension type
          # in a cimported module. Returns the extension type, or None.
          module_scope = self.obj.analyse_as_module(env)
          if module_scope:
              entry = module_scope.lookup_here(self.attribute)
              if entry and entry.is_type:
                  if entry.type.is_extension_type or entry.type.is_builtin_type:
                      return entry.type
          return None
  
      def analyse_as_module(self, env):
          # Try to interpret this as a reference to a cimported module
          # in another cimported module. Returns the module scope, or None.
          module_scope = self.obj.analyse_as_module(env)
          if module_scope:
              entry = module_scope.lookup_here(self.attribute)
              if entry and entry.as_module:
                  return entry.as_module
          return None
  
      def as_name_node(self, env, entry, target):
          # Create a corresponding NameNode from this node and complete the
          # analyse_types phase.
          node = NameNode.from_node(self, name=self.attribute, entry=entry)
          if target:
              node = node.analyse_target_types(env)
          else:
              node = node.analyse_rvalue_entry(env)
          node.entry.used = 1
          return node
  
      def analyse_as_ordinary_attribute_node(self, env, target):
          self.obj = self.obj.analyse_types(env)
          self.analyse_attribute(env)
          if self.entry and self.entry.is_cmethod and not self.is_called:
  #            error(self.pos, "C method can only be called")
              pass
          ## Reference to C array turns into pointer to first element.
          #while self.type.is_array:
          #    self.type = self.type.element_ptr_type()
          if self.is_py_attr:
              if not target:
                  self.is_temp = 1
                  self.result_ctype = py_object_type
          elif target and self.obj.type.is_builtin_type:
              error(self.pos, "Assignment to an immutable object field")
          elif self.entry and self.entry.is_cproperty:
              if not target:
                  return SimpleCallNode.for_cproperty(self.pos, self.obj, self.entry).analyse_types(env)
              # TODO: implement writable C-properties?
              error(self.pos, "Assignment to a read-only property")
          #elif self.type.is_memoryviewslice and not target:
          #    self.is_temp = True
          return self
  
      def analyse_attribute(self, env, obj_type = None):
          # Look up attribute and set self.type and self.member.
          immutable_obj = obj_type is not None  # used during type inference
          self.is_py_attr = 0
          self.member = self.attribute
          if obj_type is None:
              if self.obj.type.is_string or self.obj.type.is_pyunicode_ptr:
                  self.obj = self.obj.coerce_to_pyobject(env)
              obj_type = self.obj.type
          else:
              if obj_type.is_string or obj_type.is_pyunicode_ptr:
                  obj_type = py_object_type
          if obj_type.is_ptr or obj_type.is_array:
              obj_type = obj_type.base_type
              self.op = "->"
          elif obj_type.is_extension_type or obj_type.is_builtin_type:
              self.op = "->"
          elif obj_type.is_reference and obj_type.is_fake_reference:
              self.op = "->"
          else:
              self.op = "."
          if obj_type.has_attributes:
              if obj_type.attributes_known():
                  entry = obj_type.scope.lookup_here(self.attribute)
                  if obj_type.is_memoryviewslice and not entry:
                      if self.attribute == 'T':
                          self.is_memslice_transpose = True
                          self.is_temp = True
                          self.use_managed_ref = True
                          self.type = self.obj.type.transpose(self.pos)
                          return
                      else:
                          obj_type.declare_attribute(self.attribute, env, self.pos)
                          entry = obj_type.scope.lookup_here(self.attribute)
                  if entry and entry.is_member:
                      entry = None
              else:
                  error(self.pos,
                      "Cannot select attribute of incomplete type '%s'"
                      % obj_type)
                  self.type = PyrexTypes.error_type
                  return
              self.entry = entry
              if entry:
                  if obj_type.is_extension_type and entry.name == "__weakref__":
                      error(self.pos, "Illegal use of special attribute __weakref__")
  
                  # def methods need the normal attribute lookup
                  # because they do not have struct entries
                  # fused function go through assignment synthesis
                  # (foo = pycfunction(foo_func_obj)) and need to go through
                  # regular Python lookup as well
                  if entry.is_cproperty:
                      self.type = entry.type
                      return
                  elif (entry.is_variable and not entry.fused_cfunction) or entry.is_cmethod:
                      self.type = entry.type
                      self.member = entry.cname
                      return
                  else:
                      # If it's not a variable or C method, it must be a Python
                      # method of an extension type, so we treat it like a Python
                      # attribute.
                      pass
          # If we get here, the base object is not a struct/union/extension
          # type, or it is an extension type and the attribute is either not
          # declared or is declared as a Python method. Treat it as a Python
          # attribute reference.
          self.analyse_as_python_attribute(env, obj_type, immutable_obj)
  
      def analyse_as_python_attribute(self, env, obj_type=None, immutable_obj=False):
          if obj_type is None:
              obj_type = self.obj.type
          # mangle private '__*' Python attributes used inside of a class
          self.attribute = env.mangle_class_private_name(self.attribute)
          self.member = self.attribute
          self.type = py_object_type
          self.is_py_attr = 1
  
          if not obj_type.is_pyobject and not obj_type.is_error:
              # Expose python methods for immutable objects.
              if (obj_type.is_string or obj_type.is_cpp_string
                      or obj_type.is_buffer or obj_type.is_memoryviewslice
                      or obj_type.is_numeric
                      or (obj_type.is_ctuple and obj_type.can_coerce_to_pyobject(env))
                      or (obj_type.is_struct and obj_type.can_coerce_to_pyobject(env))):
                  if not immutable_obj:
                      self.obj = self.obj.coerce_to_pyobject(env)
              elif (obj_type.is_cfunction and (self.obj.is_name or self.obj.is_attribute)
                      and self.obj.entry.as_variable
                      and self.obj.entry.as_variable.type.is_pyobject):
                  # might be an optimised builtin function => unpack it
                  if not immutable_obj:
                      self.obj = self.obj.coerce_to_pyobject(env)
              else:
                  error(self.pos,
                        "Object of type '%s' has no attribute '%s'" %
                        (obj_type, self.attribute))
  
      def wrap_obj_in_nonecheck(self, env):
          if not env.directives['nonecheck']:
              return
  
          msg = None
          format_args = ()
          if (self.obj.type.is_extension_type and self.needs_none_check and not
                  self.is_py_attr):
              msg = "'NoneType' object has no attribute '%{0}s'".format('.30' if len(self.attribute) <= 30 else '')
              format_args = (self.attribute,)
          elif self.obj.type.is_memoryviewslice:
              if self.is_memslice_transpose:
                  msg = "Cannot transpose None memoryview slice"
              else:
                  entry = self.obj.type.scope.lookup_here(self.attribute)
                  if entry:
                      # copy/is_c_contig/shape/strides etc
                      msg = "Cannot access '%s' attribute of None memoryview slice"
                      format_args = (entry.name,)
  
          if msg:
              self.obj = self.obj.as_none_safe_node(msg, 'PyExc_AttributeError',
                                                    format_args=format_args)
  
      def nogil_check(self, env):
          if self.is_py_attr:
              self.gil_error()
  
      gil_message = "Accessing Python attribute"
  
      def is_cimported_module_without_shadow(self, env):
          return self.obj.is_cimported_module_without_shadow(env)
  
      def is_simple(self):
          if self.obj:
              return self.result_in_temp() or self.obj.is_simple()
          else:
              return NameNode.is_simple(self)
  
      def is_lvalue(self):
          if self.obj:
              return True
          else:
              return NameNode.is_lvalue(self)
  
      def is_ephemeral(self):
          if self.obj:
              return self.obj.is_ephemeral()
          else:
              return NameNode.is_ephemeral(self)
  
      def calculate_result_code(self):
          #print "AttributeNode.calculate_result_code:", self.member ###
          #print "...obj node =", self.obj, "code", self.obj.result() ###
          #print "...obj type", self.obj.type, "ctype", self.obj.ctype() ###
          obj = self.obj
          obj_code = obj.result_as(obj.type)
          #print "...obj_code =", obj_code ###
          if self.entry and self.entry.is_cmethod:
              if obj.type.is_extension_type and not self.entry.is_builtin_cmethod:
                  if self.entry.final_func_cname:
                      return self.entry.final_func_cname
  
                  if self.type.from_fused:
                      # If the attribute was specialized through indexing, make
                      # sure to get the right fused name, as our entry was
                      # replaced by our parent index node
                      # (AnalyseExpressionsTransform)
                      self.member = self.entry.cname
  
                  return "((struct %s *)%s%s%s)->%s" % (
                      obj.type.vtabstruct_cname, obj_code, self.op,
                      obj.type.vtabslot_cname, self.member)
              elif self.result_is_used:
                  return self.member
              # Generating no code at all for unused access to optimised builtin
              # methods fixes the problem that some optimisations only exist as
              # macros, i.e. there is no function pointer to them, so we would
              # generate invalid C code here.
              return
          elif obj.type.is_complex:
              return "__Pyx_C%s(%s)" % (self.member.upper(), obj_code)
          else:
              if obj.type.is_builtin_type and self.entry and self.entry.is_variable:
                  # accessing a field of a builtin type, need to cast better than result_as() does
                  obj_code = obj.type.cast_code(obj.result(), to_object_struct = True)
              return "%s%s%s" % (obj_code, self.op, self.member)
  
      def generate_result_code(self, code):
          if self.is_py_attr:
              if self.is_special_lookup:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("PyObjectLookupSpecial", "ObjectHandling.c"))
                  lookup_func_name = '__Pyx_PyObject_LookupSpecial'
              else:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("PyObjectGetAttrStr", "ObjectHandling.c"))
                  lookup_func_name = '__Pyx_PyObject_GetAttrStr'
              code.putln(
                  '%s = %s(%s, %s); %s' % (
                      self.result(),
                      lookup_func_name,
                      self.obj.py_result(),
                      code.intern_identifier(self.attribute),
                      code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
          elif self.type.is_memoryviewslice:
              if self.is_memslice_transpose:
                  # transpose the slice
                  for access, packing in self.type.axes:
                      if access == 'ptr':
                          error(self.pos, "Transposing not supported for slices "
                                          "with indirect dimensions")
                          return
  
                  code.putln("%s = %s;" % (self.result(), self.obj.result()))
                  code.put_incref_memoryviewslice(self.result(), self.type,
                                  have_gil=True)
  
                  T = "__pyx_memslice_transpose(&%s)" % self.result()
                  code.putln(code.error_goto_if_neg(T, self.pos))
              elif self.initialized_check:
                  code.putln(
                      'if (unlikely(!%s.memview)) {'
                          'PyErr_SetString(PyExc_AttributeError,'
                                          '"Memoryview is not initialized");'
                          '%s'
                      '}' % (self.result(), code.error_goto(self.pos)))
          else:
              # result_code contains what is needed, but we may need to insert
              # a check and raise an exception
              if self.obj.type and self.obj.type.is_extension_type:
                  pass
              elif self.entry and self.entry.is_cmethod:
                  # C method implemented as function call with utility code
                  code.globalstate.use_entry_utility_code(self.entry)
  
      def generate_disposal_code(self, code):
          if self.is_temp and self.type.is_memoryviewslice and self.is_memslice_transpose:
              # mirror condition for putting the memview incref here:
              code.put_xdecref_clear(self.result(), self.type, have_gil=True)
          else:
              ExprNode.generate_disposal_code(self, code)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          self.obj.generate_evaluation_code(code)
          if self.is_py_attr:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectSetAttrStr", "ObjectHandling.c"))
              code.put_error_if_neg(self.pos,
                  '__Pyx_PyObject_SetAttrStr(%s, %s, %s)' % (
                      self.obj.py_result(),
                      code.intern_identifier(self.attribute),
                      rhs.py_result()))
              rhs.generate_disposal_code(code)
              rhs.free_temps(code)
          elif self.obj.type.is_complex:
              code.putln("__Pyx_SET_C%s(%s, %s);" % (
                  self.member.upper(),
                  self.obj.result_as(self.obj.type),
                  rhs.result_as(self.ctype())))
              rhs.generate_disposal_code(code)
              rhs.free_temps(code)
          else:
              select_code = self.result()
              if self.type.is_pyobject and self.use_managed_ref:
                  rhs.make_owned_reference(code)
                  rhs.generate_giveref(code)
                  code.put_gotref(select_code, self.type)
                  code.put_decref(select_code, self.ctype())
              elif self.type.is_memoryviewslice:
                  from . import MemoryView
                  MemoryView.put_assign_to_memviewslice(
                          select_code, rhs, rhs.result(), self.type, code)
  
              if not self.type.is_memoryviewslice:
                  code.putln(
                      "%s = %s;" % (
                          select_code,
                          rhs.move_result_rhs_as(self.ctype())))
                          #rhs.result()))
              rhs.generate_post_assignment_code(code)
              rhs.free_temps(code)
          self.obj.generate_disposal_code(code)
          self.obj.free_temps(code)
  
      def generate_deletion_code(self, code, ignore_nonexisting=False):
          self.obj.generate_evaluation_code(code)
          if self.is_py_attr or (self.entry.scope.is_property_scope
                                 and u'__del__' in self.entry.scope.entries):
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("PyObjectSetAttrStr", "ObjectHandling.c"))
              code.put_error_if_neg(self.pos,
                  '__Pyx_PyObject_DelAttrStr(%s, %s)' % (
                      self.obj.py_result(),
                      code.intern_identifier(self.attribute)))
          else:
              error(self.pos, "Cannot delete C attribute of extension type")
          self.obj.generate_disposal_code(code)
          self.obj.free_temps(code)
  
      def annotate(self, code):
          if self.is_py_attr:
              style, text = 'py_attr', 'python attribute (%s)'
          else:
              style, text = 'c_attr', 'c attribute (%s)'
          code.annotate(self.pos, AnnotationItem(style, text % self.type, size=len(self.attribute)))
  
  
  #-------------------------------------------------------------------
  #
  #  Constructor nodes
  #
  #-------------------------------------------------------------------
  
  class StarredUnpackingNode(ExprNode):
      #  A starred expression like "*a"
      #
      #  This is only allowed in sequence assignment or construction such as
      #
      #      a, *b = (1,2,3,4)    =>     a = 1 ; b = [2,3,4]
      #
      #  and will be special cased during type analysis (or generate an error
      #  if it's found at unexpected places).
      #
      #  target          ExprNode
  
      subexprs = ['target']
      is_starred = 1
      type = py_object_type
      is_temp = 1
      starred_expr_allowed_here = False
  
      def __init__(self, pos, target):
          ExprNode.__init__(self, pos, target=target)
  
      def analyse_declarations(self, env):
          if not self.starred_expr_allowed_here:
              error(self.pos, "starred expression is not allowed here")
          self.target.analyse_declarations(env)
  
      def infer_type(self, env):
          return self.target.infer_type(env)
  
      def analyse_types(self, env):
          if not self.starred_expr_allowed_here:
              error(self.pos, "starred expression is not allowed here")
          self.target = self.target.analyse_types(env)
          self.type = self.target.type
          return self
  
      def analyse_target_declaration(self, env):
          self.target.analyse_target_declaration(env)
  
      def analyse_target_types(self, env):
          self.target = self.target.analyse_target_types(env)
          self.type = self.target.type
          return self
  
      def calculate_result_code(self):
          return ""
  
      def generate_result_code(self, code):
          pass
  
  
  class SequenceNode(ExprNode):
      #  Base class for list and tuple constructor nodes.
      #  Contains common code for performing sequence unpacking.
      #
      #  args                    [ExprNode]
      #  unpacked_items          [ExprNode] or None
      #  coerced_unpacked_items  [ExprNode] or None
      # mult_factor              ExprNode     the integer number of content repetitions ([1,2]*3)
  
      subexprs = ['args', 'mult_factor']
  
      is_sequence_constructor = 1
      unpacked_items = None
      mult_factor = None
      slow = False  # trade speed for code size (e.g. use PyTuple_Pack())
  
      def compile_time_value_list(self, denv):
          return [arg.compile_time_value(denv) for arg in self.args]
  
      def replace_starred_target_node(self):
          # replace a starred node in the targets by the contained expression
          self.starred_assignment = False
          args = []
          for arg in self.args:
              if arg.is_starred:
                  if self.starred_assignment:
                      error(arg.pos, "more than 1 starred expression in assignment")
                  self.starred_assignment = True
                  arg = arg.target
                  arg.is_starred = True
              args.append(arg)
          self.args = args
  
      def analyse_target_declaration(self, env):
          self.replace_starred_target_node()
          for arg in self.args:
              arg.analyse_target_declaration(env)
  
      def analyse_types(self, env, skip_children=False):
          for i, arg in enumerate(self.args):
              if not skip_children:
                  arg = arg.analyse_types(env)
              self.args[i] = arg.coerce_to_pyobject(env)
          if self.mult_factor:
              self.mult_factor = self.mult_factor.analyse_types(env)
              if not self.mult_factor.type.is_int:
                  self.mult_factor = self.mult_factor.coerce_to_pyobject(env)
          self.is_temp = 1
          # not setting self.type here, subtypes do this
          return self
  
      def coerce_to_ctuple(self, dst_type, env):
          if self.type == dst_type:
              return self
          assert not self.mult_factor
          if len(self.args) != dst_type.size:
              error(self.pos, "trying to coerce sequence to ctuple of wrong length, expected %d, got %d" % (
                  dst_type.size, len(self.args)))
          coerced_args = [arg.coerce_to(type, env) for arg, type in zip(self.args, dst_type.components)]
          return TupleNode(self.pos, args=coerced_args, type=dst_type, is_temp=True)
  
      def _create_merge_node_if_necessary(self, env):
          self._flatten_starred_args()
          if not any(arg.is_starred for arg in self.args):
              return self
          # convert into MergedSequenceNode by building partial sequences
          args = []
          values = []
          for arg in self.args:
              if arg.is_starred:
                  if values:
                      args.append(TupleNode(values[0].pos, args=values).analyse_types(env, skip_children=True))
                      values = []
                  args.append(arg.target)
              else:
                  values.append(arg)
          if values:
              args.append(TupleNode(values[0].pos, args=values).analyse_types(env, skip_children=True))
          node = MergedSequenceNode(self.pos, args, self.type)
          if self.mult_factor:
              node = binop_node(
                  self.pos, '*', node, self.mult_factor.coerce_to_pyobject(env),
                  inplace=True, type=self.type, is_temp=True)
          return node
  
      def _flatten_starred_args(self):
          args = []
          for arg in self.args:
              if arg.is_starred and arg.target.is_sequence_constructor and not arg.target.mult_factor:
                  args.extend(arg.target.args)
              else:
                  args.append(arg)
          self.args[:] = args
  
      def may_be_none(self):
          return False
  
      def analyse_target_types(self, env):
          if self.mult_factor:
              error(self.pos, "can't assign to multiplied sequence")
          self.unpacked_items = []
          self.coerced_unpacked_items = []
          self.any_coerced_items = False
          for i, arg in enumerate(self.args):
              arg = self.args[i] = arg.analyse_target_types(env)
              if arg.is_starred:
                  if not arg.type.assignable_from(list_type):
                      error(arg.pos,
                            "starred target must have Python object (list) type")
                  if arg.type is py_object_type:
                      arg.type = list_type
              unpacked_item = PyTempNode(self.pos, env)
              coerced_unpacked_item = unpacked_item.coerce_to(arg.type, env)
              if unpacked_item is not coerced_unpacked_item:
                  self.any_coerced_items = True
              self.unpacked_items.append(unpacked_item)
              self.coerced_unpacked_items.append(coerced_unpacked_item)
          self.type = py_object_type
          return self
  
      def generate_result_code(self, code):
          self.generate_operation_code(code)
  
      def generate_sequence_packing_code(self, code, target=None, plain=False):
          if target is None:
              target = self.result()
          size_factor = c_mult = ''
          mult_factor = None
  
          if self.mult_factor and not plain:
              mult_factor = self.mult_factor
              if mult_factor.type.is_int:
                  c_mult = mult_factor.result()
                  if (isinstance(mult_factor.constant_result, _py_int_types) and
                          mult_factor.constant_result > 0):
                      size_factor = ' * %s' % mult_factor.constant_result
                  elif mult_factor.type.signed:
                      size_factor = ' * ((%s<0) ? 0:%s)' % (c_mult, c_mult)
                  else:
                      size_factor = ' * (%s)' % (c_mult,)
  
          if self.type is tuple_type and (self.is_literal or self.slow) and not c_mult:
              # use PyTuple_Pack() to avoid generating huge amounts of one-time code
              code.putln('%s = PyTuple_Pack(%d, %s); %s' % (
                  target,
                  len(self.args),
                  ', '.join(arg.py_result() for arg in self.args),
                  code.error_goto_if_null(target, self.pos)))
              code.put_gotref(target, py_object_type)
          elif self.type.is_ctuple:
              for i, arg in enumerate(self.args):
                  code.putln("%s.f%s = %s;" % (
                      target, i, arg.result()))
          else:
              # build the tuple/list step by step, potentially multiplying it as we go
              if self.type is list_type:
                  create_func, set_item_func = 'PyList_New', 'PyList_SET_ITEM'
              elif self.type is tuple_type:
                  create_func, set_item_func = 'PyTuple_New', 'PyTuple_SET_ITEM'
              else:
                  raise InternalError("sequence packing for unexpected type %s" % self.type)
              arg_count = len(self.args)
              code.putln("%s = %s(%s%s); %s" % (
                  target, create_func, arg_count, size_factor,
                  code.error_goto_if_null(target, self.pos)))
              code.put_gotref(target, py_object_type)
  
              if c_mult:
                  # FIXME: can't use a temp variable here as the code may
                  # end up in the constant building function.  Temps
                  # currently don't work there.
  
                  #counter = code.funcstate.allocate_temp(mult_factor.type, manage_ref=False)
                  counter = Naming.quick_temp_cname
                  code.putln('{ Py_ssize_t %s;' % counter)
                  if arg_count == 1:
                      offset = counter
                  else:
                      offset = '%s * %s' % (counter, arg_count)
                  code.putln('for (%s=0; %s < %s; %s++) {' % (
                      counter, counter, c_mult, counter
                      ))
              else:
                  offset = ''
  
              for i in range(arg_count):
                  arg = self.args[i]
                  if c_mult or not arg.result_in_temp():
                      code.put_incref(arg.result(), arg.ctype())
                  arg.generate_giveref(code)
                  code.putln("%s(%s, %s, %s);" % (
                      set_item_func,
                      target,
                      (offset and i) and ('%s + %s' % (offset, i)) or (offset or i),
                      arg.py_result()))
  
              if c_mult:
                  code.putln('}')
                  #code.funcstate.release_temp(counter)
                  code.putln('}')
  
          if mult_factor is not None and mult_factor.type.is_pyobject:
              code.putln('{ PyObject* %s = PyNumber_InPlaceMultiply(%s, %s); %s' % (
                  Naming.quick_temp_cname, target, mult_factor.py_result(),
                  code.error_goto_if_null(Naming.quick_temp_cname, self.pos)
                  ))
              code.put_gotref(Naming.quick_temp_cname, py_object_type)
              code.put_decref(target, py_object_type)
              code.putln('%s = %s;' % (target, Naming.quick_temp_cname))
              code.putln('}')
  
      def generate_subexpr_disposal_code(self, code):
          if self.mult_factor and self.mult_factor.type.is_int:
              super(SequenceNode, self).generate_subexpr_disposal_code(code)
          elif self.type is tuple_type and (self.is_literal or self.slow):
              super(SequenceNode, self).generate_subexpr_disposal_code(code)
          else:
              # We call generate_post_assignment_code here instead
              # of generate_disposal_code, because values were stored
              # in the tuple using a reference-stealing operation.
              for arg in self.args:
                  arg.generate_post_assignment_code(code)
                  # Should NOT call free_temps -- this is invoked by the default
                  # generate_evaluation_code which will do that.
              if self.mult_factor:
                  self.mult_factor.generate_disposal_code(code)
  
      def generate_assignment_code(self, rhs, code, overloaded_assignment=False,
                                   exception_check=None, exception_value=None):
          if self.starred_assignment:
              self.generate_starred_assignment_code(rhs, code)
          else:
              self.generate_parallel_assignment_code(rhs, code)
  
          for item in self.unpacked_items:
              item.release(code)
          rhs.free_temps(code)
  
      _func_iternext_type = PyrexTypes.CPtrType(PyrexTypes.CFuncType(
          PyrexTypes.py_object_type, [
              PyrexTypes.CFuncTypeArg("it", PyrexTypes.py_object_type, None),
              ]))
  
      def generate_parallel_assignment_code(self, rhs, code):
          # Need to work around the fact that generate_evaluation_code
          # allocates the temps in a rather hacky way -- the assignment
          # is evaluated twice, within each if-block.
          for item in self.unpacked_items:
              item.allocate(code)
          special_unpack = (rhs.type is py_object_type
                            or rhs.type in (tuple_type, list_type)
                            or not rhs.type.is_builtin_type)
          long_enough_for_a_loop = len(self.unpacked_items) > 3
  
          if special_unpack:
              self.generate_special_parallel_unpacking_code(
                  code, rhs, use_loop=long_enough_for_a_loop)
          else:
              code.putln("{")
              self.generate_generic_parallel_unpacking_code(
                  code, rhs, self.unpacked_items, use_loop=long_enough_for_a_loop)
              code.putln("}")
  
          for value_node in self.coerced_unpacked_items:
              value_node.generate_evaluation_code(code)
          for i in range(len(self.args)):
              self.args[i].generate_assignment_code(
                  self.coerced_unpacked_items[i], code)
  
      def generate_special_parallel_unpacking_code(self, code, rhs, use_loop):
          sequence_type_test = '1'
          none_check = "likely(%s != Py_None)" % rhs.py_result()
          if rhs.type is list_type:
              sequence_types = ['List']
              if rhs.may_be_none():
                  sequence_type_test = none_check
          elif rhs.type is tuple_type:
              sequence_types = ['Tuple']
              if rhs.may_be_none():
                  sequence_type_test = none_check
          else:
              sequence_types = ['Tuple', 'List']
              tuple_check = 'likely(PyTuple_CheckExact(%s))' % rhs.py_result()
              list_check  = 'PyList_CheckExact(%s)' % rhs.py_result()
              sequence_type_test = "(%s) || (%s)" % (tuple_check, list_check)
  
          code.putln("if (%s) {" % sequence_type_test)
          code.putln("PyObject* sequence = %s;" % rhs.py_result())
  
          # list/tuple => check size
          code.putln("Py_ssize_t size = __Pyx_PySequence_SIZE(sequence);")
          code.putln("if (unlikely(size != %d)) {" % len(self.args))
          code.globalstate.use_utility_code(raise_too_many_values_to_unpack)
          code.putln("if (size > %d) __Pyx_RaiseTooManyValuesError(%d);" % (
              len(self.args), len(self.args)))
          code.globalstate.use_utility_code(raise_need_more_values_to_unpack)
          code.putln("else if (size >= 0) __Pyx_RaiseNeedMoreValuesError(size);")
          # < 0 => exception
          code.putln(code.error_goto(self.pos))
          code.putln("}")
  
          code.putln("#if CYTHON_ASSUME_SAFE_MACROS && !CYTHON_AVOID_BORROWED_REFS")
          # unpack items from list/tuple in unrolled loop (can't fail)
          if len(sequence_types) == 2:
              code.putln("if (likely(Py%s_CheckExact(sequence))) {" % sequence_types[0])
          for i, item in enumerate(self.unpacked_items):
              code.putln("%s = Py%s_GET_ITEM(sequence, %d); " % (
                  item.result(), sequence_types[0], i))
          if len(sequence_types) == 2:
              code.putln("} else {")
              for i, item in enumerate(self.unpacked_items):
                  code.putln("%s = Py%s_GET_ITEM(sequence, %d); " % (
                      item.result(), sequence_types[1], i))
              code.putln("}")
          for item in self.unpacked_items:
              code.put_incref(item.result(), item.ctype())
  
          code.putln("#else")
          # in non-CPython, use the PySequence protocol (which can fail)
          if not use_loop:
              for i, item in enumerate(self.unpacked_items):
                  code.putln("%s = PySequence_ITEM(sequence, %d); %s" % (
                      item.result(), i,
                      code.error_goto_if_null(item.result(), self.pos)))
                  code.put_gotref(item.result(), item.type)
          else:
              code.putln("{")
              code.putln("Py_ssize_t i;")
              code.putln("PyObject** temps[%s] = {%s};" % (
                  len(self.unpacked_items),
                  ','.join(['&%s' % item.result() for item in self.unpacked_items])))
              code.putln("for (i=0; i < %s; i++) {" % len(self.unpacked_items))
              code.putln("PyObject* item = PySequence_ITEM(sequence, i); %s" % (
                  code.error_goto_if_null('item', self.pos)))
              code.put_gotref('item', py_object_type)
              code.putln("*(temps[i]) = item;")
              code.putln("}")
              code.putln("}")
  
          code.putln("#endif")
          rhs.generate_disposal_code(code)
  
          if sequence_type_test == '1':
              code.putln("}")  # all done
          elif sequence_type_test == none_check:
              # either tuple/list or None => save some code by generating the error directly
              code.putln("} else {")
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("RaiseNoneIterError", "ObjectHandling.c"))
              code.putln("__Pyx_RaiseNoneNotIterableError(); %s" % code.error_goto(self.pos))
              code.putln("}")  # all done
          else:
              code.putln("} else {")  # needs iteration fallback code
              self.generate_generic_parallel_unpacking_code(
                  code, rhs, self.unpacked_items, use_loop=use_loop)
              code.putln("}")
  
      def generate_generic_parallel_unpacking_code(self, code, rhs, unpacked_items, use_loop, terminate=True):
          code.globalstate.use_utility_code(raise_need_more_values_to_unpack)
          code.globalstate.use_utility_code(UtilityCode.load_cached("IterFinish", "ObjectHandling.c"))
          code.putln("Py_ssize_t index = -1;")  # must be at the start of a C block!
  
          if use_loop:
              code.putln("PyObject** temps[%s] = {%s};" % (
                  len(self.unpacked_items),
                  ','.join(['&%s' % item.result() for item in unpacked_items])))
  
          iterator_temp = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
          code.putln(
              "%s = PyObject_GetIter(%s); %s" % (
                  iterator_temp,
                  rhs.py_result(),
                  code.error_goto_if_null(iterator_temp, self.pos)))
          code.put_gotref(iterator_temp, py_object_type)
          rhs.generate_disposal_code(code)
  
          iternext_func = code.funcstate.allocate_temp(self._func_iternext_type, manage_ref=False)
          code.putln("%s = __Pyx_PyObject_GetIterNextFunc(%s);" % (
              iternext_func, iterator_temp))
  
          unpacking_error_label = code.new_label('unpacking_failed')
          unpack_code = "%s(%s)" % (iternext_func, iterator_temp)
          if use_loop:
              code.putln("for (index=0; index < %s; index++) {" % len(unpacked_items))
              code.put("PyObject* item = %s; if (unlikely(!item)) " % unpack_code)
              code.put_goto(unpacking_error_label)
              code.put_gotref("item", py_object_type)
              code.putln("*(temps[index]) = item;")
              code.putln("}")
          else:
              for i, item in enumerate(unpacked_items):
                  code.put(
                      "index = %d; %s = %s; if (unlikely(!%s)) " % (
                          i,
                          item.result(),
                          unpack_code,
                          item.result()))
                  code.put_goto(unpacking_error_label)
                  item.generate_gotref(code)
  
          if terminate:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("UnpackItemEndCheck", "ObjectHandling.c"))
              code.put_error_if_neg(self.pos, "__Pyx_IternextUnpackEndCheck(%s, %d)" % (
                  unpack_code,
                  len(unpacked_items)))
              code.putln("%s = NULL;" % iternext_func)
              code.put_decref_clear(iterator_temp, py_object_type)
  
          unpacking_done_label = code.new_label('unpacking_done')
          code.put_goto(unpacking_done_label)
  
          code.put_label(unpacking_error_label)
          code.put_decref_clear(iterator_temp, py_object_type)
          code.putln("%s = NULL;" % iternext_func)
          code.putln("if (__Pyx_IterFinish() == 0) __Pyx_RaiseNeedMoreValuesError(index);")
          code.putln(code.error_goto(self.pos))
          code.put_label(unpacking_done_label)
  
          code.funcstate.release_temp(iternext_func)
          if terminate:
              code.funcstate.release_temp(iterator_temp)
              iterator_temp = None
  
          return iterator_temp
  
      def generate_starred_assignment_code(self, rhs, code):
          for i, arg in enumerate(self.args):
              if arg.is_starred:
                  starred_target = self.unpacked_items[i]
                  unpacked_fixed_items_left  = self.unpacked_items[:i]
                  unpacked_fixed_items_right = self.unpacked_items[i+1:]
                  break
          else:
              assert False
  
          iterator_temp = None
          if unpacked_fixed_items_left:
              for item in unpacked_fixed_items_left:
                  item.allocate(code)
              code.putln('{')
              iterator_temp = self.generate_generic_parallel_unpacking_code(
                  code, rhs, unpacked_fixed_items_left,
                  use_loop=True, terminate=False)
              for i, item in enumerate(unpacked_fixed_items_left):
                  value_node = self.coerced_unpacked_items[i]
                  value_node.generate_evaluation_code(code)
              code.putln('}')
  
          starred_target.allocate(code)
          target_list = starred_target.result()
          code.putln("%s = %s(%s); %s" % (
              target_list,
              "__Pyx_PySequence_ListKeepNew" if (
                      not iterator_temp and rhs.is_temp and rhs.type in (py_object_type, list_type))
                  else "PySequence_List",
              iterator_temp or rhs.py_result(),
              code.error_goto_if_null(target_list, self.pos)))
          starred_target.generate_gotref(code)
  
          if iterator_temp:
              code.put_decref_clear(iterator_temp, py_object_type)
              code.funcstate.release_temp(iterator_temp)
          else:
              rhs.generate_disposal_code(code)
  
          if unpacked_fixed_items_right:
              code.globalstate.use_utility_code(raise_need_more_values_to_unpack)
              length_temp = code.funcstate.allocate_temp(PyrexTypes.c_py_ssize_t_type, manage_ref=False)
              code.putln('%s = PyList_GET_SIZE(%s);' % (length_temp, target_list))
              code.putln("if (unlikely(%s < %d)) {" % (length_temp, len(unpacked_fixed_items_right)))
              code.putln("__Pyx_RaiseNeedMoreValuesError(%d+%s); %s" % (
                   len(unpacked_fixed_items_left), length_temp,
                   code.error_goto(self.pos)))
              code.putln('}')
  
              for item in unpacked_fixed_items_right[::-1]:
                  item.allocate(code)
              for i, (item, coerced_arg) in enumerate(zip(unpacked_fixed_items_right[::-1],
                                                          self.coerced_unpacked_items[::-1])):
                  code.putln('#if CYTHON_COMPILING_IN_CPYTHON')
                  code.putln("%s = PyList_GET_ITEM(%s, %s-%d); " % (
                      item.py_result(), target_list, length_temp, i+1))
                  # resize the list the hard way
                  code.putln("((PyVarObject*)%s)->ob_size--;" % target_list)
                  code.putln('#else')
                  code.putln("%s = PySequence_ITEM(%s, %s-%d); " % (
                      item.py_result(), target_list, length_temp, i+1))
                  code.putln('#endif')
                  item.generate_gotref(code)
                  coerced_arg.generate_evaluation_code(code)
  
              code.putln('#if !CYTHON_COMPILING_IN_CPYTHON')
              sublist_temp = code.funcstate.allocate_temp(py_object_type, manage_ref=True)
              code.putln('%s = PySequence_GetSlice(%s, 0, %s-%d); %s' % (
                  sublist_temp, target_list, length_temp, len(unpacked_fixed_items_right),
                  code.error_goto_if_null(sublist_temp, self.pos)))
              code.put_gotref(sublist_temp, py_object_type)
              code.funcstate.release_temp(length_temp)
              code.put_decref(target_list, py_object_type)
              code.putln('%s = %s; %s = NULL;' % (target_list, sublist_temp, sublist_temp))
              code.putln('#else')
              code.putln('(void)%s;' % sublist_temp)  # avoid warning about unused variable
              code.funcstate.release_temp(sublist_temp)
              code.putln('#endif')
  
          for i, arg in enumerate(self.args):
              arg.generate_assignment_code(self.coerced_unpacked_items[i], code)
  
      def annotate(self, code):
          for arg in self.args:
              arg.annotate(code)
          if self.unpacked_items:
              for arg in self.unpacked_items:
                  arg.annotate(code)
              for arg in self.coerced_unpacked_items:
                  arg.annotate(code)
  
  
  class TupleNode(SequenceNode):
      #  Tuple constructor.
  
      type = tuple_type
      is_partly_literal = False
  
      gil_message = "Constructing Python tuple"
  
      def infer_type(self, env):
          if self.mult_factor or not self.args:
              return tuple_type
          arg_types = [arg.infer_type(env) for arg in self.args]
          if any(type.is_pyobject or type.is_memoryviewslice or type.is_unspecified or type.is_fused
                 for type in arg_types):
              return tuple_type
          return env.declare_tuple_type(self.pos, arg_types).type
  
      def analyse_types(self, env, skip_children=False):
          if len(self.args) == 0:
              self.is_temp = False
              self.is_literal = True
              return self
  
          if not skip_children:
              for i, arg in enumerate(self.args):
                  if arg.is_starred:
                      arg.starred_expr_allowed_here = True
                  self.args[i] = arg.analyse_types(env)
          if (not self.mult_factor and
                  not any((arg.is_starred or arg.type.is_pyobject or arg.type.is_memoryviewslice or arg.type.is_fused)
                          for arg in self.args)):
              self.type = env.declare_tuple_type(self.pos, (arg.type for arg in self.args)).type
              self.is_temp = 1
              return self
  
          node = SequenceNode.analyse_types(self, env, skip_children=True)
          node = node._create_merge_node_if_necessary(env)
          if not node.is_sequence_constructor:
              return node
  
          if not all(child.is_literal for child in node.args):
              return node
          if not node.mult_factor or (
                  node.mult_factor.is_literal and
                  isinstance(node.mult_factor.constant_result, _py_int_types)):
              node.is_temp = False
              node.is_literal = True
          else:
              if not node.mult_factor.type.is_pyobject:
                  node.mult_factor = node.mult_factor.coerce_to_pyobject(env)
              node.is_temp = True
              node.is_partly_literal = True
          return node
  
      def analyse_as_type(self, env):
          # ctuple type
          if not self.args:
              return None
          item_types = [arg.analyse_as_type(env) for arg in self.args]
          if any(t is None for t in item_types):
              return None
          entry = env.declare_tuple_type(self.pos, item_types)
          return entry.type
  
      def coerce_to(self, dst_type, env):
          if self.type.is_ctuple:
              if dst_type.is_ctuple and self.type.size == dst_type.size:
                  return self.coerce_to_ctuple(dst_type, env)
              elif dst_type is tuple_type or dst_type is py_object_type:
                  coerced_args = [arg.coerce_to_pyobject(env) for arg in self.args]
                  return TupleNode(self.pos, args=coerced_args, type=tuple_type, is_temp=1).analyse_types(env, skip_children=True)
              else:
                  return self.coerce_to_pyobject(env).coerce_to(dst_type, env)
          elif dst_type.is_ctuple and not self.mult_factor:
              return self.coerce_to_ctuple(dst_type, env)
          else:
              return SequenceNode.coerce_to(self, dst_type, env)
  
      def as_list(self):
          t = ListNode(self.pos, args=self.args, mult_factor=self.mult_factor)
          if isinstance(self.constant_result, tuple):
              t.constant_result = list(self.constant_result)
          return t
  
      def is_simple(self):
          # either temp or constant => always simple
          return True
  
      def nonlocally_immutable(self):
          # either temp or constant => always safe
          return True
  
      def calculate_result_code(self):
          if len(self.args) > 0:
              return self.result_code
          else:
              return Naming.empty_tuple
  
      def calculate_constant_result(self):
          self.constant_result = tuple([
                  arg.constant_result for arg in self.args])
  
      def compile_time_value(self, denv):
          values = self.compile_time_value_list(denv)
          try:
              return tuple(values)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def generate_operation_code(self, code):
          if len(self.args) == 0:
              # result_code is Naming.empty_tuple
              return
  
          if self.is_literal or self.is_partly_literal:
              # The "mult_factor" is part of the deduplication if it is also constant, i.e. when
              # we deduplicate the multiplied result.  Otherwise, only deduplicate the constant part.
              dedup_key = make_dedup_key(self.type, [self.mult_factor if self.is_literal else None] + self.args)
              tuple_target = code.get_py_const(py_object_type, 'tuple', cleanup_level=2, dedup_key=dedup_key)
              const_code = code.get_cached_constants_writer(tuple_target)
              if const_code is not None:
                  # constant is not yet initialised
                  const_code.mark_pos(self.pos)
                  self.generate_sequence_packing_code(const_code, tuple_target, plain=not self.is_literal)
                  const_code.put_giveref(tuple_target, py_object_type)
              if self.is_literal:
                  self.result_code = tuple_target
              else:
                  code.putln('%s = PyNumber_Multiply(%s, %s); %s' % (
                      self.result(), tuple_target, self.mult_factor.py_result(),
                      code.error_goto_if_null(self.result(), self.pos)
                  ))
                  self.generate_gotref(code)
          else:
              self.type.entry.used = True
              self.generate_sequence_packing_code(code)
  
  
  class ListNode(SequenceNode):
      #  List constructor.
  
      # obj_conversion_errors    [PyrexError]   used internally
      # orignial_args            [ExprNode]     used internally
  
      obj_conversion_errors = []
      type = list_type
      in_module_scope = False
  
      gil_message = "Constructing Python list"
  
      def type_dependencies(self, env):
          return ()
  
      def infer_type(self, env):
          # TODO: Infer non-object list arrays.
          return list_type
  
      def analyse_expressions(self, env):
          for arg in self.args:
              if arg.is_starred:
                  arg.starred_expr_allowed_here = True
          node = SequenceNode.analyse_expressions(self, env)
          return node.coerce_to_pyobject(env)
  
      def analyse_types(self, env):
          with local_errors(ignore=True) as errors:
              self.original_args = list(self.args)
              node = SequenceNode.analyse_types(self, env)
          node.obj_conversion_errors = errors
          if env.is_module_scope:
              self.in_module_scope = True
          node = node._create_merge_node_if_necessary(env)
          return node
  
      def coerce_to(self, dst_type, env):
          if dst_type.is_pyobject:
              for err in self.obj_conversion_errors:
                  report_error(err)
              self.obj_conversion_errors = []
              if not self.type.subtype_of(dst_type):
                  error(self.pos, "Cannot coerce list to type '%s'" % dst_type)
          elif (dst_type.is_array or dst_type.is_ptr) and dst_type.base_type is not PyrexTypes.c_void_type:
              array_length = len(self.args)
              if self.mult_factor:
                  if isinstance(self.mult_factor.constant_result, _py_int_types):
                      if self.mult_factor.constant_result <= 0:
                          error(self.pos, "Cannot coerce non-positively multiplied list to '%s'" % dst_type)
                      else:
                          array_length *= self.mult_factor.constant_result
                  else:
                      error(self.pos, "Cannot coerce dynamically multiplied list to '%s'" % dst_type)
              base_type = dst_type.base_type
              self.type = PyrexTypes.CArrayType(base_type, array_length)
              for i in range(len(self.original_args)):
                  arg = self.args[i]
                  if isinstance(arg, CoerceToPyTypeNode):
                      arg = arg.arg
                  self.args[i] = arg.coerce_to(base_type, env)
          elif dst_type.is_cpp_class:
              # TODO(robertwb): Avoid object conversion for vector/list/set.
              return TypecastNode(self.pos, operand=self, type=PyrexTypes.py_object_type).coerce_to(dst_type, env)
          elif self.mult_factor:
              error(self.pos, "Cannot coerce multiplied list to '%s'" % dst_type)
          elif dst_type.is_struct:
              if len(self.args) > len(dst_type.scope.var_entries):
                  error(self.pos, "Too many members for '%s'" % dst_type)
              else:
                  if len(self.args) < len(dst_type.scope.var_entries):
                      warning(self.pos, "Too few members for '%s'" % dst_type, 1)
                  for i, (arg, member) in enumerate(zip(self.original_args, dst_type.scope.var_entries)):
                      if isinstance(arg, CoerceToPyTypeNode):
                          arg = arg.arg
                      self.args[i] = arg.coerce_to(member.type, env)
              self.type = dst_type
          elif dst_type.is_ctuple:
              return self.coerce_to_ctuple(dst_type, env)
          else:
              self.type = error_type
              error(self.pos, "Cannot coerce list to type '%s'" % dst_type)
          return self
  
      def as_list(self):  # dummy for compatibility with TupleNode
          return self
  
      def as_tuple(self):
          t = TupleNode(self.pos, args=self.args, mult_factor=self.mult_factor)
          if isinstance(self.constant_result, list):
              t.constant_result = tuple(self.constant_result)
          return t
  
      def allocate_temp_result(self, code):
          if self.type.is_array:
              if self.in_module_scope:
                  self.temp_code = code.funcstate.allocate_temp(
                      self.type, manage_ref=False, static=True, reusable=False)
              else:
                  # To be valid C++, we must allocate the memory on the stack
                  # manually and be sure not to reuse it for something else.
                  # Yes, this means that we leak a temp array variable.
                  self.temp_code = code.funcstate.allocate_temp(
                      self.type, manage_ref=False, reusable=False)
          else:
              SequenceNode.allocate_temp_result(self, code)
  
      def calculate_constant_result(self):
          if self.mult_factor:
              raise ValueError()  # may exceed the compile time memory
          self.constant_result = [
              arg.constant_result for arg in self.args]
  
      def compile_time_value(self, denv):
          l = self.compile_time_value_list(denv)
          if self.mult_factor:
              l *= self.mult_factor.compile_time_value(denv)
          return l
  
      def generate_operation_code(self, code):
          if self.type.is_pyobject:
              for err in self.obj_conversion_errors:
                  report_error(err)
              self.generate_sequence_packing_code(code)
          elif self.type.is_array:
              if self.mult_factor:
                  code.putln("{")
                  code.putln("Py_ssize_t %s;" % Naming.quick_temp_cname)
                  code.putln("for ({i} = 0; {i} < {count}; {i}++) {{".format(
                      i=Naming.quick_temp_cname, count=self.mult_factor.result()))
                  offset = '+ (%d * %s)' % (len(self.args), Naming.quick_temp_cname)
              else:
                  offset = ''
              for i, arg in enumerate(self.args):
                  if arg.type.is_array:
                      code.globalstate.use_utility_code(UtilityCode.load_cached("IncludeStringH", "StringTools.c"))
                      code.putln("memcpy(&(%s[%s%s]), %s, sizeof(%s[0]));" % (
                          self.result(), i, offset,
                          arg.result(), self.result()
                      ))
                  else:
                      code.putln("%s[%s%s] = %s;" % (
                          self.result(),
                          i,
                          offset,
                          arg.result()))
              if self.mult_factor:
                  code.putln("}")
                  code.putln("}")
          elif self.type.is_struct:
              for arg, member in zip(self.args, self.type.scope.var_entries):
                  code.putln("%s.%s = %s;" % (
                      self.result(),
                      member.cname,
                      arg.result()))
          else:
              raise InternalError("List type never specified")
  
  
  class ScopedExprNode(ExprNode):
      # Abstract base class for ExprNodes that have their own local
      # scope, such as generator expressions.
      #
      # expr_scope    Scope  the inner scope of the expression
  
      subexprs = []
      expr_scope = None
  
      # does this node really have a local scope, e.g. does it leak loop
      # variables or not?  non-leaking Py3 behaviour is default, except
      # for list comprehensions where the behaviour differs in Py2 and
      # Py3 (set in Parsing.py based on parser context)
      has_local_scope = True
  
      def init_scope(self, outer_scope, expr_scope=None):
          if expr_scope is not None:
              self.expr_scope = expr_scope
          elif self.has_local_scope:
              self.expr_scope = Symtab.GeneratorExpressionScope(outer_scope)
          else:
              self.expr_scope = None
  
      def analyse_declarations(self, env):
          self.init_scope(env)
  
      def analyse_scoped_declarations(self, env):
          # this is called with the expr_scope as env
          pass
  
      def analyse_types(self, env):
          # no recursion here, the children will be analysed separately below
          return self
  
      def analyse_scoped_expressions(self, env):
          # this is called with the expr_scope as env
          return self
  
      def generate_evaluation_code(self, code):
          # set up local variables and free their references on exit
          generate_inner_evaluation_code = super(ScopedExprNode, self).generate_evaluation_code
          if not self.has_local_scope or not self.expr_scope.var_entries:
              # no local variables => delegate, done
              generate_inner_evaluation_code(code)
              return
  
          code.putln('{ /* enter inner scope */')
          py_entries = []
          for _, entry in sorted(item for item in self.expr_scope.entries.items() if item[0]):
              if not entry.in_closure:
                  if entry.type.is_pyobject and entry.used:
                      py_entries.append(entry)
          if not py_entries:
              # no local Python references => no cleanup required
              generate_inner_evaluation_code(code)
              code.putln('} /* exit inner scope */')
              return
  
          # must free all local Python references at each exit point
          old_loop_labels = code.new_loop_labels()
          old_error_label = code.new_error_label()
  
          generate_inner_evaluation_code(code)
  
          # normal (non-error) exit
          self._generate_vars_cleanup(code, py_entries)
  
          # error/loop body exit points
          exit_scope = code.new_label('exit_scope')
          code.put_goto(exit_scope)
          for label, old_label in ([(code.error_label, old_error_label)] +
                                   list(zip(code.get_loop_labels(), old_loop_labels))):
              if code.label_used(label):
                  code.put_label(label)
                  self._generate_vars_cleanup(code, py_entries)
                  code.put_goto(old_label)
          code.put_label(exit_scope)
          code.putln('} /* exit inner scope */')
  
          code.set_loop_labels(old_loop_labels)
          code.error_label = old_error_label
  
      def _generate_vars_cleanup(self, code, py_entries):
          for entry in py_entries:
              if entry.is_cglobal:
                  code.put_var_gotref(entry)
                  code.put_var_decref_set(entry, "Py_None")
              else:
                  code.put_var_xdecref_clear(entry)
  
  
  class ComprehensionNode(ScopedExprNode):
      # A list/set/dict comprehension
  
      child_attrs = ["loop"]
  
      is_temp = True
      constant_result = not_a_constant
  
      def infer_type(self, env):
          return self.type
  
      def analyse_declarations(self, env):
          self.append.target = self  # this is used in the PyList_Append of the inner loop
          self.init_scope(env)
  
      def analyse_scoped_declarations(self, env):
          self.loop.analyse_declarations(env)
  
      def analyse_types(self, env):
          if not self.has_local_scope:
              self.loop = self.loop.analyse_expressions(env)
          return self
  
      def analyse_scoped_expressions(self, env):
          if self.has_local_scope:
              self.loop = self.loop.analyse_expressions(env)
          return self
  
      def may_be_none(self):
          return False
  
      def generate_result_code(self, code):
          self.generate_operation_code(code)
  
      def generate_operation_code(self, code):
          if self.type is Builtin.list_type:
              create_code = 'PyList_New(0)'
          elif self.type is Builtin.set_type:
              create_code = 'PySet_New(NULL)'
          elif self.type is Builtin.dict_type:
              create_code = 'PyDict_New()'
          else:
              raise InternalError("illegal type for comprehension: %s" % self.type)
          code.putln('%s = %s; %s' % (
              self.result(), create_code,
              code.error_goto_if_null(self.result(), self.pos)))
  
          self.generate_gotref(code)
          self.loop.generate_execution_code(code)
  
      def annotate(self, code):
          self.loop.annotate(code)
  
  
  class ComprehensionAppendNode(Node):
      # Need to be careful to avoid infinite recursion:
      # target must not be in child_attrs/subexprs
  
      child_attrs = ['expr']
      target = None
  
      type = PyrexTypes.c_int_type
  
      def analyse_expressions(self, env):
          self.expr = self.expr.analyse_expressions(env)
          if not self.expr.type.is_pyobject:
              self.expr = self.expr.coerce_to_pyobject(env)
          return self
  
      def generate_execution_code(self, code):
          if self.target.type is list_type:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("ListCompAppend", "Optimize.c"))
              function = "__Pyx_ListComp_Append"
          elif self.target.type is set_type:
              function = "PySet_Add"
          else:
              raise InternalError(
                  "Invalid type for comprehension node: %s" % self.target.type)
  
          self.expr.generate_evaluation_code(code)
          code.putln(code.error_goto_if("%s(%s, (PyObject*)%s)" % (
              function,
              self.target.result(),
              self.expr.result()
              ), self.pos))
          self.expr.generate_disposal_code(code)
          self.expr.free_temps(code)
  
      def generate_function_definitions(self, env, code):
          self.expr.generate_function_definitions(env, code)
  
      def annotate(self, code):
          self.expr.annotate(code)
  
  class DictComprehensionAppendNode(ComprehensionAppendNode):
      child_attrs = ['key_expr', 'value_expr']
  
      def analyse_expressions(self, env):
          self.key_expr = self.key_expr.analyse_expressions(env)
          if not self.key_expr.type.is_pyobject:
              self.key_expr = self.key_expr.coerce_to_pyobject(env)
          self.value_expr = self.value_expr.analyse_expressions(env)
          if not self.value_expr.type.is_pyobject:
              self.value_expr = self.value_expr.coerce_to_pyobject(env)
          return self
  
      def generate_execution_code(self, code):
          self.key_expr.generate_evaluation_code(code)
          self.value_expr.generate_evaluation_code(code)
          code.putln(code.error_goto_if("PyDict_SetItem(%s, (PyObject*)%s, (PyObject*)%s)" % (
              self.target.result(),
              self.key_expr.result(),
              self.value_expr.result()
              ), self.pos))
          self.key_expr.generate_disposal_code(code)
          self.key_expr.free_temps(code)
          self.value_expr.generate_disposal_code(code)
          self.value_expr.free_temps(code)
  
      def generate_function_definitions(self, env, code):
          self.key_expr.generate_function_definitions(env, code)
          self.value_expr.generate_function_definitions(env, code)
  
      def annotate(self, code):
          self.key_expr.annotate(code)
          self.value_expr.annotate(code)
  
  
  class InlinedGeneratorExpressionNode(ExprNode):
      # An inlined generator expression for which the result is calculated
      # inside of the loop and returned as a single, first and only Generator
      # return value.
      # This will only be created by transforms when replacing safe builtin
      # calls on generator expressions.
      #
      # gen            GeneratorExpressionNode      the generator, not containing any YieldExprNodes
      # orig_func      String                       the name of the builtin function this node replaces
      # target         ExprNode or None             a 'target' for a ComprehensionAppend node
  
      subexprs = ["gen"]
      orig_func = None
      target = None
      is_temp = True
      type = py_object_type
  
      def __init__(self, pos, gen, comprehension_type=None, **kwargs):
          gbody = gen.def_node.gbody
          gbody.is_inlined = True
          if comprehension_type is not None:
              assert comprehension_type in (list_type, set_type, dict_type), comprehension_type
              gbody.inlined_comprehension_type = comprehension_type
              kwargs.update(
                  target=RawCNameExprNode(pos, comprehension_type, Naming.retval_cname),
                  type=comprehension_type,
              )
          super(InlinedGeneratorExpressionNode, self).__init__(pos, gen=gen, **kwargs)
  
      def may_be_none(self):
          return self.orig_func not in ('any', 'all', 'sorted')
  
      def infer_type(self, env):
          return self.type
  
      def analyse_types(self, env):
          self.gen = self.gen.analyse_expressions(env)
          return self
  
      def generate_result_code(self, code):
          code.putln("%s = __Pyx_Generator_Next(%s); %s" % (
              self.result(), self.gen.result(),
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class MergedSequenceNode(ExprNode):
      """
      Merge a sequence of iterables into a set/list/tuple.
  
      The target collection is determined by self.type, which must be set externally.
  
      args    [ExprNode]
      """
      subexprs = ['args']
      is_temp = True
      gil_message = "Constructing Python collection"
  
      def __init__(self, pos, args, type):
          if type in (list_type, tuple_type) and args and args[0].is_sequence_constructor:
              # construct a list directly from the first argument that we can then extend
              if args[0].type is not list_type:
                  args[0] = ListNode(args[0].pos, args=args[0].args, is_temp=True)
          ExprNode.__init__(self, pos, args=args, type=type)
  
      def calculate_constant_result(self):
          result = []
          for item in self.args:
              if item.is_sequence_constructor and item.mult_factor:
                  if item.mult_factor.constant_result <= 0:
                      continue
                  # otherwise, adding each item once should be enough
              if item.is_set_literal or item.is_sequence_constructor:
                  # process items in order
                  items = (arg.constant_result for arg in item.args)
              else:
                  items = item.constant_result
              result.extend(items)
          if self.type is set_type:
              result = set(result)
          elif self.type is tuple_type:
              result = tuple(result)
          else:
              assert self.type is list_type
          self.constant_result = result
  
      def compile_time_value(self, denv):
          result = []
          for item in self.args:
              if item.is_sequence_constructor and item.mult_factor:
                  if item.mult_factor.compile_time_value(denv) <= 0:
                      continue
              if item.is_set_literal or item.is_sequence_constructor:
                  # process items in order
                  items = (arg.compile_time_value(denv) for arg in item.args)
              else:
                  items = item.compile_time_value(denv)
              result.extend(items)
          if self.type is set_type:
              try:
                  result = set(result)
              except Exception as e:
                  self.compile_time_value_error(e)
          elif self.type is tuple_type:
              result = tuple(result)
          else:
              assert self.type is list_type
          return result
  
      def type_dependencies(self, env):
          return ()
  
      def infer_type(self, env):
          return self.type
  
      def analyse_types(self, env):
          args = [
              arg.analyse_types(env).coerce_to_pyobject(env).as_none_safe_node(
                  # FIXME: CPython's error message starts with the runtime function name
                  'argument after * must be an iterable, not NoneType')
              for arg in self.args
          ]
  
          if len(args) == 1 and args[0].type is self.type:
              # strip this intermediate node and use the bare collection
              return args[0]
  
          assert self.type in (set_type, list_type, tuple_type)
  
          self.args = args
          return self
  
      def may_be_none(self):
          return False
  
      def generate_evaluation_code(self, code):
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
  
          is_set = self.type is set_type
  
          args = iter(self.args)
          item = next(args)
          item.generate_evaluation_code(code)
          if (is_set and item.is_set_literal or
                  not is_set and item.is_sequence_constructor and item.type is list_type):
              code.putln("%s = %s;" % (self.result(), item.py_result()))
              item.generate_post_assignment_code(code)
          else:
              code.putln("%s = %s(%s); %s" % (
                  self.result(),
                  'PySet_New' if is_set
                      else "__Pyx_PySequence_ListKeepNew" if item.is_temp and item.type in (py_object_type, list_type)
                      else "PySequence_List",
                  item.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
              item.generate_disposal_code(code)
          item.free_temps(code)
  
          helpers = set()
          if is_set:
              add_func = "PySet_Add"
              extend_func = "__Pyx_PySet_Update"
          else:
              add_func = "__Pyx_ListComp_Append"
              extend_func = "__Pyx_PyList_Extend"
  
          for item in args:
              if (is_set and (item.is_set_literal or item.is_sequence_constructor) or
                      (item.is_sequence_constructor and not item.mult_factor)):
                  if not is_set and item.args:
                      helpers.add(("ListCompAppend", "Optimize.c"))
                  for arg in item.args:
                      arg.generate_evaluation_code(code)
                      code.put_error_if_neg(arg.pos, "%s(%s, %s)" % (
                          add_func,
                          self.result(),
                          arg.py_result()))
                      arg.generate_disposal_code(code)
                      arg.free_temps(code)
                  continue
  
              if is_set:
                  helpers.add(("PySet_Update", "Builtins.c"))
              else:
                  helpers.add(("ListExtend", "Optimize.c"))
  
              item.generate_evaluation_code(code)
              code.put_error_if_neg(item.pos, "%s(%s, %s)" % (
                  extend_func,
                  self.result(),
                  item.py_result()))
              item.generate_disposal_code(code)
              item.free_temps(code)
  
          if self.type is tuple_type:
              code.putln("{")
              code.putln("PyObject *%s = PyList_AsTuple(%s);" % (
                  Naming.quick_temp_cname,
                  self.result()))
              code.put_decref(self.result(), py_object_type)
              code.putln("%s = %s; %s" % (
                  self.result(),
                  Naming.quick_temp_cname,
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
              code.putln("}")
  
          for helper in sorted(helpers):
              code.globalstate.use_utility_code(UtilityCode.load_cached(*helper))
  
      def annotate(self, code):
          for item in self.args:
              item.annotate(code)
  
  
  class SetNode(ExprNode):
      """
      Set constructor.
      """
      subexprs = ['args']
      type = set_type
      is_set_literal = True
      gil_message = "Constructing Python set"
  
      def analyse_types(self, env):
          for i in range(len(self.args)):
              arg = self.args[i]
              arg = arg.analyse_types(env)
              self.args[i] = arg.coerce_to_pyobject(env)
          self.type = set_type
          self.is_temp = 1
          return self
  
      def may_be_none(self):
          return False
  
      def calculate_constant_result(self):
          self.constant_result = {arg.constant_result for arg in self.args}
  
      def compile_time_value(self, denv):
          values = [arg.compile_time_value(denv) for arg in self.args]
          try:
              return set(values)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def generate_evaluation_code(self, code):
          for arg in self.args:
              arg.generate_evaluation_code(code)
          self.allocate_temp_result(code)
          code.putln(
              "%s = PySet_New(0); %s" % (
                  self.result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
          for arg in self.args:
              code.put_error_if_neg(
                  self.pos,
                  "PySet_Add(%s, %s)" % (self.result(), arg.py_result()))
              arg.generate_disposal_code(code)
              arg.free_temps(code)
  
  
  class DictNode(ExprNode):
      #  Dictionary constructor.
      #
      #  key_value_pairs     [DictItemNode]
      #  exclude_null_values [boolean]          Do not add NULL values to dict
      #
      # obj_conversion_errors    [PyrexError]   used internally
  
      subexprs = ['key_value_pairs']
      is_temp = 1
      exclude_null_values = False
      type = dict_type
      is_dict_literal = True
      reject_duplicates = False
  
      obj_conversion_errors = []
  
      @classmethod
      def from_pairs(cls, pos, pairs):
          return cls(pos, key_value_pairs=[
                  DictItemNode(pos, key=k, value=v) for k, v in pairs])
  
      def calculate_constant_result(self):
          self.constant_result = dict([
                  item.constant_result for item in self.key_value_pairs])
  
      def compile_time_value(self, denv):
          pairs = [(item.key.compile_time_value(denv), item.value.compile_time_value(denv))
              for item in self.key_value_pairs]
          try:
              return dict(pairs)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def type_dependencies(self, env):
          return ()
  
      def infer_type(self, env):
          # TODO: Infer struct constructors.
          return dict_type
  
      def analyse_types(self, env):
          with local_errors(ignore=True) as errors:
              self.key_value_pairs = [
                  item.analyse_types(env)
                  for item in self.key_value_pairs
              ]
          self.obj_conversion_errors = errors
          return self
  
      def may_be_none(self):
          return False
  
      def coerce_to(self, dst_type, env):
          if dst_type.is_pyobject:
              self.release_errors()
              if self.type.is_struct_or_union:
                  if not dict_type.subtype_of(dst_type):
                      error(self.pos, "Cannot interpret struct as non-dict type '%s'" % dst_type)
                  return DictNode(self.pos, key_value_pairs=[
                      DictItemNode(item.pos, key=item.key.coerce_to_pyobject(env),
                                   value=item.value.coerce_to_pyobject(env))
                      for item in self.key_value_pairs])
              if not self.type.subtype_of(dst_type):
                  error(self.pos, "Cannot interpret dict as type '%s'" % dst_type)
          elif dst_type.is_struct_or_union:
              self.type = dst_type
              if not dst_type.is_struct and len(self.key_value_pairs) != 1:
                  error(self.pos, "Exactly one field must be specified to convert to union '%s'" % dst_type)
              elif dst_type.is_struct and len(self.key_value_pairs) < len(dst_type.scope.var_entries):
                  warning(self.pos, "Not all members given for struct '%s'" % dst_type, 1)
              for item in self.key_value_pairs:
                  if isinstance(item.key, CoerceToPyTypeNode):
                      item.key = item.key.arg
                  if not item.key.is_string_literal:
                      error(item.key.pos, "Invalid struct field identifier")
                      item.key = StringNode(item.key.pos, value="<error>")
                  else:
                      key = str(item.key.value)  # converts string literals to unicode in Py3
                      member = dst_type.scope.lookup_here(key)
                      if not member:
                          error(item.key.pos, "struct '%s' has no field '%s'" % (dst_type, key))
                      else:
                          value = item.value
                          if isinstance(value, CoerceToPyTypeNode):
                              value = value.arg
                          item.value = value.coerce_to(member.type, env)
          else:
              self.type = error_type
              error(self.pos, "Cannot interpret dict as type '%s'" % dst_type)
          return self
  
      def release_errors(self):
          for err in self.obj_conversion_errors:
              report_error(err)
          self.obj_conversion_errors = []
  
      gil_message = "Constructing Python dict"
  
      def generate_evaluation_code(self, code):
          #  Custom method used here because key-value
          #  pairs are evaluated and used one at a time.
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
  
          is_dict = self.type.is_pyobject
          if is_dict:
              self.release_errors()
              code.putln(
                  "%s = __Pyx_PyDict_NewPresized(%d); %s" % (
                      self.result(),
                      len(self.key_value_pairs),
                      code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
  
          keys_seen = set()
          key_type = None
          needs_error_helper = False
  
          for item in self.key_value_pairs:
              item.generate_evaluation_code(code)
              if is_dict:
                  if self.exclude_null_values:
                      code.putln('if (%s) {' % item.value.py_result())
                  key = item.key
                  if self.reject_duplicates:
                      if keys_seen is not None:
                          # avoid runtime 'in' checks for literals that we can do at compile time
                          if not key.is_string_literal:
                              keys_seen = None
                          elif key.value in keys_seen:
                              # FIXME: this could be a compile time error, at least in Cython code
                              keys_seen = None
                          elif key_type is not type(key.value):
                              if key_type is None:
                                  key_type = type(key.value)
                                  keys_seen.add(key.value)
                              else:
                                  # different types => may not be able to compare at compile time
                                  keys_seen = None
                          else:
                              keys_seen.add(key.value)
  
                      if keys_seen is None:
                          code.putln('if (unlikely(PyDict_Contains(%s, %s))) {' % (
                              self.result(), key.py_result()))
                          # currently only used in function calls
                          needs_error_helper = True
                          code.putln('__Pyx_RaiseDoubleKeywordsError("function", %s); %s' % (
                              key.py_result(),
                              code.error_goto(item.pos)))
                          code.putln("} else {")
  
                  code.put_error_if_neg(self.pos, "PyDict_SetItem(%s, %s, %s)" % (
                      self.result(),
                      item.key.py_result(),
                      item.value.py_result()))
                  if self.reject_duplicates and keys_seen is None:
                      code.putln('}')
                  if self.exclude_null_values:
                      code.putln('}')
              else:
                  code.putln("%s.%s = %s;" % (
                          self.result(),
                          item.key.value,
                          item.value.result()))
              item.generate_disposal_code(code)
              item.free_temps(code)
  
          if needs_error_helper:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("RaiseDoubleKeywords", "FunctionArguments.c"))
  
      def annotate(self, code):
          for item in self.key_value_pairs:
              item.annotate(code)
  
  
  class DictItemNode(ExprNode):
      # Represents a single item in a DictNode
      #
      # key          ExprNode
      # value        ExprNode
      subexprs = ['key', 'value']
  
      nogil_check = None  # Parent DictNode takes care of it
  
      def calculate_constant_result(self):
          self.constant_result = (
              self.key.constant_result, self.value.constant_result)
  
      def analyse_types(self, env):
          self.key = self.key.analyse_types(env)
          self.value = self.value.analyse_types(env)
          self.key = self.key.coerce_to_pyobject(env)
          self.value = self.value.coerce_to_pyobject(env)
          return self
  
      def generate_evaluation_code(self, code):
          self.key.generate_evaluation_code(code)
          self.value.generate_evaluation_code(code)
  
      def generate_disposal_code(self, code):
          self.key.generate_disposal_code(code)
          self.value.generate_disposal_code(code)
  
      def free_temps(self, code):
          self.key.free_temps(code)
          self.value.free_temps(code)
  
      def __iter__(self):
          return iter([self.key, self.value])
  
  
  class SortedDictKeysNode(ExprNode):
      # build sorted list of dict keys, e.g. for dir()
      subexprs = ['arg']
  
      is_temp = True
  
      def __init__(self, arg):
          ExprNode.__init__(self, arg.pos, arg=arg)
          self.type = Builtin.list_type
  
      def analyse_types(self, env):
          arg = self.arg.analyse_types(env)
          if arg.type is Builtin.dict_type:
              arg = arg.as_none_safe_node(
                  "'NoneType' object is not iterable")
          self.arg = arg
          return self
  
      def may_be_none(self):
          return False
  
      def generate_result_code(self, code):
          dict_result = self.arg.py_result()
          if self.arg.type is Builtin.dict_type:
              code.putln('%s = PyDict_Keys(%s); %s' % (
                  self.result(), dict_result,
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
          else:
              # originally used PyMapping_Keys() here, but that may return a tuple
              code.globalstate.use_utility_code(UtilityCode.load_cached(
                  'PyObjectCallMethod0', 'ObjectHandling.c'))
              keys_cname = code.intern_identifier(StringEncoding.EncodedString("keys"))
              code.putln('%s = __Pyx_PyObject_CallMethod0(%s, %s); %s' % (
                  self.result(), dict_result, keys_cname,
                  code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
              code.putln("if (unlikely(!PyList_Check(%s))) {" % self.result())
              self.generate_decref_set(code, "PySequence_List(%s)" % self.result())
              code.putln(code.error_goto_if_null(self.result(), self.pos))
              self.generate_gotref(code)
              code.putln("}")
          code.put_error_if_neg(
              self.pos, 'PyList_Sort(%s)' % self.py_result())
  
  
  class ModuleNameMixin(object):
      def get_py_mod_name(self, code):
          return code.get_py_string_const(
              self.module_name, identifier=True)
  
      def get_py_qualified_name(self, code):
          return code.get_py_string_const(
              self.qualname, identifier=True)
  
  
  class ClassNode(ExprNode, ModuleNameMixin):
      #  Helper class used in the implementation of Python
      #  class definitions. Constructs a class object given
      #  a name, tuple of bases and class dictionary.
      #
      #  name         EncodedString      Name of the class
      #  class_def_node  PyClassDefNode  PyClassDefNode defining this class
      #  doc          ExprNode or None   Doc string
      #  module_name  EncodedString      Name of defining module
  
      subexprs = ['doc']
      type = py_object_type
      is_temp = True
  
      def analyse_annotations(self, env):
          pass
  
      def infer_type(self, env):
          # TODO: could return 'type' in some cases
          return py_object_type
  
      def analyse_types(self, env):
          if self.doc:
              self.doc = self.doc.analyse_types(env)
              self.doc = self.doc.coerce_to_pyobject(env)
          env.use_utility_code(UtilityCode.load_cached("CreateClass", "ObjectHandling.c"))
          return self
  
      def may_be_none(self):
          return True
  
      gil_message = "Constructing Python class"
  
      def generate_result_code(self, code):
          class_def_node = self.class_def_node
          cname = code.intern_identifier(self.name)
  
          if self.doc:
              code.put_error_if_neg(self.pos,
                  'PyDict_SetItem(%s, %s, %s)' % (
                      class_def_node.dict.py_result(),
                      code.intern_identifier(
                          StringEncoding.EncodedString("__doc__")),
                      self.doc.py_result()))
          py_mod_name = self.get_py_mod_name(code)
          qualname = self.get_py_qualified_name(code)
          code.putln(
              '%s = __Pyx_CreateClass(%s, %s, %s, %s, %s); %s' % (
                  self.result(),
                  class_def_node.bases.py_result(),
                  class_def_node.dict.py_result(),
                  cname,
                  qualname,
                  py_mod_name,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class Py3ClassNode(ExprNode):
      #  Helper class used in the implementation of Python3+
      #  class definitions. Constructs a class object given
      #  a name, tuple of bases and class dictionary.
      #
      #  name         EncodedString      Name of the class
      #  module_name  EncodedString      Name of defining module
      #  class_def_node  PyClassDefNode  PyClassDefNode defining this class
      #  calculate_metaclass  bool       should call CalculateMetaclass()
      #  allow_py2_metaclass  bool       should look for Py2 metaclass
      #  force_type           bool       always create a "new style" class, even with no bases
  
      subexprs = []
      type = py_object_type
      force_type = False
      is_temp = True
  
      def infer_type(self, env):
          # TODO: could return 'type' in some cases
          return py_object_type
  
      def analyse_types(self, env):
          return self
  
      def may_be_none(self):
          return True
  
      gil_message = "Constructing Python class"
  
      def analyse_annotations(self, env):
          from .AutoDocTransforms import AnnotationWriter
          position = self.class_def_node.pos
          dict_items = [
              DictItemNode(
                  entry.pos,
                  key=IdentifierStringNode(entry.pos, value=entry.name),
                  value=entry.annotation.string
              )
              for entry in env.entries.values() if entry.annotation
          ]
          # Annotations dict shouldn't exist for classes which don't declare any.
          if dict_items:
              annotations_dict = DictNode(position, key_value_pairs=dict_items)
              lhs = NameNode(position, name=StringEncoding.EncodedString(u"__annotations__"))
              lhs.entry = env.lookup_here(lhs.name) or env.declare_var(lhs.name, dict_type, position)
              node = SingleAssignmentNode(position, lhs=lhs, rhs=annotations_dict)
              node.analyse_declarations(env)
              self.class_def_node.body.stats.insert(0, node)
  
      def generate_result_code(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("Py3ClassCreate", "ObjectHandling.c"))
          cname = code.intern_identifier(self.name)
          class_def_node = self.class_def_node
          mkw = class_def_node.mkw.py_result() if class_def_node.mkw else 'NULL'
          if class_def_node.metaclass:
              metaclass = class_def_node.metaclass.py_result()
          elif self.force_type:
              metaclass = "((PyObject*)&PyType_Type)"
          else:
              metaclass = "((PyObject*)&__Pyx_DefaultClassType)"
          code.putln(
              '%s = __Pyx_Py3ClassCreate(%s, %s, %s, %s, %s, %d, %d); %s' % (
                  self.result(),
                  metaclass,
                  cname,
                  class_def_node.bases.py_result(),
                  class_def_node.dict.py_result(),
                  mkw,
                  self.calculate_metaclass,
                  self.allow_py2_metaclass,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class PyClassMetaclassNode(ExprNode):
      # Helper class holds Python3 metaclass object
      #
      #  class_def_node  PyClassDefNode  PyClassDefNode defining this class
  
      subexprs = []
  
      def analyse_types(self, env):
          self.type = py_object_type
          self.is_temp = True
          return self
  
      def may_be_none(self):
          return True
  
      def generate_result_code(self, code):
          bases = self.class_def_node.bases
          mkw = self.class_def_node.mkw
          if mkw:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("Py3MetaclassGet", "ObjectHandling.c"))
              call = "__Pyx_Py3MetaclassGet(%s, %s)" % (
                  bases.result(),
                  mkw.result())
          else:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("CalculateMetaclass", "ObjectHandling.c"))
              call = "__Pyx_CalculateMetaclass(NULL, %s)" % (
                  bases.result())
          code.putln(
              "%s = %s; %s" % (
                  self.result(), call,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class PyClassNamespaceNode(ExprNode, ModuleNameMixin):
      # Helper class holds Python3 namespace object
      #
      # All this are not owned by this node
      #  class_def_node  PyClassDefNode  PyClassDefNode defining this class
      #  doc          ExprNode or None   Doc string (owned)
  
      subexprs = ['doc']
  
      def analyse_types(self, env):
          if self.doc:
              self.doc = self.doc.analyse_types(env).coerce_to_pyobject(env)
          self.type = py_object_type
          self.is_temp = 1
          return self
  
      def may_be_none(self):
          return True
  
      def generate_result_code(self, code):
          cname = code.intern_identifier(self.name)
          py_mod_name = self.get_py_mod_name(code)
          qualname = self.get_py_qualified_name(code)
          class_def_node = self.class_def_node
          null = "(PyObject *) NULL"
          doc_code = self.doc.result() if self.doc else null
          mkw = class_def_node.mkw.py_result() if class_def_node.mkw else null
          metaclass = class_def_node.metaclass.py_result() if class_def_node.metaclass else null
          code.putln(
              "%s = __Pyx_Py3MetaclassPrepare(%s, %s, %s, %s, %s, %s, %s); %s" % (
                  self.result(),
                  metaclass,
                  class_def_node.bases.result(),
                  cname,
                  qualname,
                  mkw,
                  py_mod_name,
                  doc_code,
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class ClassCellInjectorNode(ExprNode):
      # Initialize CyFunction.func_classobj
      is_temp = True
      type = py_object_type
      subexprs = []
      is_active = False
  
      def analyse_expressions(self, env):
          return self
  
      def generate_result_code(self, code):
          assert self.is_active
          code.putln(
              '%s = PyList_New(0); %s' % (
                  self.result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
      def generate_injection_code(self, code, classobj_cname):
          assert self.is_active
          code.globalstate.use_utility_code(
              UtilityCode.load_cached("CyFunctionClassCell", "CythonFunction.c"))
          code.put_error_if_neg(self.pos, '__Pyx_CyFunction_InitClassCell(%s, %s)' % (
              self.result(), classobj_cname))
  
  
  class ClassCellNode(ExprNode):
      # Class Cell for noargs super()
      subexprs = []
      is_temp = True
      is_generator = False
      type = py_object_type
  
      def analyse_types(self, env):
          return self
  
      def generate_result_code(self, code):
          if not self.is_generator:
              code.putln('%s = __Pyx_CyFunction_GetClassObj(%s);' % (
                  self.result(),
                  Naming.self_cname))
          else:
              code.putln('%s =  %s->classobj;' % (
                  self.result(), Naming.generator_cname))
          code.putln(
              'if (!%s) { PyErr_SetString(PyExc_SystemError, '
              '"super(): empty __class__ cell"); %s }' % (
                  self.result(),
                  code.error_goto(self.pos)))
          code.put_incref(self.result(), py_object_type)
  
  
  class PyCFunctionNode(ExprNode, ModuleNameMixin):
      #  Helper class used in the implementation of Python
      #  functions.  Constructs a PyCFunction object
      #  from a PyMethodDef struct.
      #
      #  pymethdef_cname   string             PyMethodDef structure
      #  binding           bool
      #  def_node          DefNode            the Python function node
      #  module_name       EncodedString      Name of defining module
      #  code_object       CodeObjectNode     the PyCodeObject creator node
  
      subexprs = ['code_object', 'defaults_tuple', 'defaults_kwdict',
                  'annotations_dict']
  
      code_object = None
      binding = False
      def_node = None
      defaults = None
      defaults_struct = None
      defaults_pyobjects = 0
      defaults_tuple = None
      defaults_kwdict = None
      annotations_dict = None
  
      type = py_object_type
      is_temp = 1
  
      specialized_cpdefs = None
      is_specialization = False
  
      @classmethod
      def from_defnode(cls, node, binding):
          return cls(node.pos,
                     def_node=node,
                     pymethdef_cname=node.entry.pymethdef_cname,
                     binding=binding or node.specialized_cpdefs,
                     specialized_cpdefs=node.specialized_cpdefs,
                     code_object=CodeObjectNode(node))
  
      def analyse_types(self, env):
          if self.binding:
              self.analyse_default_args(env)
          return self
  
      def analyse_default_args(self, env):
          """
          Handle non-literal function's default arguments.
          """
          nonliteral_objects = []
          nonliteral_other = []
          default_args = []
          default_kwargs = []
          annotations = []
  
          # For global cpdef functions and def/cpdef methods in cdef classes, we must use global constants
          # for default arguments to avoid the dependency on the CyFunction object as 'self' argument
          # in the underlying C function.  Basically, cpdef functions/methods are static C functions,
          # so their optional arguments must be static, too.
          # TODO: change CyFunction implementation to pass both function object and owning object for method calls
          must_use_constants = env.is_c_class_scope or (self.def_node.is_wrapper and env.is_module_scope)
  
          for arg in self.def_node.args:
              if arg.default:
                  if not must_use_constants:
                      if arg.default.is_literal:
                          arg.default = DefaultLiteralArgNode(arg.pos, arg.default)
                      else:
                          arg.is_dynamic = True
                          if arg.type.is_pyobject:
                              nonliteral_objects.append(arg)
                          else:
                              nonliteral_other.append(arg)
                  if arg.default.type and arg.default.type.can_coerce_to_pyobject(env):
                      if arg.kw_only:
                          default_kwargs.append(arg)
                      else:
                          default_args.append(arg)
              if arg.annotation:
                  arg.annotation = arg.annotation.analyse_types(env)
                  annotations.append((arg.pos, arg.name, arg.annotation.string))
  
          for arg in (self.def_node.star_arg, self.def_node.starstar_arg):
              if arg and arg.annotation:
                  arg.annotation = arg.annotation.analyse_types(env)
                  annotations.append((arg.pos, arg.name, arg.annotation.string))
  
          annotation = self.def_node.return_type_annotation
          if annotation:
              self.def_node.return_type_annotation = annotation.analyse_types(env)
              annotations.append((annotation.pos, StringEncoding.EncodedString("return"),
                                  annotation.string))
  
          if nonliteral_objects or nonliteral_other:
              module_scope = env.global_scope()
              cname = module_scope.next_id(Naming.defaults_struct_prefix)
              scope = Symtab.StructOrUnionScope(cname)
              self.defaults = []
              for arg in nonliteral_objects:
                  type_ = arg.type
                  if type_.is_buffer:
                      type_ = type_.base
                  entry = scope.declare_var(arg.name, type_, None,
                                            Naming.arg_prefix + arg.name,
                                            allow_pyobject=True)
                  self.defaults.append((arg, entry))
              for arg in nonliteral_other:
                  entry = scope.declare_var(arg.name, arg.type, None,
                                            Naming.arg_prefix + arg.name,
                                            allow_pyobject=False, allow_memoryview=True)
                  self.defaults.append((arg, entry))
              entry = module_scope.declare_struct_or_union(
                  None, 'struct', scope, 1, None, cname=cname)
              self.defaults_struct = scope
              self.defaults_pyobjects = len(nonliteral_objects)
              for arg, entry in self.defaults:
                  arg.default_value = '%s->%s' % (
                      Naming.dynamic_args_cname, entry.cname)
              self.def_node.defaults_struct = self.defaults_struct.name
  
          if default_args or default_kwargs:
              if self.defaults_struct is None:
                  if default_args:
                      defaults_tuple = TupleNode(self.pos, args=[
                          arg.default for arg in default_args])
                      self.defaults_tuple = defaults_tuple.analyse_types(env).coerce_to_pyobject(env)
                  if default_kwargs:
                      defaults_kwdict = DictNode(self.pos, key_value_pairs=[
                          DictItemNode(
                              arg.pos,
                              key=IdentifierStringNode(arg.pos, value=arg.name),
                              value=arg.default)
                          for arg in default_kwargs])
                      self.defaults_kwdict = defaults_kwdict.analyse_types(env)
              elif not self.specialized_cpdefs:
                  # Fused dispatch functions do not support (dynamic) default arguments, only the specialisations do.
                  if default_args:
                      defaults_tuple = DefaultsTupleNode(
                          self.pos, default_args, self.defaults_struct)
                  else:
                      defaults_tuple = NoneNode(self.pos)
                  if default_kwargs:
                      defaults_kwdict = DefaultsKwDictNode(
                          self.pos, default_kwargs, self.defaults_struct)
                  else:
                      defaults_kwdict = NoneNode(self.pos)
  
                  defaults_getter = Nodes.DefNode(
                      self.pos, args=[], star_arg=None, starstar_arg=None,
                      body=Nodes.ReturnStatNode(
                          self.pos, return_type=py_object_type,
                          value=TupleNode(
                              self.pos, args=[defaults_tuple, defaults_kwdict])),
                      decorators=None,
                      name=StringEncoding.EncodedString("__defaults__"))
                  # defaults getter must never live in class scopes, it's always a module function
                  module_scope = env.global_scope()
                  defaults_getter.analyse_declarations(module_scope)
                  defaults_getter = defaults_getter.analyse_expressions(module_scope)
                  defaults_getter.body = defaults_getter.body.analyse_expressions(
                      defaults_getter.local_scope)
                  defaults_getter.py_wrapper_required = False
                  defaults_getter.pymethdef_required = False
                  self.def_node.defaults_getter = defaults_getter
          if annotations:
              annotations_dict = DictNode(self.pos, key_value_pairs=[
                  DictItemNode(
                      pos, key=IdentifierStringNode(pos, value=name),
                      value=value)
                  for pos, name, value in annotations])
              self.annotations_dict = annotations_dict.analyse_types(env)
  
      def may_be_none(self):
          return False
  
      gil_message = "Constructing Python function"
  
      def closure_result_code(self):
          return "NULL"
  
      def generate_result_code(self, code):
          if self.binding:
              self.generate_cyfunction_code(code)
          else:
              self.generate_pycfunction_code(code)
  
      def generate_pycfunction_code(self, code):
          py_mod_name = self.get_py_mod_name(code)
          code.putln(
              '%s = PyCFunction_NewEx(&%s, %s, %s); %s' % (
                  self.result(),
                  self.pymethdef_cname,
                  self.closure_result_code(),
                  py_mod_name,
                  code.error_goto_if_null(self.result(), self.pos)))
  
          self.generate_gotref(code)
  
      def generate_cyfunction_code(self, code):
          if self.specialized_cpdefs:
              def_node = self.specialized_cpdefs[0]
          else:
              def_node = self.def_node
  
          if self.specialized_cpdefs or self.is_specialization:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("FusedFunction", "CythonFunction.c"))
              constructor = "__pyx_FusedFunction_New"
          else:
              code.globalstate.use_utility_code(
                  UtilityCode.load_cached("CythonFunction", "CythonFunction.c"))
              constructor = "__Pyx_CyFunction_New"
  
          if self.code_object:
              code_object_result = self.code_object.py_result()
          else:
              code_object_result = 'NULL'
  
          flags = []
          if def_node.is_staticmethod:
              flags.append('__Pyx_CYFUNCTION_STATICMETHOD')
          elif def_node.is_classmethod:
              flags.append('__Pyx_CYFUNCTION_CLASSMETHOD')
  
          if def_node.local_scope.parent_scope.is_c_class_scope and not def_node.entry.is_anonymous:
              flags.append('__Pyx_CYFUNCTION_CCLASS')
  
          if def_node.is_coroutine:
              flags.append('__Pyx_CYFUNCTION_COROUTINE')
  
          if flags:
              flags = ' | '.join(flags)
          else:
              flags = '0'
  
          code.putln(
              '%s = %s(&%s, %s, %s, %s, %s, %s, %s); %s' % (
                  self.result(),
                  constructor,
                  self.pymethdef_cname,
                  flags,
                  self.get_py_qualified_name(code),
                  self.closure_result_code(),
                  self.get_py_mod_name(code),
                  Naming.moddict_cname,
                  code_object_result,
                  code.error_goto_if_null(self.result(), self.pos)))
  
          self.generate_gotref(code)
  
          if def_node.requires_classobj:
              assert code.pyclass_stack, "pyclass_stack is empty"
              class_node = code.pyclass_stack[-1]
              code.put_incref(self.py_result(), py_object_type)
              code.putln(
                  'PyList_Append(%s, %s);' % (
                      class_node.class_cell.result(),
                      self.result()))
              self.generate_giveref(code)
  
          if self.defaults:
              code.putln(
                  'if (!__Pyx_CyFunction_InitDefaults(%s, sizeof(%s), %d)) %s' % (
                      self.result(), self.defaults_struct.name,
                      self.defaults_pyobjects, code.error_goto(self.pos)))
              defaults = '__Pyx_CyFunction_Defaults(%s, %s)' % (
                  self.defaults_struct.name, self.result())
              for arg, entry in self.defaults:
                  arg.generate_assignment_code(code, target='%s->%s' % (
                      defaults, entry.cname))
  
          if self.defaults_tuple:
              code.putln('__Pyx_CyFunction_SetDefaultsTuple(%s, %s);' % (
                  self.result(), self.defaults_tuple.py_result()))
          if not self.specialized_cpdefs:
              # disable introspection functions for fused dispatcher function since the user never sees it
              # TODO: this is mostly disabled because the attributes end up pointing to ones belonging
              #  to the specializations - ideally this would be fixed instead
              if self.defaults_kwdict:
                  code.putln('__Pyx_CyFunction_SetDefaultsKwDict(%s, %s);' % (
                      self.result(), self.defaults_kwdict.py_result()))
              if def_node.defaults_getter:
                  code.putln('__Pyx_CyFunction_SetDefaultsGetter(%s, %s);' % (
                      self.result(), def_node.defaults_getter.entry.pyfunc_cname))
              if self.annotations_dict:
                  code.putln('__Pyx_CyFunction_SetAnnotationsDict(%s, %s);' % (
                      self.result(), self.annotations_dict.py_result()))
  
  
  class InnerFunctionNode(PyCFunctionNode):
      # Special PyCFunctionNode that depends on a closure class
  
      binding = True
      needs_closure_code = True
  
      def closure_result_code(self):
          if self.needs_closure_code:
              return "((PyObject*)%s)" % Naming.cur_scope_cname
          return "NULL"
  
  
  class CodeObjectNode(ExprNode):
      # Create a PyCodeObject for a CyFunction instance.
      #
      # def_node   DefNode    the Python function node
      # varnames   TupleNode  a tuple with all local variable names
  
      subexprs = ['varnames']
      is_temp = False
      result_code = None
  
      def __init__(self, def_node):
          ExprNode.__init__(self, def_node.pos, def_node=def_node)
          args = list(def_node.args)
          # if we have args/kwargs, then the first two in var_entries are those
          local_vars = [arg for arg in def_node.local_scope.var_entries if arg.name]
          self.varnames = TupleNode(
              def_node.pos,
              args=[IdentifierStringNode(arg.pos, value=arg.name)
                    for arg in args + local_vars],
              is_temp=0,
              is_literal=1)
  
      def may_be_none(self):
          return False
  
      def calculate_result_code(self, code=None):
          if self.result_code is None:
              self.result_code = code.get_py_const(py_object_type, 'codeobj', cleanup_level=2)
          return self.result_code
  
      def generate_result_code(self, code):
          if self.result_code is None:
              self.result_code = code.get_py_const(py_object_type, 'codeobj', cleanup_level=2)
  
          code = code.get_cached_constants_writer(self.result_code)
          if code is None:
              return  # already initialised
          code.mark_pos(self.pos)
          func = self.def_node
          func_name = code.get_py_string_const(
              func.name, identifier=True, is_str=False, unicode_value=func.name)
          # FIXME: better way to get the module file path at module init time? Encoding to use?
          file_path = StringEncoding.bytes_literal(func.pos[0].get_filenametable_entry().encode('utf8'), 'utf8')
          file_path_const = code.get_py_string_const(file_path, identifier=False, is_str=True)
  
          # This combination makes CPython create a new dict for "frame.f_locals" (see GH #1836).
          flags = ['CO_OPTIMIZED', 'CO_NEWLOCALS']
  
          if self.def_node.star_arg:
              flags.append('CO_VARARGS')
          if self.def_node.starstar_arg:
              flags.append('CO_VARKEYWORDS')
  
          code.putln("%s = (PyObject*)__Pyx_PyCode_New(%d, %d, %d, %d, 0, %s, %s, %s, %s, %s, %s, %s, %s, %s, %d, %s); %s" % (
              self.result_code,
              len(func.args) - func.num_kwonly_args,  # argcount
              func.num_posonly_args,     # posonlyargcount (Py3.8+ only)
              func.num_kwonly_args,      # kwonlyargcount (Py3 only)
              len(self.varnames.args),   # nlocals
              '|'.join(flags) or '0',    # flags
              Naming.empty_bytes,        # code
              Naming.empty_tuple,        # consts
              Naming.empty_tuple,        # names (FIXME)
              self.varnames.result(),    # varnames
              Naming.empty_tuple,        # freevars (FIXME)
              Naming.empty_tuple,        # cellvars (FIXME)
              file_path_const,           # filename
              func_name,                 # name
              self.pos[1],               # firstlineno
              Naming.empty_bytes,        # lnotab
              code.error_goto_if_null(self.result_code, self.pos),
              ))
  
  
  class DefaultLiteralArgNode(ExprNode):
      # CyFunction's literal argument default value
      #
      # Evaluate literal only once.
  
      subexprs = []
      is_literal = True
      is_temp = False
  
      def __init__(self, pos, arg):
          super(DefaultLiteralArgNode, self).__init__(pos)
          self.arg = arg
          self.type = self.arg.type
          self.evaluated = False
  
      def analyse_types(self, env):
          return self
  
      def generate_result_code(self, code):
          pass
  
      def generate_evaluation_code(self, code):
          if not self.evaluated:
              self.arg.generate_evaluation_code(code)
              self.evaluated = True
  
      def result(self):
          return self.type.cast_code(self.arg.result())
  
  
  class DefaultNonLiteralArgNode(ExprNode):
      # CyFunction's non-literal argument default value
  
      subexprs = []
  
      def __init__(self, pos, arg, defaults_struct):
          super(DefaultNonLiteralArgNode, self).__init__(pos)
          self.arg = arg
          self.defaults_struct = defaults_struct
  
      def analyse_types(self, env):
          self.type = self.arg.type
          self.is_temp = False
          return self
  
      def generate_result_code(self, code):
          pass
  
      def result(self):
          return '__Pyx_CyFunction_Defaults(%s, %s)->%s' % (
              self.defaults_struct.name, Naming.self_cname,
              self.defaults_struct.lookup(self.arg.name).cname)
  
  
  class DefaultsTupleNode(TupleNode):
      # CyFunction's __defaults__ tuple
  
      def __init__(self, pos, defaults, defaults_struct):
          args = []
          for arg in defaults:
              if not arg.default.is_literal:
                  arg = DefaultNonLiteralArgNode(pos, arg, defaults_struct)
              else:
                  arg = arg.default
              args.append(arg)
          super(DefaultsTupleNode, self).__init__(pos, args=args)
  
      def analyse_types(self, env, skip_children=False):
          return super(DefaultsTupleNode, self).analyse_types(env, skip_children).coerce_to_pyobject(env)
  
  
  class DefaultsKwDictNode(DictNode):
      # CyFunction's __kwdefaults__ dict
  
      def __init__(self, pos, defaults, defaults_struct):
          items = []
          for arg in defaults:
              name = IdentifierStringNode(arg.pos, value=arg.name)
              if not arg.default.is_literal:
                  arg = DefaultNonLiteralArgNode(pos, arg, defaults_struct)
              else:
                  arg = arg.default
              items.append(DictItemNode(arg.pos, key=name, value=arg))
          super(DefaultsKwDictNode, self).__init__(pos, key_value_pairs=items)
  
  
  class LambdaNode(InnerFunctionNode):
      # Lambda expression node (only used as a function reference)
      #
      # args          [CArgDeclNode]         formal arguments
      # star_arg      PyArgDeclNode or None  * argument
      # starstar_arg  PyArgDeclNode or None  ** argument
      # lambda_name   string                 a module-globally unique lambda name
      # result_expr   ExprNode
      # def_node      DefNode                the underlying function 'def' node
  
      child_attrs = ['def_node']
  
      name = StringEncoding.EncodedString('<lambda>')
  
      def analyse_declarations(self, env):
          self.lambda_name = self.def_node.lambda_name = env.next_id('lambda')
          self.def_node.no_assignment_synthesis = True
          self.def_node.pymethdef_required = True
          self.def_node.is_cyfunction = True
          self.def_node.analyse_declarations(env)
          self.pymethdef_cname = self.def_node.entry.pymethdef_cname
          env.add_lambda_def(self.def_node)
  
      def analyse_types(self, env):
          self.def_node = self.def_node.analyse_expressions(env)
          return super(LambdaNode, self).analyse_types(env)
  
      def generate_result_code(self, code):
          self.def_node.generate_execution_code(code)
          super(LambdaNode, self).generate_result_code(code)
  
  
  class GeneratorExpressionNode(LambdaNode):
      # A generator expression, e.g.  (i for i in range(10))
      #
      # Result is a generator.
      #
      # loop      ForStatNode   the for-loop, containing a YieldExprNode
      # def_node  DefNode       the underlying generator 'def' node
  
      name = StringEncoding.EncodedString('genexpr')
      binding = False
  
      def analyse_declarations(self, env):
          self.genexpr_name = env.next_id('genexpr')
          super(GeneratorExpressionNode, self).analyse_declarations(env)
          # No pymethdef required
          self.def_node.pymethdef_required = False
          self.def_node.py_wrapper_required = False
          self.def_node.is_cyfunction = False
          # Force genexpr signature
          self.def_node.entry.signature = TypeSlots.pyfunction_noargs
  
      def generate_result_code(self, code):
          code.putln(
              '%s = %s(%s); %s' % (
                  self.result(),
                  self.def_node.entry.pyfunc_cname,
                  self.closure_result_code(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class YieldExprNode(ExprNode):
      # Yield expression node
      #
      # arg         ExprNode   the value to return from the generator
      # label_num   integer    yield label number
      # is_yield_from  boolean is a YieldFromExprNode to delegate to another generator
  
      subexprs = ['arg']
      type = py_object_type
      label_num = 0
      is_yield_from = False
      is_await = False
      in_async_gen = False
      expr_keyword = 'yield'
  
      def analyse_types(self, env):
          if not self.label_num or (self.is_yield_from and self.in_async_gen):
              error(self.pos, "'%s' not supported here" % self.expr_keyword)
          self.is_temp = 1
          if self.arg is not None:
              self.arg = self.arg.analyse_types(env)
              if not self.arg.type.is_pyobject:
                  self.coerce_yield_argument(env)
          return self
  
      def coerce_yield_argument(self, env):
          self.arg = self.arg.coerce_to_pyobject(env)
  
      def generate_evaluation_code(self, code):
          if self.arg:
              self.arg.generate_evaluation_code(code)
              self.arg.make_owned_reference(code)
              code.putln(
                  "%s = %s;" % (
                      Naming.retval_cname,
                      self.arg.result_as(py_object_type)))
              self.arg.generate_post_assignment_code(code)
              self.arg.free_temps(code)
          else:
              code.put_init_to_py_none(Naming.retval_cname, py_object_type)
          self.generate_yield_code(code)
  
      def generate_yield_code(self, code):
          """
          Generate the code to return the argument in 'Naming.retval_cname'
          and to continue at the yield label.
          """
          label_num, label_name = code.new_yield_label(
              self.expr_keyword.replace(' ', '_'))
          code.use_label(label_name)
  
          saved = []
          code.funcstate.closure_temps.reset()
          for cname, type, manage_ref in code.funcstate.temps_in_use():
              save_cname = code.funcstate.closure_temps.allocate_temp(type)
              saved.append((cname, save_cname, type))
              code.put_xgiveref(cname, type)
              code.putln('%s->%s = %s;' % (Naming.cur_scope_cname, save_cname, cname))
  
          code.put_xgiveref(Naming.retval_cname, py_object_type)
          profile = code.globalstate.directives['profile']
          linetrace = code.globalstate.directives['linetrace']
          if profile or linetrace:
              code.put_trace_return(Naming.retval_cname,
                                    nogil=not code.funcstate.gil_owned)
          code.put_finish_refcount_context()
  
          if code.funcstate.current_except is not None:
              # inside of an except block => save away currently handled exception
              code.putln("__Pyx_Coroutine_SwapException(%s);" % Naming.generator_cname)
          else:
              # no exceptions being handled => restore exception state of caller
              code.putln("__Pyx_Coroutine_ResetAndClearException(%s);" % Naming.generator_cname)
  
          code.putln("/* return from %sgenerator, %sing value */" % (
              'async ' if self.in_async_gen else '',
              'await' if self.is_await else 'yield'))
          code.putln("%s->resume_label = %d;" % (
              Naming.generator_cname, label_num))
          if self.in_async_gen and not self.is_await:
              # __Pyx__PyAsyncGenValueWrapperNew() steals a reference to the return value
              code.putln("return __Pyx__PyAsyncGenValueWrapperNew(%s);" % Naming.retval_cname)
          else:
              code.putln("return %s;" % Naming.retval_cname)
  
          code.put_label(label_name)
          for cname, save_cname, type in saved:
              code.putln('%s = %s->%s;' % (cname, Naming.cur_scope_cname, save_cname))
              if type.is_pyobject:
                  code.putln('%s->%s = 0;' % (Naming.cur_scope_cname, save_cname))
                  code.put_xgotref(cname, type)
          self.generate_sent_value_handling_code(code, Naming.sent_value_cname)
          if self.result_is_used:
              self.allocate_temp_result(code)
              code.put('%s = %s; ' % (self.result(), Naming.sent_value_cname))
              code.put_incref(self.result(), py_object_type)
  
      def generate_sent_value_handling_code(self, code, value_cname):
          code.putln(code.error_goto_if_null(value_cname, self.pos))
  
  
  class _YieldDelegationExprNode(YieldExprNode):
      def yield_from_func(self, code):
          raise NotImplementedError()
  
      def generate_evaluation_code(self, code, source_cname=None, decref_source=False):
          if source_cname is None:
              self.arg.generate_evaluation_code(code)
          code.putln("%s = %s(%s, %s);" % (
              Naming.retval_cname,
              self.yield_from_func(code),
              Naming.generator_cname,
              self.arg.py_result() if source_cname is None else source_cname))
          if source_cname is None:
              self.arg.generate_disposal_code(code)
              self.arg.free_temps(code)
          elif decref_source:
              code.put_decref_clear(source_cname, py_object_type)
          code.put_xgotref(Naming.retval_cname, py_object_type)
  
          code.putln("if (likely(%s)) {" % Naming.retval_cname)
          self.generate_yield_code(code)
          code.putln("} else {")
          # either error or sub-generator has normally terminated: return value => node result
          if self.result_is_used:
              self.fetch_iteration_result(code)
          else:
              self.handle_iteration_exception(code)
          code.putln("}")
  
      def fetch_iteration_result(self, code):
          # YieldExprNode has allocated the result temp for us
          code.putln("%s = NULL;" % self.result())
          code.put_error_if_neg(self.pos, "__Pyx_PyGen_FetchStopIterationValue(&%s)" % self.result())
          self.generate_gotref(code)
  
      def handle_iteration_exception(self, code):
          code.putln("PyObject* exc_type = __Pyx_PyErr_Occurred();")
          code.putln("if (exc_type) {")
          code.putln("if (likely(exc_type == PyExc_StopIteration || (exc_type != PyExc_GeneratorExit &&"
                     " __Pyx_PyErr_GivenExceptionMatches(exc_type, PyExc_StopIteration)))) PyErr_Clear();")
          code.putln("else %s" % code.error_goto(self.pos))
          code.putln("}")
  
  
  class YieldFromExprNode(_YieldDelegationExprNode):
      # "yield from GEN" expression
      is_yield_from = True
      expr_keyword = 'yield from'
  
      def coerce_yield_argument(self, env):
          if not self.arg.type.is_string:
              # FIXME: support C arrays and C++ iterators?
              error(self.pos, "yielding from non-Python object not supported")
          self.arg = self.arg.coerce_to_pyobject(env)
  
      def yield_from_func(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("GeneratorYieldFrom", "Coroutine.c"))
          return "__Pyx_Generator_Yield_From"
  
  
  class AwaitExprNode(_YieldDelegationExprNode):
      # 'await' expression node
      #
      # arg         ExprNode   the Awaitable value to await
      # label_num   integer    yield label number
  
      is_await = True
      expr_keyword = 'await'
  
      def coerce_yield_argument(self, env):
          if self.arg is not None:
              # FIXME: use same check as in YieldFromExprNode.coerce_yield_argument() ?
              self.arg = self.arg.coerce_to_pyobject(env)
  
      def yield_from_func(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("CoroutineYieldFrom", "Coroutine.c"))
          return "__Pyx_Coroutine_Yield_From"
  
  
  class AwaitIterNextExprNode(AwaitExprNode):
      # 'await' expression node as part of 'async for' iteration
      #
      # Breaks out of loop on StopAsyncIteration exception.
  
      def _generate_break(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("StopAsyncIteration", "Coroutine.c"))
          code.putln("PyObject* exc_type = __Pyx_PyErr_Occurred();")
          code.putln("if (unlikely(exc_type && (exc_type == __Pyx_PyExc_StopAsyncIteration || ("
                     " exc_type != PyExc_StopIteration && exc_type != PyExc_GeneratorExit &&"
                     " __Pyx_PyErr_GivenExceptionMatches(exc_type, __Pyx_PyExc_StopAsyncIteration))))) {")
          code.putln("PyErr_Clear();")
          code.putln("break;")
          code.putln("}")
  
      def fetch_iteration_result(self, code):
          assert code.break_label, "AwaitIterNextExprNode outside of 'async for' loop"
          self._generate_break(code)
          super(AwaitIterNextExprNode, self).fetch_iteration_result(code)
  
      def generate_sent_value_handling_code(self, code, value_cname):
          assert code.break_label, "AwaitIterNextExprNode outside of 'async for' loop"
          code.putln("if (unlikely(!%s)) {" % value_cname)
          self._generate_break(code)
          # all non-break exceptions are errors, as in parent class
          code.putln(code.error_goto(self.pos))
          code.putln("}")
  
  
  class GlobalsExprNode(AtomicExprNode):
      type = dict_type
      is_temp = 1
  
      def analyse_types(self, env):
          env.use_utility_code(Builtin.globals_utility_code)
          return self
  
      gil_message = "Constructing globals dict"
  
      def may_be_none(self):
          return False
  
      def generate_result_code(self, code):
          code.putln('%s = __Pyx_Globals(); %s' % (
              self.result(),
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  
  class LocalsDictItemNode(DictItemNode):
      def analyse_types(self, env):
          self.key = self.key.analyse_types(env)
          self.value = self.value.analyse_types(env)
          self.key = self.key.coerce_to_pyobject(env)
          if self.value.type.can_coerce_to_pyobject(env):
              self.value = self.value.coerce_to_pyobject(env)
          else:
              self.value = None
          return self
  
  
  class FuncLocalsExprNode(DictNode):
      def __init__(self, pos, env):
          local_vars = sorted([
              entry.name for entry in env.entries.values() if entry.name])
          items = [LocalsDictItemNode(
              pos, key=IdentifierStringNode(pos, value=var),
              value=NameNode(pos, name=var, allow_null=True))
                   for var in local_vars]
          DictNode.__init__(self, pos, key_value_pairs=items,
                            exclude_null_values=True)
  
      def analyse_types(self, env):
          node = super(FuncLocalsExprNode, self).analyse_types(env)
          node.key_value_pairs = [ i for i in node.key_value_pairs
                                   if i.value is not None ]
          return node
  
  
  class PyClassLocalsExprNode(AtomicExprNode):
      def __init__(self, pos, pyclass_dict):
          AtomicExprNode.__init__(self, pos)
          self.pyclass_dict = pyclass_dict
  
      def analyse_types(self, env):
          self.type = self.pyclass_dict.type
          self.is_temp = False
          return self
  
      def may_be_none(self):
          return False
  
      def result(self):
          return self.pyclass_dict.result()
  
      def generate_result_code(self, code):
          pass
  
  
  def LocalsExprNode(pos, scope_node, env):
      if env.is_module_scope:
          return GlobalsExprNode(pos)
      if env.is_py_class_scope:
          return PyClassLocalsExprNode(pos, scope_node.dict)
      return FuncLocalsExprNode(pos, env)
  
  
  #-------------------------------------------------------------------
  #
  #  Unary operator nodes
  #
  #-------------------------------------------------------------------
  
  compile_time_unary_operators = {
      'not': operator.not_,
      '~': operator.inv,
      '-': operator.neg,
      '+': operator.pos,
  }
  
  class UnopNode(ExprNode):
      #  operator     string
      #  operand      ExprNode
      #
      #  Processing during analyse_expressions phase:
      #
      #    analyse_c_operation
      #      Called when the operand is not a pyobject.
      #      - Check operand type and coerce if needed.
      #      - Determine result type and result code fragment.
      #      - Allocate temporary for result if needed.
  
      subexprs = ['operand']
      infix = True
  
      def calculate_constant_result(self):
          func = compile_time_unary_operators[self.operator]
          self.constant_result = func(self.operand.constant_result)
  
      def compile_time_value(self, denv):
          func = compile_time_unary_operators.get(self.operator)
          if not func:
              error(self.pos,
                  "Unary '%s' not supported in compile-time expression"
                      % self.operator)
          operand = self.operand.compile_time_value(denv)
          try:
              return func(operand)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def infer_type(self, env):
          operand_type = self.operand.infer_type(env)
          if operand_type.is_cpp_class or operand_type.is_ptr:
              cpp_type = operand_type.find_cpp_operation_type(self.operator)
              if cpp_type is not None:
                  return cpp_type
          return self.infer_unop_type(env, operand_type)
  
      def infer_unop_type(self, env, operand_type):
          if operand_type.is_pyobject:
              return py_object_type
          else:
              return operand_type
  
      def may_be_none(self):
          if self.operand.type and self.operand.type.is_builtin_type:
              if self.operand.type is not type_type:
                  return False
          return ExprNode.may_be_none(self)
  
      def analyse_types(self, env):
          self.operand = self.operand.analyse_types(env)
          if self.is_pythran_operation(env):
              self.type = PythranExpr(pythran_unaryop_type(self.operator, self.operand.type))
              self.is_temp = 1
          elif self.is_py_operation():
              self.coerce_operand_to_pyobject(env)
              self.type = py_object_type
              self.is_temp = 1
          elif self.is_cpp_operation():
              self.analyse_cpp_operation(env)
          else:
              self.analyse_c_operation(env)
          return self
  
      def check_const(self):
          return self.operand.check_const()
  
      def is_py_operation(self):
          return self.operand.type.is_pyobject or self.operand.type.is_ctuple
  
      def is_pythran_operation(self, env):
          np_pythran = has_np_pythran(env)
          op_type = self.operand.type
          return np_pythran and (op_type.is_buffer or op_type.is_pythran_expr)
  
      def nogil_check(self, env):
          if self.is_py_operation():
              self.gil_error()
  
      def is_cpp_operation(self):
          type = self.operand.type
          return type.is_cpp_class
  
      def coerce_operand_to_pyobject(self, env):
          self.operand = self.operand.coerce_to_pyobject(env)
  
      def generate_result_code(self, code):
          if self.type.is_pythran_expr:
              code.putln("// Pythran unaryop")
              code.putln("__Pyx_call_destructor(%s);" % self.result())
              code.putln("new (&%s) decltype(%s){%s%s};" % (
                  self.result(),
                  self.result(),
                  self.operator,
                  self.operand.pythran_result()))
          elif self.operand.type.is_pyobject:
              self.generate_py_operation_code(code)
          elif self.is_temp:
              if self.is_cpp_operation() and self.exception_check == '+':
                  translate_cpp_exception(code, self.pos,
                      "%s = %s %s;" % (self.result(), self.operator, self.operand.result()),
                      self.result() if self.type.is_pyobject else None,
                      self.exception_value, self.in_nogil_context)
              else:
                  code.putln("%s = %s %s;" % (self.result(), self.operator, self.operand.result()))
  
      def generate_py_operation_code(self, code):
          function = self.py_operation_function(code)
          code.putln(
              "%s = %s(%s); %s" % (
                  self.result(),
                  function,
                  self.operand.py_result(),
                  code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
      def type_error(self):
          if not self.operand.type.is_error:
              error(self.pos, "Invalid operand type for '%s' (%s)" %
                  (self.operator, self.operand.type))
          self.type = PyrexTypes.error_type
  
      def analyse_cpp_operation(self, env, overload_check=True):
          entry = env.lookup_operator(self.operator, [self.operand])
          if overload_check and not entry:
              self.type_error()
              return
          if entry:
              self.exception_check = entry.type.exception_check
              self.exception_value = entry.type.exception_value
              if self.exception_check == '+':
                  self.is_temp = True
                  if self.exception_value is None:
                      env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
          else:
              self.exception_check = ''
              self.exception_value = ''
          cpp_type = self.operand.type.find_cpp_operation_type(self.operator)
          if overload_check and cpp_type is None:
              error(self.pos, "'%s' operator not defined for %s" % (
                  self.operator, type))
              self.type_error()
              return
          self.type = cpp_type
  
  
  class NotNode(UnopNode):
      #  'not' operator
      #
      #  operand   ExprNode
      operator = '!'
  
      type = PyrexTypes.c_bint_type
  
      def calculate_constant_result(self):
          self.constant_result = not self.operand.constant_result
  
      def compile_time_value(self, denv):
          operand = self.operand.compile_time_value(denv)
          try:
              return not operand
          except Exception as e:
              self.compile_time_value_error(e)
  
      def infer_unop_type(self, env, operand_type):
          return PyrexTypes.c_bint_type
  
      def analyse_types(self, env):
          self.operand = self.operand.analyse_types(env)
          operand_type = self.operand.type
          if operand_type.is_cpp_class:
              self.analyse_cpp_operation(env)
          else:
              self.operand = self.operand.coerce_to_boolean(env)
          return self
  
      def calculate_result_code(self):
          return "(!%s)" % self.operand.result()
  
  
  class UnaryPlusNode(UnopNode):
      #  unary '+' operator
  
      operator = '+'
  
      def analyse_c_operation(self, env):
          self.type = PyrexTypes.widest_numeric_type(
              self.operand.type, PyrexTypes.c_int_type)
  
      def py_operation_function(self, code):
          return "PyNumber_Positive"
  
      def calculate_result_code(self):
          if self.is_cpp_operation():
              return "(+%s)" % self.operand.result()
          else:
              return self.operand.result()
  
  
  class UnaryMinusNode(UnopNode):
      #  unary '-' operator
  
      operator = '-'
  
      def analyse_c_operation(self, env):
          if self.operand.type.is_numeric:
              self.type = PyrexTypes.widest_numeric_type(
                  self.operand.type, PyrexTypes.c_int_type)
          elif self.operand.type.is_enum:
              self.type = PyrexTypes.c_int_type
          else:
              self.type_error()
          if self.type.is_complex:
              self.infix = False
  
      def py_operation_function(self, code):
          return "PyNumber_Negative"
  
      def calculate_result_code(self):
          if self.infix:
              return "(-%s)" % self.operand.result()
          else:
              return "%s(%s)" % (self.operand.type.unary_op('-'), self.operand.result())
  
      def get_constant_c_result_code(self):
          value = self.operand.get_constant_c_result_code()
          if value:
              return "(-%s)" % value
  
  class TildeNode(UnopNode):
      #  unary '~' operator
  
      def analyse_c_operation(self, env):
          if self.operand.type.is_int:
              self.type = PyrexTypes.widest_numeric_type(
                  self.operand.type, PyrexTypes.c_int_type)
          elif self.operand.type.is_enum:
              self.type = PyrexTypes.c_int_type
          else:
              self.type_error()
  
      def py_operation_function(self, code):
          return "PyNumber_Invert"
  
      def calculate_result_code(self):
          return "(~%s)" % self.operand.result()
  
  
  class CUnopNode(UnopNode):
  
      def is_py_operation(self):
          return False
  
  class DereferenceNode(CUnopNode):
      #  unary * operator
  
      operator = '*'
  
      def infer_unop_type(self, env, operand_type):
          if operand_type.is_ptr:
              return operand_type.base_type
          else:
              return PyrexTypes.error_type
  
      def analyse_c_operation(self, env):
          if self.operand.type.is_ptr:
              if env.is_cpp:
                  self.type = PyrexTypes.CReferenceType(self.operand.type.base_type)
              else:
                  self.type = self.operand.type.base_type
          else:
              self.type_error()
  
      def calculate_result_code(self):
          return "(*%s)" % self.operand.result()
  
  
  class DecrementIncrementNode(CUnopNode):
      #  unary ++/-- operator
  
      def analyse_c_operation(self, env):
          if self.operand.type.is_numeric:
              self.type = PyrexTypes.widest_numeric_type(
                  self.operand.type, PyrexTypes.c_int_type)
          elif self.operand.type.is_ptr:
              self.type = self.operand.type
          else:
              self.type_error()
  
      def calculate_result_code(self):
          if self.is_prefix:
              return "(%s%s)" % (self.operator, self.operand.result())
          else:
              return "(%s%s)" % (self.operand.result(), self.operator)
  
  def inc_dec_constructor(is_prefix, operator):
      return lambda pos, **kwds: DecrementIncrementNode(pos, is_prefix=is_prefix, operator=operator, **kwds)
  
  
  class AmpersandNode(CUnopNode):
      #  The C address-of operator.
      #
      #  operand  ExprNode
      operator = '&'
  
      def infer_unop_type(self, env, operand_type):
          return PyrexTypes.c_ptr_type(operand_type)
  
      def analyse_types(self, env):
          self.operand = self.operand.analyse_types(env)
          argtype = self.operand.type
          if argtype.is_cpp_class:
              self.analyse_cpp_operation(env, overload_check=False)
          if not (argtype.is_cfunction or argtype.is_reference or self.operand.is_addressable()):
              if argtype.is_memoryviewslice:
                  self.error("Cannot take address of memoryview slice")
              else:
                  self.error("Taking address of non-lvalue (type %s)" % argtype)
              return self
          if argtype.is_pyobject:
              self.error("Cannot take address of Python %s" % (
                  "variable '%s'" % self.operand.name if self.operand.is_name else
                  "object attribute '%s'" % self.operand.attribute if self.operand.is_attribute else
                  "object"))
              return self
          if not argtype.is_cpp_class or not self.type:
              self.type = PyrexTypes.c_ptr_type(argtype)
          return self
  
      def check_const(self):
          return self.operand.check_const_addr()
  
      def error(self, mess):
          error(self.pos, mess)
          self.type = PyrexTypes.error_type
          self.result_code = "<error>"
  
      def calculate_result_code(self):
          return "(&%s)" % self.operand.result()
  
      def generate_result_code(self, code):
          if (self.operand.type.is_cpp_class and self.exception_check == '+'):
              translate_cpp_exception(code, self.pos,
                  "%s = %s %s;" % (self.result(), self.operator, self.operand.result()),
                  self.result() if self.type.is_pyobject else None,
                  self.exception_value, self.in_nogil_context)
  
  
  unop_node_classes = {
      "+":  UnaryPlusNode,
      "-":  UnaryMinusNode,
      "~":  TildeNode,
  }
  
  def unop_node(pos, operator, operand):
      # Construct unnop node of appropriate class for
      # given operator.
      if isinstance(operand, IntNode) and operator == '-':
          return IntNode(pos = operand.pos, value = str(-Utils.str_to_number(operand.value)),
                         longness=operand.longness, unsigned=operand.unsigned)
      elif isinstance(operand, UnopNode) and operand.operator == operator in '+-':
          warning(pos, "Python has no increment/decrement operator: %s%sx == %s(%sx) == x" % ((operator,)*4), 5)
      return unop_node_classes[operator](pos,
          operator = operator,
          operand = operand)
  
  
  class TypecastNode(ExprNode):
      #  C type cast
      #
      #  operand      ExprNode
      #  base_type    CBaseTypeNode
      #  declarator   CDeclaratorNode
      #  typecheck    boolean
      #
      #  If used from a transform, one can if wanted specify the attribute
      #  "type" directly and leave base_type and declarator to None
  
      subexprs = ['operand']
      base_type = declarator = type = None
  
      def type_dependencies(self, env):
          return ()
  
      def infer_type(self, env):
          if self.type is None:
              base_type = self.base_type.analyse(env)
              _, self.type = self.declarator.analyse(base_type, env)
          return self.type
  
      def analyse_types(self, env):
          if self.type is None:
              base_type = self.base_type.analyse(env)
              _, self.type = self.declarator.analyse(base_type, env)
          if self.operand.has_constant_result():
              # Must be done after self.type is resolved.
              self.calculate_constant_result()
          if self.type.is_cfunction:
              error(self.pos,
                  "Cannot cast to a function type")
              self.type = PyrexTypes.error_type
          self.operand = self.operand.analyse_types(env)
          if self.type is PyrexTypes.c_bint_type:
              # short circuit this to a coercion
              return self.operand.coerce_to_boolean(env)
          to_py = self.type.is_pyobject
          from_py = self.operand.type.is_pyobject
          if from_py and not to_py and self.operand.is_ephemeral():
              if not self.type.is_numeric and not self.type.is_cpp_class:
                  error(self.pos, "Casting temporary Python object to non-numeric non-Python type")
          if to_py and not from_py:
              if self.type is bytes_type and self.operand.type.is_int:
                  return CoerceIntToBytesNode(self.operand, env)
              elif self.operand.type.can_coerce_to_pyobject(env):
                  self.result_ctype = py_object_type
                  self.operand = self.operand.coerce_to(self.type, env)
              else:
                  if self.operand.type.is_ptr:
                      if not (self.operand.type.base_type.is_void or self.operand.type.base_type.is_struct):
                          error(self.pos, "Python objects cannot be cast from pointers of primitive types")
                  else:
                      # Should this be an error?
                      warning(self.pos, "No conversion from %s to %s, python object pointer used." % (
                          self.operand.type, self.type))
                  self.operand = self.operand.coerce_to_simple(env)
          elif from_py and not to_py:
              if self.type.create_from_py_utility_code(env):
                  self.operand = self.operand.coerce_to(self.type, env)
              elif self.type.is_ptr:
                  if not (self.type.base_type.is_void or self.type.base_type.is_struct):
                      error(self.pos, "Python objects cannot be cast to pointers of primitive types")
              else:
                  warning(self.pos, "No conversion from %s to %s, python object pointer used." % (
                      self.type, self.operand.type))
          elif from_py and to_py:
              if self.typecheck:
                  self.operand = PyTypeTestNode(self.operand, self.type, env, notnone=True)
              elif isinstance(self.operand, SliceIndexNode):
                  # This cast can influence the created type of string slices.
                  self.operand = self.operand.coerce_to(self.type, env)
          elif self.type.is_complex and self.operand.type.is_complex:
              self.operand = self.operand.coerce_to_simple(env)
          elif self.operand.type.is_fused:
              self.operand = self.operand.coerce_to(self.type, env)
              #self.type = self.operand.type
          if self.type.is_ptr and self.type.base_type.is_cfunction and self.type.base_type.nogil:
              op_type = self.operand.type
              if op_type.is_ptr:
                  op_type = op_type.base_type
              if op_type.is_cfunction and not op_type.nogil:
                  warning(self.pos,
                          "Casting a GIL-requiring function into a nogil function circumvents GIL validation", 1)
          return self
  
      def is_simple(self):
          # either temp or a C cast => no side effects other than the operand's
          return self.operand.is_simple()
  
      def is_ephemeral(self):
          # either temp or a C cast => no side effects other than the operand's
          return self.operand.is_ephemeral()
  
      def nonlocally_immutable(self):
          return self.is_temp or self.operand.nonlocally_immutable()
  
      def nogil_check(self, env):
          if self.type and self.type.is_pyobject and self.is_temp:
              self.gil_error()
  
      def check_const(self):
          return self.operand.check_const()
  
      def calculate_constant_result(self):
          self.constant_result = self.calculate_result_code(self.operand.constant_result)
  
      def calculate_result_code(self, operand_result = None):
          if operand_result is None:
              operand_result = self.operand.result()
          if self.type.is_complex:
              operand_result = self.operand.result()
              if self.operand.type.is_complex:
                  real_part = self.type.real_type.cast_code("__Pyx_CREAL(%s)" % operand_result)
                  imag_part = self.type.real_type.cast_code("__Pyx_CIMAG(%s)" % operand_result)
              else:
                  real_part = self.type.real_type.cast_code(operand_result)
                  imag_part = "0"
              return "%s(%s, %s)" % (
                      self.type.from_parts,
                      real_part,
                      imag_part)
          else:
              return self.type.cast_code(operand_result)
  
      def get_constant_c_result_code(self):
          operand_result = self.operand.get_constant_c_result_code()
          if operand_result:
              return self.type.cast_code(operand_result)
  
      def result_as(self, type):
          if self.type.is_pyobject and not self.is_temp:
              #  Optimise away some unnecessary casting
              return self.operand.result_as(type)
          else:
              return ExprNode.result_as(self, type)
  
      def generate_result_code(self, code):
          if self.is_temp:
              code.putln(
                  "%s = (PyObject *)%s;" % (
                      self.result(),
                      self.operand.result()))
              code.put_incref(self.result(), self.ctype())
  
  
  ERR_START = "Start may not be given"
  ERR_NOT_STOP = "Stop must be provided to indicate shape"
  ERR_STEPS = ("Strides may only be given to indicate contiguity. "
               "Consider slicing it after conversion")
  ERR_NOT_POINTER = "Can only create cython.array from pointer or array"
  ERR_BASE_TYPE = "Pointer base type does not match cython.array base type"
  
  
  class CythonArrayNode(ExprNode):
      """
      Used when a pointer of base_type is cast to a memoryviewslice with that
      base type. i.e.
  
          <int[:M:1, :N]> p
  
      creates a fortran-contiguous cython.array.
  
      We leave the type set to object so coercions to object are more efficient
      and less work. Acquiring a memoryviewslice from this will be just as
      efficient. ExprNode.coerce_to() will do the additional typecheck on
      self.compile_time_type
  
      This also handles <int[:, :]> my_c_array
  
  
      operand             ExprNode                 the thing we're casting
      base_type_node      MemoryViewSliceTypeNode  the cast expression node
      """
  
      subexprs = ['operand', 'shapes']
  
      shapes = None
      is_temp = True
      mode = "c"
      array_dtype = None
  
      shape_type = PyrexTypes.c_py_ssize_t_type
  
      def analyse_types(self, env):
          from . import MemoryView
  
          self.operand = self.operand.analyse_types(env)
          if self.array_dtype:
              array_dtype = self.array_dtype
          else:
              array_dtype = self.base_type_node.base_type_node.analyse(env)
          axes = self.base_type_node.axes
  
          self.type = error_type
          self.shapes = []
          ndim = len(axes)
  
          # Base type of the pointer or C array we are converting
          base_type = self.operand.type
  
          if not self.operand.type.is_ptr and not self.operand.type.is_array:
              error(self.operand.pos, ERR_NOT_POINTER)
              return self
  
          # Dimension sizes of C array
          array_dimension_sizes = []
          if base_type.is_array:
              while base_type.is_array:
                  array_dimension_sizes.append(base_type.size)
                  base_type = base_type.base_type
          elif base_type.is_ptr:
              base_type = base_type.base_type
          else:
              error(self.pos, "unexpected base type %s found" % base_type)
              return self
  
          if not (base_type.same_as(array_dtype) or base_type.is_void):
              error(self.operand.pos, ERR_BASE_TYPE)
              return self
          elif self.operand.type.is_array and len(array_dimension_sizes) != ndim:
              error(self.operand.pos,
                    "Expected %d dimensions, array has %d dimensions" %
                                              (ndim, len(array_dimension_sizes)))
              return self
  
          # Verify the start, stop and step values
          # In case of a C array, use the size of C array in each dimension to
          # get an automatic cast
          for axis_no, axis in enumerate(axes):
              if not axis.start.is_none:
                  error(axis.start.pos, ERR_START)
                  return self
  
              if axis.stop.is_none:
                  if array_dimension_sizes:
                      dimsize = array_dimension_sizes[axis_no]
                      axis.stop = IntNode(self.pos, value=str(dimsize),
                                          constant_result=dimsize,
                                          type=PyrexTypes.c_int_type)
                  else:
                      error(axis.pos, ERR_NOT_STOP)
                      return self
  
              axis.stop = axis.stop.analyse_types(env)
              shape = axis.stop.coerce_to(self.shape_type, env)
              if not shape.is_literal:
                  shape.coerce_to_temp(env)
  
              self.shapes.append(shape)
  
              first_or_last = axis_no in (0, ndim - 1)
              if not axis.step.is_none and first_or_last:
                  # '1' in the first or last dimension denotes F or C contiguity
                  axis.step = axis.step.analyse_types(env)
                  if (not axis.step.type.is_int and axis.step.is_literal and not
                          axis.step.type.is_error):
                      error(axis.step.pos, "Expected an integer literal")
                      return self
  
                  if axis.step.compile_time_value(env) != 1:
                      error(axis.step.pos, ERR_STEPS)
                      return self
  
                  if axis_no == 0:
                      self.mode = "fortran"
  
              elif not axis.step.is_none and not first_or_last:
                  # step provided in some other dimension
                  error(axis.step.pos, ERR_STEPS)
                  return self
  
          if not self.operand.is_name:
              self.operand = self.operand.coerce_to_temp(env)
  
          axes = [('direct', 'follow')] * len(axes)
          if self.mode == "fortran":
              axes[0] = ('direct', 'contig')
          else:
              axes[-1] = ('direct', 'contig')
  
          self.coercion_type = PyrexTypes.MemoryViewSliceType(array_dtype, axes)
          self.coercion_type.validate_memslice_dtype(self.pos)
          self.type = self.get_cython_array_type(env)
          MemoryView.use_cython_array_utility_code(env)
          env.use_utility_code(MemoryView.typeinfo_to_format_code)
          return self
  
      def allocate_temp_result(self, code):
          if self.temp_code:
              raise RuntimeError("temp allocated multiple times")
  
          self.temp_code = code.funcstate.allocate_temp(self.type, True)
  
      def infer_type(self, env):
          return self.get_cython_array_type(env)
  
      def get_cython_array_type(self, env):
          cython_scope = env.global_scope().context.cython_scope
          cython_scope.load_cythonscope()
          return cython_scope.viewscope.lookup("array").type
  
      def generate_result_code(self, code):
          from . import Buffer
  
          shapes = [self.shape_type.cast_code(shape.result())
                        for shape in self.shapes]
          dtype = self.coercion_type.dtype
  
          shapes_temp = code.funcstate.allocate_temp(py_object_type, True)
          format_temp = code.funcstate.allocate_temp(py_object_type, True)
  
          itemsize = "sizeof(%s)" % dtype.empty_declaration_code()
          type_info = Buffer.get_type_information_cname(code, dtype)
  
          if self.operand.type.is_ptr:
              code.putln("if (!%s) {" % self.operand.result())
              code.putln(    'PyErr_SetString(PyExc_ValueError,'
                                  '"Cannot create cython.array from NULL pointer");')
              code.putln(code.error_goto(self.operand.pos))
              code.putln("}")
  
          code.putln("%s = __pyx_format_from_typeinfo(&%s); %s" % (
              format_temp,
              type_info,
              code.error_goto_if_null(format_temp, self.pos),
          ))
          code.put_gotref(format_temp, py_object_type)
  
          buildvalue_fmt = " __PYX_BUILD_PY_SSIZE_T " * len(shapes)
          code.putln('%s = Py_BuildValue((char*) "(" %s ")", %s); %s' % (
              shapes_temp,
              buildvalue_fmt,
              ", ".join(shapes),
              code.error_goto_if_null(shapes_temp, self.pos),
          ))
          code.put_gotref(shapes_temp, py_object_type)
  
          code.putln('%s = __pyx_array_new(%s, %s, PyBytes_AS_STRING(%s), (char *) "%s", (char *) %s); %s' % (
              self.result(),
              shapes_temp, itemsize, format_temp, self.mode, self.operand.result(),
              code.error_goto_if_null(self.result(), self.pos),
          ))
          self.generate_gotref(code)
  
          def dispose(temp):
              code.put_decref_clear(temp, py_object_type)
              code.funcstate.release_temp(temp)
  
          dispose(shapes_temp)
          dispose(format_temp)
  
      @classmethod
      def from_carray(cls, src_node, env):
          """
          Given a C array type, return a CythonArrayNode
          """
          pos = src_node.pos
          base_type = src_node.type
  
          none_node = NoneNode(pos)
          axes = []
  
          while base_type.is_array:
              axes.append(SliceNode(pos, start=none_node, stop=none_node,
                                         step=none_node))
              base_type = base_type.base_type
          axes[-1].step = IntNode(pos, value="1", is_c_literal=True)
  
          memslicenode = Nodes.MemoryViewSliceTypeNode(pos, axes=axes,
                                                       base_type_node=base_type)
          result = CythonArrayNode(pos, base_type_node=memslicenode,
                                   operand=src_node, array_dtype=base_type)
          result = result.analyse_types(env)
          return result
  
  class SizeofNode(ExprNode):
      #  Abstract base class for sizeof(x) expression nodes.
  
      type = PyrexTypes.c_size_t_type
  
      def check_const(self):
          return True
  
      def generate_result_code(self, code):
          pass
  
  
  class SizeofTypeNode(SizeofNode):
      #  C sizeof function applied to a type
      #
      #  base_type   CBaseTypeNode
      #  declarator  CDeclaratorNode
  
      subexprs = []
      arg_type = None
  
      def analyse_types(self, env):
          # we may have incorrectly interpreted a dotted name as a type rather than an attribute
          # this could be better handled by more uniformly treating types as runtime-available objects
          if 0 and self.base_type.module_path:
              path = self.base_type.module_path
              obj = env.lookup(path[0])
              if obj.as_module is None:
                  operand = NameNode(pos=self.pos, name=path[0])
                  for attr in path[1:]:
                      operand = AttributeNode(pos=self.pos, obj=operand, attribute=attr)
                  operand = AttributeNode(pos=self.pos, obj=operand, attribute=self.base_type.name)
                  node = SizeofVarNode(self.pos, operand=operand).analyse_types(env)
                  return node
          if self.arg_type is None:
              base_type = self.base_type.analyse(env)
              _, arg_type = self.declarator.analyse(base_type, env)
              self.arg_type = arg_type
          self.check_type()
          return self
  
      def check_type(self):
          arg_type = self.arg_type
          if not arg_type:
              return
          if arg_type.is_pyobject and not arg_type.is_extension_type:
              error(self.pos, "Cannot take sizeof Python object")
          elif arg_type.is_void:
              error(self.pos, "Cannot take sizeof void")
          elif not arg_type.is_complete():
              error(self.pos, "Cannot take sizeof incomplete type '%s'" % arg_type)
  
      def calculate_result_code(self):
          if self.arg_type.is_extension_type:
              # the size of the pointer is boring
              # we want the size of the actual struct
              arg_code = self.arg_type.declaration_code("", deref=1)
          else:
              arg_code = self.arg_type.empty_declaration_code()
          return "(sizeof(%s))" % arg_code
  
  
  class SizeofVarNode(SizeofNode):
      #  C sizeof function applied to a variable
      #
      #  operand   ExprNode
  
      subexprs = ['operand']
  
      def analyse_types(self, env):
          # We may actually be looking at a type rather than a variable...
          # If we are, traditional analysis would fail...
          operand_as_type = self.operand.analyse_as_type(env)
          if operand_as_type:
              self.arg_type = operand_as_type
              if self.arg_type.is_fused:
                  try:
                      self.arg_type = self.arg_type.specialize(env.fused_to_specific)
                  except CannotSpecialize:
                      error(self.operand.pos,
                            "Type cannot be specialized since it is not a fused argument to this function")
              self.__class__ = SizeofTypeNode
              self.check_type()
          else:
              self.operand = self.operand.analyse_types(env)
          return self
  
      def calculate_result_code(self):
          return "(sizeof(%s))" % self.operand.result()
  
      def generate_result_code(self, code):
          pass
  
  
  class TypeidNode(ExprNode):
      #  C++ typeid operator applied to a type or variable
      #
      #  operand       ExprNode
      #  arg_type      ExprNode
      #  is_variable   boolean
  
      type = PyrexTypes.error_type
  
      subexprs = ['operand']
  
      arg_type = None
      is_variable = None
      is_temp = 1
  
      def get_type_info_type(self, env):
          env_module = env
          while not env_module.is_module_scope:
              env_module = env_module.outer_scope
          typeinfo_module = env_module.find_module('libcpp.typeinfo', self.pos)
          typeinfo_entry = typeinfo_module.lookup('type_info')
          return PyrexTypes.CFakeReferenceType(PyrexTypes.c_const_type(typeinfo_entry.type))
  
      cpp_message = 'typeid operator'
  
      def analyse_types(self, env):
          self.cpp_check(env)
          type_info = self.get_type_info_type(env)
          if not type_info:
              self.error("The 'libcpp.typeinfo' module must be cimported to use the typeid() operator")
              return self
          self.type = type_info
          as_type = self.operand.analyse_as_specialized_type(env)
          if as_type:
              self.arg_type = as_type
              self.is_type = True
          else:
              self.arg_type = self.operand.analyse_types(env)
              self.is_type = False
              if self.arg_type.type.is_pyobject:
                  self.error("Cannot use typeid on a Python object")
                  return self
              elif self.arg_type.type.is_void:
                  self.error("Cannot use typeid on void")
                  return self
              elif not self.arg_type.type.is_complete():
                  self.error("Cannot use typeid on incomplete type '%s'" % self.arg_type.type)
                  return self
          env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
          return self
  
      def error(self, mess):
          error(self.pos, mess)
          self.type = PyrexTypes.error_type
          self.result_code = "<error>"
  
      def check_const(self):
          return True
  
      def calculate_result_code(self):
          return self.temp_code
  
      def generate_result_code(self, code):
          if self.is_type:
              arg_code = self.arg_type.empty_declaration_code()
          else:
              arg_code = self.arg_type.result()
          translate_cpp_exception(code, self.pos,
              "%s = typeid(%s);" % (self.temp_code, arg_code),
              None, None, self.in_nogil_context)
  
  class TypeofNode(ExprNode):
      #  Compile-time type of an expression, as a string.
      #
      #  operand   ExprNode
      #  literal   StringNode # internal
  
      literal = None
      type = py_object_type
  
      subexprs = ['literal']  # 'operand' will be ignored after type analysis!
  
      def analyse_types(self, env):
          self.operand = self.operand.analyse_types(env)
          value = StringEncoding.EncodedString(str(self.operand.type))  #self.operand.type.typeof_name())
          literal = StringNode(self.pos, value=value)
          literal = literal.analyse_types(env)
          self.literal = literal.coerce_to_pyobject(env)
          return self
  
      def analyse_as_type(self, env):
          self.operand = self.operand.analyse_types(env)
          return self.operand.type
  
      def may_be_none(self):
          return False
  
      def generate_evaluation_code(self, code):
          self.literal.generate_evaluation_code(code)
  
      def calculate_result_code(self):
          return self.literal.calculate_result_code()
  
  #-------------------------------------------------------------------
  #
  #  Binary operator nodes
  #
  #-------------------------------------------------------------------
  
  try:
      matmul_operator = operator.matmul
  except AttributeError:
      def matmul_operator(a, b):
          try:
              func = a.__matmul__
          except AttributeError:
              func = b.__rmatmul__
          return func(a, b)
  
  compile_time_binary_operators = {
      '<': operator.lt,
      '<=': operator.le,
      '==': operator.eq,
      '!=': operator.ne,
      '>=': operator.ge,
      '>': operator.gt,
      'is': operator.is_,
      'is_not': operator.is_not,
      '+': operator.add,
      '&': operator.and_,
      '/': operator.truediv,
      '//': operator.floordiv,
      '<<': operator.lshift,
      '%': operator.mod,
      '*': operator.mul,
      '|': operator.or_,
      '**': operator.pow,
      '>>': operator.rshift,
      '-': operator.sub,
      '^': operator.xor,
      '@': matmul_operator,
      'in': lambda x, seq: x in seq,
      'not_in': lambda x, seq: x not in seq,
  }
  
  def get_compile_time_binop(node):
      func = compile_time_binary_operators.get(node.operator)
      if not func:
          error(node.pos,
              "Binary '%s' not supported in compile-time expression"
                  % node.operator)
      return func
  
  
  class BinopNode(ExprNode):
      #  operator     string
      #  operand1     ExprNode
      #  operand2     ExprNode
      #
      #  Processing during analyse_expressions phase:
      #
      #    analyse_c_operation
      #      Called when neither operand is a pyobject.
      #      - Check operand types and coerce if needed.
      #      - Determine result type and result code fragment.
      #      - Allocate temporary for result if needed.
  
      subexprs = ['operand1', 'operand2']
      inplace = False
  
      def calculate_constant_result(self):
          func = compile_time_binary_operators[self.operator]
          self.constant_result = func(
              self.operand1.constant_result,
              self.operand2.constant_result)
  
      def compile_time_value(self, denv):
          func = get_compile_time_binop(self)
          operand1 = self.operand1.compile_time_value(denv)
          operand2 = self.operand2.compile_time_value(denv)
          try:
              return func(operand1, operand2)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def infer_type(self, env):
          return self.result_type(self.operand1.infer_type(env),
                                  self.operand2.infer_type(env), env)
  
      def analyse_types(self, env):
          self.operand1 = self.operand1.analyse_types(env)
          self.operand2 = self.operand2.analyse_types(env)
          self.analyse_operation(env)
          return self
  
      def analyse_operation(self, env):
          if self.is_pythran_operation(env):
              self.type = self.result_type(self.operand1.type,
                                           self.operand2.type, env)
              assert self.type.is_pythran_expr
              self.is_temp = 1
          elif self.is_py_operation():
              self.coerce_operands_to_pyobjects(env)
              self.type = self.result_type(self.operand1.type,
                                           self.operand2.type, env)
              assert self.type.is_pyobject
              self.is_temp = 1
          elif self.is_cpp_operation():
              self.analyse_cpp_operation(env)
          else:
              self.analyse_c_operation(env)
  
      def is_py_operation(self):
          return self.is_py_operation_types(self.operand1.type, self.operand2.type)
  
      def is_py_operation_types(self, type1, type2):
          return type1.is_pyobject or type2.is_pyobject or type1.is_ctuple or type2.is_ctuple
  
      def is_pythran_operation(self, env):
          return self.is_pythran_operation_types(self.operand1.type, self.operand2.type, env)
  
      def is_pythran_operation_types(self, type1, type2, env):
          # Support only expr op supported_type, or supported_type op expr
          return has_np_pythran(env) and \
                 (is_pythran_supported_operation_type(type1) and is_pythran_supported_operation_type(type2)) and \
                 (is_pythran_expr(type1) or is_pythran_expr(type2))
  
      def is_cpp_operation(self):
          return (self.operand1.type.is_cpp_class
              or self.operand2.type.is_cpp_class)
  
      def analyse_cpp_operation(self, env):
          entry = env.lookup_operator(self.operator, [self.operand1, self.operand2])
          if not entry:
              self.type_error()
              return
          func_type = entry.type
          self.exception_check = func_type.exception_check
          self.exception_value = func_type.exception_value
          if self.exception_check == '+':
              # Used by NumBinopNodes to break up expressions involving multiple
              # operators so that exceptions can be handled properly.
              self.is_temp = 1
              if self.exception_value is None:
                  env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
          if func_type.is_ptr:
              func_type = func_type.base_type
          if len(func_type.args) == 1:
              self.operand2 = self.operand2.coerce_to(func_type.args[0].type, env)
          else:
              self.operand1 = self.operand1.coerce_to(func_type.args[0].type, env)
              self.operand2 = self.operand2.coerce_to(func_type.args[1].type, env)
          self.type = func_type.return_type
  
      def result_type(self, type1, type2, env):
          if self.is_pythran_operation_types(type1, type2, env):
              return PythranExpr(pythran_binop_type(self.operator, type1, type2))
          if self.is_py_operation_types(type1, type2):
              if type2.is_string:
                  type2 = Builtin.bytes_type
              elif type2.is_pyunicode_ptr:
                  type2 = Builtin.unicode_type
              if type1.is_string:
                  type1 = Builtin.bytes_type
              elif type1.is_pyunicode_ptr:
                  type1 = Builtin.unicode_type
              if type1.is_builtin_type or type2.is_builtin_type:
                  if type1 is type2 and self.operator in '**%+|&^':
                      # FIXME: at least these operators should be safe - others?
                      return type1
                  result_type = self.infer_builtin_types_operation(type1, type2)
                  if result_type is not None:
                      return result_type
              return py_object_type
          elif type1.is_error or type2.is_error:
              return PyrexTypes.error_type
          else:
              return self.compute_c_result_type(type1, type2)
  
      def infer_builtin_types_operation(self, type1, type2):
          return None
  
      def nogil_check(self, env):
          if self.is_py_operation():
              self.gil_error()
  
      def coerce_operands_to_pyobjects(self, env):
          self.operand1 = self.operand1.coerce_to_pyobject(env)
          self.operand2 = self.operand2.coerce_to_pyobject(env)
  
      def check_const(self):
          return self.operand1.check_const() and self.operand2.check_const()
  
      def is_ephemeral(self):
          return (super(BinopNode, self).is_ephemeral() or
                  self.operand1.is_ephemeral() or self.operand2.is_ephemeral())
  
      def generate_result_code(self, code):
          if self.type.is_pythran_expr:
              code.putln("// Pythran binop")
              code.putln("__Pyx_call_destructor(%s);" % self.result())
              if self.operator == '**':
                  code.putln("new (&%s) decltype(%s){pythonic::numpy::functor::power{}(%s, %s)};" % (
                      self.result(),
                      self.result(),
                      self.operand1.pythran_result(),
                      self.operand2.pythran_result()))
              else:
                  code.putln("new (&%s) decltype(%s){%s %s %s};" % (
                      self.result(),
                      self.result(),
                      self.operand1.pythran_result(),
                      self.operator,
                      self.operand2.pythran_result()))
          elif self.operand1.type.is_pyobject:
              function = self.py_operation_function(code)
              if self.operator == '**':
                  extra_args = ", Py_None"
              else:
                  extra_args = ""
              code.putln(
                  "%s = %s(%s, %s%s); %s" % (
                      self.result(),
                      function,
                      self.operand1.py_result(),
                      self.operand2.py_result(),
                      extra_args,
                      code.error_goto_if_null(self.result(), self.pos)))
              self.generate_gotref(code)
          elif self.is_temp:
              # C++ overloaded operators with exception values are currently all
              # handled through temporaries.
              if self.is_cpp_operation() and self.exception_check == '+':
                  translate_cpp_exception(code, self.pos,
                                          "%s = %s;" % (self.result(), self.calculate_result_code()),
                                          self.result() if self.type.is_pyobject else None,
                                          self.exception_value, self.in_nogil_context)
              else:
                  code.putln("%s = %s;" % (self.result(), self.calculate_result_code()))
  
      def type_error(self):
          if not (self.operand1.type.is_error
                  or self.operand2.type.is_error):
              error(self.pos, "Invalid operand types for '%s' (%s; %s)" %
                  (self.operator, self.operand1.type,
                      self.operand2.type))
          self.type = PyrexTypes.error_type
  
  
  class CBinopNode(BinopNode):
  
      def analyse_types(self, env):
          node = BinopNode.analyse_types(self, env)
          if node.is_py_operation():
              node.type = PyrexTypes.error_type
          return node
  
      def py_operation_function(self, code):
          return ""
  
      def calculate_result_code(self):
          return "(%s %s %s)" % (
              self.operand1.result(),
              self.operator,
              self.operand2.result())
  
      def compute_c_result_type(self, type1, type2):
          cpp_type = None
          if type1.is_cpp_class or type1.is_ptr:
              cpp_type = type1.find_cpp_operation_type(self.operator, type2)
          if cpp_type is None and (type2.is_cpp_class or type2.is_ptr):
              cpp_type = type2.find_cpp_operation_type(self.operator, type1)
          # FIXME: do we need to handle other cases here?
          return cpp_type
  
  
  def c_binop_constructor(operator):
      def make_binop_node(pos, **operands):
          return CBinopNode(pos, operator=operator, **operands)
      return make_binop_node
  
  class NumBinopNode(BinopNode):
      #  Binary operation taking numeric arguments.
  
      infix = True
      overflow_check = False
      overflow_bit_node = None
  
      def analyse_c_operation(self, env):
          type1 = self.operand1.type
          type2 = self.operand2.type
          self.type = self.compute_c_result_type(type1, type2)
          if not self.type:
              self.type_error()
              return
          if self.type.is_complex:
              self.infix = False
          if (self.type.is_int
                  and env.directives['overflowcheck']
                  and self.operator in self.overflow_op_names):
              if (self.operator in ('+', '*')
                      and self.operand1.has_constant_result()
                      and not self.operand2.has_constant_result()):
                  self.operand1, self.operand2 = self.operand2, self.operand1
              self.overflow_check = True
              self.overflow_fold = env.directives['overflowcheck.fold']
              self.func = self.type.overflow_check_binop(
                  self.overflow_op_names[self.operator],
                  env,
                  const_rhs = self.operand2.has_constant_result())
              self.is_temp = True
          if not self.infix or (type1.is_numeric and type2.is_numeric):
              self.operand1 = self.operand1.coerce_to(self.type, env)
              self.operand2 = self.operand2.coerce_to(self.type, env)
  
      def compute_c_result_type(self, type1, type2):
          if self.c_types_okay(type1, type2):
              widest_type = PyrexTypes.widest_numeric_type(type1, type2)
              if widest_type is PyrexTypes.c_bint_type:
                  if self.operator not in '|^&':
                      # False + False == 0 # not False!
                      widest_type = PyrexTypes.c_int_type
              else:
                  widest_type = PyrexTypes.widest_numeric_type(
                      widest_type, PyrexTypes.c_int_type)
              return widest_type
          else:
              return None
  
      def may_be_none(self):
          if self.type and self.type.is_builtin_type:
              # if we know the result type, we know the operation, so it can't be None
              return False
          type1 = self.operand1.type
          type2 = self.operand2.type
          if type1 and type1.is_builtin_type and type2 and type2.is_builtin_type:
              # XXX: I can't think of any case where a binary operation
              # on builtin types evaluates to None - add a special case
              # here if there is one.
              return False
          return super(NumBinopNode, self).may_be_none()
  
      def get_constant_c_result_code(self):
          value1 = self.operand1.get_constant_c_result_code()
          value2 = self.operand2.get_constant_c_result_code()
          if value1 and value2:
              return "(%s %s %s)" % (value1, self.operator, value2)
          else:
              return None
  
      def c_types_okay(self, type1, type2):
          #print "NumBinopNode.c_types_okay:", type1, type2 ###
          return (type1.is_numeric or type1.is_enum) \
              and (type2.is_numeric or type2.is_enum)
  
      def generate_evaluation_code(self, code):
          if self.overflow_check:
              self.overflow_bit_node = self
              self.overflow_bit = code.funcstate.allocate_temp(PyrexTypes.c_int_type, manage_ref=False)
              code.putln("%s = 0;" % self.overflow_bit)
          super(NumBinopNode, self).generate_evaluation_code(code)
          if self.overflow_check:
              code.putln("if (unlikely(%s)) {" % self.overflow_bit)
              code.putln('PyErr_SetString(PyExc_OverflowError, "value too large");')
              code.putln(code.error_goto(self.pos))
              code.putln("}")
              code.funcstate.release_temp(self.overflow_bit)
  
      def calculate_result_code(self):
          if self.overflow_bit_node is not None:
              return "%s(%s, %s, &%s)" % (
                  self.func,
                  self.operand1.result(),
                  self.operand2.result(),
                  self.overflow_bit_node.overflow_bit)
          elif self.type.is_cpp_class or self.infix:
              if is_pythran_expr(self.type):
                  result1, result2 = self.operand1.pythran_result(), self.operand2.pythran_result()
              else:
                  result1, result2 = self.operand1.result(), self.operand2.result()
              return "(%s %s %s)" % (result1, self.operator, result2)
          else:
              func = self.type.binary_op(self.operator)
              if func is None:
                  error(self.pos, "binary operator %s not supported for %s" % (self.operator, self.type))
              return "%s(%s, %s)" % (
                  func,
                  self.operand1.result(),
                  self.operand2.result())
  
      def is_py_operation_types(self, type1, type2):
          return (type1.is_unicode_char or
                  type2.is_unicode_char or
                  BinopNode.is_py_operation_types(self, type1, type2))
  
      def py_operation_function(self, code):
          function_name = self.py_functions[self.operator]
          if self.inplace:
              function_name = function_name.replace('PyNumber_', 'PyNumber_InPlace')
          return function_name
  
      py_functions = {
          "|":        "PyNumber_Or",
          "^":        "PyNumber_Xor",
          "&":        "PyNumber_And",
          "<<":       "PyNumber_Lshift",
          ">>":       "PyNumber_Rshift",
          "+":        "PyNumber_Add",
          "-":        "PyNumber_Subtract",
          "*":        "PyNumber_Multiply",
          "@":        "__Pyx_PyNumber_MatrixMultiply",
          "/":        "__Pyx_PyNumber_Divide",
          "//":       "PyNumber_FloorDivide",
          "%":        "PyNumber_Remainder",
          "**":       "PyNumber_Power",
      }
  
      overflow_op_names = {
          "+":  "add",
          "-":  "sub",
          "*":  "mul",
          "<<":  "lshift",
      }
  
  
  class IntBinopNode(NumBinopNode):
      #  Binary operation taking integer arguments.
  
      def c_types_okay(self, type1, type2):
          #print "IntBinopNode.c_types_okay:", type1, type2 ###
          return (type1.is_int or type1.is_enum) \
              and (type2.is_int or type2.is_enum)
  
  
  class AddNode(NumBinopNode):
      #  '+' operator.
  
      def is_py_operation_types(self, type1, type2):
          if type1.is_string and type2.is_string or type1.is_pyunicode_ptr and type2.is_pyunicode_ptr:
              return 1
          else:
              return NumBinopNode.is_py_operation_types(self, type1, type2)
  
      def infer_builtin_types_operation(self, type1, type2):
          # b'abc' + 'abc' raises an exception in Py3,
          # so we can safely infer the Py2 type for bytes here
          string_types = (bytes_type, bytearray_type, str_type, basestring_type, unicode_type)
          if type1 in string_types and type2 in string_types:
              return string_types[max(string_types.index(type1),
                                      string_types.index(type2))]
          return None
  
      def compute_c_result_type(self, type1, type2):
          #print "AddNode.compute_c_result_type:", type1, self.operator, type2 ###
          if (type1.is_ptr or type1.is_array) and (type2.is_int or type2.is_enum):
              return type1
          elif (type2.is_ptr or type2.is_array) and (type1.is_int or type1.is_enum):
              return type2
          else:
              return NumBinopNode.compute_c_result_type(
                  self, type1, type2)
  
      def py_operation_function(self, code):
          type1, type2 = self.operand1.type, self.operand2.type
          func = None
          if type1 is unicode_type or type2 is unicode_type:
              if type1 in (unicode_type, str_type) and type2 in (unicode_type, str_type):
                  is_unicode_concat = True
              elif isinstance(self.operand1, FormattedValueNode) or isinstance(self.operand2, FormattedValueNode):
                  # Assume that even if we don't know the second type, it's going to be a string.
                  is_unicode_concat = True
              else:
                  # Operation depends on the second type.
                  is_unicode_concat = False
  
              if is_unicode_concat:
                  if self.inplace or self.operand1.is_temp:
                      code.globalstate.use_utility_code(
                          UtilityCode.load_cached("UnicodeConcatInPlace", "ObjectHandling.c"))
                  func = '__Pyx_PyUnicode_Concat'
          elif type1 is str_type and type2 is str_type:
              code.globalstate.use_utility_code(
                      UtilityCode.load_cached("StrConcatInPlace", "ObjectHandling.c"))
              func = '__Pyx_PyStr_Concat'
  
          if func:
              # any necessary utility code will be got by "NumberAdd" in generate_evaluation_code
              if self.inplace or self.operand1.is_temp:
                  func += 'InPlace'  # upper case to indicate unintuitive macro
              if self.operand1.may_be_none() or self.operand2.may_be_none():
                  func += 'Safe'
              return func
  
          return super(AddNode, self).py_operation_function(code)
  
  
  class SubNode(NumBinopNode):
      #  '-' operator.
  
      def compute_c_result_type(self, type1, type2):
          if (type1.is_ptr or type1.is_array) and (type2.is_int or type2.is_enum):
              return type1
          elif (type1.is_ptr or type1.is_array) and (type2.is_ptr or type2.is_array):
              return PyrexTypes.c_ptrdiff_t_type
          else:
              return NumBinopNode.compute_c_result_type(
                  self, type1, type2)
  
  
  class MulNode(NumBinopNode):
      #  '*' operator.
  
      def is_py_operation_types(self, type1, type2):
          if ((type1.is_string and type2.is_int) or
                  (type2.is_string and type1.is_int)):
              return 1
          else:
              return NumBinopNode.is_py_operation_types(self, type1, type2)
  
      def infer_builtin_types_operation(self, type1, type2):
          # let's assume that whatever builtin type you multiply a string with
          # will either return a string of the same type or fail with an exception
          string_types = (bytes_type, bytearray_type, str_type, basestring_type, unicode_type)
          if type1 in string_types and type2.is_builtin_type:
              return type1
          if type2 in string_types and type1.is_builtin_type:
              return type2
          # multiplication of containers/numbers with an integer value
          # always (?) returns the same type
          if type1.is_int:
              return type2
          if type2.is_int:
              return type1
          return None
  
  
  class MatMultNode(NumBinopNode):
      #  '@' operator.
  
      def is_py_operation_types(self, type1, type2):
          return True
  
      def generate_evaluation_code(self, code):
          code.globalstate.use_utility_code(UtilityCode.load_cached("MatrixMultiply", "ObjectHandling.c"))
          super(MatMultNode, self).generate_evaluation_code(code)
  
  
  class DivNode(NumBinopNode):
      #  '/' or '//' operator.
  
      cdivision = None
      truedivision = None   # == "unknown" if operator == '/'
      ctruedivision = False
      cdivision_warnings = False
      zerodivision_check = None
  
      def find_compile_time_binary_operator(self, op1, op2):
          func = compile_time_binary_operators[self.operator]
          if self.operator == '/' and self.truedivision is None:
              # => true div for floats, floor div for integers
              if isinstance(op1, _py_int_types) and isinstance(op2, _py_int_types):
                  func = compile_time_binary_operators['//']
          return func
  
      def calculate_constant_result(self):
          op1 = self.operand1.constant_result
          op2 = self.operand2.constant_result
          func = self.find_compile_time_binary_operator(op1, op2)
          self.constant_result = func(
              self.operand1.constant_result,
              self.operand2.constant_result)
  
      def compile_time_value(self, denv):
          operand1 = self.operand1.compile_time_value(denv)
          operand2 = self.operand2.compile_time_value(denv)
          try:
              func = self.find_compile_time_binary_operator(
                  operand1, operand2)
              return func(operand1, operand2)
          except Exception as e:
              self.compile_time_value_error(e)
  
      def _check_truedivision(self, env):
          if self.cdivision or env.directives['cdivision']:
              self.ctruedivision = False
          else:
              self.ctruedivision = self.truedivision
  
      def infer_type(self, env):
          self._check_truedivision(env)
          return self.result_type(
              self.operand1.infer_type(env),
              self.operand2.infer_type(env), env)
  
      def analyse_operation(self, env):
          self._check_truedivision(env)
          NumBinopNode.analyse_operation(self, env)
          if self.is_cpp_operation():
              self.cdivision = True
          if not self.type.is_pyobject:
              self.zerodivision_check = (
                  self.cdivision is None and not env.directives['cdivision']
                  and (not self.operand2.has_constant_result() or
                       self.operand2.constant_result == 0))
              if self.zerodivision_check or env.directives['cdivision_warnings']:
                  # Need to check ahead of time to warn or raise zero division error
                  self.operand1 = self.operand1.coerce_to_simple(env)
                  self.operand2 = self.operand2.coerce_to_simple(env)
  
      def compute_c_result_type(self, type1, type2):
          if self.operator == '/' and self.ctruedivision and not type1.is_cpp_class and not type2.is_cpp_class:
              if not type1.is_float and not type2.is_float:
                  widest_type = PyrexTypes.widest_numeric_type(type1, PyrexTypes.c_double_type)
                  widest_type = PyrexTypes.widest_numeric_type(type2, widest_type)
                  return widest_type
          return NumBinopNode.compute_c_result_type(self, type1, type2)
  
      def zero_division_message(self):
          if self.type.is_int:
              return "integer division or modulo by zero"
          else:
              return "float division"
  
      def generate_evaluation_code(self, code):
          if not self.type.is_pyobject and not self.type.is_complex:
              if self.cdivision is None:
                  self.cdivision = (
                      code.globalstate.directives['cdivision']
                      or self.type.is_float
                      or ((self.type.is_numeric or self.type.is_enum) and not self.type.signed)
                  )
              if not self.cdivision:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("DivInt", "CMath.c").specialize(self.type))
          NumBinopNode.generate_evaluation_code(self, code)
          self.generate_div_warning_code(code)
  
      def generate_div_warning_code(self, code):
          in_nogil = self.in_nogil_context
          if not self.type.is_pyobject:
              if self.zerodivision_check:
                  if not self.infix:
                      zero_test = "%s(%s)" % (self.type.unary_op('zero'), self.operand2.result())
                  else:
                      zero_test = "%s == 0" % self.operand2.result()
                  code.putln("if (unlikely(%s)) {" % zero_test)
                  if in_nogil:
                      code.put_ensure_gil()
                  code.putln('PyErr_SetString(PyExc_ZeroDivisionError, "%s");' % self.zero_division_message())
                  if in_nogil:
                      code.put_release_ensured_gil()
                  code.putln(code.error_goto(self.pos))
                  code.putln("}")
                  if self.type.is_int and self.type.signed and self.operator != '%':
                      code.globalstate.use_utility_code(UtilityCode.load_cached("UnaryNegOverflows", "Overflow.c"))
                      if self.operand2.type.signed == 2:
                          # explicitly signed, no runtime check needed
                          minus1_check = 'unlikely(%s == -1)' % self.operand2.result()
                      else:
                          type_of_op2 = self.operand2.type.empty_declaration_code()
                          minus1_check = '(!(((%s)-1) > 0)) && unlikely(%s == (%s)-1)' % (
                              type_of_op2, self.operand2.result(), type_of_op2)
                      code.putln("else if (sizeof(%s) == sizeof(long) && %s "
                                 " && unlikely(__Pyx_UNARY_NEG_WOULD_OVERFLOW(%s))) {" % (
                                 self.type.empty_declaration_code(),
                                 minus1_check,
                                 self.operand1.result()))
                      if in_nogil:
                          code.put_ensure_gil()
                      code.putln('PyErr_SetString(PyExc_OverflowError, "value too large to perform division");')
                      if in_nogil:
                          code.put_release_ensured_gil()
                      code.putln(code.error_goto(self.pos))
                      code.putln("}")
              if code.globalstate.directives['cdivision_warnings'] and self.operator != '/':
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("CDivisionWarning", "CMath.c"))
                  code.putln("if (unlikely((%s < 0) ^ (%s < 0))) {" % (
                                  self.operand1.result(),
                                  self.operand2.result()))
                  warning_code = "__Pyx_cdivision_warning(%(FILENAME)s, %(LINENO)s)" % {
                      'FILENAME': Naming.filename_cname,
                      'LINENO':  Naming.lineno_cname,
                  }
  
                  if in_nogil:
                      result_code = 'result'
                      code.putln("int %s;" % result_code)
                      code.put_ensure_gil()
                      code.putln(code.set_error_info(self.pos, used=True))
                      code.putln("%s = %s;" % (result_code, warning_code))
                      code.put_release_ensured_gil()
                  else:
                      result_code = warning_code
                      code.putln(code.set_error_info(self.pos, used=True))
  
                  code.put("if (unlikely(%s)) " % result_code)
                  code.put_goto(code.error_label)
                  code.putln("}")
  
      def calculate_result_code(self):
          if self.type.is_complex or self.is_cpp_operation():
              return NumBinopNode.calculate_result_code(self)
          elif self.type.is_float and self.operator == '//':
              return "floor(%s / %s)" % (
                  self.operand1.result(),
                  self.operand2.result())
          elif self.truedivision or self.cdivision:
              op1 = self.operand1.result()
              op2 = self.operand2.result()
              if self.truedivision:
                  if self.type != self.operand1.type:
                      op1 = self.type.cast_code(op1)
                  if self.type != self.operand2.type:
                      op2 = self.type.cast_code(op2)
              return "(%s / %s)" % (op1, op2)
          else:
              return "__Pyx_div_%s(%s, %s)" % (
                  self.type.specialization_name(),
                  self.operand1.result(),
                  self.operand2.result())
  
  
  _find_formatting_types = re.compile(
      br"%"
      br"(?:%|"  # %%
      br"(?:\([^)]+\))?"  # %(name)
      br"[-+#,0-9 ]*([a-z])"  # %.2f  etc.
      br")").findall
  
  # These format conversion types can never trigger a Unicode string conversion in Py2.
  _safe_bytes_formats = frozenset({
      # Excludes 's' and 'r', which can generate non-bytes strings.
      b'd', b'i', b'o', b'u', b'x', b'X', b'e', b'E', b'f', b'F', b'g', b'G', b'c', b'b', b'a',
  })
  
  
  class ModNode(DivNode):
      #  '%' operator.
  
      def is_py_operation_types(self, type1, type2):
          return (type1.is_string
                  or type2.is_string
                  or NumBinopNode.is_py_operation_types(self, type1, type2))
  
      def infer_builtin_types_operation(self, type1, type2):
          # b'%s' % xyz  raises an exception in Py3<3.5, so it's safe to infer the type for Py2 and later Py3's.
          if type1 is unicode_type:
              # None + xyz  may be implemented by RHS
              if type2.is_builtin_type or not self.operand1.may_be_none():
                  return type1
          elif type1 in (bytes_type, str_type, basestring_type):
              if type2 is unicode_type:
                  return type2
              elif type2.is_numeric:
                  return type1
              elif self.operand1.is_string_literal:
                  if type1 is str_type or type1 is bytes_type:
                      if set(_find_formatting_types(self.operand1.value)) <= _safe_bytes_formats:
                          return type1
                  return basestring_type
              elif type1 is bytes_type and not type2.is_builtin_type:
                  return None   # RHS might implement '% operator differently in Py3
              else:
                  return basestring_type  # either str or unicode, can't tell
          return None
  
      def zero_division_message(self):
          if self.type.is_int:
              return "integer division or modulo by zero"
          else:
              return "float divmod()"
  
      def analyse_operation(self, env):
          DivNode.analyse_operation(self, env)
          if not self.type.is_pyobject:
              if self.cdivision is None:
                  self.cdivision = env.directives['cdivision'] or not self.type.signed
              if not self.cdivision and not self.type.is_int and not self.type.is_float:
                  error(self.pos, "mod operator not supported for type '%s'" % self.type)
  
      def generate_evaluation_code(self, code):
          if not self.type.is_pyobject and not self.cdivision:
              if self.type.is_int:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("ModInt", "CMath.c").specialize(self.type))
              else:  # float
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("ModFloat", "CMath.c").specialize(
                          self.type, math_h_modifier=self.type.math_h_modifier))
          # NOTE: skipping over DivNode here
          NumBinopNode.generate_evaluation_code(self, code)
          self.generate_div_warning_code(code)
  
      def calculate_result_code(self):
          if self.cdivision:
              if self.type.is_float:
                  return "fmod%s(%s, %s)" % (
                      self.type.math_h_modifier,
                      self.operand1.result(),
                      self.operand2.result())
              else:
                  return "(%s %% %s)" % (
                      self.operand1.result(),
                      self.operand2.result())
          else:
              return "__Pyx_mod_%s(%s, %s)" % (
                      self.type.specialization_name(),
                      self.operand1.result(),
                      self.operand2.result())
  
      def py_operation_function(self, code):
          type1, type2 = self.operand1.type, self.operand2.type
          # ("..." % x)  must call "x.__rmod__()" for string subtypes.
          if type1 is unicode_type:
              if self.operand1.may_be_none() or (
                      type2.is_extension_type and type2.subtype_of(type1) or
                      type2 is py_object_type and not isinstance(self.operand2, CoerceToPyTypeNode)):
                  return '__Pyx_PyUnicode_FormatSafe'
              else:
                  return 'PyUnicode_Format'
          elif type1 is str_type:
              if self.operand1.may_be_none() or (
                      type2.is_extension_type and type2.subtype_of(type1) or
                      type2 is py_object_type and not isinstance(self.operand2, CoerceToPyTypeNode)):
                  return '__Pyx_PyString_FormatSafe'
              else:
                  return '__Pyx_PyString_Format'
          return super(ModNode, self).py_operation_function(code)
  
  
  class PowNode(NumBinopNode):
      #  '**' operator.
  
      def analyse_c_operation(self, env):
          NumBinopNode.analyse_c_operation(self, env)
          if self.type.is_complex:
              if self.type.real_type.is_float:
                  self.operand1 = self.operand1.coerce_to(self.type, env)
                  self.operand2 = self.operand2.coerce_to(self.type, env)
                  self.pow_func = self.type.binary_op('**')
              else:
                  error(self.pos, "complex int powers not supported")
                  self.pow_func = "<error>"
          elif self.type.is_float:
              self.pow_func = "pow" + self.type.math_h_modifier
          elif self.type.is_int:
              self.pow_func = "__Pyx_pow_%s" % self.type.empty_declaration_code().replace(' ', '_')
              env.use_utility_code(
                  UtilityCode.load_cached("IntPow", "CMath.c").specialize(
                      func_name=self.pow_func,
                      type=self.type.empty_declaration_code(),
                      signed=self.type.signed and 1 or 0))
          elif not self.type.is_error:
              error(self.pos, "got unexpected types for C power operator: %s, %s" %
                              (self.operand1.type, self.operand2.type))
  
      def compute_c_result_type(self, type1, type2):
          c_result_type = super(PowNode, self).compute_c_result_type(type1, type2)
          if isinstance(self.operand2.constant_result, _py_int_types) and self.operand2.constant_result < 0:
              c_result_type = PyrexTypes.widest_numeric_type(c_result_type, PyrexTypes.c_double_type)
          return c_result_type
  
      def calculate_result_code(self):
          # Work around MSVC overloading ambiguity.
          def typecast(operand):
              if self.type == operand.type:
                  return operand.result()
              else:
                  return self.type.cast_code(operand.result())
          return "%s(%s, %s)" % (
              self.pow_func,
              typecast(self.operand1),
              typecast(self.operand2))
  
      def py_operation_function(self, code):
          if (self.type.is_pyobject and
                  self.operand1.constant_result == 2 and
                  isinstance(self.operand1.constant_result, _py_int_types) and
                  self.operand2.type is py_object_type):
              code.globalstate.use_utility_code(UtilityCode.load_cached('PyNumberPow2', 'Optimize.c'))
              if self.inplace:
                  return '__Pyx_PyNumber_InPlacePowerOf2'
              else:
                  return '__Pyx_PyNumber_PowerOf2'
          return super(PowNode, self).py_operation_function(code)
  
  
  class BoolBinopNode(ExprNode):
      """
      Short-circuiting boolean operation.
  
      Note that this node provides the same code generation method as
      BoolBinopResultNode to simplify expression nesting.
  
      operator  string                              "and"/"or"
      operand1  BoolBinopNode/BoolBinopResultNode   left operand
      operand2  BoolBinopNode/BoolBinopResultNode   right operand
      """
      subexprs = ['operand1', 'operand2']
      is_temp = True
      operator = None
      operand1 = None
      operand2 = None
  
      def infer_type(self, env):
          type1 = self.operand1.infer_type(env)
          type2 = self.operand2.infer_type(env)
          return PyrexTypes.independent_spanning_type(type1, type2)
  
      def may_be_none(self):
          if self.operator == 'or':
              return self.operand2.may_be_none()
          else:
              return self.operand1.may_be_none() or self.operand2.may_be_none()
  
      def calculate_constant_result(self):
          operand1 = self.operand1.constant_result
          operand2 = self.operand2.constant_result
          if self.operator == 'and':
              self.constant_result = operand1 and operand2
          else:
              self.constant_result = operand1 or operand2
  
      def compile_time_value(self, denv):
          operand1 = self.operand1.compile_time_value(denv)
          operand2 = self.operand2.compile_time_value(denv)
          if self.operator == 'and':
              return operand1 and operand2
          else:
              return operand1 or operand2
  
      def is_ephemeral(self):
          return self.operand1.is_ephemeral() or self.operand2.is_ephemeral()
  
      def analyse_types(self, env):
          # Note: we do not do any coercion here as we most likely do not know the final type anyway.
          # We even accept to set self.type to ErrorType if both operands do not have a spanning type.
          # The coercion to the final type and to a "simple" value is left to coerce_to().
          operand1 = self.operand1.analyse_types(env)
          operand2 = self.operand2.analyse_types(env)
          self.type = PyrexTypes.independent_spanning_type(
              operand1.type, operand2.type)
          self.operand1 = self._wrap_operand(operand1, env)
          self.operand2 = self._wrap_operand(operand2, env)
          return self
  
      def _wrap_operand(self, operand, env):
          if not isinstance(operand, (BoolBinopNode, BoolBinopResultNode)):
              operand = BoolBinopResultNode(operand, self.type, env)
          return operand
  
      def wrap_operands(self, env):
          """
          Must get called by transforms that want to create a correct BoolBinopNode
          after the type analysis phase.
          """
          self.operand1 = self._wrap_operand(self.operand1, env)
          self.operand2 = self._wrap_operand(self.operand2, env)
  
      def coerce_to_boolean(self, env):
          return self.coerce_to(PyrexTypes.c_bint_type, env)
  
      def coerce_to(self, dst_type, env):
          operand1 = self.operand1.coerce_to(dst_type, env)
          operand2 = self.operand2.coerce_to(dst_type, env)
          return BoolBinopNode.from_node(
              self, type=dst_type,
              operator=self.operator,
              operand1=operand1, operand2=operand2)
  
      def generate_bool_evaluation_code(self, code, final_result_temp, final_result_type, and_label, or_label, end_label, fall_through):
          code.mark_pos(self.pos)
  
          outer_labels = (and_label, or_label)
          if self.operator == 'and':
              my_label = and_label = code.new_label('next_and')
          else:
              my_label = or_label = code.new_label('next_or')
          self.operand1.generate_bool_evaluation_code(
              code, final_result_temp, final_result_type, and_label, or_label, end_label, my_label)
  
          and_label, or_label = outer_labels
  
          code.put_label(my_label)
          self.operand2.generate_bool_evaluation_code(
              code, final_result_temp, final_result_type, and_label, or_label, end_label, fall_through)
  
      def generate_evaluation_code(self, code):
          self.allocate_temp_result(code)
          result_type = PyrexTypes.py_object_type if self.type.is_pyobject else self.type
          or_label = and_label = None
          end_label = code.new_label('bool_binop_done')
          self.generate_bool_evaluation_code(code, self.result(), result_type, and_label, or_label, end_label, end_label)
          code.put_label(end_label)
  
      gil_message = "Truth-testing Python object"
  
      def check_const(self):
          return self.operand1.check_const() and self.operand2.check_const()
  
      def generate_subexpr_disposal_code(self, code):
          pass  # nothing to do here, all done in generate_evaluation_code()
  
      def free_subexpr_temps(self, code):
          pass  # nothing to do here, all done in generate_evaluation_code()
  
      def generate_operand1_test(self, code):
          #  Generate code to test the truth of the first operand.
          if self.type.is_pyobject:
              test_result = code.funcstate.allocate_temp(
                  PyrexTypes.c_bint_type, manage_ref=False)
              code.putln(
                  "%s = __Pyx_PyObject_IsTrue(%s); %s" % (
                      test_result,
                      self.operand1.py_result(),
                      code.error_goto_if_neg(test_result, self.pos)))
          else:
              test_result = self.operand1.result()
          return (test_result, self.type.is_pyobject)
  
  
  class BoolBinopResultNode(ExprNode):
      """
      Intermediate result of a short-circuiting and/or expression.
      Tests the result for 'truthiness' and takes care of coercing the final result
      of the overall expression to the target type.
  
      Note that this node provides the same code generation method as
      BoolBinopNode to simplify expression nesting.
  
      arg     ExprNode    the argument to test
      value   ExprNode    the coerced result value node
      """
  
      subexprs = ['arg', 'value']
      is_temp = True
      arg = None
      value = None
  
      def __init__(self, arg, result_type, env):
          # using 'arg' multiple times, so it must be a simple/temp value
          arg = arg.coerce_to_simple(env)
          # wrap in ProxyNode, in case a transform wants to replace self.arg later
          arg = ProxyNode(arg)
          super(BoolBinopResultNode, self).__init__(
              arg.pos, arg=arg, type=result_type,
              value=CloneNode(arg).coerce_to(result_type, env))
  
      def coerce_to_boolean(self, env):
          return self.coerce_to(PyrexTypes.c_bint_type, env)
  
      def coerce_to(self, dst_type, env):
          # unwrap, coerce, rewrap
          arg = self.arg.arg
          if dst_type is PyrexTypes.c_bint_type:
              arg = arg.coerce_to_boolean(env)
          # TODO: unwrap more coercion nodes?
          return BoolBinopResultNode(arg, dst_type, env)
  
      def nogil_check(self, env):
          # let's leave all errors to BoolBinopNode
          pass
  
      def generate_operand_test(self, code):
          #  Generate code to test the truth of the first operand.
          if self.arg.type.is_pyobject:
              test_result = code.funcstate.allocate_temp(
                  PyrexTypes.c_bint_type, manage_ref=False)
              code.putln(
                  "%s = __Pyx_PyObject_IsTrue(%s); %s" % (
                      test_result,
                      self.arg.py_result(),
                      code.error_goto_if_neg(test_result, self.pos)))
          else:
              test_result = self.arg.result()
          return (test_result, self.arg.type.is_pyobject)
  
      def generate_bool_evaluation_code(self, code, final_result_temp, final_result_type, and_label, or_label, end_label, fall_through):
          code.mark_pos(self.pos)
  
          # x => x
          # x and ... or ... => next 'and' / 'or'
          # False ... or x => next 'or'
          # True and x => next 'and'
          # True or x => True (operand)
  
          self.arg.generate_evaluation_code(code)
          if and_label or or_label:
              test_result, uses_temp = self.generate_operand_test(code)
              if uses_temp and (and_label and or_label):
                  # cannot become final result => free early
                  # disposal: uses_temp and (and_label and or_label)
                  self.arg.generate_disposal_code(code)
              sense = '!' if or_label else ''
              code.putln("if (%s%s) {" % (sense, test_result))
              if uses_temp:
                  code.funcstate.release_temp(test_result)
              if not uses_temp or not (and_label and or_label):
                  # disposal: (not uses_temp) or {not (and_label and or_label) [if]}
                  self.arg.generate_disposal_code(code)
  
              if or_label and or_label != fall_through:
                  # value is false => short-circuit to next 'or'
                  code.put_goto(or_label)
              if and_label:
                  # value is true => go to next 'and'
                  if or_label:
                      code.putln("} else {")
                      if not uses_temp:
                          # disposal: (not uses_temp) and {(and_label and or_label) [else]}
                          self.arg.generate_disposal_code(code)
                  if and_label != fall_through:
                      code.put_goto(and_label)
  
          if not and_label or not or_label:
              # if no next 'and' or 'or', we provide the result
              if and_label or or_label:
                  code.putln("} else {")
              self.value.generate_evaluation_code(code)
              self.value.make_owned_reference(code)
              code.putln("%s = %s;" % (final_result_temp, self.value.result_as(final_result_type)))
              self.value.generate_post_assignment_code(code)
              # disposal: {not (and_label and or_label) [else]}
              self.arg.generate_disposal_code(code)
              self.value.free_temps(code)
              if end_label != fall_through:
                  code.put_goto(end_label)
  
          if and_label or or_label:
              code.putln("}")
          self.arg.free_temps(code)
  
      def analyse_types(self, env):
          return self
  
  
  class CondExprNode(ExprNode):
      #  Short-circuiting conditional expression.
      #
      #  test        ExprNode
      #  true_val    ExprNode
      #  false_val   ExprNode
  
      true_val = None
      false_val = None
      is_temp = True
  
      subexprs = ['test', 'true_val', 'false_val']
  
      def type_dependencies(self, env):
          return self.true_val.type_dependencies(env) + self.false_val.type_dependencies(env)
  
      def infer_type(self, env):
          return PyrexTypes.independent_spanning_type(
              self.true_val.infer_type(env),
              self.false_val.infer_type(env))
  
      def calculate_constant_result(self):
          if self.test.constant_result:
              self.constant_result = self.true_val.constant_result
          else:
              self.constant_result = self.false_val.constant_result
  
      def is_ephemeral(self):
          return self.true_val.is_ephemeral() or self.false_val.is_ephemeral()
  
      def analyse_types(self, env):
          self.test = self.test.analyse_types(env).coerce_to_boolean(env)
          self.true_val = self.true_val.analyse_types(env)
          self.false_val = self.false_val.analyse_types(env)
          return self.analyse_result_type(env)
  
      def analyse_result_type(self, env):
          self.type = PyrexTypes.independent_spanning_type(
              self.true_val.type, self.false_val.type)
          if self.type.is_reference:
              self.type = PyrexTypes.CFakeReferenceType(self.type.ref_base_type)
          if self.type.is_pyobject:
              self.result_ctype = py_object_type
          elif self.true_val.is_ephemeral() or self.false_val.is_ephemeral():
              error(self.pos, "Unsafe C derivative of temporary Python reference used in conditional expression")
          if self.true_val.type.is_pyobject or self.false_val.type.is_pyobject:
              self.true_val = self.true_val.coerce_to(self.type, env)
              self.false_val = self.false_val.coerce_to(self.type, env)
          if self.type.is_error:
              self.type_error()
          return self
  
      def coerce_to_integer(self, env):
          self.true_val = self.true_val.coerce_to_integer(env)
          self.false_val = self.false_val.coerce_to_integer(env)
          self.result_ctype = None
          return self.analyse_result_type(env)
  
      def coerce_to(self, dst_type, env):
          self.true_val = self.true_val.coerce_to(dst_type, env)
          self.false_val = self.false_val.coerce_to(dst_type, env)
          self.result_ctype = None
          return self.analyse_result_type(env)
  
      def type_error(self):
          if not (self.true_val.type.is_error or self.false_val.type.is_error):
              error(self.pos, "Incompatible types in conditional expression (%s; %s)" %
                  (self.true_val.type, self.false_val.type))
          self.type = PyrexTypes.error_type
  
      def check_const(self):
          return (self.test.check_const()
              and self.true_val.check_const()
              and self.false_val.check_const())
  
      def generate_evaluation_code(self, code):
          # Because subexprs may not be evaluated we can use a more optimal
          # subexpr allocation strategy than the default, so override evaluation_code.
  
          code.mark_pos(self.pos)
          self.allocate_temp_result(code)
          self.test.generate_evaluation_code(code)
          code.putln("if (%s) {" % self.test.result())
          self.eval_and_get(code, self.true_val)
          code.putln("} else {")
          self.eval_and_get(code, self.false_val)
          code.putln("}")
          self.test.generate_disposal_code(code)
          self.test.free_temps(code)
  
      def eval_and_get(self, code, expr):
          expr.generate_evaluation_code(code)
          if self.type.is_memoryviewslice:
              expr.make_owned_memoryviewslice(code)
          else:
              expr.make_owned_reference(code)
          code.putln('%s = %s;' % (self.result(), expr.result_as(self.ctype())))
          expr.generate_post_assignment_code(code)
          expr.free_temps(code)
  
      def generate_subexpr_disposal_code(self, code):
          pass  # done explicitly above (cleanup must separately happen within the if/else blocks)
  
      def free_subexpr_temps(self, code):
          pass  # done explicitly above (cleanup must separately happen within the if/else blocks)
  
  
  richcmp_constants = {
      "<" : "Py_LT",
      "<=": "Py_LE",
      "==": "Py_EQ",
      "!=": "Py_NE",
      "<>": "Py_NE",
      ">" : "Py_GT",
      ">=": "Py_GE",
      # the following are faked by special compare functions
      "in"    : "Py_EQ",
      "not_in": "Py_NE",
  }
  
  class CmpNode(object):
      #  Mixin class containing code common to PrimaryCmpNodes
      #  and CascadedCmpNodes.
  
      special_bool_cmp_function = None
      special_bool_cmp_utility_code = None
  
      def infer_type(self, env):
          # TODO: Actually implement this (after merging with -unstable).
          return py_object_type
  
      def calculate_cascaded_constant_result(self, operand1_result):
          func = compile_time_binary_operators[self.operator]
          operand2_result = self.operand2.constant_result
          if (isinstance(operand1_result, any_string_type) and
                  isinstance(operand2_result, any_string_type) and
                  type(operand1_result) != type(operand2_result)):
              # string comparison of different types isn't portable
              return
  
          if self.operator in ('in', 'not_in'):
              if isinstance(self.operand2, (ListNode, TupleNode, SetNode)):
                  if not self.operand2.args:
                      self.constant_result = self.operator == 'not_in'
                      return
                  elif isinstance(self.operand2, ListNode) and not self.cascade:
                      # tuples are more efficient to store than lists
                      self.operand2 = self.operand2.as_tuple()
              elif isinstance(self.operand2, DictNode):
                  if not self.operand2.key_value_pairs:
                      self.constant_result = self.operator == 'not_in'
                      return
  
          self.constant_result = func(operand1_result, operand2_result)
  
      def cascaded_compile_time_value(self, operand1, denv):
          func = get_compile_time_binop(self)
          operand2 = self.operand2.compile_time_value(denv)
          try:
              result = func(operand1, operand2)
          except Exception as e:
              self.compile_time_value_error(e)
              result = None
          if result:
              cascade = self.cascade
              if cascade:
                  result = result and cascade.cascaded_compile_time_value(operand2, denv)
          return result
  
      def is_cpp_comparison(self):
          return self.operand1.type.is_cpp_class or self.operand2.type.is_cpp_class
  
      def find_common_int_type(self, env, op, operand1, operand2):
          # type1 != type2 and at least one of the types is not a C int
          type1 = operand1.type
          type2 = operand2.type
          type1_can_be_int = False
          type2_can_be_int = False
  
          if operand1.is_string_literal and operand1.can_coerce_to_char_literal():
              type1_can_be_int = True
          if operand2.is_string_literal and operand2.can_coerce_to_char_literal():
              type2_can_be_int = True
  
          if type1.is_int:
              if type2_can_be_int:
                  return type1
          elif type2.is_int:
              if type1_can_be_int:
                  return type2
          elif type1_can_be_int:
              if type2_can_be_int:
                  if Builtin.unicode_type in (type1, type2):
                      return PyrexTypes.c_py_ucs4_type
                  else:
                      return PyrexTypes.c_uchar_type
  
          return None
  
      def find_common_type(self, env, op, operand1, common_type=None):
          operand2 = self.operand2
          type1 = operand1.type
          type2 = operand2.type
  
          new_common_type = None
  
          # catch general errors
          if (type1 == str_type and (type2.is_string or type2 in (bytes_type, unicode_type)) or
                  type2 == str_type and (type1.is_string or type1 in (bytes_type, unicode_type))):
              error(self.pos, "Comparisons between bytes/unicode and str are not portable to Python 3")
              new_common_type = error_type
  
          # try to use numeric comparisons where possible
          elif type1.is_complex or type2.is_complex:
              if (op not in ('==', '!=')
                      and (type1.is_complex or type1.is_numeric)
                      and (type2.is_complex or type2.is_numeric)):
                  error(self.pos, "complex types are unordered")
                  new_common_type = error_type
              elif type1.is_pyobject:
                  new_common_type = Builtin.complex_type if type1.subtype_of(Builtin.complex_type) else py_object_type
              elif type2.is_pyobject:
                  new_common_type = Builtin.complex_type if type2.subtype_of(Builtin.complex_type) else py_object_type
              else:
                  new_common_type = PyrexTypes.widest_numeric_type(type1, type2)
          elif type1.is_numeric and type2.is_numeric:
              new_common_type = PyrexTypes.widest_numeric_type(type1, type2)
          elif common_type is None or not common_type.is_pyobject:
              new_common_type = self.find_common_int_type(env, op, operand1, operand2)
  
          if new_common_type is None:
              # fall back to generic type compatibility tests
              if type1.is_ctuple or type2.is_ctuple:
                  new_common_type = py_object_type
              elif type1 == type2:
                  new_common_type = type1
              elif type1.is_pyobject or type2.is_pyobject:
                  if type2.is_numeric or type2.is_string:
                      if operand2.check_for_coercion_error(type1, env):
                          new_common_type = error_type
                      else:
                          new_common_type = py_object_type
                  elif type1.is_numeric or type1.is_string:
                      if operand1.check_for_coercion_error(type2, env):
                          new_common_type = error_type
                      else:
                          new_common_type = py_object_type
                  elif py_object_type.assignable_from(type1) and py_object_type.assignable_from(type2):
                      new_common_type = py_object_type
                  else:
                      # one Python type and one non-Python type, not assignable
                      self.invalid_types_error(operand1, op, operand2)
                      new_common_type = error_type
              elif type1.assignable_from(type2):
                  new_common_type = type1
              elif type2.assignable_from(type1):
                  new_common_type = type2
              else:
                  # C types that we couldn't handle up to here are an error
                  self.invalid_types_error(operand1, op, operand2)
                  new_common_type = error_type
  
          if new_common_type.is_string and (isinstance(operand1, BytesNode) or
                                            isinstance(operand2, BytesNode)):
              # special case when comparing char* to bytes literal: must
              # compare string values!
              new_common_type = bytes_type
  
          # recursively merge types
          if common_type is None or new_common_type.is_error:
              common_type = new_common_type
          else:
              # we could do a lot better by splitting the comparison
              # into a non-Python part and a Python part, but this is
              # safer for now
              common_type = PyrexTypes.spanning_type(common_type, new_common_type)
  
          if self.cascade:
              common_type = self.cascade.find_common_type(env, self.operator, operand2, common_type)
  
          return common_type
  
      def invalid_types_error(self, operand1, op, operand2):
          error(self.pos, "Invalid types for '%s' (%s, %s)" %
                (op, operand1.type, operand2.type))
  
      def is_python_comparison(self):
          return (not self.is_ptr_contains()
              and not self.is_c_string_contains()
              and (self.has_python_operands()
                   or (self.cascade and self.cascade.is_python_comparison())
                   or self.operator in ('in', 'not_in')))
  
      def coerce_operands_to(self, dst_type, env):
          operand2 = self.operand2
          if operand2.type != dst_type:
              self.operand2 = operand2.coerce_to(dst_type, env)
          if self.cascade:
              self.cascade.coerce_operands_to(dst_type, env)
  
      def is_python_result(self):
          return ((self.has_python_operands() and
                   self.special_bool_cmp_function is None and
                   self.operator not in ('is', 'is_not', 'in', 'not_in') and
                   not self.is_c_string_contains() and
                   not self.is_ptr_contains())
              or (self.cascade and self.cascade.is_python_result()))
  
      def is_c_string_contains(self):
          return self.operator in ('in', 'not_in') and \
                 ((self.operand1.type.is_int
                   and (self.operand2.type.is_string or self.operand2.type is bytes_type)) or
                  (self.operand1.type.is_unicode_char
                   and self.operand2.type is unicode_type))
  
      def is_ptr_contains(self):
          if self.operator in ('in', 'not_in'):
              container_type = self.operand2.type
              return (container_type.is_ptr or container_type.is_array) \
                  and not container_type.is_string
  
      def find_special_bool_compare_function(self, env, operand1, result_is_bool=False):
          # note: currently operand1 must get coerced to a Python object if we succeed here!
          if self.operator in ('==', '!='):
              type1, type2 = operand1.type, self.operand2.type
              if result_is_bool or (type1.is_builtin_type and type2.is_builtin_type):
                  if type1 is Builtin.unicode_type or type2 is Builtin.unicode_type:
                      self.special_bool_cmp_utility_code = UtilityCode.load_cached("UnicodeEquals", "StringTools.c")
                      self.special_bool_cmp_function = "__Pyx_PyUnicode_Equals"
                      return True
                  elif type1 is Builtin.bytes_type or type2 is Builtin.bytes_type:
                      self.special_bool_cmp_utility_code = UtilityCode.load_cached("BytesEquals", "StringTools.c")
                      self.special_bool_cmp_function = "__Pyx_PyBytes_Equals"
                      return True
                  elif type1 is Builtin.basestring_type or type2 is Builtin.basestring_type:
                      self.special_bool_cmp_utility_code = UtilityCode.load_cached("UnicodeEquals", "StringTools.c")
                      self.special_bool_cmp_function = "__Pyx_PyUnicode_Equals"
                      return True
                  elif type1 is Builtin.str_type or type2 is Builtin.str_type:
                      self.special_bool_cmp_utility_code = UtilityCode.load_cached("StrEquals", "StringTools.c")
                      self.special_bool_cmp_function = "__Pyx_PyString_Equals"
                      return True
          elif self.operator in ('in', 'not_in'):
              if self.operand2.type is Builtin.dict_type:
                  self.operand2 = self.operand2.as_none_safe_node("'NoneType' object is not iterable")
                  self.special_bool_cmp_utility_code = UtilityCode.load_cached("PyDictContains", "ObjectHandling.c")
                  self.special_bool_cmp_function = "__Pyx_PyDict_ContainsTF"
                  return True
              elif self.operand2.type is Builtin.set_type:
                  self.operand2 = self.operand2.as_none_safe_node("'NoneType' object is not iterable")
                  self.special_bool_cmp_utility_code = UtilityCode.load_cached("PySetContains", "ObjectHandling.c")
                  self.special_bool_cmp_function = "__Pyx_PySet_ContainsTF"
                  return True
              elif self.operand2.type is Builtin.unicode_type:
                  self.operand2 = self.operand2.as_none_safe_node("'NoneType' object is not iterable")
                  self.special_bool_cmp_utility_code = UtilityCode.load_cached("PyUnicodeContains", "StringTools.c")
                  self.special_bool_cmp_function = "__Pyx_PyUnicode_ContainsTF"
                  return True
              else:
                  if not self.operand2.type.is_pyobject:
                      self.operand2 = self.operand2.coerce_to_pyobject(env)
                  self.special_bool_cmp_utility_code = UtilityCode.load_cached("PySequenceContains", "ObjectHandling.c")
                  self.special_bool_cmp_function = "__Pyx_PySequence_ContainsTF"
                  return True
          return False
  
      def generate_operation_code(self, code, result_code,
              operand1, op , operand2):
          if self.type.is_pyobject:
              error_clause = code.error_goto_if_null
              got_ref = "__Pyx_XGOTREF(%s); " % result_code
              if self.special_bool_cmp_function:
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("PyBoolOrNullFromLong", "ObjectHandling.c"))
                  coerce_result = "__Pyx_PyBoolOrNull_FromLong"
              else:
                  coerce_result = "__Pyx_PyBool_FromLong"
          else:
              error_clause = code.error_goto_if_neg
              got_ref = ""
              coerce_result = ""
  
          if self.special_bool_cmp_function:
              if operand1.type.is_pyobject:
                  result1 = operand1.py_result()
              else:
                  result1 = operand1.result()
              if operand2.type.is_pyobject:
                  result2 = operand2.py_result()
              else:
                  result2 = operand2.result()
              if self.special_bool_cmp_utility_code:
                  code.globalstate.use_utility_code(self.special_bool_cmp_utility_code)
              code.putln(
                  "%s = %s(%s(%s, %s, %s)); %s%s" % (
                      result_code,
                      coerce_result,
                      self.special_bool_cmp_function,
                      result1, result2, richcmp_constants[op],
                      got_ref,
                      error_clause(result_code, self.pos)))
  
          elif operand1.type.is_pyobject and op not in ('is', 'is_not'):
              assert op not in ('in', 'not_in'), op
              code.putln("%s = PyObject_RichCompare(%s, %s, %s); %s%s" % (
                      result_code,
                      operand1.py_result(),
                      operand2.py_result(),
                      richcmp_constants[op],
                      got_ref,
                      error_clause(result_code, self.pos)))
  
          elif operand1.type.is_complex:
              code.putln("%s = %s(%s%s(%s, %s));" % (
                  result_code,
                  coerce_result,
                  op == "!=" and "!" or "",
                  operand1.type.unary_op('eq'),
                  operand1.result(),
                  operand2.result()))
  
          else:
              type1 = operand1.type
              type2 = operand2.type
              if (type1.is_extension_type or type2.is_extension_type) \
                      and not type1.same_as(type2):
                  common_type = py_object_type
              elif type1.is_numeric:
                  common_type = PyrexTypes.widest_numeric_type(type1, type2)
              else:
                  common_type = type1
              code1 = operand1.result_as(common_type)
              code2 = operand2.result_as(common_type)
              statement = "%s = %s(%s %s %s);" % (
                  result_code,
                  coerce_result,
                  code1,
                  self.c_operator(op),
                  code2)
              if self.is_cpp_comparison() and self.exception_check == '+':
                  translate_cpp_exception(
                      code,
                      self.pos,
                      statement,
                      result_code if self.type.is_pyobject else None,
                      self.exception_value,
                      self.in_nogil_context)
              else:
                  code.putln(statement)
  
      def c_operator(self, op):
          if op == 'is':
              return "=="
          elif op == 'is_not':
              return "!="
          else:
              return op
  
  class PrimaryCmpNode(ExprNode, CmpNode):
      #  Non-cascaded comparison or first comparison of
      #  a cascaded sequence.
      #
      #  operator      string
      #  operand1      ExprNode
      #  operand2      ExprNode
      #  cascade       CascadedCmpNode
  
      #  We don't use the subexprs mechanism, because
      #  things here are too complicated for it to handle.
      #  Instead, we override all the framework methods
      #  which use it.
  
      child_attrs = ['operand1', 'operand2', 'coerced_operand2', 'cascade']
  
      cascade = None
      coerced_operand2 = None
      is_memslice_nonecheck = False
  
      def infer_type(self, env):
          type1 = self.operand1.infer_type(env)
          type2 = self.operand2.infer_type(env)
  
          if is_pythran_expr(type1) or is_pythran_expr(type2):
              if is_pythran_supported_type(type1) and is_pythran_supported_type(type2):
                  return PythranExpr(pythran_binop_type(self.operator, type1, type2))
  
          # TODO: implement this for other types.
          return py_object_type
  
      def type_dependencies(self, env):
          return ()
  
      def calculate_constant_result(self):
          assert not self.cascade
          self.calculate_cascaded_constant_result(self.operand1.constant_result)
  
      def compile_time_value(self, denv):
          operand1 = self.operand1.compile_time_value(denv)
          return self.cascaded_compile_time_value(operand1, denv)
  
      def analyse_types(self, env):
          self.operand1 = self.operand1.analyse_types(env)
          self.operand2 = self.operand2.analyse_types(env)
          if self.is_cpp_comparison():
              self.analyse_cpp_comparison(env)
              if self.cascade:
                  error(self.pos, "Cascading comparison not yet supported for cpp types.")
              return self
  
          type1 = self.operand1.type
          type2 = self.operand2.type
          if is_pythran_expr(type1) or is_pythran_expr(type2):
              if is_pythran_supported_type(type1) and is_pythran_supported_type(type2):
                  self.type = PythranExpr(pythran_binop_type(self.operator, type1, type2))
                  self.is_pycmp = False
                  return self
  
          if self.analyse_memoryviewslice_comparison(env):
              return self
  
          if self.cascade:
              self.cascade = self.cascade.analyse_types(env)
  
          if self.operator in ('in', 'not_in'):
              if self.is_c_string_contains():
                  self.is_pycmp = False
                  common_type = None
                  if self.cascade:
                      error(self.pos, "Cascading comparison not yet supported for 'int_val in string'.")
                      return self
                  if self.operand2.type is unicode_type:
                      env.use_utility_code(UtilityCode.load_cached("PyUCS4InUnicode", "StringTools.c"))
                  else:
                      if self.operand1.type is PyrexTypes.c_uchar_type:
                          self.operand1 = self.operand1.coerce_to(PyrexTypes.c_char_type, env)
                      if self.operand2.type is not bytes_type:
                          self.operand2 = self.operand2.coerce_to(bytes_type, env)
                      env.use_utility_code(UtilityCode.load_cached("BytesContains", "StringTools.c"))
                  self.operand2 = self.operand2.as_none_safe_node(
                      "argument of type 'NoneType' is not iterable")
              elif self.is_ptr_contains():
                  if self.cascade:
                      error(self.pos, "Cascading comparison not supported for 'val in sliced pointer'.")
                  self.type = PyrexTypes.c_bint_type
                  # Will be transformed by IterationTransform
                  return self
              elif self.find_special_bool_compare_function(env, self.operand1):
                  if not self.operand1.type.is_pyobject:
                      self.operand1 = self.operand1.coerce_to_pyobject(env)
                  common_type = None  # if coercion needed, the method call above has already done it
                  self.is_pycmp = False  # result is bint
              else:
                  common_type = py_object_type
                  self.is_pycmp = True
          elif self.find_special_bool_compare_function(env, self.operand1):
              if not self.operand1.type.is_pyobject:
                  self.operand1 = self.operand1.coerce_to_pyobject(env)
              common_type = None  # if coercion needed, the method call above has already done it
              self.is_pycmp = False  # result is bint
          else:
              common_type = self.find_common_type(env, self.operator, self.operand1)
              self.is_pycmp = common_type.is_pyobject
  
          if common_type is not None and not common_type.is_error:
              if self.operand1.type != common_type:
                  self.operand1 = self.operand1.coerce_to(common_type, env)
              self.coerce_operands_to(common_type, env)
  
          if self.cascade:
              self.operand2 = self.operand2.coerce_to_simple(env)
              self.cascade.coerce_cascaded_operands_to_temp(env)
              operand2 = self.cascade.optimise_comparison(self.operand2, env)
              if operand2 is not self.operand2:
                  self.coerced_operand2 = operand2
          if self.is_python_result():
              self.type = PyrexTypes.py_object_type
          else:
              self.type = PyrexTypes.c_bint_type
          cdr = self.cascade
          while cdr:
              cdr.type = self.type
              cdr = cdr.cascade
          if self.is_pycmp or self.cascade or self.special_bool_cmp_function:
              # 1) owned reference, 2) reused value, 3) potential function error return value
              self.is_temp = 1
          return self
  
      def analyse_cpp_comparison(self, env):
          type1 = self.operand1.type
          type2 = self.operand2.type
          self.is_pycmp = False
          entry = env.lookup_operator(self.operator, [self.operand1, self.operand2])
          if entry is None:
              error(self.pos, "Invalid types for '%s' (%s, %s)" %
                  (self.operator, type1, type2))
              self.type = PyrexTypes.error_type
              self.result_code = "<error>"
              return
          func_type = entry.type
          if func_type.is_ptr:
              func_type = func_type.base_type
          self.exception_check = func_type.exception_check
          self.exception_value = func_type.exception_value
          if self.exception_check == '+':
              self.is_temp = True
              if self.exception_value is None:
                  env.use_utility_code(UtilityCode.load_cached("CppExceptionConversion", "CppSupport.cpp"))
          if len(func_type.args) == 1:
              self.operand2 = self.operand2.coerce_to(func_type.args[0].type, env)
          else:
              self.operand1 = self.operand1.coerce_to(func_type.args[0].type, env)
              self.operand2 = self.operand2.coerce_to(func_type.args[1].type, env)
          self.type = func_type.return_type
  
      def analyse_memoryviewslice_comparison(self, env):
          have_none = self.operand1.is_none or self.operand2.is_none
          have_slice = (self.operand1.type.is_memoryviewslice or
                        self.operand2.type.is_memoryviewslice)
          ops = ('==', '!=', 'is', 'is_not')
          if have_slice and have_none and self.operator in ops:
              self.is_pycmp = False
              self.type = PyrexTypes.c_bint_type
              self.is_memslice_nonecheck = True
              return True
  
          return False
  
      def coerce_to_boolean(self, env):
          if self.is_pycmp:
              # coercing to bool => may allow for more efficient comparison code
              if self.find_special_bool_compare_function(
                      env, self.operand1, result_is_bool=True):
                  self.is_pycmp = False
                  self.type = PyrexTypes.c_bint_type
                  self.is_temp = 1
                  if self.cascade:
                      operand2 = self.cascade.optimise_comparison(
                          self.operand2, env, result_is_bool=True)
                      if operand2 is not self.operand2:
                          self.coerced_operand2 = operand2
                  return self
          # TODO: check if we can optimise parts of the cascade here
          return ExprNode.coerce_to_boolean(self, env)
  
      def has_python_operands(self):
          return (self.operand1.type.is_pyobject
              or self.operand2.type.is_pyobject)
  
      def check_const(self):
          if self.cascade:
              self.not_const()
              return False
          else:
              return self.operand1.check_const() and self.operand2.check_const()
  
      def calculate_result_code(self):
          operand1, operand2 = self.operand1, self.operand2
          if operand1.type.is_complex:
              if self.operator == "!=":
                  negation = "!"
              else:
                  negation = ""
              return "(%s%s(%s, %s))" % (
                  negation,
                  operand1.type.binary_op('=='),
                  operand1.result(),
                  operand2.result())
          elif self.is_c_string_contains():
              if operand2.type is unicode_type:
                  method = "__Pyx_UnicodeContainsUCS4"
              else:
                  method = "__Pyx_BytesContains"
              if self.operator == "not_in":
                  negation = "!"
              else:
                  negation = ""
              return "(%s%s(%s, %s))" % (
                  negation,
                  method,
                  operand2.result(),
                  operand1.result())
          else:
              if is_pythran_expr(self.type):
                  result1, result2 = operand1.pythran_result(), operand2.pythran_result()
              else:
                  result1, result2 = operand1.result(), operand2.result()
                  if self.is_memslice_nonecheck:
                      if operand1.type.is_memoryviewslice:
                          result1 = "((PyObject *) %s.memview)" % result1
                      else:
                          result2 = "((PyObject *) %s.memview)" % result2
  
              return "(%s %s %s)" % (
                  result1,
                  self.c_operator(self.operator),
                  result2)
  
      def generate_evaluation_code(self, code):
          self.operand1.generate_evaluation_code(code)
          self.operand2.generate_evaluation_code(code)
          if self.is_temp:
              self.allocate_temp_result(code)
              self.generate_operation_code(code, self.result(),
                  self.operand1, self.operator, self.operand2)
              if self.cascade:
                  self.cascade.generate_evaluation_code(
                      code, self.result(), self.coerced_operand2 or self.operand2,
                      needs_evaluation=self.coerced_operand2 is not None)
              self.operand1.generate_disposal_code(code)
              self.operand1.free_temps(code)
              self.operand2.generate_disposal_code(code)
              self.operand2.free_temps(code)
  
      def generate_subexpr_disposal_code(self, code):
          #  If this is called, it is a non-cascaded cmp,
          #  so only need to dispose of the two main operands.
          self.operand1.generate_disposal_code(code)
          self.operand2.generate_disposal_code(code)
  
      def free_subexpr_temps(self, code):
          #  If this is called, it is a non-cascaded cmp,
          #  so only need to dispose of the two main operands.
          self.operand1.free_temps(code)
          self.operand2.free_temps(code)
  
      def annotate(self, code):
          self.operand1.annotate(code)
          self.operand2.annotate(code)
          if self.cascade:
              self.cascade.annotate(code)
  
  
  class CascadedCmpNode(Node, CmpNode):
      #  A CascadedCmpNode is not a complete expression node. It
      #  hangs off the side of another comparison node, shares
      #  its left operand with that node, and shares its result
      #  with the PrimaryCmpNode at the head of the chain.
      #
      #  operator      string
      #  operand2      ExprNode
      #  cascade       CascadedCmpNode
  
      child_attrs = ['operand2', 'coerced_operand2', 'cascade']
  
      cascade = None
      coerced_operand2 = None
      constant_result = constant_value_not_set  # FIXME: where to calculate this?
  
      def infer_type(self, env):
          # TODO: Actually implement this (after merging with -unstable).
          return py_object_type
  
      def type_dependencies(self, env):
          return ()
  
      def has_constant_result(self):
          return self.constant_result is not constant_value_not_set and \
                 self.constant_result is not not_a_constant
  
      def analyse_types(self, env):
          self.operand2 = self.operand2.analyse_types(env)
          if self.cascade:
              self.cascade = self.cascade.analyse_types(env)
          return self
  
      def has_python_operands(self):
          return self.operand2.type.is_pyobject
  
      def is_cpp_comparison(self):
          # cascaded comparisons aren't currently implemented for c++ classes.
          return False
  
      def optimise_comparison(self, operand1, env, result_is_bool=False):
          if self.find_special_bool_compare_function(env, operand1, result_is_bool):
              self.is_pycmp = False
              self.type = PyrexTypes.c_bint_type
              if not operand1.type.is_pyobject:
                  operand1 = operand1.coerce_to_pyobject(env)
          if self.cascade:
              operand2 = self.cascade.optimise_comparison(self.operand2, env, result_is_bool)
              if operand2 is not self.operand2:
                  self.coerced_operand2 = operand2
          return operand1
  
      def coerce_operands_to_pyobjects(self, env):
          self.operand2 = self.operand2.coerce_to_pyobject(env)
          if self.operand2.type is dict_type and self.operator in ('in', 'not_in'):
              self.operand2 = self.operand2.as_none_safe_node("'NoneType' object is not iterable")
          if self.cascade:
              self.cascade.coerce_operands_to_pyobjects(env)
  
      def coerce_cascaded_operands_to_temp(self, env):
          if self.cascade:
              #self.operand2 = self.operand2.coerce_to_temp(env) #CTT
              self.operand2 = self.operand2.coerce_to_simple(env)
              self.cascade.coerce_cascaded_operands_to_temp(env)
  
      def generate_evaluation_code(self, code, result, operand1, needs_evaluation=False):
          if self.type.is_pyobject:
              code.putln("if (__Pyx_PyObject_IsTrue(%s)) {" % result)
              code.put_decref(result, self.type)
          else:
              code.putln("if (%s) {" % result)
          if needs_evaluation:
              operand1.generate_evaluation_code(code)
          self.operand2.generate_evaluation_code(code)
          self.generate_operation_code(code, result,
              operand1, self.operator, self.operand2)
          if self.cascade:
              self.cascade.generate_evaluation_code(
                  code, result, self.coerced_operand2 or self.operand2,
                  needs_evaluation=self.coerced_operand2 is not None)
          if needs_evaluation:
              operand1.generate_disposal_code(code)
              operand1.free_temps(code)
          # Cascaded cmp result is always temp
          self.operand2.generate_disposal_code(code)
          self.operand2.free_temps(code)
          code.putln("}")
  
      def annotate(self, code):
          self.operand2.annotate(code)
          if self.cascade:
              self.cascade.annotate(code)
  
  
  binop_node_classes = {
      "or":       BoolBinopNode,
      "and":      BoolBinopNode,
      "|":        IntBinopNode,
      "^":        IntBinopNode,
      "&":        IntBinopNode,
      "<<":       IntBinopNode,
      ">>":       IntBinopNode,
      "+":        AddNode,
      "-":        SubNode,
      "*":        MulNode,
      "@":        MatMultNode,
      "/":        DivNode,
      "//":       DivNode,
      "%":        ModNode,
      "**":       PowNode,
  }
  
  
  def binop_node(pos, operator, operand1, operand2, inplace=False, **kwargs):
      # Construct binop node of appropriate class for
      # given operator.
      return binop_node_classes[operator](
          pos,
          operator=operator,
          operand1=operand1,
          operand2=operand2,
          inplace=inplace,
          **kwargs)
  
  
  #-------------------------------------------------------------------
  #
  #  Coercion nodes
  #
  #  Coercion nodes are special in that they are created during
  #  the analyse_types phase of parse tree processing.
  #  Their __init__ methods consequently incorporate some aspects
  #  of that phase.
  #
  #-------------------------------------------------------------------
  
  class CoercionNode(ExprNode):
      #  Abstract base class for coercion nodes.
      #
      #  arg       ExprNode       node being coerced
  
      subexprs = ['arg']
      constant_result = not_a_constant
  
      def __init__(self, arg):
          super(CoercionNode, self).__init__(arg.pos)
          self.arg = arg
          if debug_coercion:
              print("%s Coercing %s" % (self, self.arg))
  
      def calculate_constant_result(self):
          # constant folding can break type coercion, so this is disabled
          pass
  
      def annotate(self, code):
          self.arg.annotate(code)
          if self.arg.type != self.type:
              file, line, col = self.pos
              code.annotate((file, line, col-1), AnnotationItem(
                  style='coerce', tag='coerce', text='[%s] to [%s]' % (self.arg.type, self.type)))
  
  
  class CoerceToMemViewSliceNode(CoercionNode):
      """
      Coerce an object to a memoryview slice. This holds a new reference in
      a managed temp.
      """
  
      def __init__(self, arg, dst_type, env):
          assert dst_type.is_memoryviewslice
          assert not arg.type.is_memoryviewslice
          CoercionNode.__init__(self, arg)
          self.type = dst_type
          self.is_temp = 1
          self.use_managed_ref = True
          self.arg = arg
          self.type.create_from_py_utility_code(env)
  
      def generate_result_code(self, code):
          code.putln(self.type.from_py_call_code(
              self.arg.py_result(),
              self.result(),
              self.pos,
              code
          ))
  
  
  class CastNode(CoercionNode):
      #  Wrap a node in a C type cast.
  
      def __init__(self, arg, new_type):
          CoercionNode.__init__(self, arg)
          self.type = new_type
  
      def may_be_none(self):
          return self.arg.may_be_none()
  
      def calculate_result_code(self):
          return self.arg.result_as(self.type)
  
      def generate_result_code(self, code):
          self.arg.generate_result_code(code)
  
  
  class PyTypeTestNode(CoercionNode):
      #  This node is used to check that a generic Python
      #  object is an instance of a particular extension type.
      #  This node borrows the result of its argument node.
  
      exact_builtin_type = True
  
      def __init__(self, arg, dst_type, env, notnone=False):
          #  The arg is known to be a Python object, and
          #  the dst_type is known to be an extension type.
          assert dst_type.is_extension_type or dst_type.is_builtin_type, \
              "PyTypeTest for %s against non extension type %s" % (arg.type, dst_type)
          CoercionNode.__init__(self, arg)
          self.type = dst_type
          self.result_ctype = arg.ctype()
          self.notnone = notnone
  
      nogil_check = Node.gil_error
      gil_message = "Python type test"
  
      def analyse_types(self, env):
          return self
  
      def may_be_none(self):
          if self.notnone:
              return False
          return self.arg.may_be_none()
  
      def is_simple(self):
          return self.arg.is_simple()
  
      def result_in_temp(self):
          return self.arg.result_in_temp()
  
      def is_ephemeral(self):
          return self.arg.is_ephemeral()
  
      def nonlocally_immutable(self):
          return self.arg.nonlocally_immutable()
  
      def reanalyse(self):
          if self.type != self.arg.type or not self.arg.is_temp:
              return self
          if not self.type.typeobj_is_available():
              return self
          if self.arg.may_be_none() and self.notnone:
              return self.arg.as_none_safe_node("Cannot convert NoneType to %.200s" % self.type.name)
          return self.arg
  
      def calculate_constant_result(self):
          # FIXME
          pass
  
      def calculate_result_code(self):
          return self.arg.result()
  
      def generate_result_code(self, code):
          if self.type.typeobj_is_available():
              if self.type.is_builtin_type:
                  type_test = self.type.type_test_code(
                      self.arg.py_result(),
                      self.notnone, exact=self.exact_builtin_type)
                  code.globalstate.use_utility_code(UtilityCode.load_cached(
                      "RaiseUnexpectedTypeError", "ObjectHandling.c"))
              else:
                  type_test = self.type.type_test_code(
                      self.arg.py_result(), self.notnone)
                  code.globalstate.use_utility_code(
                      UtilityCode.load_cached("ExtTypeTest", "ObjectHandling.c"))
              code.putln("if (!(%s)) %s" % (
                  type_test, code.error_goto(self.pos)))
          else:
              error(self.pos, "Cannot test type of extern C class "
                  "without type object name specification")
  
      def generate_post_assignment_code(self, code):
          self.arg.generate_post_assignment_code(code)
  
      def allocate_temp_result(self, code):
          pass
  
      def release_temp_result(self, code):
          pass
  
      def free_temps(self, code):
          self.arg.free_temps(code)
  
      def free_subexpr_temps(self, code):
          self.arg.free_subexpr_temps(code)
  
  
  class NoneCheckNode(CoercionNode):
      # This node is used to check that a Python object is not None and
      # raises an appropriate exception (as specified by the creating
      # transform).
  
      is_nonecheck = True
  
      def __init__(self, arg, exception_type_cname, exception_message,
                   exception_format_args=()):
          CoercionNode.__init__(self, arg)
          self.type = arg.type
          self.result_ctype = arg.ctype()
          self.exception_type_cname = exception_type_cname
          self.exception_message = exception_message
          self.exception_format_args = tuple(exception_format_args or ())
  
      nogil_check = None  # this node only guards an operation that would fail already
  
      def analyse_types(self, env):
          return self
  
      def may_be_none(self):
          return False
  
      def is_simple(self):
          return self.arg.is_simple()
  
      def result_in_temp(self):
          return self.arg.result_in_temp()
  
      def nonlocally_immutable(self):
          return self.arg.nonlocally_immutable()
  
      def calculate_result_code(self):
          return self.arg.result()
  
      def condition(self):
          if self.type.is_pyobject:
              return self.arg.py_result()
          elif self.type.is_memoryviewslice:
              return "((PyObject *) %s.memview)" % self.arg.result()
          else:
              raise Exception("unsupported type")
  
      @classmethod
      def generate(cls, arg, code, exception_message,
                   exception_type_cname="PyExc_TypeError", exception_format_args=(), in_nogil_context=False):
          node = cls(arg, exception_type_cname, exception_message, exception_format_args)
          node.in_nogil_context = in_nogil_context
          node.put_nonecheck(code)
  
      @classmethod
      def generate_if_needed(cls, arg, code, exception_message,
                             exception_type_cname="PyExc_TypeError", exception_format_args=(), in_nogil_context=False):
          if arg.may_be_none():
              cls.generate(arg, code, exception_message, exception_type_cname, exception_format_args, in_nogil_context)
  
      def put_nonecheck(self, code):
          code.putln(
              "if (unlikely(%s == Py_None)) {" % self.condition())
  
          if self.in_nogil_context:
              code.put_ensure_gil()
  
          escape = StringEncoding.escape_byte_string
          if self.exception_format_args:
              code.putln('PyErr_Format(%s, "%s", %s);' % (
                  self.exception_type_cname,
                  StringEncoding.escape_byte_string(
                      self.exception_message.encode('UTF-8')),
                  ', '.join([ '"%s"' % escape(str(arg).encode('UTF-8'))
                              for arg in self.exception_format_args ])))
          else:
              code.putln('PyErr_SetString(%s, "%s");' % (
                  self.exception_type_cname,
                  escape(self.exception_message.encode('UTF-8'))))
  
          if self.in_nogil_context:
              code.put_release_ensured_gil()
  
          code.putln(code.error_goto(self.pos))
          code.putln("}")
  
      def generate_result_code(self, code):
          self.put_nonecheck(code)
  
      def generate_post_assignment_code(self, code):
          self.arg.generate_post_assignment_code(code)
  
      def free_temps(self, code):
          self.arg.free_temps(code)
  
  
  class CoerceToPyTypeNode(CoercionNode):
      #  This node is used to convert a C data type
      #  to a Python object.
  
      type = py_object_type
      target_type = py_object_type
      is_temp = 1
  
      def __init__(self, arg, env, type=py_object_type):
          if not arg.type.create_to_py_utility_code(env):
              error(arg.pos, "Cannot convert '%s' to Python object" % arg.type)
          elif arg.type.is_complex:
              # special case: complex coercion is so complex that it
              # uses a macro ("__pyx_PyComplex_FromComplex()"), for
              # which the argument must be simple
              arg = arg.coerce_to_simple(env)
          CoercionNode.__init__(self, arg)
          if type is py_object_type:
              # be specific about some known types
              if arg.type.is_string or arg.type.is_cpp_string:
                  self.type = default_str_type(env)
              elif arg.type.is_pyunicode_ptr or arg.type.is_unicode_char:
                  self.type = unicode_type
              elif arg.type.is_complex:
                  self.type = Builtin.complex_type
              self.target_type = self.type
          elif arg.type.is_string or arg.type.is_cpp_string:
              if (type not in (bytes_type, bytearray_type)
                      and not env.directives['c_string_encoding']):
                  error(arg.pos,
                      "default encoding required for conversion from '%s' to '%s'" %
                      (arg.type, type))
              self.type = self.target_type = type
          else:
              # FIXME: check that the target type and the resulting type are compatible
              self.target_type = type
  
      gil_message = "Converting to Python object"
  
      def may_be_none(self):
          # FIXME: is this always safe?
          return False
  
      def coerce_to_boolean(self, env):
          arg_type = self.arg.type
          if (arg_type == PyrexTypes.c_bint_type or
                  (arg_type.is_pyobject and arg_type.name == 'bool')):
              return self.arg.coerce_to_temp(env)
          else:
              return CoerceToBooleanNode(self, env)
  
      def coerce_to_integer(self, env):
          # If not already some C integer type, coerce to longint.
          if self.arg.type.is_int:
              return self.arg
          else:
              return self.arg.coerce_to(PyrexTypes.c_long_type, env)
  
      def analyse_types(self, env):
          # The arg is always already analysed
          return self
  
      def generate_result_code(self, code):
          code.putln('%s; %s' % (
              self.arg.type.to_py_call_code(
                  self.arg.result(),
                  self.result(),
                  self.target_type),
              code.error_goto_if_null(self.result(), self.pos)))
  
          self.generate_gotref(code)
  
  
  class CoerceIntToBytesNode(CoerceToPyTypeNode):
      #  This node is used to convert a C int type to a Python bytes
      #  object.
  
      is_temp = 1
  
      def __init__(self, arg, env):
          arg = arg.coerce_to_simple(env)
          CoercionNode.__init__(self, arg)
          self.type = Builtin.bytes_type
  
      def generate_result_code(self, code):
          arg = self.arg
          arg_result = arg.result()
          if arg.type not in (PyrexTypes.c_char_type,
                              PyrexTypes.c_uchar_type,
                              PyrexTypes.c_schar_type):
              if arg.type.signed:
                  code.putln("if ((%s < 0) || (%s > 255)) {" % (
                      arg_result, arg_result))
              else:
                  code.putln("if (%s > 255) {" % arg_result)
              code.putln('PyErr_SetString(PyExc_OverflowError, '
                         '"value too large to pack into a byte"); %s' % (
                             code.error_goto(self.pos)))
              code.putln('}')
          temp = None
          if arg.type is not PyrexTypes.c_char_type:
              temp = code.funcstate.allocate_temp(PyrexTypes.c_char_type, manage_ref=False)
              code.putln("%s = (char)%s;" % (temp, arg_result))
              arg_result = temp
          code.putln('%s = PyBytes_FromStringAndSize(&%s, 1); %s' % (
              self.result(),
              arg_result,
              code.error_goto_if_null(self.result(), self.pos)))
          if temp is not None:
              code.funcstate.release_temp(temp)
          self.generate_gotref(code)
  
  
  class CoerceFromPyTypeNode(CoercionNode):
      #  This node is used to convert a Python object
      #  to a C data type.
  
      def __init__(self, result_type, arg, env):
          CoercionNode.__init__(self, arg)
          self.type = result_type
          self.is_temp = 1
          if not result_type.create_from_py_utility_code(env):
              error(arg.pos,
                    "Cannot convert Python object to '%s'" % result_type)
          if self.type.is_string or self.type.is_pyunicode_ptr:
              if self.arg.is_name and self.arg.entry and self.arg.entry.is_pyglobal:
                  warning(arg.pos,
                          "Obtaining '%s' from externally modifiable global Python value" % result_type,
                          level=1)
  
      def analyse_types(self, env):
          # The arg is always already analysed
          return self
  
      def is_ephemeral(self):
          return (self.type.is_ptr and not self.type.is_array) and self.arg.is_ephemeral()
  
      def generate_result_code(self, code):
          from_py_function = None
          # for certain source types, we can do better than the generic coercion
          if self.type.is_string and self.arg.type is bytes_type:
              if self.type.from_py_function.startswith('__Pyx_PyObject_As'):
                  from_py_function = '__Pyx_PyBytes' + self.type.from_py_function[len('__Pyx_PyObject'):]
                  NoneCheckNode.generate_if_needed(self.arg, code, "expected bytes, NoneType found")
  
          code.putln(self.type.from_py_call_code(
              self.arg.py_result(), self.result(), self.pos, code, from_py_function=from_py_function))
          if self.type.is_pyobject:
              self.generate_gotref(code)
  
      def nogil_check(self, env):
          error(self.pos, "Coercion from Python not allowed without the GIL")
  
  
  class CoerceToBooleanNode(CoercionNode):
      #  This node is used when a result needs to be used
      #  in a boolean context.
  
      type = PyrexTypes.c_bint_type
  
      _special_builtins = {
          Builtin.list_type:       'PyList_GET_SIZE',
          Builtin.tuple_type:      'PyTuple_GET_SIZE',
          Builtin.set_type:        'PySet_GET_SIZE',
          Builtin.frozenset_type:  'PySet_GET_SIZE',
          Builtin.bytes_type:      'PyBytes_GET_SIZE',
          Builtin.bytearray_type:  'PyByteArray_GET_SIZE',
          Builtin.unicode_type:    '__Pyx_PyUnicode_IS_TRUE',
      }
  
      def __init__(self, arg, env):
          CoercionNode.__init__(self, arg)
          if arg.type.is_pyobject:
              self.is_temp = 1
  
      def nogil_check(self, env):
          if self.arg.type.is_pyobject and self._special_builtins.get(self.arg.type) is None:
              self.gil_error()
  
      gil_message = "Truth-testing Python object"
  
      def check_const(self):
          if self.is_temp:
              self.not_const()
              return False
          return self.arg.check_const()
  
      def calculate_result_code(self):
          return "(%s != 0)" % self.arg.result()
  
      def generate_result_code(self, code):
          if not self.is_temp:
              return
          test_func = self._special_builtins.get(self.arg.type)
          if test_func is not None:
              checks = ["(%s != Py_None)" % self.arg.py_result()] if self.arg.may_be_none() else []
              checks.append("(%s(%s) != 0)" % (test_func, self.arg.py_result()))
              code.putln("%s = %s;" % (self.result(), '&&'.join(checks)))
          else:
              code.putln(
                  "%s = __Pyx_PyObject_IsTrue(%s); %s" % (
                      self.result(),
                      self.arg.py_result(),
                      code.error_goto_if_neg(self.result(), self.pos)))
  
      def analyse_types(self, env):
          return self
  
  
  class CoerceToComplexNode(CoercionNode):
  
      def __init__(self, arg, dst_type, env):
          if arg.type.is_complex:
              arg = arg.coerce_to_simple(env)
          self.type = dst_type
          CoercionNode.__init__(self, arg)
          dst_type.create_declaration_utility_code(env)
  
      def calculate_result_code(self):
          if self.arg.type.is_complex:
              real_part = "__Pyx_CREAL(%s)" % self.arg.result()
              imag_part = "__Pyx_CIMAG(%s)" % self.arg.result()
          else:
              real_part = self.arg.result()
              imag_part = "0"
          return "%s(%s, %s)" % (
                  self.type.from_parts,
                  real_part,
                  imag_part)
  
      def generate_result_code(self, code):
          pass
  
      def analyse_types(self, env):
          return self
  
  class CoerceToTempNode(CoercionNode):
      #  This node is used to force the result of another node
      #  to be stored in a temporary. It is only used if the
      #  argument node's result is not already in a temporary.
  
      def __init__(self, arg, env):
          CoercionNode.__init__(self, arg)
          self.type = self.arg.type.as_argument_type()
          self.constant_result = self.arg.constant_result
          self.is_temp = 1
          if self.type.is_pyobject:
              self.result_ctype = py_object_type
  
      gil_message = "Creating temporary Python reference"
  
      def analyse_types(self, env):
          # The arg is always already analysed
          return self
  
      def may_be_none(self):
          return self.arg.may_be_none()
  
      def coerce_to_boolean(self, env):
          self.arg = self.arg.coerce_to_boolean(env)
          if self.arg.is_simple():
              return self.arg
          self.type = self.arg.type
          self.result_ctype = self.type
          return self
  
      def generate_result_code(self, code):
          #self.arg.generate_evaluation_code(code) # Already done
          # by generic generate_subexpr_evaluation_code!
          code.putln("%s = %s;" % (
              self.result(), self.arg.result_as(self.ctype())))
          if self.use_managed_ref:
              if not self.type.is_memoryviewslice:
                  code.put_incref(self.result(), self.ctype())
              else:
                  code.put_incref_memoryviewslice(self.result(), self.type,
                                              have_gil=not self.in_nogil_context)
  
  class ProxyNode(CoercionNode):
      """
      A node that should not be replaced by transforms or other means,
      and hence can be useful to wrap the argument to a clone node
  
      MyNode    -> ProxyNode -> ArgNode
      CloneNode -^
      """
  
      nogil_check = None
  
      def __init__(self, arg):
          super(ProxyNode, self).__init__(arg)
          self.constant_result = arg.constant_result
          self._proxy_type()
  
      def analyse_types(self, env):
          self.arg = self.arg.analyse_expressions(env)
          self._proxy_type()
          return self
  
      def infer_type(self, env):
          return self.arg.infer_type(env)
  
      def _proxy_type(self):
          type = getattr(self.arg, 'type', None)
          if type:
              self.type = type
              self.result_ctype = self.arg.result_ctype
          arg_entry = getattr(self.arg, 'entry', None)
          if arg_entry:
              self.entry = arg_entry
  
      def generate_result_code(self, code):
          self.arg.generate_result_code(code)
  
      def result(self):
          return self.arg.result()
  
      def is_simple(self):
          return self.arg.is_simple()
  
      def may_be_none(self):
          return self.arg.may_be_none()
  
      def generate_evaluation_code(self, code):
          self.arg.generate_evaluation_code(code)
  
      def generate_disposal_code(self, code):
          self.arg.generate_disposal_code(code)
  
      def free_temps(self, code):
          self.arg.free_temps(code)
  
  class CloneNode(CoercionNode):
      #  This node is employed when the result of another node needs
      #  to be used multiple times. The argument node's result must
      #  be in a temporary. This node "borrows" the result from the
      #  argument node, and does not generate any evaluation or
      #  disposal code for it. The original owner of the argument
      #  node is responsible for doing those things.
  
      subexprs = []  # Arg is not considered a subexpr
      nogil_check = None
  
      def __init__(self, arg):
          CoercionNode.__init__(self, arg)
          self.constant_result = arg.constant_result
          type = getattr(arg, 'type', None)
          if type:
              self.type = type
              self.result_ctype = arg.result_ctype
          arg_entry = getattr(arg, 'entry', None)
          if arg_entry:
              self.entry = arg_entry
  
      def result(self):
          return self.arg.result()
  
      def may_be_none(self):
          return self.arg.may_be_none()
  
      def type_dependencies(self, env):
          return self.arg.type_dependencies(env)
  
      def infer_type(self, env):
          return self.arg.infer_type(env)
  
      def analyse_types(self, env):
          self.type = self.arg.type
          self.result_ctype = self.arg.result_ctype
          self.is_temp = 1
          arg_entry = getattr(self.arg, 'entry', None)
          if arg_entry:
              self.entry = arg_entry
          return self
  
      def coerce_to(self, dest_type, env):
          if self.arg.is_literal:
              return self.arg.coerce_to(dest_type, env)
          return super(CloneNode, self).coerce_to(dest_type, env)
  
      def is_simple(self):
          return True  # result is always in a temp (or a name)
  
      def generate_evaluation_code(self, code):
          pass
  
      def generate_result_code(self, code):
          pass
  
      def generate_disposal_code(self, code):
          pass
  
      def free_temps(self, code):
          pass
  
  
  class CMethodSelfCloneNode(CloneNode):
      # Special CloneNode for the self argument of builtin C methods
      # that accepts subtypes of the builtin type.  This is safe only
      # for 'final' subtypes, as subtypes of the declared type may
      # override the C method.
  
      def coerce_to(self, dst_type, env):
          if dst_type.is_builtin_type and self.type.subtype_of(dst_type):
              return self
          return CloneNode.coerce_to(self, dst_type, env)
  
  
  class ModuleRefNode(ExprNode):
      # Simple returns the module object
  
      type = py_object_type
      is_temp = False
      subexprs = []
  
      def analyse_types(self, env):
          return self
  
      def may_be_none(self):
          return False
  
      def calculate_result_code(self):
          return Naming.module_cname
  
      def generate_result_code(self, code):
          pass
  
  class DocstringRefNode(ExprNode):
      # Extracts the docstring of the body element
  
      subexprs = ['body']
      type = py_object_type
      is_temp = True
  
      def __init__(self, pos, body):
          ExprNode.__init__(self, pos)
          assert body.type.is_pyobject
          self.body = body
  
      def analyse_types(self, env):
          return self
  
      def generate_result_code(self, code):
          code.putln('%s = __Pyx_GetAttr(%s, %s); %s' % (
              self.result(), self.body.result(),
              code.intern_identifier(StringEncoding.EncodedString("__doc__")),
              code.error_goto_if_null(self.result(), self.pos)))
          self.generate_gotref(code)
  
  class AnnotationNode(ExprNode):
      # Deals with the two possible uses of an annotation.
      # 1. The post PEP-563 use where an annotation is stored
      #  as a string
      # 2. The Cython use where the annotation can indicate an
      #  object type
      #
      # Doesn't handle the pre PEP-563 version where the
      # annotation is evaluated into a Python Object.
  
      subexprs = []
  
      # 'untyped' is set for fused specializations:
      # Once a fused function has been created we don't want
      # annotations to override an already set type.
      untyped = False
  
      def __init__(self, pos, expr, string=None):
          """string is expected to already be a StringNode or None"""
          ExprNode.__init__(self, pos)
          if string is None:
              # import doesn't work at top of file?
              from .AutoDocTransforms import AnnotationWriter
              string = StringEncoding.EncodedString(
                  AnnotationWriter(description="annotation").write(expr))
              string = StringNode(pos, unicode_value=string, value=string.as_utf8_string())
          self.string = string
          self.expr = expr
  
      def analyse_types(self, env):
          return self  # nothing needs doing
  
      def analyse_as_type(self, env):
          # for compatibility when used as a return_type_node, have this interface too
          return self.analyse_type_annotation(env)[1]
  
      def analyse_type_annotation(self, env, assigned_value=None):
          if self.untyped:
              # Already applied as a fused type, not re-evaluating it here.
              return None, None
          annotation = self.expr
          base_type = None
          is_ambiguous = False
          explicit_pytype = explicit_ctype = False
          if annotation.is_dict_literal:
              warning(annotation.pos,
                      "Dicts should no longer be used as type annotations. Use 'cython.int' etc. directly.", level=1)
              for name, value in annotation.key_value_pairs:
                  if not name.is_string_literal:
                      continue
                  if name.value in ('type', b'type'):
                      explicit_pytype = True
                      if not explicit_ctype:
                          annotation = value
                  elif name.value in ('ctype', b'ctype'):
                      explicit_ctype = True
                      annotation = value
              if explicit_pytype and explicit_ctype:
                  warning(annotation.pos, "Duplicate type declarations found in signature annotation", level=1)
          arg_type = annotation.analyse_as_type(env)
          if annotation.is_name and not annotation.cython_attribute and annotation.name in ('int', 'long', 'float'):
              # Map builtin numeric Python types to C types in safe cases.
              if assigned_value is not None and arg_type is not None and not arg_type.is_pyobject:
                  assigned_type = assigned_value.infer_type(env)
                  if assigned_type and assigned_type.is_pyobject:
                      # C type seems unsafe, e.g. due to 'None' default value  => ignore annotation type
                      is_ambiguous = True
                      arg_type = None
              # ignore 'int' and require 'cython.int' to avoid unsafe integer declarations
              if arg_type in (PyrexTypes.c_long_type, PyrexTypes.c_int_type, PyrexTypes.c_float_type):
                  arg_type = PyrexTypes.c_double_type if annotation.name == 'float' else py_object_type
          elif arg_type is not None and annotation.is_string_literal:
              warning(annotation.pos,
                      "Strings should no longer be used for type declarations. Use 'cython.int' etc. directly.",
                      level=1)
          elif arg_type is not None and arg_type.is_complex:
              # creating utility code needs to be special-cased for complex types
              arg_type.create_declaration_utility_code(env)
          if arg_type is not None:
              if explicit_pytype and not explicit_ctype and not arg_type.is_pyobject:
                  warning(annotation.pos,
                          "Python type declaration in signature annotation does not refer to a Python type")
              base_type = Nodes.CAnalysedBaseTypeNode(
                  annotation.pos, type=arg_type, is_arg=True)
          elif is_ambiguous:
              warning(annotation.pos, "Ambiguous types in annotation, ignoring")
          else:
              warning(annotation.pos, "Unknown type declaration in annotation, ignoring")
          return base_type, arg_type
  
  #------------------------------------------------------------------------------------
  #
  #  Runtime support code
  #
  #------------------------------------------------------------------------------------
  
  pyerr_occurred_withgil_utility_code= UtilityCode(
  proto = """
  static CYTHON_INLINE int __Pyx_ErrOccurredWithGIL(void); /* proto */
  """,
  impl = """
  static CYTHON_INLINE int __Pyx_ErrOccurredWithGIL(void) {
    int err;
    #ifdef WITH_THREAD
    PyGILState_STATE _save = PyGILState_Ensure();
    #endif
    err = !!PyErr_Occurred();
    #ifdef WITH_THREAD
    PyGILState_Release(_save);
    #endif
    return err;
  }
  """
  )
  
  #------------------------------------------------------------------------------------
  
  raise_unbound_local_error_utility_code = UtilityCode(
  proto = """
  static CYTHON_INLINE void __Pyx_RaiseUnboundLocalError(const char *varname);
  """,
  impl = """
  static CYTHON_INLINE void __Pyx_RaiseUnboundLocalError(const char *varname) {
      PyErr_Format(PyExc_UnboundLocalError, "local variable '%s' referenced before assignment", varname);
  }
  """)
  
  raise_closure_name_error_utility_code = UtilityCode(
  proto = """
  static CYTHON_INLINE void __Pyx_RaiseClosureNameError(const char *varname);
  """,
  impl = """
  static CYTHON_INLINE void __Pyx_RaiseClosureNameError(const char *varname) {
      PyErr_Format(PyExc_NameError, "free variable '%s' referenced before assignment in enclosing scope", varname);
  }
  """)
  
  # Don't inline the function, it should really never be called in production
  raise_unbound_memoryview_utility_code_nogil = UtilityCode(
  proto = """
  static void __Pyx_RaiseUnboundMemoryviewSliceNogil(const char *varname);
  """,
  impl = """
  static void __Pyx_RaiseUnboundMemoryviewSliceNogil(const char *varname) {
      #ifdef WITH_THREAD
      PyGILState_STATE gilstate = PyGILState_Ensure();
      #endif
      __Pyx_RaiseUnboundLocalError(varname);
      #ifdef WITH_THREAD
      PyGILState_Release(gilstate);
      #endif
  }
  """,
  requires = [raise_unbound_local_error_utility_code])
  
  #------------------------------------------------------------------------------------
  
  raise_too_many_values_to_unpack = UtilityCode.load_cached("RaiseTooManyValuesToUnpack", "ObjectHandling.c")
  raise_need_more_values_to_unpack = UtilityCode.load_cached("RaiseNeedMoreValuesToUnpack", "ObjectHandling.c")
  tuple_unpacking_error_code = UtilityCode.load_cached("UnpackTupleError", "ObjectHandling.c")
  