text: #! /usr/bin/env python
  """Generate C code from an ASDL description."""
  
  # TO DO
  # handle fields that have a type but no name
  
  import os, sys
  
  import asdl
  
  TABSIZE = 8
  MAX_COL = 100
  
  def get_c_type(name):
      """Return a string for the C name of the type.
  
      This function special cases the default types provided by asdl:
      identifier, string, int, bool.
      """
      # XXX ack!  need to figure out where Id is useful and where string
      if isinstance(name, asdl.Id):
          name = name.value
      if name in asdl.builtin_types:
          return name
      else:
          return "%s_ty" % name
  
  def reflow_lines(s, depth):
      """Reflow the line s indented depth tabs.
  
      Return a sequence of lines where no line extends beyond MAX_COL
      when properly indented.  The first line is properly indented based
      exclusively on depth * TABSIZE.  All following lines -- these are
      the reflowed lines generated by this function -- start at the same
      column as the first character beyond the opening { in the first
      line.
      """
      size = MAX_COL - depth * TABSIZE
      if len(s) < size:
          return [s]
  
      lines = []
      cur = s
      padding = ""
      while len(cur) > size:
          i = cur.rfind(' ', 0, size)
          # XXX this should be fixed for real
          if i == -1 and 'GeneratorExp' in cur:
              i = size + 3
          assert i != -1, "Impossible line %d to reflow: %r" % (size, s)
          lines.append(padding + cur[:i])
          if len(lines) == 1:
              # find new size based on brace
              j = cur.find('{', 0, i)
              if j >= 0:
                  j += 2 # account for the brace and the space after it
                  size -= j
                  padding = " " * j
              else:
                  j = cur.find('(', 0, i)
                  if j >= 0:
                      j += 1 # account for the paren (no space after it)
                      size -= j
                      padding = " " * j
          cur = cur[i+1:]
      else:
          lines.append(padding + cur)
      return lines
  
  def is_simple(sum):
      """Return True if a sum is a simple.
  
      A sum is simple if its types have no fields, e.g.
      unaryop = Invert | Not | UAdd | USub
      """
      for t in sum.types:
          if t.fields:
              return False
      return True
  
  
  class EmitVisitor(asdl.VisitorBase):
      """Visit that emits lines"""
  
      def __init__(self, file):
          self.file = file
          super(EmitVisitor, self).__init__()
  
      def emit(self, s, depth, reflow=True):
          # XXX reflow long lines?
          if reflow:
              lines = reflow_lines(s, depth)
          else:
              lines = [s]
          for line in lines:
              line = (" " * TABSIZE * depth) + line + "\n"
              self.file.write(line)
  
  
  class TypeDefVisitor(EmitVisitor):
      def visitModule(self, mod):
          for dfn in mod.dfns:
              self.visit(dfn)
  
      def visitType(self, type, depth=0):
          self.visit(type.value, type.name, depth)
  
      def visitSum(self, sum, name, depth):
          if is_simple(sum):
              self.simple_sum(sum, name, depth)
          else:
              self.sum_with_constructors(sum, name, depth)
  
      def simple_sum(self, sum, name, depth):
          enum = []
          for i in range(len(sum.types)):
              type = sum.types[i]
              enum.append("%s=%d" % (type.name, i + 1))
          enums = ", ".join(enum)
          ctype = get_c_type(name)
          s = "typedef enum _%s { %s } %s;" % (name, enums, ctype)
          self.emit(s, depth)
          self.emit("", depth)
  
      def sum_with_constructors(self, sum, name, depth):
          ctype = get_c_type(name)
          s = "typedef struct _%(name)s *%(ctype)s;" % locals()
          self.emit(s, depth)
          self.emit("", depth)
  
      def visitProduct(self, product, name, depth):
          ctype = get_c_type(name)
          s = "typedef struct _%(name)s *%(ctype)s;" % locals()
          self.emit(s, depth)
          self.emit("", depth)
  
  
  class StructVisitor(EmitVisitor):
      """Visitor to generate typdefs for AST."""
  
      def visitModule(self, mod):
          for dfn in mod.dfns:
              self.visit(dfn)
  
      def visitType(self, type, depth=0):
          self.visit(type.value, type.name, depth)
  
      def visitSum(self, sum, name, depth):
          if not is_simple(sum):
              self.sum_with_constructors(sum, name, depth)
  
      def sum_with_constructors(self, sum, name, depth):
          def emit(s, depth=depth):
              self.emit(s % sys._getframe(1).f_locals, depth)
          enum = []
          for i in range(len(sum.types)):
              type = sum.types[i]
              enum.append("%s_kind=%d" % (type.name, i + 1))
  
          emit("enum _%(name)s_kind {" + ", ".join(enum) + "};")
  
          emit("struct _%(name)s {")
          emit("enum _%(name)s_kind kind;", depth + 1)
          emit("union {", depth + 1)
          for t in sum.types:
              self.visit(t, depth + 2)
          emit("} v;", depth + 1)
          for field in sum.attributes:
              # rudimentary attribute handling
              type = str(field.type)
              assert type in asdl.builtin_types, type
              emit("%s %s;" % (type, field.name), depth + 1);
          emit("};")
          emit("")
  
      def visitConstructor(self, cons, depth):
          if cons.fields:
              self.emit("struct {", depth)
              for f in cons.fields:
                  self.visit(f, depth + 1)
              self.emit("} %s;" % cons.name, depth)
              self.emit("", depth)
          else:
              # XXX not sure what I want here, nothing is probably fine
              pass
  
      def visitField(self, field, depth):
          # XXX need to lookup field.type, because it might be something
          # like a builtin...
          ctype = get_c_type(field.type)
          name = field.name
          if field.seq:
              if field.type.value in ('cmpop',):
                  self.emit("asdl_int_seq *%(name)s;" % locals(), depth)
              else:
                  self.emit("asdl_seq *%(name)s;" % locals(), depth)
          else:
              self.emit("%(ctype)s %(name)s;" % locals(), depth)
  
      def visitProduct(self, product, name, depth):
          self.emit("struct _%(name)s {" % locals(), depth)
          for f in product.fields:
              self.visit(f, depth + 1)
          self.emit("};", depth)
          self.emit("", depth)
  
  
  class PrototypeVisitor(EmitVisitor):
      """Generate function prototypes for the .h file"""
  
      def visitModule(self, mod):
          for dfn in mod.dfns:
              self.visit(dfn)
  
      def visitType(self, type):
          self.visit(type.value, type.name)
  
      def visitSum(self, sum, name):
          if is_simple(sum):
              pass # XXX
          else:
              for t in sum.types:
                  self.visit(t, name, sum.attributes)
  
      def get_args(self, fields):
          """Return list of C argument into, one for each field.
  
          Argument info is 3-tuple of a C type, variable name, and flag
          that is true if type can be NULL.
          """
          args = []
          unnamed = {}
          for f in fields:
              if f.name is None:
                  name = f.type
                  c = unnamed[name] = unnamed.get(name, 0) + 1
                  if c > 1:
                      name = "name%d" % (c - 1)
              else:
                  name = f.name
              # XXX should extend get_c_type() to handle this
              if f.seq:
                  if f.type.value in ('cmpop',):
                      ctype = "asdl_int_seq *"
                  else:
                      ctype = "asdl_seq *"
              else:
                  ctype = get_c_type(f.type)
              args.append((ctype, name, f.opt or f.seq))
          return args
  
      def visitConstructor(self, cons, type, attrs):
          args = self.get_args(cons.fields)
          attrs = self.get_args(attrs)
          ctype = get_c_type(type)
          self.emit_function(cons.name, ctype, args, attrs)
  
      def emit_function(self, name, ctype, args, attrs, union=True):
          args = args + attrs
          if args:
              argstr = ", ".join(["%s %s" % (atype, aname)
                                  for atype, aname, opt in args])
              argstr += ", PyArena *arena"
          else:
              argstr = "PyArena *arena"
          margs = "a0"
          for i in range(1, len(args)+1):
              margs += ", a%d" % i
          self.emit("#define %s(%s) _Ta27_%s(%s)" % (name, margs, name, margs), 0,
                  reflow=False)
          self.emit("%s _Ta27_%s(%s);" % (ctype, name, argstr), False)
  
      def visitProduct(self, prod, name):
          self.emit_function(name, get_c_type(name),
                             self.get_args(prod.fields), [], union=False)
  
  
  class FunctionVisitor(PrototypeVisitor):
      """Visitor to generate constructor functions for AST."""
  
      def emit_function(self, name, ctype, args, attrs, union=True):
          def emit(s, depth=0, reflow=True):
              self.emit(s, depth, reflow)
          argstr = ", ".join(["%s %s" % (atype, aname)
                              for atype, aname, opt in args + attrs])
          if argstr:
              argstr += ", PyArena *arena"
          else:
              argstr = "PyArena *arena"
          self.emit("%s" % ctype, 0)
          emit("%s(%s)" % (name, argstr))
          emit("{")
          emit("%s p;" % ctype, 1)
          for argtype, argname, opt in args:
              # XXX hack alert: false is allowed for a bool
              if not opt and not (argtype == "bool" or argtype == "int"):
                  emit("if (!%s) {" % argname, 1)
                  emit("PyErr_SetString(PyExc_ValueError,", 2)
                  msg = "field %s is required for %s" % (argname, name)
                  emit('                "%s");' % msg,
                       2, reflow=False)
                  emit('return NULL;', 2)
                  emit('}', 1)
  
          emit("p = (%s)PyArena_Malloc(arena, sizeof(*p));" % ctype, 1);
          emit("if (!p)", 1)
          emit("return NULL;", 2)
          if union:
              self.emit_body_union(name, args, attrs)
          else:
              self.emit_body_struct(name, args, attrs)
          emit("return p;", 1)
          emit("}")
          emit("")
  
      def emit_body_union(self, name, args, attrs):
          def emit(s, depth=0, reflow=True):
              self.emit(s, depth, reflow)
          emit("p->kind = %s_kind;" % name, 1)
          for argtype, argname, opt in args:
              emit("p->v.%s.%s = %s;" % (name, argname, argname), 1)
          for argtype, argname, opt in attrs:
              emit("p->%s = %s;" % (argname, argname), 1)
  
      def emit_body_struct(self, name, args, attrs):
          def emit(s, depth=0, reflow=True):
              self.emit(s, depth, reflow)
          for argtype, argname, opt in args:
              emit("p->%s = %s;" % (argname, argname), 1)
          assert not attrs
  
  
  class PickleVisitor(EmitVisitor):
  
      def visitModule(self, mod):
          for dfn in mod.dfns:
              self.visit(dfn)
  
      def visitType(self, type):
          self.visit(type.value, type.name)
  
      def visitSum(self, sum, name):
          pass
  
      def visitProduct(self, sum, name):
          pass
  
      def visitConstructor(self, cons, name):
          pass
  
      def visitField(self, sum):
          pass
  
  
  class Obj2ModPrototypeVisitor(PickleVisitor):
      def visitProduct(self, prod, name):
          code = "static int obj2ast_%s(PyObject* obj, %s* out, PyArena* arena);"
          self.emit(code % (name, get_c_type(name)), 0)
  
      visitSum = visitProduct
  
  
  class Obj2ModVisitor(PickleVisitor):
      def funcHeader(self, name):
          ctype = get_c_type(name)
          self.emit("int", 0)
          self.emit("obj2ast_%s(PyObject* obj, %s* out, PyArena* arena)" % (name, ctype), 0)
          self.emit("{", 0)
          self.emit("PyObject* tmp = NULL;", 1)
          self.emit("int isinstance;", 1)
          self.emit("", 0)
  
      def sumTrailer(self, name):
          self.emit("", 0)
          self.emit("tmp = PyObject_Repr(obj);", 1)
          # there's really nothing more we can do if this fails ...
          self.emit("if (tmp == NULL) goto failed;", 1)
          error = "expected some sort of %s, but got %%.400s" % name
          format = "PyErr_Format(PyExc_TypeError, \"%s\", _PyUnicode_AsString(tmp));"
          self.emit(format % error, 1, reflow=False)
          self.emit("failed:", 0)
          self.emit("Py_XDECREF(tmp);", 1)
          self.emit("return 1;", 1)
          self.emit("}", 0)
          self.emit("", 0)
  
      def simpleSum(self, sum, name):
          self.funcHeader(name)
          for t in sum.types:
              line = ("isinstance = PyObject_IsInstance(obj, "
                      "(PyObject *)%s_type);")
              self.emit(line % (t.name,), 1)
              self.emit("if (isinstance == -1) {", 1)
              self.emit("return 1;", 2)
              self.emit("}", 1)
              self.emit("if (isinstance) {", 1)
              self.emit("*out = %s;" % t.name, 2)
              self.emit("return 0;", 2)
              self.emit("}", 1)
          self.sumTrailer(name)
  
      def buildArgs(self, fields):
          return ", ".join(fields + ["arena"])
  
      def complexSum(self, sum, name):
          self.funcHeader(name)
          for a in sum.attributes:
              self.visitAttributeDeclaration(a, name, sum=sum)
          self.emit("", 0)
          # XXX: should we only do this for 'expr'?
          self.emit("if (obj == Py_None) {", 1)
          self.emit("*out = NULL;", 2)
          self.emit("return 0;", 2)
          self.emit("}", 1)
          for a in sum.attributes:
              self.visitField(a, name, sum=sum, depth=1)
          for t in sum.types:
              line = "isinstance = PyObject_IsInstance(obj, (PyObject*)%s_type);"
              self.emit(line % (t.name,), 1)
              self.emit("if (isinstance == -1) {", 1)
              self.emit("return 1;", 2)
              self.emit("}", 1)
              self.emit("if (isinstance) {", 1)
              for f in t.fields:
                  self.visitFieldDeclaration(f, t.name, sum=sum, depth=2)
              self.emit("", 0)
              for f in t.fields:
                  self.visitField(f, t.name, sum=sum, depth=2)
              args = [f.name.value for f in t.fields] + [a.name.value for a in sum.attributes]
              self.emit("*out = %s(%s);" % (t.name, self.buildArgs(args)), 2)
              self.emit("if (*out == NULL) goto failed;", 2)
              self.emit("return 0;", 2)
              self.emit("}", 1)
          self.sumTrailer(name)
  
      def visitAttributeDeclaration(self, a, name, sum=sum):
          ctype = get_c_type(a.type)
          self.emit("%s %s;" % (ctype, a.name), 1)
  
      def visitSum(self, sum, name):
          if is_simple(sum):
              self.simpleSum(sum, name)
          else:
              self.complexSum(sum, name)
  
      def visitProduct(self, prod, name):
          ctype = get_c_type(name)
          self.emit("int", 0)
          self.emit("obj2ast_%s(PyObject* obj, %s* out, PyArena* arena)" % (name, ctype), 0)
          self.emit("{", 0)
          self.emit("PyObject* tmp = NULL;", 1)
          for f in prod.fields:
              self.visitFieldDeclaration(f, name, prod=prod, depth=1)
          self.emit("", 0)
          for f in prod.fields:
              self.visitField(f, name, prod=prod, depth=1)
          args = [f.name.value for f in prod.fields]
          self.emit("*out = %s(%s);" % (name, self.buildArgs(args)), 1)
          self.emit("return 0;", 1)
          self.emit("failed:", 0)
          self.emit("Py_XDECREF(tmp);", 1)
          self.emit("return 1;", 1)
          self.emit("}", 0)
          self.emit("", 0)
  
      def visitFieldDeclaration(self, field, name, sum=None, prod=None, depth=0):
          ctype = get_c_type(field.type)
          if field.seq:
              if self.isSimpleType(field):
                  self.emit("asdl_int_seq* %s;" % field.name, depth)
              else:
                  self.emit("asdl_seq* %s;" % field.name, depth)
          else:
              ctype = get_c_type(field.type)
              self.emit("%s %s;" % (ctype, field.name), depth)
  
      def isSimpleSum(self, field):
          # XXX can the members of this list be determined automatically?
          return field.type.value in ('expr_context', 'boolop', 'operator',
                                      'unaryop', 'cmpop')
  
      def isNumeric(self, field):
          return get_c_type(field.type) in ("int", "bool")
  
      def isSimpleType(self, field):
          return self.isSimpleSum(field) or self.isNumeric(field)
  
      def visitField(self, field, name, sum=None, prod=None, depth=0):
          ctype = get_c_type(field.type)
          self.emit("if (PyObject_HasAttrString(obj, \"%s\")) {" % field.name, depth)
          self.emit("int res;", depth+1)
          if field.seq:
              self.emit("Py_ssize_t len;", depth+1)
              self.emit("Py_ssize_t i;", depth+1)
          self.emit("tmp = PyObject_GetAttrString(obj, \"%s\");" % field.name, depth+1)
          self.emit("if (tmp == NULL) goto failed;", depth+1)
          if field.seq:
              self.emit("if (!PyList_Check(tmp)) {", depth+1)
              self.emit("PyErr_Format(PyExc_TypeError, \"%s field \\\"%s\\\" must "
                        "be a list, not a %%.200s\", tmp->ob_type->tp_name);" %
                        (name, field.name),
                        depth+2, reflow=False)
              self.emit("goto failed;", depth+2)
              self.emit("}", depth+1)
              self.emit("len = PyList_GET_SIZE(tmp);", depth+1)
              if self.isSimpleType(field):
                  self.emit("%s = asdl_int_seq_new(len, arena);" % field.name, depth+1)
              else:
                  self.emit("%s = asdl_seq_new(len, arena);" % field.name, depth+1)
              self.emit("if (%s == NULL) goto failed;" % field.name, depth+1)
              self.emit("for (i = 0; i < len; i++) {", depth+1)
              self.emit("%s value;" % ctype, depth+2)
              self.emit("res = obj2ast_%s(PyList_GET_ITEM(tmp, i), &value, arena);" %
                        field.type, depth+2, reflow=False)
              self.emit("if (res != 0) goto failed;", depth+2)
              self.emit("asdl_seq_SET(%s, i, value);" % field.name, depth+2)
              self.emit("}", depth+1)
          else:
              self.emit("res = obj2ast_%s(tmp, &%s, arena);" %
                        (field.type, field.name), depth+1)
              self.emit("if (res != 0) goto failed;", depth+1)
  
          self.emit("Py_XDECREF(tmp);", depth+1)
          self.emit("tmp = NULL;", depth+1)
          self.emit("} else {", depth)
          if not field.opt:
              message = "required field \\\"%s\\\" missing from %s" % (field.name, name)
              format = "PyErr_SetString(PyExc_TypeError, \"%s\");"
              self.emit(format % message, depth+1, reflow=False)
              self.emit("return 1;", depth+1)
          else:
              if self.isNumeric(field):
                  self.emit("%s = 0;" % field.name, depth+1)
              elif not self.isSimpleType(field):
                  self.emit("%s = NULL;" % field.name, depth+1)
              else:
                  raise TypeError("could not determine the default value for %s" % field.name)
          self.emit("}", depth)
  
  
  class MarshalPrototypeVisitor(PickleVisitor):
  
      def prototype(self, sum, name):
          ctype = get_c_type(name)
          self.emit("static int marshal_write_%s(PyObject **, int *, %s);"
                    % (name, ctype), 0)
  
      visitProduct = visitSum = prototype
  
  
  class PyTypesDeclareVisitor(PickleVisitor):
  
      def visitProduct(self, prod, name):
          self.emit("static PyTypeObject *%s_type;" % name, 0)
          self.emit("static PyObject* ast2obj_%s(void*);" % name, 0)
          if prod.fields:
              self.emit("static char *%s_fields[]={" % name,0)
              for f in prod.fields:
                  self.emit('"%s",' % f.name, 1)
              self.emit("};", 0)
  
      def visitSum(self, sum, name):
          self.emit("static PyTypeObject *%s_type;" % name, 0)
          if sum.attributes:
              self.emit("static char *%s_attributes[] = {" % name, 0)
              for a in sum.attributes:
                  self.emit('"%s",' % a.name, 1)
              self.emit("};", 0)
          ptype = "void*"
          if is_simple(sum):
              ptype = get_c_type(name)
              tnames = []
              for t in sum.types:
                  tnames.append(str(t.name)+"_singleton")
              tnames = ", *".join(tnames)
              self.emit("static PyObject *%s;" % tnames, 0)
          self.emit("static PyObject* ast2obj_%s(%s);" % (name, ptype), 0)
          for t in sum.types:
              self.visitConstructor(t, name)
  
      def visitConstructor(self, cons, name):
          self.emit("static PyTypeObject *%s_type;" % cons.name, 0)
          if cons.fields:
              self.emit("static char *%s_fields[]={" % cons.name, 0)
              for t in cons.fields:
                  self.emit('"%s",' % t.name, 1)
              self.emit("};",0)
  
  class PyTypesVisitor(PickleVisitor):
  
      def visitModule(self, mod):
          self.emit("""
  static int
  ast_type_init(PyObject *self, PyObject *args, PyObject *kw)
  {
      Py_ssize_t i, numfields = 0;
      int res = -1;
      PyObject *key, *value, *fields;
      fields = PyObject_GetAttrString((PyObject*)Py_TYPE(self), "_fields");
      if (!fields)
          PyErr_Clear();
      if (fields) {
          numfields = PySequence_Size(fields);
          if (numfields == -1)
              goto cleanup;
      }
      res = 0; /* if no error occurs, this stays 0 to the end */
      if (PyTuple_GET_SIZE(args) > 0) {
          if (numfields != PyTuple_GET_SIZE(args)) {
              PyErr_Format(PyExc_TypeError, "%.400s constructor takes %s"
                           "%zd positional argument%s",
                           Py_TYPE(self)->tp_name,
                           numfields == 0 ? "" : "either 0 or ",
                           numfields, numfields == 1 ? "" : "s");
              res = -1;
              goto cleanup;
          }
          for (i = 0; i < PyTuple_GET_SIZE(args); i++) {
              /* cannot be reached when fields is NULL */
              PyObject *name = PySequence_GetItem(fields, i);
              if (!name) {
                  res = -1;
                  goto cleanup;
              }
              res = PyObject_SetAttr(self, name, PyTuple_GET_ITEM(args, i));
              Py_DECREF(name);
              if (res < 0)
                  goto cleanup;
          }
      }
      if (kw) {
          i = 0;  /* needed by PyDict_Next */
          while (PyDict_Next(kw, &i, &key, &value)) {
              res = PyObject_SetAttr(self, key, value);
              if (res < 0)
                  goto cleanup;
          }
      }
    cleanup:
      Py_XDECREF(fields);
      return res;
  }
  
  /* Pickling support */
  static PyObject *
  ast_type_reduce(PyObject *self, PyObject *unused)
  {
      PyObject *res;
      PyObject *dict = PyObject_GetAttrString(self, "__dict__");
      if (dict == NULL) {
          if (PyErr_ExceptionMatches(PyExc_AttributeError))
              PyErr_Clear();
          else
              return NULL;
      }
      if (dict) {
          res = Py_BuildValue("O()O", Py_TYPE(self), dict);
          Py_DECREF(dict);
          return res;
      }
      return Py_BuildValue("O()", Py_TYPE(self));
  }
  
  static PyMethodDef ast_type_methods[] = {
      {"__reduce__", ast_type_reduce, METH_NOARGS, NULL},
      {NULL}
  };
  
  static PyTypeObject AST_type = {
      PyVarObject_HEAD_INIT(NULL, 0)
      "_ast27.AST",
      sizeof(PyObject),
      0,
      0,                       /* tp_dealloc */
      0,                       /* tp_print */
      0,                       /* tp_getattr */
      0,                       /* tp_setattr */
      0,                       /* tp_compare */
      0,                       /* tp_repr */
      0,                       /* tp_as_number */
      0,                       /* tp_as_sequence */
      0,                       /* tp_as_mapping */
      0,                       /* tp_hash */
      0,                       /* tp_call */
      0,                       /* tp_str */
      PyObject_GenericGetAttr, /* tp_getattro */
      PyObject_GenericSetAttr, /* tp_setattro */
      0,                       /* tp_as_buffer */
      Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
      0,                       /* tp_doc */
      0,                       /* tp_traverse */
      0,                       /* tp_clear */
      0,                       /* tp_richcompare */
      0,                       /* tp_weaklistoffset */
      0,                       /* tp_iter */
      0,                       /* tp_iternext */
      ast_type_methods,        /* tp_methods */
      0,                       /* tp_members */
      0,                       /* tp_getset */
      0,                       /* tp_base */
      0,                       /* tp_dict */
      0,                       /* tp_descr_get */
      0,                       /* tp_descr_set */
      0,                       /* tp_dictoffset */
      (initproc)ast_type_init, /* tp_init */
      PyType_GenericAlloc,     /* tp_alloc */
      PyType_GenericNew,       /* tp_new */
      PyObject_Del,            /* tp_free */
  };
  
  
  static PyTypeObject* make_type(char *type, PyTypeObject* base, char**fields, int num_fields)
  {
      PyObject *fnames, *result;
      int i;
      fnames = PyTuple_New(num_fields);
      if (!fnames) return NULL;
      for (i = 0; i < num_fields; i++) {
          PyObject *field = PyUnicode_FromString(fields[i]);
          if (!field) {
              Py_DECREF(fnames);
              return NULL;
          }
          PyTuple_SET_ITEM(fnames, i, field);
      }
      result = PyObject_CallFunction((PyObject*)&PyType_Type, "s(O){sOss}",
                      type, base, "_fields", fnames, "__module__", "_ast27");
      Py_DECREF(fnames);
      return (PyTypeObject*)result;
  }
  
  static int add_attributes(PyTypeObject* type, char**attrs, int num_fields)
  {
      int i, result;
      PyObject *s, *l = PyTuple_New(num_fields);
      if (!l)
          return 0;
      for (i = 0; i < num_fields; i++) {
          s = PyUnicode_FromString(attrs[i]);
          if (!s) {
              Py_DECREF(l);
              return 0;
          }
          PyTuple_SET_ITEM(l, i, s);
      }
      result = PyObject_SetAttrString((PyObject*)type, "_attributes", l) >= 0;
      Py_DECREF(l);
      return result;
  }
  
  /* Conversion AST -> Python */
  
  static PyObject* ast2obj_list(asdl_seq *seq, PyObject* (*func)(void*))
  {
      int i, n = asdl_seq_LEN(seq);
      PyObject *result = PyList_New(n);
      PyObject *value;
      if (!result)
          return NULL;
      for (i = 0; i < n; i++) {
          value = func(asdl_seq_GET(seq, i));
          if (!value) {
              Py_DECREF(result);
              return NULL;
          }
          PyList_SET_ITEM(result, i, value);
      }
      return result;
  }
  
  static PyObject* ast2obj_object(void *o)
  {
      if (!o)
          o = Py_None;
      Py_INCREF((PyObject*)o);
      return (PyObject*)o;
  }
  #define ast2obj_identifier ast2obj_object
  #define ast2obj_string ast2obj_object
  static PyObject* ast2obj_bool(bool b)
  {
      return PyBool_FromLong(b);
  }
  
  static PyObject* ast2obj_int(long b)
  {
      return PyLong_FromLong(b);
  }
  
  /* Conversion Python -> AST */
  
  static int obj2ast_object(PyObject* obj, PyObject** out, PyArena* arena)
  {
      if (obj == Py_None)
          obj = NULL;
      if (obj)
          PyArena_AddPyObject(arena, obj);
      Py_XINCREF(obj);
      *out = obj;
      return 0;
  }
  
  static int obj2ast_identifier(PyObject* obj, PyObject** out, PyArena* arena)
  {
      if (!PyUnicode_CheckExact(obj) && obj != Py_None) {
          PyErr_Format(PyExc_TypeError,
                      "AST identifier must be of type str");
          return 1;
      }
      return obj2ast_object(obj, out, arena);
  }
  
  static int obj2ast_string(PyObject* obj, PyObject** out, PyArena* arena)
  {
      if (!PyUnicode_CheckExact(obj) && !PyUnicode_CheckExact(obj)) {
          PyErr_SetString(PyExc_TypeError,
                         "AST string must be of type str or unicode");
          return 1;
      }
      return obj2ast_object(obj, out, arena);
  }
  
  static int obj2ast_int(PyObject* obj, int* out, PyArena* arena)
  {
      int i;
      if (!PyLong_Check(obj) && !PyLong_Check(obj)) {
          PyObject *s = PyObject_Repr(obj);
          if (s == NULL) return 1;
          PyErr_Format(PyExc_ValueError, "invalid integer value: %.400s",
                       _PyUnicode_AsString(s));
          Py_DECREF(s);
          return 1;
      }
  
      i = (int)PyLong_AsLong(obj);
      if (i == -1 && PyErr_Occurred())
          return 1;
      *out = i;
      return 0;
  }
  
  static int obj2ast_bool(PyObject* obj, bool* out, PyArena* arena)
  {
      if (!PyBool_Check(obj)) {
          PyObject *s = PyObject_Repr(obj);
          if (s == NULL) return 1;
          PyErr_Format(PyExc_ValueError, "invalid boolean value: %.400s",
                       _PyUnicode_AsString(s));
          Py_DECREF(s);
          return 1;
      }
  
      *out = (obj == Py_True);
      return 0;
  }
  
  static int add_ast_fields(void)
  {
      PyObject *empty_tuple, *d;
      if (PyType_Ready(&AST_type) < 0)
          return -1;
      d = AST_type.tp_dict;
      empty_tuple = PyTuple_New(0);
      if (!empty_tuple ||
          PyDict_SetItemString(d, "_fields", empty_tuple) < 0 ||
          PyDict_SetItemString(d, "_attributes", empty_tuple) < 0) {
          Py_XDECREF(empty_tuple);
          return -1;
      }
      Py_DECREF(empty_tuple);
      return 0;
  }
  
  """, 0, reflow=False)
  
          self.emit("static int init_types(void)",0)
          self.emit("{", 0)
          self.emit("static int initialized;", 1)
          self.emit("if (initialized) return 1;", 1)
          self.emit("if (add_ast_fields() < 0) return 0;", 1)
          for dfn in mod.dfns:
              self.visit(dfn)
          self.emit("initialized = 1;", 1)
          self.emit("return 1;", 1);
          self.emit("}", 0)
  
      def visitProduct(self, prod, name):
          if prod.fields:
              fields = name.value+"_fields"
          else:
              fields = "NULL"
          self.emit('%s_type = make_type("%s", &AST_type, %s, %d);' %
                          (name, name, fields, len(prod.fields)), 1)
          self.emit("if (!%s_type) return 0;" % name, 1)
  
      def visitSum(self, sum, name):
          self.emit('%s_type = make_type("%s", &AST_type, NULL, 0);' %
                    (name, name), 1)
          self.emit("if (!%s_type) return 0;" % name, 1)
          if sum.attributes:
              self.emit("if (!add_attributes(%s_type, %s_attributes, %d)) return 0;" %
                              (name, name, len(sum.attributes)), 1)
          else:
              self.emit("if (!add_attributes(%s_type, NULL, 0)) return 0;" % name, 1)
          simple = is_simple(sum)
          for t in sum.types:
              self.visitConstructor(t, name, simple)
  
      def visitConstructor(self, cons, name, simple):
          if cons.fields:
              fields = cons.name.value+"_fields"
          else:
              fields = "NULL"
          self.emit('%s_type = make_type("%s", %s_type, %s, %d);' %
                              (cons.name, cons.name, name, fields, len(cons.fields)), 1)
          self.emit("if (!%s_type) return 0;" % cons.name, 1)
          if simple:
              self.emit("%s_singleton = PyType_GenericNew(%s_type, NULL, NULL);" %
                               (cons.name, cons.name), 1)
              self.emit("if (!%s_singleton) return 0;" % cons.name, 1)
  
  
  class ASTModuleVisitor(PickleVisitor):
  
      def visitModule(self, mod):
          self.emit('PyObject *ast27_parse(PyObject *self, PyObject *args);', 0)
          self.emit('static PyMethodDef ast27_methods[] = {', 0)
          self.emit('{"parse",  ast27_parse, METH_VARARGS, "Parse string into typed AST."},', 1)
          self.emit('{NULL, NULL, 0, NULL}', 1)
          self.emit('};', 0)
  
          self.emit("static struct PyModuleDef _astmodule27 = {", 0)
          self.emit('  PyModuleDef_HEAD_INIT, "_ast27", NULL, 0, ast27_methods', 0)
          self.emit("};", 0)
          self.emit("PyMODINIT_FUNC", 0)
          self.emit("PyInit__ast27(void)", 0)
          self.emit("{", 0)
          self.emit("PyObject *m, *d;", 1)
          self.emit("if (!init_types()) return NULL;", 1)
          self.emit('m = PyModule_Create(&_astmodule27);', 1)
          self.emit("if (!m) return NULL;", 1)
          self.emit("d = PyModule_GetDict(m);", 1)
          self.emit('if (PyDict_SetItemString(d, "AST", (PyObject*)&AST_type) < 0) return NULL;', 1)
          self.emit('if (PyModule_AddIntMacro(m, PyCF_ONLY_AST) < 0)', 1)
          self.emit("return NULL;", 2)
          for dfn in mod.dfns:
              self.visit(dfn)
          self.emit("return m;", 1)
          self.emit("}", 0)
  
      def visitProduct(self, prod, name):
          self.addObj(name)
  
      def visitSum(self, sum, name):
          self.addObj(name)
          for t in sum.types:
              self.visitConstructor(t, name)
  
      def visitConstructor(self, cons, name):
          self.addObj(cons.name)
  
      def addObj(self, name):
          self.emit('if (PyDict_SetItemString(d, "%s", (PyObject*)%s_type) < 0) return NULL;' % (name, name), 1)
  
  
  _SPECIALIZED_SEQUENCES = ('stmt', 'expr')
  
  def find_sequence(fields, doing_specialization):
      """Return True if any field uses a sequence."""
      for f in fields:
          if f.seq:
              if not doing_specialization:
                  return True
              if str(f.type) not in _SPECIALIZED_SEQUENCES:
                  return True
      return False
  
  def has_sequence(types, doing_specialization):
      for t in types:
          if find_sequence(t.fields, doing_specialization):
              return True
      return False
  
  
  class StaticVisitor(PickleVisitor):
      CODE = '''Very simple, always emit this static code.  Override CODE'''
  
      def visit(self, object):
          self.emit(self.CODE, 0, reflow=False)
  
  
  class ObjVisitor(PickleVisitor):
  
      def func_begin(self, name):
          ctype = get_c_type(name)
          self.emit("PyObject*", 0)
          self.emit("ast2obj_%s(void* _o)" % (name), 0)
          self.emit("{", 0)
          self.emit("%s o = (%s)_o;" % (ctype, ctype), 1)
          self.emit("PyObject *result = NULL, *value = NULL;", 1)
          self.emit('if (!o) {', 1)
          self.emit("Py_INCREF(Py_None);", 2)
          self.emit('return Py_None;', 2)
          self.emit("}", 1)
          self.emit('', 0)
  
      def func_end(self):
          self.emit("return result;", 1)
          self.emit("failed:", 0)
          self.emit("Py_XDECREF(value);", 1)
          self.emit("Py_XDECREF(result);", 1)
          self.emit("return NULL;", 1)
          self.emit("}", 0)
          self.emit("", 0)
  
      def visitSum(self, sum, name):
          if is_simple(sum):
              self.simpleSum(sum, name)
              return
          self.func_begin(name)
          self.emit("switch (o->kind) {", 1)
          for i in range(len(sum.types)):
              t = sum.types[i]
              self.visitConstructor(t, i + 1, name)
          self.emit("}", 1)
          for a in sum.attributes:
              self.emit("value = ast2obj_%s(o->%s);" % (a.type, a.name), 1)
              self.emit("if (!value) goto failed;", 1)
              self.emit('if (PyObject_SetAttrString(result, "%s", value) < 0)' % a.name, 1)
              self.emit('goto failed;', 2)
              self.emit('Py_DECREF(value);', 1)
          self.func_end()
  
      def simpleSum(self, sum, name):
          self.emit("PyObject* ast2obj_%s(%s_ty o)" % (name, name), 0)
          self.emit("{", 0)
          self.emit("switch(o) {", 1)
          for t in sum.types:
              self.emit("case %s:" % t.name, 2)
              self.emit("Py_INCREF(%s_singleton);" % t.name, 3)
              self.emit("return %s_singleton;" % t.name, 3)
          self.emit("default:", 2)
          self.emit('/* should never happen, but just in case ... */', 3)
          code = "PyErr_Format(PyExc_SystemError, \"unknown %s found\");" % name
          self.emit(code, 3, reflow=False)
          self.emit("return NULL;", 3)
          self.emit("}", 1)
          self.emit("}", 0)
  
      def visitProduct(self, prod, name):
          self.func_begin(name)
          self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % name, 1);
          self.emit("if (!result) return NULL;", 1)
          for field in prod.fields:
              self.visitField(field, name, 1, True)
          self.func_end()
  
      def visitConstructor(self, cons, enum, name):
          self.emit("case %s_kind:" % cons.name, 1)
          self.emit("result = PyType_GenericNew(%s_type, NULL, NULL);" % cons.name, 2);
          self.emit("if (!result) goto failed;", 2)
          for f in cons.fields:
              self.visitField(f, cons.name, 2, False)
          self.emit("break;", 2)
  
      def visitField(self, field, name, depth, product):
          def emit(s, d):
              self.emit(s, depth + d)
          if product:
              value = "o->%s" % field.name
          else:
              value = "o->v.%s.%s" % (name, field.name)
          self.set(field, value, depth)
          emit("if (!value) goto failed;", 0)
          emit('if (PyObject_SetAttrString(result, "%s", value) == -1)' % field.name, 0)
          emit("goto failed;", 1)
          emit("Py_DECREF(value);", 0)
  
      def emitSeq(self, field, value, depth, emit):
          emit("seq = %s;" % value, 0)
          emit("n = asdl_seq_LEN(seq);", 0)
          emit("value = PyList_New(n);", 0)
          emit("if (!value) goto failed;", 0)
          emit("for (i = 0; i < n; i++) {", 0)
          self.set("value", field, "asdl_seq_GET(seq, i)", depth + 1)
          emit("if (!value1) goto failed;", 1)
          emit("PyList_SET_ITEM(value, i, value1);", 1)
          emit("value1 = NULL;", 1)
          emit("}", 0)
  
      def set(self, field, value, depth):
          if field.seq:
              # XXX should really check for is_simple, but that requires a symbol table
              if field.type.value == "cmpop":
                  # While the sequence elements are stored as void*,
                  # ast2obj_cmpop expects an enum
                  self.emit("{", depth)
                  self.emit("int i, n = asdl_seq_LEN(%s);" % value, depth+1)
                  self.emit("value = PyList_New(n);", depth+1)
                  self.emit("if (!value) goto failed;", depth+1)
                  self.emit("for(i = 0; i < n; i++)", depth+1)
                  # This cannot fail, so no need for error handling
                  self.emit("PyList_SET_ITEM(value, i, ast2obj_cmpop((cmpop_ty)asdl_seq_GET(%s, i)));" % value,
                            depth+2, reflow=False)
                  self.emit("}", depth)
              else:
                  self.emit("value = ast2obj_list(%s, ast2obj_%s);" % (value, field.type), depth)
          else:
              ctype = get_c_type(field.type)
              self.emit("value = ast2obj_%s(%s);" % (field.type, value), depth, reflow=False)
  
  
  class PartingShots(StaticVisitor):
  
      CODE = """
  PyObject* Ta27AST_mod2obj(mod_ty t)
  {
      init_types();
      return ast2obj_mod(t);
  }
  
  /* mode is 0 for "exec", 1 for "eval" and 2 for "single" input */
  mod_ty Ta27AST_obj2mod(PyObject* ast, PyArena* arena, int mode)
  {
      mod_ty res;
      PyObject *req_type[3];
      char *req_name[3];
      int isinstance;
  
      req_type[0] = (PyObject*)Module_type;
      req_type[1] = (PyObject*)Expression_type;
      req_type[2] = (PyObject*)Interactive_type;
  
      req_name[0] = "Module";
      req_name[1] = "Expression";
      req_name[2] = "Interactive";
  
      assert(0 <= mode && mode <= 2);
  
      init_types();
  
      isinstance = PyObject_IsInstance(ast, req_type[mode]);
      if (isinstance == -1)
          return NULL;
      if (!isinstance) {
          PyErr_Format(PyExc_TypeError, "expected %s node, got %.400s",
                       req_name[mode], Py_TYPE(ast)->tp_name);
          return NULL;
      }
      if (obj2ast_mod(ast, &res, arena) != 0)
          return NULL;
      else
          return res;
  }
  
  int Ta27AST_Check(PyObject* obj)
  {
      init_types();
      return PyObject_IsInstance(obj, (PyObject*)&AST_type);
  }
  """
  
  class ChainOfVisitors:
      def __init__(self, *visitors):
          self.visitors = visitors
  
      def visit(self, object):
          for v in self.visitors:
              v.visit(object)
              v.emit("", 0)
  
  common_msg = "/* File automatically generated by %s. */\n\n"
  
  c_file_msg = """
  /*
     __version__ %s.
  
     This module must be committed separately after each AST grammar change;
     The __version__ number is set to the revision number of the commit
     containing the grammar change.
  */
  
  """
  
  def main(srcfile):
      argv0 = sys.argv[0]
      components = argv0.split(os.sep)
      argv0 = os.sep.join(components[-2:])
      auto_gen_msg = common_msg % argv0
      mod = asdl.parse(srcfile)
      mod.version = "82160"
      if not asdl.check(mod):
          sys.exit(1)
      if INC_DIR:
          p = "%s/%s-ast.h" % (INC_DIR, mod.name)
          f = open(p, "wb")
          f.write(auto_gen_msg)
          f.write('#include "asdl.h"\n\n')
          c = ChainOfVisitors(TypeDefVisitor(f),
                              StructVisitor(f),
                              PrototypeVisitor(f),
                              )
          c.visit(mod)
          f.write("PyObject* Ta27AST_mod2obj(mod_ty t);\n")
          f.write("mod_ty Ta27AST_obj2mod(PyObject* ast, PyArena* arena, int mode);\n")
          f.write("int Ta27AST_Check(PyObject* obj);\n")
          f.close()
  
      if SRC_DIR:
          p = os.path.join(SRC_DIR, str(mod.name) + "-ast.c")
          f = open(p, "wb")
          f.write(auto_gen_msg)
          f.write(c_file_msg % mod.version)
          f.write('#include "Python.h"\n')
          f.write('#include "%s-ast.h"\n' % mod.name)
          f.write('\n')
          f.write("static PyTypeObject AST_type;\n")
          v = ChainOfVisitors(
              PyTypesDeclareVisitor(f),
              PyTypesVisitor(f),
              Obj2ModPrototypeVisitor(f),
              FunctionVisitor(f),
              ObjVisitor(f),
              Obj2ModVisitor(f),
              ASTModuleVisitor(f),
              PartingShots(f),
              )
          v.visit(mod)
          f.close()
  
  if __name__ == "__main__":
      import sys
      import getopt
  
      INC_DIR = ''
      SRC_DIR = ''
      opts, args = getopt.getopt(sys.argv[1:], "h:c:")
      if len(opts) != 1:
          print "Must specify exactly one output file"
          sys.exit(1)
      for o, v in opts:
          if o == '-h':
              INC_DIR = v
          if o == '-c':
              SRC_DIR = v
      if len(args) != 1:
          print "Must specify single input file"
          sys.exit(1)
      main(args[0])
  