text: # copyright 2003-2015 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
  # contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
  #
  # This file is part of astroid.
  #
  # astroid is free software: you can redistribute it and/or modify it
  # under the terms of the GNU Lesser General Public License as published by the
  # Free Software Foundation, either version 2.1 of the License, or (at your
  # option) any later version.
  #
  # astroid is distributed in the hope that it will be useful, but
  # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
  # for more details.
  #
  # You should have received a copy of the GNU Lesser General Public License along
  # with astroid. If not, see <http://www.gnu.org/licenses/>.
  
  """
  Inference objects are a way to represent composite AST nodes,
  which are used only as inference results, so they can't be found in the
  code tree. For instance, inferring the following frozenset use, leads to an
  inferred FrozenSet:
  
      CallFunc(func=Name('frozenset'), args=Tuple(...))
  
  """
  
  import six
  
  from astroid import MANAGER
  from astroid.bases import (
      BUILTINS, NodeNG, Instance, _infer_stmts,
      BoundMethod, _is_property
  )
  from astroid.decorators import cachedproperty
  from astroid.exceptions import (
      SuperError, SuperArgumentTypeError,
      NotFoundError, MroError
  )
  from astroid.node_classes import const_factory
  from astroid.scoped_nodes import ClassDef, FunctionDef
  from astroid.mixins import ParentAssignTypeMixin
  
  
  class FrozenSet(NodeNG, Instance, ParentAssignTypeMixin):
      """class representing a FrozenSet composite node"""
  
      def __init__(self, elts=None):
          if elts is None:
              self.elts = []
          else:
              self.elts = [const_factory(e) for e in elts]
  
      def pytype(self):
          return '%s.frozenset' % BUILTINS
  
      def itered(self):
          return self.elts
  
      def _infer(self, context=None):
          yield self
  
      @cachedproperty
      def _proxied(self):
          builtins = MANAGER.astroid_cache[BUILTINS]
          return builtins.getattr('frozenset')[0]
  
  
  class Super(NodeNG):
      """Proxy class over a super call.
  
      This class offers almost the same behaviour as Python's super,
      which is MRO lookups for retrieving attributes from the parents.
  
      The *mro_pointer* is the place in the MRO from where we should
      start looking, not counting it. *mro_type* is the object which
      provides the MRO, it can be both a type or an instance.
      *self_class* is the class where the super call is, while
      *scope* is the function where the super call is.
      """
  
      def __init__(self, mro_pointer, mro_type, self_class, scope):
          self.type = mro_type
          self.mro_pointer = mro_pointer
          self._class_based = False
          self._self_class = self_class
          self._scope = scope
          self._model = {
              '__thisclass__': self.mro_pointer,
              '__self_class__': self._self_class,
              '__self__': self.type,
              '__class__': self._proxied,
          }
  
      def _infer(self, context=None):
          yield self
  
      def super_mro(self):
          """Get the MRO which will be used to lookup attributes in this super."""
          if not isinstance(self.mro_pointer, ClassDef):
              raise SuperArgumentTypeError("The first super argument must be type.")
  
          if isinstance(self.type, ClassDef):
              # `super(type, type)`, most likely in a class method.
              self._class_based = True
              mro_type = self.type
          else:
              mro_type = getattr(self.type, '_proxied', None)
              if not isinstance(mro_type, (Instance, ClassDef)):
                  raise SuperArgumentTypeError("super(type, obj): obj must be an "
                                               "instance or subtype of type")
  
          if not mro_type.newstyle:
              raise SuperError("Unable to call super on old-style classes.")
  
          mro = mro_type.mro()
          if self.mro_pointer not in mro:
              raise SuperArgumentTypeError("super(type, obj): obj must be an "
                                           "instance or subtype of type")
  
          index = mro.index(self.mro_pointer)
          return mro[index + 1:]
  
      @cachedproperty
      def _proxied(self):
          builtins = MANAGER.astroid_cache[BUILTINS]
          return builtins.getattr('super')[0]
  
      def pytype(self):
          return '%s.super' % BUILTINS
  
      def display_type(self):
          return 'Super of'
  
      @property
      def name(self):
          """Get the name of the MRO pointer."""
          return self.mro_pointer.name
  
      def igetattr(self, name, context=None):
          """Retrieve the inferred values of the given attribute name."""
  
          local_name = self._model.get(name)
          if local_name:
              yield local_name
              return
  
          try:
              mro = self.super_mro()
          except (MroError, SuperError) as exc:
              # Don't let invalid MROs or invalid super calls
              # to leak out as is from this function.
              six.raise_from(NotFoundError, exc)
  
          found = False
          for cls in mro:
              if name not in cls._locals:
                  continue
  
              found = True
              for infered in _infer_stmts([cls[name]], context, frame=self):
                  if not isinstance(infered, FunctionDef):
                      yield infered
                      continue
  
                  # We can obtain different descriptors from a super depending
                  # on what we are accessing and where the super call is.
                  if infered.type == 'classmethod':
                      yield BoundMethod(infered, cls)
                  elif self._scope.type == 'classmethod' and infered.type == 'method':
                      yield infered
                  elif self._class_based or infered.type == 'staticmethod':
                      yield infered
                  elif _is_property(infered):
                      # TODO: support other descriptors as well.
                      for value in infered.infer_call_result(self, context):
                          yield value
                  else:
                      yield BoundMethod(infered, cls)
  
          if not found:
              raise NotFoundError(name)
  
      def getattr(self, name, context=None):
          return list(self.igetattr(name, context=context))
  