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- ##############################################################################
- #
- # Copyright (c) 2003 Zope Foundation and Contributors.
- # All Rights Reserved.
- #
- # This software is subject to the provisions of the Zope Public License,
- # Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution.
- # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
- # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
- # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
- # FOR A PARTICULAR PURPOSE.
- #
- ##############################################################################
- """Odd meta class that doesn't subclass type.
-
- This is used for testing support for ExtensionClass in new interfaces.
-
- >>> class A(object):
- ... __metaclass__ = MetaClass
- ... a = 1
- ...
- >>> A.__name__
- 'A'
- >>> A.__bases__ == (object,)
- True
- >>> class B(object):
- ... __metaclass__ = MetaClass
- ... b = 1
- ...
- >>> class C(A, B): pass
- ...
- >>> C.__name__
- 'C'
- >>> int(C.__bases__ == (A, B))
- 1
- >>> a = A()
- >>> aa = A()
- >>> a.a
- 1
- >>> aa.a
- 1
- >>> aa.a = 2
- >>> a.a
- 1
- >>> aa.a
- 2
- >>> c = C()
- >>> c.a
- 1
- >>> c.b
- 1
- >>> c.b = 2
- >>> c.b
- 2
- >>> C.c = 1
- >>> c.c
- 1
-
- >>> int(C.__class__.__class__ is C.__class__)
- 1
- """
-
- # class OddClass is an odd meta class
-
- class MetaMetaClass(type):
-
- def __getattribute__(cls, name):
- if name == '__class__':
- return cls
- # Under Python 3.6, __prepare__ gets requested
- return type.__getattribute__(cls, name)
-
-
- class MetaClass:
- """Odd classes
- """
-
- def __init__(self, name, bases, dict):
- self.__name__ = name
- self.__bases__ = bases
- self.__dict__.update(dict)
-
- def __call__(self):
- return OddInstance(self)
-
- def __getattr__(self, name):
- for b in self.__bases__:
- v = getattr(b, name, self)
- if v is not self:
- return v
- raise AttributeError(name)
-
- def __repr__(self): # pragma: no cover
- return "<odd class {} at {}>".format(self.__name__, hex(id(self)))
-
-
- MetaClass = MetaMetaClass('MetaClass',
- MetaClass.__bases__,
- {k: v for k, v in MetaClass.__dict__.items()
- if k not in ('__dict__',)})
-
- class OddInstance:
-
- def __init__(self, cls):
- self.__dict__['__class__'] = cls
-
- def __getattribute__(self, name):
- dict = object.__getattribute__(self, '__dict__')
- if name == '__dict__':
- return dict
- v = dict.get(name, self)
- if v is not self:
- return v
- return getattr(dict['__class__'], name)
-
- def __setattr__(self, name, v):
- self.__dict__[name] = v
-
- def __delattr__(self, name):
- raise NotImplementedError()
-
- def __repr__(self): # pragma: no cover
- return "<odd {} instance at {}>".format(
- self.__class__.__name__, hex(id(self)))
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