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cimport cython
class Base(type):
def __new__(cls, name, bases, attrs):
attrs['metaclass_was_here'] = True
return type.__new__(cls, name, bases, attrs)
@cython.test_assert_path_exists("//PyClassMetaclassNode", "//Py3ClassNode")
class Foo(object):
"""
>>> obj = Foo()
>>> obj.metaclass_was_here
True
"""
__metaclass__ = Base
def non_type_metaclass(name, bases, namespace):
namespace['BASES'] = [b.__name__ for b in bases]
namespace['NAME'] = name
return type(name, bases, namespace)
class FunctionAsPy2Metaclass(object):
"""
>>> obj = FunctionAsPy2Metaclass()
>>> obj.NAME
'FunctionAsPy2Metaclass'
>>> obj.BASES
['object']
>>> obj.x
1
"""
__metaclass__ = non_type_metaclass
x = 1
class ODict(dict):
def __init__(self):
dict.__init__(self)
self._order = []
dict.__setitem__(self, '_order', self._order)
def __setitem__(self, key, value):
dict.__setitem__(self, key, value)
self._order.append(key)
class Py3MetaclassPlusAttr(type):
def __new__(cls, name, bases, attrs, **kwargs):
assert isinstance(attrs, ODict), str(type(attrs))
for key, value in kwargs.items():
attrs[key] = value
attrs['metaclass_was_here'] = True
return type.__new__(cls, name, bases, attrs)
def __init__(self, cls, attrs, obj, **kwargs):
pass
@staticmethod
def __prepare__(*args, **kwargs):
return ODict()
@cython.test_fail_if_path_exists("//PyClassMetaclassNode")
@cython.test_assert_path_exists("//Py3ClassNode")
class Py3ClassMCOnly(object, metaclass=Py3MetaclassPlusAttr):
"""
>>> obj = Py3ClassMCOnly()
>>> obj.bar
321
>>> obj.metaclass_was_here
True
>>> [n for n in obj._order if n not in {"__qualname__", "__annotations__"}]
['__module__', '__doc__', 'bar', 'metaclass_was_here']
"""
bar = 321
class Py3InheritedMetaclass(Py3ClassMCOnly):
"""
>>> obj = Py3InheritedMetaclass()
>>> obj.bar
345
>>> obj.metaclass_was_here
True
>>> [n for n in obj._order if n not in {"__qualname__", "__annotations__"}]
['__module__', '__doc__', 'bar', 'metaclass_was_here']
"""
bar = 345
class Py3Base(type):
def __new__(cls, name, bases, attrs, **kwargs):
assert isinstance(attrs, ODict), str(type(attrs))
for key, value in kwargs.items():
attrs[key] = value
return type.__new__(cls, name, bases, attrs)
def __init__(self, cls, attrs, obj, **kwargs):
pass
@staticmethod
def __prepare__(*args, **kwargs):
return ODict()
@cython.test_fail_if_path_exists("//PyClassMetaclassNode")
@cython.test_assert_path_exists("//Py3ClassNode")
class Py3Foo(object, metaclass=Py3Base, foo=123):
"""
>>> obj = Py3Foo()
>>> obj.foo
123
>>> obj.bar
321
>>> [n for n in obj._order if n not in {"__qualname__", "__annotations__"}]
['__module__', '__doc__', 'bar', 'foo']
"""
bar = 321
@cython.test_assert_path_exists("//PyClassMetaclassNode", "//Py3ClassNode")
class Py3FooInherited(Py3Foo, foo=567):
"""
>>> obj = Py3FooInherited()
>>> obj.foo
567
>>> obj.bar
321
>>> [n for n in obj._order if n not in {"__qualname__", "__annotations__"}]
['__module__', '__doc__', 'bar', 'foo']
"""
bar = 321
kwargs = {'foo': 123, 'bar': 456}
@cython.test_assert_path_exists("//PyClassMetaclassNode", "//Py3ClassNode")
class Py3Mixed(metaclass=Py3Base, **kwargs):
"""
>>> Py3Mixed.foo
123
>>> Py3Mixed.bar
456
"""
kwargs['metaclass'] = Py3Base
@cython.test_assert_path_exists("//PyClassMetaclassNode")
class Py3Kwargs(**kwargs):
"""
>>> Py3Kwargs.foo
123
>>> Py3Kwargs.bar
456
"""
class Base3(type):
def __new__(cls, name, bases, attrs, **kwargs):
kwargs['b'] = 2
return type.__new__(cls, name, bases, attrs)
def __init__(self, *args, **kwargs):
self.kwargs = kwargs
@staticmethod
def __prepare__(*args, **kwargs):
kwargs['a'] = 1
return {}
kwargs = {'c': 0}
@cython.test_assert_path_exists("//PyClassMetaclassNode", "//Py3ClassNode")
class Foo3(metaclass=Base3, a=0, b=0, **kwargs):
"""
>>> sorted(Foo3.kwargs.items())
[('a', 0), ('b', 0), ('c', 0)]
"""
class PyClassWithNew(object):
"""
>>> PyClassWithNew(389)
389
"""
def __new__(self, arg):
return arg
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