Created
January 12, 2016 13:51
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Testing metaclass support in Pylint.
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| """ | |
| Testing metaclass support in Pylint. | |
| Inspired by http://stackoverflow.com/questions/100003/what-is-a-metaclass-in-python | |
| """ | |
| import typing | |
| class MyMetaclass(type): | |
| """ This is my metaclass. """ | |
| def __new__(mcs, name, bases, attrs): | |
| """ Constructs a class with this metaclass as its metaclass. """ | |
| return super(MyMetaclass, mcs).__new__(mcs, name, bases, attrs) | |
| def __init__(cls, name, bases, attrs): | |
| """ Constructs MyMetaclass. """ | |
| super(MyMetaclass, cls).__init__(name, bases, attrs) | |
| #def __isinstancecheck__(cls, inst): | |
| def __issubclasscheck__(cls, sub): | |
| pass | |
| def __getitem__(cls, item): | |
| #if item.__class__ is MyMetaclass: | |
| # print('item', item, 'comes from MyMetaclass!') | |
| #else: | |
| # print('item', item, 'comes from', item.__class__) | |
| name = cls.__name__ #+ '[' + item.__name__ + ']' | |
| attrs = {'__item__': (item,)} | |
| return MyMetaclass.__new__(MyMetaclass, name, (), attrs) | |
| def __str__(cls): | |
| #desc = super(MyMetaclass, cls).__str__() | |
| desc = cls.__name__ | |
| try: | |
| desc += '[' + ', '.join([str(item) for item in cls.__item__]) + ']' | |
| except AttributeError: | |
| pass | |
| return desc | |
| class MyClass(object, metaclass=MyMetaclass): | |
| """ This is my class with my metaclass. """ | |
| __item__ = (None, ) | |
| def __init__(self): | |
| pass | |
| def fooo(self, param): | |
| """ foo """ | |
| pass | |
| def barr(self, param): | |
| """ bar """ | |
| pass | |
| class MySubclass(MyClass): | |
| """ This is a subclass that iheriths my metaclass. """ | |
| pass | |
| def print_info_about_classes(classes): | |
| """ Print basic info about given classes. """ | |
| for cls in classes: | |
| print(cls.__name__) | |
| print(' - class: ', cls.__class__) | |
| print(' - obj: ', cls) | |
| print(' - id(): ', id(cls)) | |
| try: | |
| obj = cls() | |
| print(cls.__name__, 'instance') | |
| print(' - class: ', obj.__class__) | |
| print(' - obj: ', obj) | |
| print(' - id(): ', id(obj)) | |
| if not isinstance(cls, obj): | |
| print(' !', obj, 'is not instance of its class') | |
| except TypeError: | |
| print(' ! no instance') | |
| def check_if_classes_are_themselves(classes1, classes2): | |
| """ For all classes in list, check if that class is itself. """ | |
| assert len(classes1) == len(classes2) | |
| classes_count = len(classes1) | |
| for i in range(classes_count): | |
| if classes1[i] is not classes2[i]: | |
| print(classes1[i], 'is not itself') | |
| if not issubclass(classes1[i], classes2[i]): | |
| print(classes1[i], 'is not subclass of itself') | |
| if __name__ == '__main__': | |
| C1 = [ | |
| MyClass, MyClass[int], MyClass[str], MySubclass, MySubclass[int], MySubclass[str], | |
| MySubclass[MyClass[int]] | |
| ] | |
| C2 = [ | |
| MyClass, MyClass[int], MyClass[str], MySubclass, MySubclass[int], MySubclass[str], | |
| MySubclass[MyClass[int]] | |
| ] | |
| print_info_about_classes(C1) | |
| check_if_classes_are_themselves(C1, C2) | |
| T1 = [ | |
| typing.Any, typing.Optional, typing.Optional[typing.Any], | |
| typing.Sequence, typing.Sequence[int], typing.Sequence[str], | |
| typing.Sequence[MyClass], typing.Callable, typing.Callable[[int, int], bool] | |
| ] | |
| T2 = [ | |
| typing.Any, typing.Optional, typing.Optional[typing.Any], | |
| typing.Sequence, typing.Sequence[int], typing.Sequence[str], | |
| typing.Sequence[MyClass], typing.Callable, typing.Callable[[int, int], bool] | |
| ] | |
| print_info_about_classes(T1) | |
| check_if_classes_are_themselves(T1, T2) |
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