Although ENUMs are already complicated enough, this proposals frees up messing with the EnumMeta metaclass in some cases - it makes sense. I've subclassed EnumMeta once for adding some feature in a project, and it never feels the "quite right" thing to do. On Tue, Apr 26, 2022 at 6:12 PM Stefan Nelson-Lindall < stefan.nelsonlindall@gmail.com> wrote:
EnumMeta implements its own __getitem__ function which doesn't respect __class_getitem__. Now that __class_getitem__ exists, this behavior feels unintuitive. For instance
``` class Directions(enum.Enum): LEFT = "LEFT" RIGHT = "RIGHT"
def __class_getitem__(cls, name): return super().__class_getitem__(name.upper())
# fails with KeyError -- __class_getitem__ never called assert Directions["left"] == Directions["LEFT"] == Directions.LEFT ```
doesn't work, and the only way to implement this behavior is something like
``` class MyEnumMeta(enum.EnumMeta): def __getitem__(cls, name): return cls.__class_getitem__(name)
class MyEnum(enum.Enum, metaclass=MyEnumMeta): def __class_getitem__(cls, name): return cls._member_map_[name]
class Directions(MyEnum): ... ```
there might be some compatibility issues with code written between 3.4 and 3.11, but not supporting __class_getitem__ feels like it violates the principle of least surprise with the more recent data models. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-leave@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/4VURZ4... Code of Conduct: http://python.org/psf/codeofconduct/