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.nelsonlind...@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-le...@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/4VURZ4ZXPZRQ726KZH5DAOI47XXUKBI2/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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