[Python-Dev] PEP 435 -- Adding an Enum type to the Python standard library

Nikolaus Rath Nikolaus at rath.org
Sat Apr 27 04:10:53 CEST 2013

Steven D'Aprano <steve at pearwood.info> writes:
> On 26/04/13 13:22, Greg wrote:
>> On 26/04/2013 3:12 p.m., Glenn Linderman wrote:
>>> On 4/25/2013 7:49 PM, Nick Coghlan wrote:
>>>> You couldn't create an enum of callables, but that would be a
>>>> seriously weird thing to do anyway....
>>> But aren't all classes callable?
>> An enum of classes would be seriously weird as well, I think.
> I don't think iscallable will work, since that descriptors like
> staticmethod and classmethod aren't callable. Nor are properties.
> I think a solution may be an explicit decorator that tells the
> metaclass not to skip the object into an enum value:
> class Insect(enum.Enum):
>     ant = 1
>     bee = 2
>     @enum.skip
>     @classmethod
>     def spam(cls, args):
>         pass

In this case, wouldn't it be nicer to "decorate" those attributes that
are meant to be enum values? I think having to use the class keyword to
define something that really doesn't behave like an ordinary class is
pretty confusing, and the following syntax would be a lot easier to
understand at first sight:

class Insect(enum.Enum):
    ant = enum.EnumValue(1)
    bee = enum.EnumValue(2)

    def spam(cls, args):

    def ham(self, args):

Obviously, EnumValue() would automatically assign a suitable number.



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