[Python-Dev] backported Enum

[Barry Warsaw]

On Jun 28, 2013, at 01:07 PM, Jim J. Jewett wrote:

>> Switching from getitem syntax to call syntax for looking up an
>> enum member by value, e.g.
>
>>    -        return self._enum[value]
>>    +        return self._enum(value)
>
>> Interesting that these two were exactly opposite from flufl.enum.
>
>Is there a reason why these were reversed?

The individual decisions made (begrudging) sense at the time, although I don't
think it was noticed that the combined effect was to switch the meanings.

Call syntax makes sense for converting a value to an enum because that mirrors
calling built-in types, e.g. int('7').  Getitem syntax makes sense for
lookup-by-name.

>> Switching from int() to .value to get the integer value of an
>> enum member, e.g.
>
>>    -    return (member.list_id, member.address.email, int(member.role))
>>    +    return (member.list_id, member.address.email, member.role.value)
>
>Is just this a style preference?

No.  I'm not using IntEnums and regular enums don't have an __int__, which
makes sense because their values can be anything.  .value is the way to get at
the value.  (Note that even though I don't use IntEnums, my values are all
integers.  It's just not worth it to change all my imports.)

-Barry