[Python-Dev] enum discussion: can someone please summarize open issues? (original) (raw)

Ethan Furman ethan at stoneleaf.us
Sun Apr 28 22:36:30 CEST 2013

On 04/28/2013 01:02 PM, Guido van Rossum wrote:

My opinions added

Mine also now added.

Example enumeration:

class Seasons(Enum): SPRING = 1 SUMMER = 2 AUTUMN = 3 WINTER = 4 daysinyear = 365 @property def avgtemp(self): return (75, 92, 66, 33)[int(self)+1] # enums are 1-based

Definite Issues: - should enum items be of the type of the Enum class? (i.e. type(SPRING) is Seasons) IMO Yes.

I agree.

- should an enum item be selectable via call instead of getitem (i.e. Seasons(3) is AUTUMN) No opinion.

I think the callable syntax should be supported for database integration and consistency with every (?) other type in Python. No opinion about the getitem portion.

- should daysinyear be enumerated? Yes. (If you don't want it to be, and it's not a method/descriptor, move it out of the class.)

Making it a property to have it in the class certainly works for me.

- should avgtemp be enumerated? IMO No.

I agree.

- for the above two, how should they be included/excluded? IMO Everything should be enumerated except (a) things with a get() method (i.e. descriptors) (b) dunder names

This also works for me.

Also, I believe there's still an issue on the order in which items are returned by iter(Seasons), but I don't know which way this is heading.

As somebody pointed out earlier, the only order which cannot be reconstructed after the fact is definition order (value order can be, lexical order can be, etc.). So my vote is to have the default iteration order be the original definition order, as any other desired order can be added to the class.

-- Ethan

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