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

Nick Coghlan ncoghlan at gmail.com
Fri May 3 03:06:40 CEST 2013

On Fri, May 3, 2013 at 9:57 AM, Ethan Furman <ethan at stoneleaf.us> wrote:

On 05/02/2013 04:43 PM, Greg Ewing wrote:

Guido van Rossum wrote:

you should do some other check, e.g. "if x in Color:". So you don't think it's important to have an easy way to take user input that's supposed to be a Color name and either return a Color or raise a ValueError? I don't believe that's what he said: The name lookup is only relevant if you already know that you have a valid name of an enum in the class [...] User input should qualify, and using getattr(EnumClass, userinput) will get you an AttributeError instead of a ValueError if userinput is not valid, but surely you don't mind that small difference. ;)

int(getattr(C(), "str")) Traceback (most recent call last): File "", line 1, in TypeError: int() argument must be a string or a number, not 'method-wrapper'

That's the problem Greg is complaining about: when you use getattr to do the name->enum member conversion, you have to do your own checking to exclude method names.

This is part of why I think enums should offer an "as_dict()" method that returns an ordered dictionary.

Cheers, Nick.

-- Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia

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