
On 05/05/2013 04:14 PM, Tim Delaney wrote:
1. That the dictionary returned from <enum metaclass>.__prepare__ provide a way to obtain the enum instance names once it's been populated (e.g. once it's been passed as the classdict to __new__). The reference implementation provides a _enum_names list attribute. The enum names need to be available to a metaclass subclass before calling the base metaclass __new__.
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My preferred solution is 1 (for the reason mentioned above) but it does not require exposing the metaclass publically (that's obtainable via type(Enum)). It does require a way to get the enum names before calling the base metaclass __new__, but that does not necessarily imply that I'm advocating exposing _enum_names (or at least, not directly).
My preferred way would probably be a note that the dictionary returned from the enum metaclass __prepare__ implements an enum_names() or maybe __enum_names__() method which returns an iterator over the enum instance names in definition order. The way this is implemented by the dictionary would be an implementation detail.
I like having an __enum_names__() that returns a list or tuple of (name, value) pairs in definition order. -- ~Ethan~