On Sun, Apr 21, 2013 at 11:29 AM, Steven D'Aprano <[email protected]> wrote:
> I would argue that it is the responsibility of enums to start with the least
> restrictions as is reasonable, and leave additional restrictions up to
> subclasses, rather than the other way around. (I'll just quietly mention the
> Liskov Substitution Principle here...) If some people need enums to have
> unique
> values, then enforcing that should be their responsibility, and not forced
> on
> all users whether they need that restriction or not.
>
> If there is enough demand for that, then perhaps the enum module could
> provide a
> standard mechanism for enforcing unique values, via a flag, or a subclass,
> say.
The PEP is fine, as it already allows duplicate names without encouraging them:
class Insect(Enum):
wasp = 1 # Preferred. Use this in new code.
bee = 2
ant = 3
# Backwards compatibility aliases
Insect.wsap = Insect.wasp
If you have a lot of such aliases:
aliases = {
"wasp": ["wsap"],
...
}
for attr, names in aliases.items():
for name in names:
setattr(Insect, name, getattr(Insect, attr))
A more concise syntax for handling duplicates may prove desirable at
some point in the future, but this is a case where encouraging
correctness by default is a good idea.
Cheers,
Nick.
--
Nick Coghlan | [email protected] | Brisbane, Australia
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