A question came up on stackoverflow asking about the Planet example and the need to have the constant G defined in the method instead of at the class level:
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On Tue, Aug 6, 2013 at 1:42 PM, Ethan Furman <ethan@stoneleaf.us> wrote:
A question came up on stackoverflow asking about the Planet example and the need to have the constant G defined in the method instead of at the class level:

http://stackoverflow.com/q/17911188/208880

Since methods and descriptors are immune to enumeration my proposed solution created a Constant descriptor that could be used to keep class level constants at the class level. �It's not complex, only about 7 lines. �Should we have something like that included in the enum module?

If we do include something like that, should it be constant, or should it be more like property? �(The important differences from property being that class access still returns the value, not the property itself, and setting the class-level value changes the value but doesn't replace the property.)

Personally, I dislike all non-simple uses of Enums. One such use is adding behavior to them. This can always be split to separate behavior from the Enum itself, and I would prefer that. We went to great lengths to ensure that things work in expected ways, but heaping additional features (even as separate decorators) is just aggravating thiings. So -1 from me.


Finally, I suggest we exercise restraint in adding more capabilities to enums in 3.4; enums are a new creature for Python and it will be extremely useful to see them used in the wild for a while first. We can enhance them in 3.5, but premature enhancement is IMHO much more likely to do harm than good.


Eli



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