On Wed, Jun 20, 2018 at 11:56:05AM +0200, Jeroen Demeyer wrote:
[...]
> Since it makes sense to merge the classes "classmethod" and
> "classmethod_descriptor" (PEP 579, issue 8), one of the above behaviors
> should be changed. Given that adding features is less likely to break
> stuff, I would argue that classmethod instances should become callable.
[...]
> Are there any reasons to *not* make staticmethod and classmethod callable?
(The classes themselves are callable -- you're talking about the
instances.)
+1 yes please!
The fact that classmethods and especially staticmethod instances aren't
callable has been a long-running niggling pain for me. Occasionally I
want to do something like this:
class Spam:
@staticmethod
def utility(arg):
# something which is conceptually related to the Spam class
# but doesn't need a cls/self argument.
...
value = utility(arg)
but it doesn't work as staticmethod objects aren't callable until after
they've gone through the descriptor protocol.
I'm not the only one bitten by this:
https://stackoverflow.com/questions/45375944/python-static-method-is-not-always-callable
https://mail.python.org/pipermail/python-list/2011-November/615069.html
Part of that thread, see links and discussion here:
https://mail.python.org/pipermail/python-list/2011-November/615077.html
I thought I had raised a bug report for this on the tracker, but my
google-fu is failing me and I can't find it. But my recollection is that
the simple fix is to make staticmethod.__call__ simply delegate to the
underlying decorated function. And similar for classmethod.
(Of course calling classmethod instances directly won't work unless you
provide the class argument. But that's just a simple matter of bound
versus unbound methods.)
--
Steve
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