[Python-ideas] Bring back callable()

M.-A. Lemburg mal at egenix.com
Wed Nov 24 11:59:34 CET 2010

Ram Rachum wrote:
> Antoine Pitrou <solipsis at ...> writes:
>> Python 3 has removed callable() under the justification that's it's not
>> very useful and duck typing (EAFP) should be used instead. However,
>> it has since been felt by many people that it was an annoying loss;
>> there are situations where you truly want to know whether something is a
>> callable without actually calling it (for example when writing
>> sophisticated decorators, or simply when you want to inform the user
>> of an API misuse).
>> The substitute of writing `isinstance(x, collections.Callable)` is
>> not good, 1) because it's wordier 2) because collections is really not
>> an intuitive place where to look for a Callable ABC.
>> So, I would advocate bringing back the callable() builtin, which was
>> easy to use, helpful and semantically sane.
>> Antoine.
> I actually really prefer `isinstance(x, collections.Callable)`...
> If this was accepted, I would at least want it to be called `iscallable` instead 
> of `callable`, since I sometimes want to use the name `callable` in my code.

That's still possible. callable() is a built-in function,
not a keyword.

Marc-Andre Lemburg

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