[Python-ideas] PEP proposal: unifying function/method classes

[Stefan Behnel]

Jeroen Demeyer schrieb am 24.03.2018 um 22:38:
> On 2018-03-24 09:09, Nick Coghlan wrote:
>> If it was just about introspection, then we could define a new protocol
>> method or attribute, update the inspect module to respect it, and call
>> it done.
> 
> True. In fact, I got a long way by just defining inspect.isfunction as
> 
> def isfunction(obj):
>     return hasattr(type(obj), "__code__")

This relies on the fact that Cython attaches an (empty) code object to its
C implemented functions, which could be considered a hack but is needed for
things like source file reporting, and also line reporting (although we
don't currently use that, but an even worse hack).

The main problem, though, is that a lot of code out there does not use the
"inspect" module but "types" to distinguish its input. That probably got a
bit better over time with the ABCs, but for things like functions,
generators and coroutines, I doubt that people would easily consider them.
"types" just seems too obvious at first thought.

Which suggests that it could help to add a visible note to the CPython docs
of the "types" module that it's often better to use "inspect" or the ABCs.
Seems worth a PR.

Stefan