[Python-ideas] Fix that broken callable builtin

[Chris Angelico]

On Sat, Apr 18, 2015 at 9:41 PM, Ionel Cristian Mărieș
<contact at ionelmc.ro> wrote:
>>>> class DynamicCallable:
> ...     is_callable = True
> ...
> ...     def __init__(self, target):
> ...         self.target = target
> ...
> ...     @property
> ...     def __call__(self):
> ...         if self.is_callable:
> ...             return self.target
> ...         else:
> ...             raise AttributeError("Not really ...")

Before charging ahead and making the callable() function check for
this, is it actually a supported concept? Is it intentional that
property-getter functions can raise AttributeError to signal that the
attribute does not (currently) exist? Because if that's a hack, then
there's no reason to support it, and callable() is absolutely correct
to say "there is a __call__ attribute on the class, ergo it's
callable".

ChrisA