[Python-Dev] PEP 362 minor nits

[Nick Coghlan]

On Wed, Jun 20, 2012 at 6:30 PM, Steven D'Aprano <steve at pearwood.info> wrote:
> Speaking of non-instance method descriptors, please excuse this silly
> question, I haven't quite understood the implementation well enough to
> answer this question myself. Is there anything needed to make
> signature() work correctly with custom method-like descriptors such as
> this?
>
> http://code.activestate.com/recipes/577030-dualmethod-descriptor

They're odd enough that they would probably need to implement
__signature__ as a property (or custom descriptor) and construct the
appropriate signature on the fly. However, that's only necessary if
you wanted to support passing the descriptor directly to
inspect.signature.

The result of Example.method or Example().method would be an ordinary
function, which would delegate to signature(self.func) by default
(thanks to the use of functools.wraps).

To account for the hidden argument correctly, you would actually want
to set a custom signature that dropped the first parameter.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia