[Python-Dev] collections.abc for data and non-data descriptors

[Roberto Martínez]

I need to check if some objects obey the descriptor protocol in the
construction of a metaclass. I expect to be able to write something like:

if isinstance(myobj, abc.DataDescriptor):
   # do something

The other idea crossing my mind is something like:

if all(hasattr(myobj, attr) for attr in ('__get__', '__set__')):
    # do something


El mar., 17 ene. 2017 a las 18:07, Guido van Rossum (<guido at python.org>)
escribió:

> Well, these are an example of the purest duck typing. Just implement
> __get__ and/or __set__ (and __delete__) and you're good.
>
> What's the situation where you miss them?
>
> --Guido
>
> On Tue, Jan 17, 2017 at 8:51 AM, Roberto Martínez <
> robertomartinezp at gmail.com> wrote:
>
> Hi,
>
> I miss abstract base classes in collections.abc implementing the
> descriptor protocol. Any reason why they do not exist?
>
> What do you think of adding NonDataDescriptor and DataDescriptor ABCs?
>
> Best regards,
> Roberto
>
> _______________________________________________
> Python-Dev mailing list
> Python-Dev at python.org
> https://mail.python.org/mailman/listinfo/python-dev
> Unsubscribe:
> https://mail.python.org/mailman/options/python-dev/guido%40python.org
>
>
>
>
> --
> --Guido van Rossum (python.org/~guido)
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/python-dev/attachments/20170117/e9d57120/attachment.html>