[Python-Dev] PEP 544: Protocols - second round

[Stéfane Fermigier]

On Thu, Jun 22, 2017 at 10:44 AM, Markus Wissinger <
markus.wissinger at gmail.com> wrote:

> Hi,
>
> I have to admit I am not happy with separating the concepts of 'runtime'
> and 'static' types as implied by pep544.
>
> I am currently exploring a type hint generator that produces hints out of
> types used in unit tests. It debugs the tests and collects the parameter
> types of call and return events. It ignores a type when a supertype is
> present. Failing isinstance/issubclass calls for protocols would hurt
> there. I understand that any type checker code that could provide
> isinstance functionality for pep544 protocols would rely on method
> signatures that my hint generator is just producing.
>
> proof of concept implementation (writes method docstrings, no pep484 type
> hints yet):
> https://github.com/markuswissinger/ducktestpy
>
> This is currently just some personal project that some of you will
> consider a strange idea.
>

Not a strange idea, I've had a similar idea and played a bit with it ~10
years ago (inspired by a Java project whose name eludes me now).

Also, I think PyCharm is able to do similar things (see
https://blog.jetbrains.com/pycharm/2013/02/dynamic-runtime-type-inference-in-pycharm-2-7/
).

  S.

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Stefane Fermigier - http://fermigier.com/ - http://twitter.com/sfermigier -
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