
2017-05-25 7:19 GMT-07:00 Nick Coghlan <ncoghlan@gmail.com>:
On 25 May 2017 at 21:26, Antoine Pitrou <solipsis@pitrou.net> wrote:
On Wed, 24 May 2017 23:31:47 +0200 Ivan Levkivskyi <levkivskyi@gmail.com> wrote:
Hi all,
After collecting suggestions in the previous discussion on python-dev https://mail.python.org/pipermail/python-dev/2017- March/thread.html#147629 and playing with implementation, here is an updated version of PEP 544.
-- Ivan
A link for those who don't like reading long e-mails: https://www.python.org/dev/peps/pep-0544/
=========================
PEP: 544 Title: Protocols
Can you give this PEP a more explicit title? "Protocols" sound like network protocols to me.
Especially given the existing use of the term in an asyncio context: https://www.python.org/dev/peps/pep-3156/#transports-and-protocols
Given the abstract, I'd suggest "Structural Subtyping" as a suitable title for the PEP.
That said, I think it's fine to use "protocol" throughout the rest of the PEP as is currently the case - object protocols and network protocols are clearly different things, it's just the bare word "Protocols" appearing as a PEP title in the PEP index with no other context that's potentially confusing.
I'm +1 on the general idea of the PEP, and only have one question regarding the specifics. Given:
import typing
class MyContainer: def __len__(self) -> int: ... def close(self) -> None: ...
Would that be enough for a static typechecker to consider MyContainer a structural subtype of both typing.Sized and SupportsClose from the PEP, even though neither is imported explicitly into the module? I'm assuming the answer is "Yes", but I didn't see it explicitly stated anywhere.
Yes, that should be the case. Specifically, if you pass a MyContainer object to a function whose argument is annotated as typing.Sized or SupportsClose, a type checker should accept that call.
Cheers, Nick.
-- Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/ jelle.zijlstra%40gmail.com