El lun, 17 ene 2022 a las 6:25, Petr Viktorin (<encu...@gmail.com>) escribió:
> On Wed, Nov 17, 2021 at 8:31 AM Pradeep Kumar Srinivasan > <gohan...@gmail.com> wrote: > > > > This PEP [1] introduces a simple and intuitive way to annotate methods > and classmethods that return an instance of their class. Such methods and > classmethods occur quite frequently, but the existing way to annotate them > correctly is quite arcane and error-prone. The PEP introduces a special > type `Self` to represent the type of the `self` parameter, similar to the > `this` type in TypeScript and the `Self` type in Rust. We have > implementations for mypy and pyright. The PEP does not affect CPython > directly except for the addition of one special form (Self) to typing.py > [2]. > > > > Since we have reached consensus on the PEP in typing-sig [3], we wanted > to get your comments and suggestions before submitting to the Steering > Council. > > > > Thanks, > > Pradeep Kumar Srinivasan > > James Hilton-Balfe > > > > [1]: https://www.python.org/dev/peps/pep-0673/ > > [2]: Adding `Self` to typing_extensions.py: > https://github.com/python/typing/pull/933 > > [3]: See the comments from typing-sig members on the Google doc: > https://docs.google.com/document/d/1ujuSMXDmSIOJpiZyV7mvBEC8P-y55AgSzXcvhrZciuI/edit?usp=sharing > > Hello, and thanks for the PEP! > Sorry I'm late, but I have two curious questions about the PEP. > I don't think they should hold back accepting the PEP, but I'm > interested in the answers. > > The PEP uses `reveal_type`, a function that's appeared in a few PEPs > already, but was never described. Is it a standard function in typing > tools, something specific to mypy, or pseudocode? > It's a function that doesn't exist at runtime, but when a type checker sees a call, it emits the inferred type of the argument. It originated with mypy but I believe has been adopted by all type checkers. There's been some talk of adding it to the `typing` module, but that hasn't happened so far. I opened https://bugs.python.org/issue46414 to suggest adding it. > > The PEP says "we reject Self in metaclasses." > "Metaclass" can mean "subclass of `type`", or it can refer to how a > value is used -- for example, you can write `class > Foo(metaclass=print): ...`. > In the PEP's example, is MyMetaclass rejected because: > - it's used as a metaclass in a class statement, or > - it's a subclass of `type` (so it's rejected even if unused), or > - it becomes a class of a class? > Or is the exact interpretation best left to the type checker? > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/DVOQK3U6MOYXPRXF5OVLVLJBPEJRUIM5/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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