Thanks Jakub, You're right __origin__ should point to `Annotated`. I created a pull request (https://github.com/python/typing/pull/635) that should address that. Also: def fun(x: List[Annotated[int, ‘some marker’]]) is definitely valid. On Tue, May 28, 2019 at 9:01 AM Jakub Stasiak <jakub@stasiak.at> wrote:
On 28 May 2019, at 14:53, Jakub Stasiak <jakub@stasiak.at> wrote:
On 28 May 2019, at 11:52, Ivan Levkivskyi <levkivskyi@gmail.com> wrote:
On Tue, 28 May 2019 at 04:37, Till <till.varoquaux@gmail.com> wrote: I didn't implement any good helper function because I couldn't figure out the idiomatic way to traverse type hints at runtime. It would be very easy to add a "get_extras(t: typing.<Type>) -> Tuple[Any, ...]" function. Would that work?
This reminds me about something I wanted to do for Python 3.8: there is an idea to add couple public helpers for introspection of typing objects. For example `get_origin()` and `get_args()`. That would essentially just thin public wrappers around private `__origin__`/`__args__` API.
With such API one will be able to just write `if get_origin(typ) is Annotated: ...`
-- Ivan
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This actually gave me the idea to test
x.__origin__ is Annotated
instead of
isinstance(x, _Annotated)
but with the current implementation _Annotated.__origin__ points to the type being annotated, not the Annotated class. I made a dirty typing_extensions pull request[1] that attempts to rectify this but I’m not sure i’ll be able to finish it myself right now.
On an unrelated note, something I’ve been wondering about since yesterday – is Annotated supposed to be, in principle, allowed to be used like this?
def fun(x: List[Annotated[int, ‘some marker’]])
Best, Jakub
[1] https://github.com/python/typing/pull/634 _______________________________________________ Typing-sig mailing list -- typing-sig@python.org To unsubscribe send an email to typing-sig-leave@python.org https://mail.python.org/mailman3/lists/typing-sig.python.org/
PS. Apologies for ignoring your question regarding hypothetical get_extras function Till – I don’t have an opinion on it at the moment, doing things “manually” is fine for my purposes.
Jakub