ParamSpec: use P.args and P.kwargs in other scopes, such as return types

I have a number of cases where it would be very useful to use P.args and P.kwargs of a ParamSpec to annotate tuple and dict objects, for example, when extracting arguments to pass to a function in another context.

Here's an example:

from typing import Callable, TypeVar, Tuple, Any
from typing_extensions import ParamSpec

P = ParamSpec('P')
T = TypeVar('T')


def complex(value: str, reverse: bool =False, capitalize: bool =False) -> str:
    if reverse:
        value = str(reversed(value))
    if capitalize:
        value = value.capitalize()
    return value


def call_it(func: Callable[P, T], args: P.args, kwargs: P.kwargs) -> T:
    print("calling", func)
    return func(*args, **kwargs)


def get_callable_and_args() -> Tuple[Callable[P, Any], P.args, P.kwargs]:
    return complex, ('foo',), {'reverse': True}


call_it(*get_callable_and_args())

In this scenario P.args and P.kwargs represent a kind of ad-hoc NamedTuple and TypedDict, respectively.

Does this seem like a reasonable extension for ParamSpecs?

Commencez par examiner le comportement de ParamSpec décrit dans l’issue et l’exemple utilisant P.args et P.kwargs dans un type de retour. Aucun fichier source ni test n’est indiqué ; pour considérer le travail terminé, il faudrait décider si cette extension est prise en charge et identifier les modifications nécessaires dans la spécification, l’implémentation ou la documentation.