Expose function args from high order function

[Tomperez98]

from __future__ import annotations

from typing import Callable

from typing_extensions import ParamSpec, TypeVar

P = ParamSpec("P")
T = TypeVar("T")


def run(fn: Callable[P, T]) -> T:
    return fn()


def greet(name: str) -> str: ...


def main():
    run(greet, name="tomas") # Is there a way to get type annotations for the name argument?

Is it possible to have typing annotation for the greet arguments when function being called from run? I need to define a high order function that received a function points and its arguments separately.

[erictraut]

I don't know what you mean by "get the type annotations for the name argument".

If you want run to accept arguments that it can pass to fn, you need to include *args and **kwargs parameters like this:

def run(fn: Callable[P, T], *args: P.args, **kwargs: P.kwargs) -> T:
    return fn(*args, **kwargs)

[Tomperez98]

I wanted example that. To get an error when calling run(greet) requiring me to add name as a parameter.

[Tomperez98]

All the functions the run functions will run required to have a Context argument

from __future__ import annotations

from typing import Callable

from typing_extensions import ParamSpec, TypeVar, Concatenate

class Context: ...
T = TypeVar("T")
P = ParamSpec("P")


def run(fn: Callable[Concatenate[Context, P],  T], *args: P.args, **kwargs: P.kwargs) -> T:
    return fn(*args, **kwargs)


def greet(ctx: Context, name: str) -> str: ...


x = run(greet, name="tomas")

What is the correct way to use Concatenate to define this requirement and the pass all the extra args to the function?