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from collections.abc import Awaitable, Callable
from typing import TypeVar
from returns.future import FutureResult
from returns.interfaces.specific.future_result import FutureResultLikeN
from returns.primitives.hkt import Kinded, KindN, kinded
_FirstType = TypeVar('_FirstType')
_SecondType = TypeVar('_SecondType')
_ThirdType = TypeVar('_ThirdType')
_UpdatedType = TypeVar('_UpdatedType')
_FutureResultKind = TypeVar('_FutureResultKind', bound=FutureResultLikeN)
def bind_async_future_result(
function: Callable[
[_FirstType],
Awaitable[FutureResult[_UpdatedType, _SecondType]],
],
) -> Kinded[
Callable[
[KindN[_FutureResultKind, _FirstType, _SecondType, _ThirdType]],
KindN[_FutureResultKind, _UpdatedType, _SecondType, _ThirdType],
]
]:
"""
Compose a container and async function returning ``FutureResult``.
In other words, it modifies the function
signature from:
``a -> Awaitable[FutureResult[b, c]]``
to:
``Container[a, c] -> Container[b, c]``
This is how it should be used:
.. code:: python
>>> import anyio
>>> from returns.pointfree import bind_async_future_result
>>> from returns.future import FutureResult
>>> from returns.io import IOSuccess, IOFailure
>>> async def example(argument: int) -> FutureResult[int, str]:
... return FutureResult.from_value(argument + 1)
>>> assert anyio.run(
... bind_async_future_result(example)(
... FutureResult.from_value(1),
... ).awaitable,
... ) == IOSuccess(2)
>>> assert anyio.run(
... bind_async_future_result(example)(
... FutureResult.from_failure('a'),
... ).awaitable,
... ) == IOFailure('a')
.. currentmodule: returns.primitives.interfaces.specific.future_result
Note, that this function works
for all containers with ``.bind_async_future`` method.
See :class:`~FutureResultLikeN` for more info.
"""
@kinded
def factory(
container: KindN[
_FutureResultKind,
_FirstType,
_SecondType,
_ThirdType,
],
) -> KindN[_FutureResultKind, _UpdatedType, _SecondType, _ThirdType]:
return container.bind_async_future_result(function)
return factory
|
