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