Source code for returns.pointfree.bind_async_future
from typing import Awaitable, Callable, TypeVar
from returns.future import Future
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)
[docs]def bind_async_future(
function: Callable[
[_FirstType],
Awaitable[Future[_UpdatedType]],
],
) -> Kinded[Callable[
[KindN[_FutureKind, _FirstType, _SecondType, _ThirdType]],
KindN[_FutureKind, _UpdatedType, _SecondType, _ThirdType],
]]:
"""
Compose a container and async function returning ``Future``.
In other words, it modifies the function
signature from:
``a -> Awaitable[Future[b]]``
to:
``Container[a] -> Container[b]``
This is how it should be used:
.. code:: python
>>> import anyio
>>> from returns.pointfree import bind_async_future
>>> from returns.future import Future
>>> from returns.io import IO
>>> async def example(argument: int) -> Future[int]:
... return Future.from_value(argument + 1)
>>> assert anyio.run(
... bind_async_future(example)(Future.from_value(1)).awaitable,
... ) == IO(2)
Note, that this function works
for all containers with ``.bind_async_future`` 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_future(function)
return factory