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