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from __future__ import annotations
from collections.abc import Callable
from typing import TYPE_CHECKING, TypeVar
from returns.interfaces.specific.result import ResultLikeN
from returns.primitives.hkt import Kinded, KindN, kinded
if TYPE_CHECKING:
from returns.result import Result # noqa: WPS433
_FirstType = TypeVar('_FirstType')
_SecondType = TypeVar('_SecondType')
_ThirdType = TypeVar('_ThirdType')
_UpdatedType = TypeVar('_UpdatedType')
_ResultLikeKind = TypeVar('_ResultLikeKind', bound=ResultLikeN)
def bind_result(
function: Callable[[_FirstType], Result[_UpdatedType, _SecondType]],
) -> Kinded[
Callable[
[KindN[_ResultLikeKind, _FirstType, _SecondType, _ThirdType]],
KindN[_ResultLikeKind, _UpdatedType, _SecondType, _ThirdType],
]
]:
"""
Composes successful container with a function that returns a container.
In other words, it modifies the function's
signature from:
``a -> Result[b, c]``
to:
``Container[a, c] -> Container[b, c]``
.. code:: python
>>> from returns.io import IOSuccess
>>> from returns.context import RequiresContextResult
>>> from returns.result import Result, Success
>>> from returns.pointfree import bind_result
>>> def returns_result(arg: int) -> Result[int, str]:
... return Success(arg + 1)
>>> bound = bind_result(returns_result)
>>> assert bound(IOSuccess(1)) == IOSuccess(2)
>>> assert bound(RequiresContextResult.from_value(1))(...) == Success(2)
"""
@kinded
def factory(
container: KindN[_ResultLikeKind, _FirstType, _SecondType, _ThirdType],
) -> KindN[_ResultLikeKind, _UpdatedType, _SecondType, _ThirdType]:
return container.bind_result(function)
return factory
|
