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from collections.abc import Callable
from typing import TypeVar
from returns.interfaces.bimappable import BiMappableN
from returns.primitives.hkt import Kinded, KindN, kinded
_FirstType = TypeVar('_FirstType')
_SecondType = TypeVar('_SecondType')
_ThirdType = TypeVar('_ThirdType')
_UpdatedType1 = TypeVar('_UpdatedType1')
_UpdatedType2 = TypeVar('_UpdatedType2')
_BiMappableKind = TypeVar('_BiMappableKind', bound=BiMappableN)
def bimap(
on_first: Callable[[_FirstType], _UpdatedType1],
on_second: Callable[[_SecondType], _UpdatedType2],
) -> Kinded[
Callable[
[KindN[_BiMappableKind, _FirstType, _SecondType, _ThirdType]],
KindN[_BiMappableKind, _UpdatedType1, _UpdatedType2, _ThirdType],
]
]:
"""
Maps container on both: first and second arguments.
Can be used to synchronize state on both success and failure.
This is how it should be used:
.. code:: python
>>> from returns.io import IOSuccess, IOFailure
>>> from returns.pointfree import bimap
>>> def first(argument: int) -> float:
... return argument / 2
>>> def second(argument: str) -> bool:
... return bool(argument)
>>> assert bimap(first, second)(IOSuccess(1)) == IOSuccess(0.5)
>>> assert bimap(first, second)(IOFailure('')) == IOFailure(False)
Note, that this function works
for all containers with ``.map`` and ``.alt`` methods.
See :class:`returns.primitives.interfaces.bimappable.BiMappableN`
for more info.
"""
@kinded
def factory(
container: KindN[_BiMappableKind, _FirstType, _SecondType, _ThirdType],
) -> KindN[_BiMappableKind, _UpdatedType1, _UpdatedType2, _ThirdType]:
return container.map(on_first).alt(on_second)
return factory
|
