1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
from __future__ import annotations
from collections.abc import Callable
from typing import TYPE_CHECKING, TypeVar
from returns.interfaces.specific.io import IOLikeN
from returns.primitives.hkt import Kinded, KindN, kinded
if TYPE_CHECKING:
from returns.io import IO # noqa: WPS433
_FirstType_contra = TypeVar('_FirstType_contra', contravariant=True)
_SecondType = TypeVar('_SecondType')
_ThirdType_contra = TypeVar('_ThirdType_contra', contravariant=True)
_UpdatedType_co = TypeVar('_UpdatedType_co', covariant=True)
_IOLikeKind = TypeVar('_IOLikeKind', bound=IOLikeN)
def bind_io(
function: Callable[[_FirstType_contra], IO[_UpdatedType_co]],
) -> Kinded[
Callable[
[KindN[_IOLikeKind, _FirstType_contra, _SecondType, _ThirdType_contra]],
KindN[_IOLikeKind, _UpdatedType_co, _SecondType, _ThirdType_contra],
]
]:
"""
Composes successful container with a function that returns a container.
In other words, it modifies the function's
signature from:
``a -> IO[b]``
to:
``Container[a, c] -> Container[b, c]``
.. code:: python
>>> from returns.io import IOSuccess, IOFailure
>>> from returns.io import IO
>>> from returns.pointfree import bind_io
>>> def returns_io(arg: int) -> IO[int]:
... return IO(arg + 1)
>>> bound = bind_io(returns_io)
>>> assert bound(IO(1)) == IO(2)
>>> assert bound(IOSuccess(1)) == IOSuccess(2)
>>> assert bound(IOFailure(1)) == IOFailure(1)
"""
@kinded
def factory(
container: KindN[
_IOLikeKind, _FirstType_contra, _SecondType, _ThirdType_contra
],
) -> KindN[_IOLikeKind, _UpdatedType_co, _SecondType, _ThirdType_contra]:
return container.bind_io(function)
return factory
|
