def traverse(gap: Applicative[G], fa: Kind1[Option, A],\
f: Func1[A, Kind1[G, B]]) -> Kind2[G, Option, B]:
if dekind(fa).is_empty():
return cast(Kind2[G, Option, B], gap.pure(Nothing()))
else:
ff: Func1[B, Option[B]] = Some
return gap.map(f(dekind(fa).get), ff)
def from_iterable(
cls,
inner_value: Iterable[Kind2['IOResult', _ValueType, _ErrorType]],
) -> 'IOResult[Sequence[_ValueType], _ErrorType]':
"""
Transforms an iterable of ``IOResult`` containers into a single one.
.. code:: python
>>> from returns.io import IOResult, IOSuccess, IOFailure
>>> assert IOResult.from_iterable([
... IOSuccess(1),
... IOSuccess(2),
... ]) == IOSuccess((1, 2))
>>> assert IOResult.from_iterable([
... IOSuccess(1),
... IOFailure('a'),
... ]) == IOFailure('a')
>>> assert IOResult.from_iterable([
... IOFailure('a'),
... IOSuccess(1),
... ]) == IOFailure('a')
"""
return dekind(iterable_kind(cls, inner_value))
def apply(
self,
container: Kind3['RequiresContextFutureResult',
Callable[[_ValueType],
_NewValueType], _ErrorType, _EnvType, ],
) -> 'RequiresContextFutureResult[_NewValueType, _ErrorType, _EnvType]':
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> import anyio
>>> from returns.context import RequiresContextFutureResult
>>> from returns.io import IOSuccess, IOFailure
>>> def transform(arg: str) -> str:
... return arg + 'b'
>>> assert anyio.run(
... RequiresContextFutureResult.from_value('a').apply(
... RequiresContextFutureResult.from_value(transform),
... ),
... RequiresContextFutureResult.empty,
... ) == IOSuccess('ab')
>>> assert anyio.run(
... RequiresContextFutureResult.from_failure('a').apply(
... RequiresContextFutureResult.from_value(transform),
... ),
... RequiresContextFutureResult.empty,
... ) == IOFailure('a')
"""
return RequiresContextFutureResult(
lambda deps: self(deps).apply(dekind(container)(deps)), )
def compose_result(
self,
function: Callable[[Result[_ValueType, _ErrorType]],
Kind3[RequiresContextIOResult, _NewValueType,
_ErrorType, _EnvType, ], ],
) -> RequiresContextIOResult[_NewValueType, _ErrorType, _EnvType]:
"""
Composes inner ``Result`` with ``ReaderIOResult`` returning function.
Can be useful when you need an access to both states of the result.
.. code:: python
>>> from returns.context import ReaderIOResult, NoDeps
>>> from returns.io import IOSuccess, IOFailure
>>> from returns.result import Result
>>> def count(
... container: Result[int, int],
... ) -> ReaderIOResult[int, int, NoDeps]:
... return ReaderIOResult.from_result(
... container.map(lambda x: x + 1).alt(abs),
... )
>>> success = ReaderIOResult.from_value(1)
>>> failure = ReaderIOResult.from_failure(-1)
>>> assert success.compose_result(count)(...) == IOSuccess(2)
>>> assert failure.compose_result(count)(...) == IOFailure(1)
"""
return RequiresContextIOResult(
lambda deps: dekind(
function(self(deps)._inner_value), # noqa: WPS437
)(deps), )
def bind(
self,
function: Callable[[_ReturnType], Kind2['RequiresContext',
_NewReturnType, _EnvType], ],
) -> RequiresContext[_NewReturnType, _EnvType]:
"""
Composes a container with a function returning another container.
This is useful when you do several computations that rely on the
same context.
.. code:: python
>>> from returns.context import RequiresContext
>>> def first(lg: bool) -> RequiresContext[int, float]:
... # `deps` has `float` type here:
... return RequiresContext(
... lambda deps: deps if lg else -deps,
... )
>>> def second(number: int) -> RequiresContext[str, float]:
... # `deps` has `float` type here:
... return RequiresContext(
... lambda deps: '>=' if number >= deps else '<',
... )
>>> assert first(True).bind(second)(1) == '>='
>>> assert first(False).bind(second)(2) == '<'
"""
return RequiresContext(lambda deps: dekind(function(self(deps)))(deps))
def compose_result(
self,
function: Callable[[Result[_ValueType, _ErrorType]],
Kind2['IOResult', _NewValueType, _ErrorType], ],
) -> 'IOResult[_NewValueType, _ErrorType]':
"""
Composes inner ``Result`` with ``IOResult`` returning function.
Can be useful when you need an access to both states of the result.
.. code:: python
>>> from returns.io import IOResult, IOSuccess, IOFailure
>>> from returns.result import Result
>>> def count(container: Result[int, int]) -> IOResult[int, int]:
... return IOResult.from_result(
... container.map(lambda x: x + 1).alt(abs),
... )
>>> assert IOSuccess(1).compose_result(count) == IOSuccess(2)
>>> assert IOFailure(-1).compose_result(count) == IOFailure(1)
"""
return dekind(function(self._inner_value))
def bind(
self,
function: Callable[[_FirstType], Kind2['Pair', _NewFirstType,
_SecondType], ],
) -> 'Pair[_NewFirstType, _SecondType]':
"""Changes the first type with a function returning another Pair."""
return dekind(function(self._inner_value[0]))
def apply(
self,
container: Kind1['IO', Callable[[_ValueType], _NewValueType]],
) -> 'IO[_NewValueType]':
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> from returns.io import IO
>>> assert IO('a').apply(IO(lambda inner: inner + 'b')) == IO('ab')
Or more complex example that shows how we can work
with regular functions and multiple ``IO`` arguments:
.. code:: python
>>> from returns.curry import curry
>>> @curry
... def appliable(first: str, second: str) -> str:
... return first + second
>>> assert IO('b').apply(IO('a').apply(IO(appliable))) == IO('ab')
"""
return self.map(dekind(container)._inner_value) # noqa: WPS437
def apply(
self,
container: Kind3['RequiresContextResult', Callable[[_ValueType],
_NewValueType],
_ErrorType, _EnvType, ],
) -> 'RequiresContextResult[_NewValueType, _ErrorType, _EnvType]':
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> from returns.context import RequiresContextResult
>>> from returns.result import Success, Failure, Result
>>> def transform(arg: str) -> str:
... return arg + 'b'
>>> assert RequiresContextResult.from_value('a').apply(
... RequiresContextResult.from_value(transform),
... )(...) == Success('ab')
>>> assert RequiresContextResult.from_failure('a').apply(
... RequiresContextResult.from_value(transform),
... )(...) == Failure('a')
>>> assert isinstance(RequiresContextResult.from_value('a').apply(
... RequiresContextResult.from_failure(transform),
... )(...), Result.failure_type) is True
"""
return RequiresContextResult(
lambda deps: self(deps).apply(dekind(container)(deps)), )
def from_iterable(
cls,
inner_value: Iterable[Kind3['RequiresContextResult', _ValueType,
_ErrorType, _EnvType, ], ],
) -> 'RequiresContextResult[Sequence[_ValueType], _ErrorType, _EnvType]':
"""
Transforms an iterable of ``RequiresContextResult`` containers.
Returns a single container with multiple elements inside.
.. code:: python
>>> from returns.context import RequiresContextResult
>>> from returns.result import Success, Failure
>>> assert RequiresContextResult.from_iterable([
... RequiresContextResult.from_value(1),
... RequiresContextResult.from_value(2),
... ])(...) == Success((1, 2))
>>> assert RequiresContextResult.from_iterable([
... RequiresContextResult.from_value(1),
... RequiresContextResult.from_failure('a'),
... ])(...) == Failure('a')
>>> assert RequiresContextResult.from_iterable([
... RequiresContextResult.from_failure('a'),
... RequiresContextResult.from_value(1),
... ])(...) == Failure('a')
"""
return dekind(iterable_kind(cls, inner_value))
def from_iterable(
cls,
inner_value: Iterable[Kind2['FutureResult', _ValueType, _ErrorType]],
) -> 'FutureResult[Sequence[_ValueType], _ErrorType]':
"""
Transforms an iterable of ``FutureResult`` containers.
Returns a single container with multiple elements inside.
.. code:: python
>>> import anyio
>>> from returns.future import FutureResult
>>> from returns.io import IOSuccess, IOFailure
>>> all_success = FutureResult.from_iterable([
... FutureResult.from_value(1),
... FutureResult.from_value(2),
... ])
>>> assert anyio.run(all_success.awaitable) == IOSuccess((1, 2))
>>> mixed = FutureResult.from_iterable([
... FutureResult.from_value(1),
... FutureResult.from_failure('a'),
... ])
>>> assert anyio.run(mixed.awaitable) == IOFailure('a')
>>> mixed = FutureResult.from_iterable([
... FutureResult.from_failure('a'),
... FutureResult.from_value(1),
... ])
>>> assert anyio.run(mixed.awaitable) == IOFailure('a')
"""
return dekind(iterable_kind(cls, inner_value))
def from_iterable(
cls,
inner_value: Iterable[Kind1['Maybe', _ValueType]],
) -> 'Maybe[Sequence[_ValueType]]':
"""
Transforms an iterable of ``Maybe`` containers into a single container.
.. code:: python
>>> from returns.maybe import Maybe, Some, Nothing
>>> assert Maybe.from_iterable([
... Some(1),
... Some(2),
... ]) == Some((1, 2))
>>> assert Maybe.from_iterable([
... Some(1),
... Nothing,
... ]) == Nothing
>>> assert Maybe.from_iterable([
... Nothing,
... Some(1),
... ]) == Nothing
"""
return dekind(iterable_kind(cls, inner_value))
async def async_bind_async(
function: Callable[[_ValueType], Awaitable[Kind1['Future',
_NewValueType]], ],
inner_value: Awaitable[_ValueType],
) -> _NewValueType:
"""Async binds a coroutine with container over a value."""
inner_io = dekind(await function(await inner_value))._inner_value
return await inner_io
def lash(
self,
function: Callable[
[_SecondType],
Kind2['Pair', _FirstType, _NewSecondType],
],
) -> 'Pair[_FirstType, _NewSecondType]':
return dekind(function(self._inner_value[1]))
async def async_compose_result(
function: Callable[[Result[_ValueType, _ErrorType]],
Kind3['RequiresContextFutureResult', _NewValueType,
_ErrorType, _EnvType, ], ],
container: 'RequiresContextFutureResult[_ValueType, _ErrorType, _EnvType]',
deps: _EnvType,
) -> Result[_NewValueType, _ErrorType]:
"""Async composes ``Result`` based function."""
new_container = dekind(function((await container(deps))._inner_value))
return (await new_container(deps))._inner_value
def bind(
self,
function: Callable[[_FirstType], Kind2['Pair', _NewFirstType,
_SecondType], ],
) -> 'Pair[_NewFirstType, _SecondType]':
"""
Changes the first type with a function returning another ``Pair``.
>>> def bindable(first: int) -> Pair[str, str]:
... return Pair((str(first), ''))
>>> assert Pair((1, 'b')).bind(bindable) == Pair(('1', ''))
"""
return dekind(function(self._inner_value[0]))
def lash(
self,
function: Callable[[_SecondType], Kind2['Pair', _FirstType,
_NewSecondType], ],
) -> 'Pair[_FirstType, _NewSecondType]':
"""
Changes the second type with a function returning ``Pair``.
>>> def lashable(second: int) -> Pair[str, str]:
... return Pair(('', str(second)))
>>> assert Pair(('a', 2)).lash(lashable) == Pair(('', '2'))
"""
return dekind(function(self._inner_value[1]))
def pair(
self,
function: Callable[[_FirstType, _SecondType],
Kind2['Pair', _NewFirstType, _NewSecondType], ],
) -> 'Pair[_NewFirstType, _NewSecondType]':
"""
Creates a new ``Pair`` from an existing one via a passed function.
>>> def min_max(first: int, second: int) -> Pair[int, int]:
... return Pair((min(first, second), max(first, second)))
>>> assert Pair((2, 1)).pair(min_max) == Pair((1, 2))
>>> assert Pair((1, 2)).pair(min_max) == Pair((1, 2))
"""
return dekind(function(self._inner_value[0], self._inner_value[1]))
def bind(
self,
function: Callable[
[_ValueType],
Kind3[
RequiresContextFutureResult,
_NewValueType,
_ErrorType,
_EnvType,
],
],
) -> RequiresContextFutureResult[_NewValueType, _ErrorType, _EnvType]:
"""
Composes this container with a function returning the same type.
.. code:: python
>>> import anyio
>>> from returns.context import RequiresContextFutureResult
>>> from returns.future import FutureResult
>>> from returns.io import IOSuccess, IOFailure
>>> def function(
... number: int,
... ) -> RequiresContextFutureResult[str, int, int]:
... # `deps` has `int` type here:
... return RequiresContextFutureResult(
... lambda deps: FutureResult.from_value(str(number + deps)),
... )
>>> assert anyio.run(
... RequiresContextFutureResult.from_value(2).bind(function),
... 3,
... ) == IOSuccess('5')
>>> assert anyio.run(
... RequiresContextFutureResult.from_failure(2).bind(function),
... 3,
... ) == IOFailure(2)
"""
return RequiresContextFutureResult(
lambda deps: self(deps).bind(
lambda inner: dekind( # type: ignore[misc]
function(inner),
)(deps),
),
)
def apply(
self,
container: Kind2[
'FutureResult',
Callable[[_ValueType], _NewValueType],
_ErrorType,
],
) -> 'FutureResult[_NewValueType, _ErrorType]':
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> import anyio
>>> from returns.future import FutureResult
>>> from returns.io import IOSuccess, IOFailure
>>> def appliable(x: int) -> int:
... return x + 1
>>> assert anyio.run(
... FutureResult.from_value(1).apply(
... FutureResult.from_value(appliable),
... ).awaitable,
... ) == IOSuccess(2)
>>> assert anyio.run(
... FutureResult.from_failure(1).apply(
... FutureResult.from_value(appliable),
... ).awaitable,
... ) == IOFailure(1)
>>> assert anyio.run(
... FutureResult.from_value(1).apply(
... FutureResult.from_failure(2),
... ).awaitable,
... ) == IOFailure(2)
>>> assert anyio.run(
... FutureResult.from_failure(1).apply(
... FutureResult.from_failure(2),
... ).awaitable,
... ) == IOFailure(1)
"""
return FutureResult(_future_result.async_apply(
dekind(container), self._inner_value,
))
def bind(
self,
function: Callable[
[_ValueType],
Kind3[
'RequiresContextIOResult',
_NewValueType,
_ErrorType,
_EnvType,
],
],
) -> 'RequiresContextIOResult[_NewValueType, _ErrorType, _EnvType]':
"""
Composes this container with a function returning the same type.
.. code:: python
>>> from returns.context import RequiresContextIOResult
>>> from returns.io import IOSuccess, IOFailure
>>> def first(lg: bool) -> RequiresContextIOResult[int, int, float]:
... # `deps` has `float` type here:
... return RequiresContextIOResult(
... lambda deps: IOSuccess(deps) if lg else IOFailure(-deps),
... )
>>> def second(
... number: int,
... ) -> RequiresContextIOResult[str, int, float]:
... # `deps` has `float` type here:
... return RequiresContextIOResult(
... lambda deps: IOSuccess('>=' if number >= deps else '<'),
... )
>>> assert first(True).bind(second)(1) == IOSuccess('>=')
>>> assert first(False).bind(second)(2) == IOFailure(-2)
"""
return RequiresContextIOResult(
lambda deps: self(deps).bind(
lambda inner: dekind( # type: ignore[misc]
function(inner),
)(deps),
),
)
def apply(
self,
container: Kind2['RequiresContext',
Callable[[_ReturnType], _NewReturnType], _EnvType, ],
) -> RequiresContext[_NewReturnType, _EnvType]:
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> from returns.context import RequiresContext
>>> assert RequiresContext.from_value('a').apply(
... RequiresContext.from_value(lambda inner: inner + 'b')
... )(...) == 'ab'
"""
return RequiresContext(
lambda deps: self.map(dekind(container)(deps))(deps), )
def from_iterable(
cls,
inner_value: Iterable[Kind1['IO', _ValueType]],
) -> 'IO[Sequence[_ValueType]]':
"""
Transforms an iterable of ``IO`` containers into a single container.
.. code:: python
>>> from returns.io import IO
>>> assert IO.from_iterable([
... IO(1),
... IO(2),
... ]) == IO((1, 2))
"""
return dekind(iterable_kind(cls, inner_value))
def bind(
self,
function: Callable[[_ValueType], Kind1['IO', _NewValueType]],
) -> 'IO[_NewValueType]':
"""
Applies 'function' to the result of a previous calculation.
'function' should accept a single "normal" (non-container) argument
and return ``IO`` type object.
.. code:: python
>>> def bindable(string: str) -> IO[str]:
... return IO(string + 'b')
>>> assert IO('a').bind(bindable) == IO('ab')
"""
return dekind(function(self._inner_value))
def from_iterable(
cls,
inner_value: Iterable[Kind2['RequiresContext', _ValueType, _EnvType]],
) -> 'RequiresContext[Sequence[_ValueType], _EnvType]':
"""
Transforms an iterable of ``RequiresContext`` containers.
Returns a single container with a sequence of values.
.. code:: python
>>> from returns.context import RequiresContext
>>> assert RequiresContext.from_iterable([
... RequiresContext.from_value(1),
... RequiresContext.from_value(2),
... ])(...) == (1, 2)
"""
return dekind(iterable_kind(cls, inner_value))
def from_iterable(
cls,
inner_value: Iterable[Kind1['Future', _ValueType]],
) -> 'Future[Sequence[_ValueType]]':
"""
Transforms an iterable of ``Future`` containers into a single container.
.. code:: python
>>> import anyio
>>> from returns.future import Future
>>> from returns.io import IO
>>> assert anyio.run(Future.from_iterable([
... Future.from_value(1),
... Future.from_value(2),
... ]).awaitable) == IO((1, 2))
"""
return dekind(iterable_kind(cls, inner_value))
def apply(
self,
container: Kind1['Future', Callable[[_ValueType], _NewValueType]],
) -> 'Future[_NewValueType]':
"""
Calls a wrapped function in a container on this container.
.. code:: python
>>> import anyio
>>> from returns.future import Future
>>> def transform(arg: int) -> str:
... return str(arg) + 'b'
>>> assert anyio.run(
... Future.from_value(1).apply(
... Future.from_value(transform),
... ).awaitable,
... ) == IO('1b')
"""
return Future(_future.async_apply(dekind(container), self._inner_value))
def map_filter(fa: Kind1["TList", A], f: Func1[A, "Option.Option[B]"]) -> Kind1["TList", B]: return TList([f(a).get for a in dekind(fa) if f(a).non_empty()])
def flat_map(fa: Kind1["TList", A], f: Func1[A, Kind1["TList", B]]) -> Kind1["TList", B]: return TList([b for a in dekind(fa) for b in dekind(f(a))])
def fold_left(fa: Kind1[Option, A], b: B, f: Func2[B, A, B]) -> B:
ff: Func1[A, B] = lambda a: f(b, a)
return dekind(fa).fold(b, ff)
