from __future__ import annotations
from abc import abstractmethod
from typing import TYPE_CHECKING, Callable, ClassVar, Sequence, Type, TypeVar
from returns.interfaces.specific import ioresult, reader, reader_result
from returns.primitives.hkt import KindN
from returns.primitives.laws import (
Law,
Law2,
Lawful,
LawSpecDef,
law_definition,
)
if TYPE_CHECKING:
from returns.io import IOResult # noqa: F401, WPS433
from returns.context import ReaderIOResult # noqa: WPS433
_FirstType = TypeVar('_FirstType')
_SecondType = TypeVar('_SecondType')
_ThirdType = TypeVar('_ThirdType')
_UpdatedType = TypeVar('_UpdatedType')
_ValueType = TypeVar('_ValueType')
_ErrorType = TypeVar('_ErrorType')
_EnvType = TypeVar('_EnvType')
_ReaderIOResultLikeType = TypeVar(
'_ReaderIOResultLikeType',
bound='ReaderIOResultLikeN',
)
[docs]class ReaderIOResultLikeN(
reader_result.ReaderResultLikeN[_FirstType, _SecondType, _ThirdType],
ioresult.IOResultLikeN[_FirstType, _SecondType, _ThirdType],
):
"""
Base interface for all types that do look like ``ReaderIOResult`` instance.
Cannot be called.
"""
[docs] @abstractmethod
def bind_context_ioresult(
self: _ReaderIOResultLikeType,
function: Callable[
[_FirstType],
'ReaderIOResult[_UpdatedType, _SecondType, _ThirdType]',
],
) -> KindN[_ReaderIOResultLikeType, _UpdatedType, _SecondType, _ThirdType]:
"""Binds a ``ReaderIOResult`` returning function over a container."""
[docs] @classmethod
@abstractmethod
def from_ioresult_context(
cls: Type[_ReaderIOResultLikeType], # noqa: N805
inner_value: 'ReaderIOResult[_ValueType, _ErrorType, _EnvType]',
) -> KindN[_ReaderIOResultLikeType, _ValueType, _ErrorType, _EnvType]:
"""Unit method to create new containers from ``ReaderIOResult``."""
#: Type alias for kinds with three type arguments.
ReaderIOResultLike3 = ReaderIOResultLikeN[_FirstType, _SecondType, _ThirdType]
[docs]class _LawSpec(LawSpecDef):
"""
Concrete laws for ``ReaderIOResultBasedN``.
See: https://github.com/haskell/mtl/pull/61/files
"""
[docs] @law_definition
def asking_law(
container: ReaderIOResultBasedN[_FirstType, _SecondType, _ThirdType],
env: _ThirdType,
) -> None:
"""Asking for an env, always returns the env."""
assert container.ask().__call__( # noqa: WPS609
env,
) == container.from_value(env).__call__(env) # noqa: WPS609
[docs]class ReaderIOResultBasedN(
ReaderIOResultLikeN[_FirstType, _SecondType, _ThirdType],
reader.CallableReader3[
_FirstType,
_SecondType,
_ThirdType,
# Calls:
'IOResult[_FirstType, _SecondType]',
_ThirdType,
],
Lawful['ReaderIOResultBasedN[_FirstType, _SecondType, _ThirdType]'],
):
"""
This interface is very specific to our ``ReaderIOResult`` type.
The only thing that differs from ``ReaderIOResultLikeN`` is that we know
the specific types for its ``__call__`` method.
In this case the return type of ``__call__`` is ``IOResult``.
"""
_laws: ClassVar[Sequence[Law]] = (
Law2(_LawSpec.asking_law),
)
#: Type alias for kinds with three type arguments.
ReaderIOResultBased3 = ReaderIOResultBasedN[_FirstType, _SecondType, _ThirdType]