Source code for returns.interfaces.lashable

from abc import abstractmethod
from typing import Callable, Generic, NoReturn, TypeVar

from returns.primitives.hkt import KindN

_FirstType = TypeVar('_FirstType')
_SecondType = TypeVar('_SecondType')
_ThirdType = TypeVar('_ThirdType')
_UpdatedType = TypeVar('_UpdatedType')

_LashableType = TypeVar('_LashableType', bound='LashableN')


[docs]class LashableN(Generic[_FirstType, _SecondType, _ThirdType]):
    """
    Represents a "context" in which calculations can be executed.

    ``Rescueable`` allows you to bind together
    a series of calculations while maintaining
    the context of that specific container.

    In contrast to :class:`returns.interfaces.bindable.BinbdaleN`,
    works with the second type value.
    """

    __slots__ = ()

[docs]    @abstractmethod
    def lash(
        self: _LashableType,
        function: Callable[
            [_SecondType],
            KindN[_LashableType, _FirstType, _UpdatedType, _ThirdType],
        ],
    ) -> KindN[_LashableType, _FirstType, _UpdatedType, _ThirdType]:
        """
        Applies 'function' to the result of a previous calculation.

        And returns a new container.
        """


#: Type alias for kinds with two type arguments.
Lashable2 = LashableN[_FirstType, _SecondType, NoReturn]

#: Type alias for kinds with three type arguments.
Lashable3 = LashableN[_FirstType, _SecondType, _ThirdType]