Class Success

returns/result.py:411–467

Represents a calculation which has succeeded and contains the result. Contains the computation value.

@final
class Success(Result[_ValueType_co, Any]):
    """
    Represents a calculation which has succeeded and contains the result.

    Contains the computation value.
    """

    __slots__ = ()

    _inner_value: _ValueType_co

    def __init__(self, inner_value: _ValueType_co) -> None:
        """Success constructor."""
        super().__init__(inner_value)

    if not TYPE_CHECKING:  # noqa: WPS604  # pragma: no branch

        def alt(self, function):
            """Does nothing for ``Success``."""
            return self

        def map(self, function):
            """Composes current container with a pure function."""
            return Success(function(self._inner_value))

        def bind(self, function):
            """Binds current container to a function that returns container."""
            return function(self._inner_value)

        #: Alias for `bind` method. Part of the `ResultBasedN` interface.
        bind_result = bind

        def lash(self, function):
            """Does nothing for ``Success``."""
            return self

        def apply(self, container):
            """Calls a wrapped function in a container on this container."""
            if isinstance(container, Success):
                return self.map(container.unwrap())
            return container

        def value_or(self, default_value):
            """Returns the value for successful container."""
            return self._inner_value

    def swap(self):
        """Successes swap to :class:`Failure`."""
        return Failure(self._inner_value)

    def unwrap(self) -> _ValueType_co:
        """Returns the unwrapped value from successful container."""
        return self._inner_value

    def failure(self) -> Never:
        """Raises an exception for successful container."""
        raise UnwrapFailedError(self)