Foldable

Foldable

Bases: Protocol

A foldable can be reduced to a value.

Source code in funclift/foldable.py

class Foldable(Protocol):
    """A foldable can be reduced to a value."""

    def fold_right(self, f: Callable[[A, B], B]) -> B:
        """Reduces a foldable in a right-associative manner.

        Args:
            self: A foldable structure that contains values of type A.
            f (Callable[[A, B], B]): A function to be used while folding the
            structure.

        Returns:
            B: The value the structure reduces to.
        """
        ...

    def fold_left(self, f: Callable[[B, A], B]) -> B:
        """Reduces a foldable in a left-associative manner.

        Args:
            self: A foldable structure that contains values of type A.
            f (Callable[[B, A], B]): A function to be used while folding the
            structure.

        Returns:
            B: The value the structure reduces to.
        """
        ...

    def fold_map(self, f: Callable[[A], M]) -> M:
        """_summary_

        Args:
            f (Callable[[A], M]): _description_

        Returns:
            M: _description_
        """
        ...

fold_left(f)

Reduces a foldable in a left-associative manner.

Parameters:

Name	Type	Description	Default
self		A foldable structure that contains values of type A.	required
f	Callable[[B, A], B]	A function to be used while folding the	required

Returns:

Name	Type	Description
B	B	The value the structure reduces to.

Source code in funclift/foldable.py

def fold_left(self, f: Callable[[B, A], B]) -> B:
    """Reduces a foldable in a left-associative manner.

    Args:
        self: A foldable structure that contains values of type A.
        f (Callable[[B, A], B]): A function to be used while folding the
        structure.

    Returns:
        B: The value the structure reduces to.
    """
    ...

fold_map(f)

summary

Parameters:

Name	Type	Description	Default
f	Callable[[A], M]	description	required

Returns:

Name	Type	Description
M	M	description

Source code in funclift/foldable.py

def fold_map(self, f: Callable[[A], M]) -> M:
    """_summary_

    Args:
        f (Callable[[A], M]): _description_

    Returns:
        M: _description_
    """
    ...

fold_right(f)

Reduces a foldable in a right-associative manner.

Parameters:

Name	Type	Description	Default
self		A foldable structure that contains values of type A.	required
f	Callable[[A, B], B]	A function to be used while folding the	required

Returns:

Name	Type	Description
B	B	The value the structure reduces to.

Source code in funclift/foldable.py

def fold_right(self, f: Callable[[A, B], B]) -> B:
    """Reduces a foldable in a right-associative manner.

    Args:
        self: A foldable structure that contains values of type A.
        f (Callable[[A, B], B]): A function to be used while folding the
        structure.

    Returns:
        B: The value the structure reduces to.
    """
    ...

ListFoldable

Implements Foldable for lists.

Source code in funclift/foldable.py

class ListFoldable:
    """Implements [Foldable][funclift.foldable.Foldable] for lists."""

    @staticmethod
    def fold_right(fa: list[A], f: Callable[[A, B], B], id: B) -> B:
        acc = id
        for a in reversed(fa):
            acc = f(a, acc)
        return acc

    @staticmethod
    def fold_left(fa: list[A], f: Callable[[B, A], B], id: B) -> B:
        acc = id
        for a in fa:
            acc = f(acc, a)
        return acc

    @staticmethod
    def fold_map(fa: list[A], f: Callable[[A], M]) -> M:
        sig = signature(f)
        mcls = sig.return_annotation
        acc: M = get_mempty(mcls)

        for a in fa:
            m = f(a)
            acc = acc + m
        return acc

    @staticmethod
    def fold_map2(mcls: type, fa: list[A], f: Callable[[A], M]) -> M:
        acc: M = get_mempty(mcls)

        for a in fa:
            m = f(a)
            acc = acc + m
        return acc