Cofree

 
public final class Cofree<F, A> : CofreeOf<F, A> where F : Functor

Cofree is a type that, given any Functor, is able to provide a Comonad instance, that can be interpreted into a more restrictive one.

  • First value wrapped in this comonad.

    Declaration

    Swift

    public let head: A

  • A potentially lazy way of obtaining further values in this comonadic structure.

    Declaration

    Swift

    public let tail: Eval<Kind<F, Cofree<F, A>>>

  • Safe downcast.

    Declaration

    Swift

    public static func fix(_ fa: CofreeOf<F, A>) -> Cofree<F, A>

    Parameters

    fa

    Value in the higher-kind form.

    Return Value

    Value cast to Cofree.

  • Initializes a Cofree value.

    Declaration

    Swift

    public init(_ head: A, _ tail: Eval<Kind<F, Cofree<F, A>>>)

    Parameters

    head

    Value to be wrapped.
    tail

    A description of the potential values in the comonadic context.

  • Obtains the values in the context of this Cofree comonad.

    Declaration

    Swift

    public func tailForced() -> Kind<F, Cofree<F, A>>

    Return Value

    The result of evaluating the tail of this Cofree.

  • Constructs a Cofree from a seed and an unfolding function.

    Declaration

    Swift

    public static func unfold(
    _ a: A,
    _ f: @escaping (A) -> Kind<F, A>
) -> Cofree<F, A>

    Parameters

    a

    Seed.
    f

    Unfolding function.

    Return Value

    A Cofree value resulting from the unfolding process.

  • Constructs a Cofree from a seed and an unfolding function.

    Declaration

    Swift

    public static func create(
    _ a: A,
    _ f: @escaping (A) -> Kind<F, A>
) -> Cofree<F, A>

    Parameters

    a

    Seed.
    f

    Unfolding function.

    Return Value

    A Cofree value resulting from the unfolding process.

  • Folds this structure into a single value.

    Declaration

    Swift

    func cata<B>(_ folder: @escaping (A, Kind<F, B>) -> Eval<B>) -> Eval<B>

    Parameters

    folder

    Folding function to collapse this structure.

    Return Value

    Result from the folding process.

  • Folds this structure into a monadic value.

    Declaration

    Swift

    func cataM<B, M: Monad>(
    _ folder: @escaping (A, Kind<F, B>) -> Kind<M, B>,
    _ inclusion: FunctionK<ForEval, M>
) -> Kind<M, B>

    Parameters

    folder

    Folding function to collaps this structure.
    inclusion

    A natural transformation into the target Monad.

    Return Value

    A value in the new monadic context.