Invariant

public protocol Invariant

An Invariant Functor provides a type the ability to transform its value type into another type. An instance of Functor or Contravariant are Invariant Functors as well.


                    
                    
                    
                      imap(_:_:_:)

Transforms the value type using the functions provided.

The implementation of this function must obey the following laws:

imap(fa, id, id) == fa
imap(imap(fa, f1, g1), f2, g2) == imap(fa, compose(f2, f1), compose(g2, g1))

Declaration

Swift

static func imap<A, B>(
    _ fa: Kind<Self, A>,
    _ f: @escaping (A) -> B,
    _ g: @escaping (B) -> A) -> Kind<Self, B>

Parameters

`fa`	Value whose value type will be transformed.
`f`	Transforming function.
`g`	Transforming function.

Return Value

A new value in the same context as the original value, with the value type transformed.