Decomposition of fi.contramap(k) into its components, as it is
frequently convenient to apply k separately from sorting or
whatever process with fi, even when B is unknown, which is
very common.
This is isomorphic to F as long as F itself is a contravariant
functor. The homomorphism from F[A] to
ContravariantCoyoneda[F,A] exists even when F is not a
contravariant functor.
See ContravariantCoyonedaUsage.scala in the scalaz source tree
for an interesting usage demonstration.
As ContravariantCoyoneda(o)(identity).unlift = o, further
factoring can occur as follows, for free:
ContravariantCoyoneda(o contramap g)(f).unlift =
ContravariantCoyoneda(o)(g compose f).unlift
- See also
- Companion
- object
Type members
Types
The pivot between fi and k, usually existential.
The pivot between fi and k, usually existential.
Value members
Concrete methods
Simple function composition. Allows map fusion without touching
the underlying F.
Simple function composition. Allows map fusion without touching
the underlying F.
Converts to F[A] given that F is a contravariant.
Converts to F[A] given that F is a contravariant.