Functor module:Data package:kind-apply

module Data.PolyKinded.Functor
kind-apply
Poly-kinded Functor type class. KFunctor generalizes functors, bifunctors, profunctors, ... by declaring a list of Variances for a type constructor.
class KFunctor (f :: k) (v :: Variances) (as :: LoT k) (bs :: LoT k) | f -> v
kind-apply Data.PolyKinded.Functor
Declares that the type constructor f is a generalized functor whose variances for each type argument are given by v.