Data.Comp.Param.Difunctor

This module defines difunctors (Meijer, Hutton, FPCA '95), i.e. binary type constructors that are contravariant in the first argument and covariant in the second argument.

Documentation

difmap :: Difunctor f => (a -> b) -> f c a -> f c b

class Difunctor f where

This class represents difunctors, i.e. binary type constructors that are contravariant in the first argument and covariant in the second argument.

Minimal complete definition

dimap

Methods

dimap :: (a -> b) -> (c -> d) -> f b c -> f a d

Instances

Difunctor ((->) :: * -> * -> *)

The canonical example of a difunctor.

Defined in Data.Comp.Param.Difunctor

Methods

dimap :: (a -> b) -> (c -> d) -> (b -> c) -> a -> d

Difunctor f => Difunctor (f :&: p)

Defined in Data.Comp.Param.Ops

Methods

dimap :: (a -> b) -> (c -> d) -> (f :&: p) b c -> (f :&: p) a d

(Difunctor f, Difunctor g) => Difunctor (f :+: g)

Defined in Data.Comp.Param.Ops

Methods

dimap :: (a -> b) -> (c -> d) -> (f :+: g) b c -> (f :+: g) a d

Orphan instances

Difunctor f => Functor (f a)

Methods

fmap :: (a0 -> b) -> f a a0 -> f a b

(<$) :: a0 -> f a b -> f a a0