-----------------------------------------------------------------------------
--
-- Module      :  Data.DualCategory.Instances.GeneralisedFunctor
-- Copyright   :
-- License     :  BSD3
--
-- Maintainer  :
-- Stability   :
-- Portability :
--
-- |
--
-----------------------------------------------------------------------------

{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}

module Data.DualCategory.Instances.GeneralisedFunctor (

) where

import Data.DualCategory.DualCategory (DualCategory(DualCategory))
import Prelude hiding (Functor, fmap)
import Control.GeneralisedFunctor.Functor
  (
    FunctorParam,
    Functor(fmap, FunctorInput, FunctorOutput, FunctorCategory),
    ExoFunctor(exomap, ExoInput, ExoOutput),
    ContraFunctorParam,
    ContraFunctor(contramap, ContraFunctorInput, ContraFunctorOutput, ContraFunctorCategory),
    ExoContraFunctor(exocontramap, ExoContraInput, ExoContraOutput),
  )

instance ExoFunctor (DualCategory c1 c2) c1 where
  type ExoInput (DualCategory c1 c2) c1 t = t
  type ExoOutput (DualCategory c1 c2) c1 t = t
  exomap (DualCategory f _) = f

instance ExoContraFunctor (DualCategory c1 c2) (DualCategory c2 c1) where
  type ExoContraInput (DualCategory c1 c2) (DualCategory c2 c1) t = t
  type ExoContraOutput (DualCategory c1 c2) (DualCategory c2 c1) t = t
  exocontramap (DualCategory f g) = DualCategory g f