{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
module Data.Comp.Multi.Desugar where
import Data.Comp.Multi
class (HFunctor f, HFunctor g) => Desugar f g where
desugHom :: Hom f g
desugHom = desugHom' . hfmap Hole
desugHom' :: Alg f (Context g a)
desugHom' x = appCxt (desugHom x)
instance {-# OVERLAPPABLE #-} (Desugar f h, Desugar g h) => Desugar (f :+: g) h where
desugHom = caseH desugHom desugHom
desugar :: Desugar f g => Term f :-> Term g
desugar = appHom desugHom
desugarA :: (HFunctor f', HFunctor g', DistAnn f p f', DistAnn g p g',
Desugar f g) => Term f' :-> Term g'
desugarA = appHom (propAnn desugHom)
instance {-# OVERLAPPABLE #-} (HFunctor f, HFunctor g, f :<: g) => Desugar f g where
desugHom = simpCxt . inj