{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FunctionalDependencies #-}

data Liste a = Ende
             | MkListe a (Liste a)
			deriving (Eq, Show)

-- class Container contType elemType | contType -> elemType where
class Container contType elemType where
  insert :: contType -> elemType -> contType

instance Container [a] a where
  insert cont newElem = newElem : cont

instance Container (Liste a) a where
  insert cont newElem = MkListe newElem cont
  
-- keine fun dep: inferenz von elem-type?
ins1 elem = insert [42] elem
ins2 elem = insert (MkListe 42 Ende) elem

{-
-- keine fun dep: OK
-- fun dep a::t ambiguous
instance Container (a,b) a where
  insert (elemA,elemB) newElemA = (newElemA, elemB)
  
instance Container (a,b) b where
  insert (elemA,elemB) newElemB = (elemA, newElemB)

ins3 elem = insert (42, 'X') elem
ins4 elem = insert (42, 'X') elem
-}