Supertyping of classes
see Supertyping Suggestion for Haskell
example:
class Num a <= Group a where
(+) :: a -> a -> a
negate :: a -> a
apart from multiple inheritance, it could work like this:
import Prelude hiding ((+),negate)
import qualified Prelude ((+),negate)
class Group a where
(+) :: a -> a -> a
negate :: a -> a
instance Num a => Group a where
(+) = (Prelude.+)
negate = Prelude.negate
- coeus_at_gmx_de