Supertyping of classes

[nobody]

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