what's the difference?

11 Jul 2002

      Greetings.

What is the difference between the following two scenarios:

1)

class Eq a where 
    (==) :: a -> a -> Bool

class Eq a => Ord a where
    ( < ) :: a -> a -> Bool

2)

class Eq a where
    (==) :: a -> a -> Bool

class Ord a where
    (eq),( < ) :: a -> a -> Bool

instance Ord a => Eq a where
     (==) = eq

eq is just a rename for == to avoid the nameclash

The second scenario resembles Russell's Paradox. Typeclass of a typeclass. Anyhow we are loosing orthogonality here.

Thanks

what's the difference?

Cagdas Ozgenc