hiding import, tuple instances

31 Aug 2001

      Hi,

1) How can I hide an instance of a class imported from prelude? For example I would like to redefine

instance (Ord a, Ord b) => Ord (a,b) where
 (<=) (x,y) (z,w)
  | x < z = True
  | x == z = if y <= w then True else False
  | otherwise = False

for educational purposes.

2) I could not find an entry for this instance in Prelude instead I found

instance Ord () where

compare () () = EQ

Is this suppose to mean "for all tuples"?

How do I define functions that work on all tuples?

Thanks for taking time

Cagdas Ozgenc