Hi.
Another way is to take advantage of Haskell's laziness:
class Foo a where foo :: a -> Int
data Oof1 = Oof1 Int instance Foo Oof1 where foo (Oof1 i) = i
data Oof2 = Oof2 Int instance Foo Oof2 where foo (Oof2 i) = i
list1 = [foo (Oof1 10), foo (Oof2 20)]
That's all it takes. The applications of foo in list1 don't get evaluated until list1 is used, e.g. by sum.
Regards, Tom
_______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
