In article <[EMAIL PROTECTED]>, Alastair Reid <[EMAIL PROTECTED]> wrote:
> One way to overcome part of this problem would be to generalize the idea of > 'type synonyms' to allow 'context synonyms'. For example, we have type > synonyms like: > > type Point = (Int,Int) > > we could have 'context synonyms' like: > > class Num a => (Add a, Subtract a, FromInteger a, Eq a, Multiply a, ...) That would be quite unnecessary. Simply write this: class (Add a, Subtract a, FromInteger a, Eq a, Multiply a, ...) => Num a; instance (Add a, Subtract a, FromInteger a, Eq a, Multiply a, ...) => Num a; And now you can write this: invert :: Num a => Matrix a -> Matrix a I use this idiom quite frequently for "joining" classes together. -- Ashley Yakeley, Seattle WA _______________________________________________ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
