[Haskell-cafe] Cartesian product of a Set

Hi all, Is this a reasonable way to compute the cartesian product of a Set?

cartesian :: Ord a => S.Set a -> S.Set (a,a) cartesian x = S.fromList [(i,j) | i <- xs, j <- xs] where xs = S.toList x

It's a fairly "obvious" way to do it, but I wondered if there were any hidden gotchas. I'm particularly concerned by toList (O(n)) fromList (O(n log n)) - but for other reasons I'd really like to be using Set rather than List for this (I think). Many thanks for any thoughts, -Andy -- Andy Gimblett Computer Science Department University of Wales Swansea http://www.cs.swan.ac.uk/~csandy/