I've been frustrated by the same lack of instances; as a stopgap, here's one for a three-tuple. The pattern is pretty clear and can easily be extended to whatever size you'd like. tupCon = mkConstr 1 "(,,)" Prefix instance (Data a, Data b, Data c) => Data (a, b ,c) where gfoldl k z (a, b, c) = ((z (,,) `k` a) `k` b) `k` c toConstr _ = tupCon fromConstr _ = (undefined, undefined, undefined) dataTypeOf _ = mkDataType [tupCon] MR K P SCHUPKE writes:

Any chance of Data instances for tuples of size greater than 2... One of the nice things about generics is you can use them by deriving Data on your datatypes - of course this doesn't work if you all of a sudden have to put a load of boiler-plate in just to use tuples...

Regards, Keean Schupke _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users