> There's a remark at the beginning of 7.2 that says: > > delete, (\\), union and intersect preserve the invariant=20 > that lists don't contain duplicates, provided that=20 > their first argument contains no duplicates. > > The same applies to unionBy etc. This design is one > you might reasonably disagree with. I'd have thought > it would be more sensible to have the invariant that > *both* arguments to union and intersect are assumed > to be sets (no dups).
That's partly what I was alluding to, but either way I'd have thought that there were clearer definitions, for example: unionBy eq xs ys = xs ++ [y | y <- nubBy eq ys, not (any (eq y) xs)] Jón -- Jón Fairbairn [EMAIL PROTECTED] 31 Chalmers Road [EMAIL PROTECTED] Cambridge CB1 3SZ +44 1223 570179 (after 14:00 only, please!) _______________________________________________ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
