You probably don't want that minBound in the pattern, but rather as a comparison in a guard.
Dan On Tue, Dec 1, 2009 at 6:14 PM, Sjoerd Visscher <sjo...@w3future.com> wrote: > Hi Ted, > > Some tips: >> invlist_negate [] = [0] >> invlist_negate (0:xs) = xs >> invlist_negate xs = 0:xs > > You are doing this for generic Num instances, so 0 probably isn't the lower > bound. Haskell has another type class for this: Bounded. Then you can use > minBound instead of 0. Also the first line is just a special case of the last > one. > > invlist_negate :: (Bounded a, Num a) => [a] -> [a] > invlist_negate (minBound : xs) = xs > invlist_negate xs = minBound : xs > > Try doing invlist_member together with a function invlist_notMember (just > like there is notElem for lists), I think that would clean things up a bit. > > Keep on going, there's lots of fun ahead! > > greetings, > Sjoerd > > -- > Sjoerd Visscher > sjo...@w3future.com > > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
