Re: [Haskell-beginners] function defenition. Do I understand it right?

I am not sure where your error is coming from. module Main   where halve :: [a] -> ([a],[a]) halve xs | null xs = ([],[])          | otherwise = (take r xs, drop s xs)  where (p,q) = divMod (length xs) 2        (r,s) = if q == 0 then (p,p) else (p + 1,p) works fine for me in ghci and is approximately what you wrote :) For what it's worth your implementation has a bug in it, you only want to take an extra item in the odd case. Ben