Haskell

Please help with my Haskell code. It is supposed to return the maximum element in a list but it doesn't work

lol :: [a] -> Nothing | a
lol [] = Nothing
lol [x] = x
lol (x:xs) = if x > lol xs then x else lol xs

>>25
Programming is not science. One example does not prove that something is wrong. It just shows that in this case recursion was not the most efficient solution.