List' xs = "The list is " ++ what xs
    where what []  = "empty."
          what [x] = "a singleton list."
          what xs  = "a longer list."


describeList' :: [a] -> String
describeList' xs = "The list is " ++ what xs
    where what []  = "empty."
          what [x] = "a singleton list."
          what xs  = "a longer list."
describeList' xs = "The list is " ++ what xs
    where what []  = "empty."
          what [x] = "a singleton list."
          what xs  = "a longer list."