The quicksrt algorithm in haskell

quicksort.hs

module Sorting (main) where 

quicksort :: [Integer] -> [Integer]
quicksort [] = []
quicksort (x:xs) = quicksort smaller ++ [x] ++ larger
                where
                  smaller = [a |  a <- xs, a <= x]
                  larger = [b | b <- xs, b > x]


main = do 
  print(quicksort [1, 2, 3])
  print (quicksort [3, 2, 1])