QuickSort implemented in PureScript

QuickSort.purs

module QuickSort where

import Prelude
import Control.Monad.Eff (Eff)
import Control.Monad.Eff.Console (CONSOLE, logShow)
import Data.List (List(..), (:), filter)
import Data.List as S
import TryPureScript (render, withConsole)

-- | main :: forall e. Eff (console :: CONSOLE | e) Unit
main = render =<< withConsole do
  let sortedList = quicksort (S.fromFoldable [10,2,5,3,1,6,7,4,2,3,4,8,9])
  logShow sortedList -- (1 : 2 : 2 : 3 : 3 : 4 : 4 : 5 : 6 : 7 : 8 : 9 : 10 : Nil)

quicksort :: forall a. Ord a => List a -> List a
quicksort Nil = Nil
quicksort (x:xs) = (quicksort lesser) `append` (x : quicksort greater)
    where
        lesser = filter (\n -> n < x) xs
        greater = filter (\n -> n >= x) xs