how to implement this in scala?

gistfile1.hs

quicksort' :: (Ord a) => [a] -> [a]
quicksort' [] = []
quicksort' (x:xs) = smaller ++ [x] ++ bigger
        where smaller = quicksort' $ filter (<=x) xs
              bigger = quicksort' $ filter (>x) xs

solved, thanks老猪
def quicksort[T : Ordering](l: List[T]) : List[T] = l match {
case Nil => Nil
case x :: xs =>
val ord = Ordering[T]
import ord._

val smaller = quicksort(xs.filter(_<=x))
val bigger = quicksort(xs.filter(_>x))
smaller ++ List(x) ++ bigger

}