Quicksort in Scala

def sort(list: List[Int]): List[Int] = {
        list match {
                case List() => list
                case List(_) => list
                case List(_, _*) => {
                        val pivot = list(list.length/2)
                        sort(list.filter(x => x < pivot)) ::: list.filter(x => x == pivot) ::: sort(list.filter(x => x > pivot)) 
                }
        }
}