object sorter {

  def sort(a: List[Int]): List[Int] = {
    if (a.length < 2)
      a
    else {
      val pivot = a(a.length / 2);
      def lePivot(x: Int) = x < pivot;
      def gtPivot(x: Int) = x > pivot;
      def eqPivot(x: Int) = x == pivot;
      sort(a filter lePivot)
        ::: sort(a filter eqPivot)
        ::: sort(a filter gtPivot)
    }
  }

  def main(args: Array[String]) = {
    val xs = List(6, 2, 8, 5, 1);
    Console.println(xs);
    Console.println(sort(xs));
  }

}