foo.scala

object BubbleSort {

  def sort(xs: List[Int]) = {
    def bsort(xs: List[Int], current: Int, dest: Int): List[Int] = {
      dest match {
        case 0 => xs
        case _ if (dest == current) => bsort(xs, 0, dest - 1)
        case _ =>
          if (xs(current) > xs(current + 1)) {
            var tmp = xs(current + 1)
            xs(current + 1) = xs(current)
            xs(current) = tmp
          }

          bsort(xs, current + 1, dest)
      }
    }

    bsort(xs, 0, xs.length - 1)
  }

}

def sort(items: List[Int]): List[Int] = {
  def bSort(xs: List[Int], unsorted: List[Int] = Nil, sorted: List[Int] = Nil) = xs match {
    case x :: Nil =>
      if (unsorted.isEmpty) x :: sorted
      else bSort(unsorted, Nil, x :: sorted)
    case x :: y :: zs =>
      if (x > y) bSort(x :: zs, y :: unsorted, sorted)
      else bSort(y :: zs, x :: unsorted, sorted)
  }
  bSort(items)
}