object Test extends Application {

  object Twice {
    def apply(x: int) = x * 2
    def unapply(x: int): Option[Tuple1[int]] =
      if (x % 2 == 0) Some(Tuple1(x / 2))
      else None
  }

  def test(x: int) = x match {
    case Twice(y) => "x is two times "+y
    case _ => "x is odd"
  }

  Console.println(test(3))
  Console.println(test(4))

}