scala.swing の PartialFunction の合成っぽいのを Actor でやってみた

main.scala

trait Reactions extends scala.actors.Actor {
  type Reactor = PartialFunction[Any, Unit]
  val reactions = scala.collection.mutable.Set[Reactor]()

  override def exit() = super.exit()
  
  def act() {
    loop {
      react {
        reactions.reduceLeft { _ orElse _ }
      }
    }
  }
}

case object KEY_INPUT
case object MOUSE_INPUT

object Console extends App {
  val a = new Reactions {}
  a.reactions += {
    case KEY_INPUT =>
      println("a: key input")
  }

  val b = new Reactions {}
  b.reactions += {
    case KEY_INPUT =>
      println("b: key input")
  }
  
  b.reactions += {
    case MOUSE_INPUT =>
      println("b: mouse input")    
  }

  a.start()
  b.start()

  a ! KEY_INPUT
  b ! KEY_INPUT

  a ! MOUSE_INPUT // a には MOUSE_INPUT がないので無視される
  b ! MOUSE_INPUT

  a.exit()
  b.exit()  
}