Scala pattern matching confusion with Option[Any]

Question

I have the following Scala code.

import scala.actors.Actor

object Alice extends Actor {
  this.start
  def act{
    loop{
      react {
        case \"Hello\" =         


        

Answer 1

As already stated, you're up against erasure here.

For the solution... It's normal with Scala actor to define case classes for each message type you're likely to send:

case class MessageTypeA(s : String)
case class MessageTypeB(i : Int)

object Alice extends Actor {
  this.start
  def act{
    loop{
      react {
        case "Hello" => sender ! MessageTypeA("Hi")
        case i:Int => sender ! MessageTypeB(0)
      }
    }
  }
}
object Test {
  def test = {
    (Alice !? (100, "Hello")) match {
      case Some(MessageTypeB(i)) => println ("Int received "+i)
      case Some(MessageTypeA(s)) => println ("String received "+s)
      case _ =>
    }
    (Alice !? (100, 1)) match {
      case Some(MessageTypeB(i)) => println ("Int received " + i)
      case Some(MessageTypeA(s)) => println ("String received " + s)
      case _ =>
    }
  }
}