Improved ping pong example.

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@10896 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

docs/examples/actors/pingpong.scala

@@ -3,28 +3,26 @@ package examples.actors
 import scala.actors.Actor
 import scala.actors.Actor._
 
-case object SendPing
 case object Ping
 case object Pong
 case object Stop
 
 class Ping(count: int, pong: Actor) extends Actor {
   def act() {
-    var pingsLeft = count
+    var pingsLeft = count - 1
+    pong ! Ping
     loop {
       react {
-        case SendPing =>
-          pong ! Ping
-          pingsLeft = pingsLeft - 1
         case Pong =>
           if (pingsLeft % 1000 == 0)
             Console.println("Ping: pong")
-          if (pingsLeft > 0)
-            self ! SendPing
-          else {
+          if (pingsLeft > 0) {
+            pong ! Ping
+            pingsLeft -= 1
+          } else {
             Console.println("Ping: stop")
             pong ! Stop
-            exit('stop)
+            exit()
           }
       }
     }
@@ -40,10 +38,10 @@ class Pong extends Actor {
           if (pongCount % 1000 == 0)
             Console.println("Pong: ping "+pongCount)
           sender ! Pong
-          pongCount = pongCount + 1
+          pongCount += 1
         case Stop =>
           Console.println("Pong: stop")
-          exit('stop)
+          exit()
       }
     }
   }
@@ -54,5 +52,4 @@ object pingpong extends Application {
   val ping = new Ping(100000, pong)
   ping.start
   pong.start
-  ping ! SendPing
 }