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package examples.actors
import scala.actors.Actor._
import scala.actors.{Channel, OutputChannel}
/**
@author Philipp Haller
@version 1.0, 07/09/2007
*/
object fringe extends Application {
abstract class Tree
case class Node(left: Tree, right: Tree) extends Tree
case class Leaf(v: Int) extends Tree
val comparator = actor {
val extractor1 = actor(extractorBehavior())
val extractor2 = actor(extractorBehavior())
val ch1 = new Channel[Any]
val ch2 = new Channel[Any]
loop {
react {
case ('Fringe, tree1, tree2) =>
extractor1.send(('Fringe, tree1), ch1)
extractor2.send(('Fringe, tree2), ch2)
self ! Triple('Equal, ch1.?, ch2.?)
case ('Equal, atom1, atom2) =>
println("comparing "+atom1+" and "+atom2)
if (atom1 == atom2) atom1 match {
case None =>
println("same fringe")
exit()
case _ =>
self ! Triple('Equal, ch1.?, ch2.?)
} else {
println("fringes differ")
exit()
}
}
}
}
val extractorBehavior = () => {
var output: OutputChannel[Any] = null
loop {
react {
case ('Fringe, tree) =>
output = sender
self ! ('Extract, tree)
case ('Extract, tree) => tree match {
case atom @ Leaf(_) =>
println("sending "+Some(atom))
output ! Some(atom)
sender ! 'Continue
case Node(left, right) =>
val outer = self
val outerCont = sender
val cont = actor {
react {
case 'Continue =>
outer.send(('Extract, right), outerCont)
}
}
self.send(('Extract, left), cont)
}
case 'Continue =>
output ! None
exit()
}
}
}
comparator ! ('Fringe, Node(Leaf(5), Node(Leaf(7), Leaf(3))),
Node(Leaf(5), Node(Leaf(7), Leaf(3))))
}
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