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diff --git a/sources/scala/concurrent/jolib.scala b/sources/scala/concurrent/jolib.scala
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+/*                     __                                               *\
+**     ________ ___   / /  ___     Scala API                            **
+**    / __/ __// _ | / /  / _ |    (c) 2003, LAMP/EPFL                  **
+**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+** /____/\___/_/ |_/____/_/ | |                                         **
+**                          |/                                          **
+** $Id$
+\*                                                                  */
+
+package scala.concurrent;
+
+/**
+* Library for using join-calculus concurrent primitives in Scala.
+*/
+object jolib {
+
+  /////////////////// QUEUE /////////////////////////
+
+  class Queue[a] {
+    private var queue: List[a] = Nil;
+    def enqueue(x: a) = queue = queue ::: List(x);
+    def dequeue: a = { val x = queue.head; queue = queue.tail; x };
+    def front: a = queue.head;
+    def isEmpty = queue.isEmpty;
+  }
+
+  /////////////////// JOIN /////////////////////////
+
+  type Pattern = List[Signal];
+
+  type Rule = PartialFunction[List[Any], unit];
+
+  class Join with Monitor {
+
+    private var ruls: List[Pair[Pattern, Rule]] = null;
+
+    def canMatch(p: Pattern) =
+      p forall { s => !s.queue.isEmpty };
+
+    def values(p: Pattern) =
+      p map { s => s.queue.dequeue };
+
+    def rules(rs: Pair[Pattern, Rule]*) =
+      ruls = rs.asInstanceOf[List[Pair[Pattern, Rule]]];
+
+    def tryMatch =
+      (ruls find { case Pair(p, _) => canMatch(p) }) match {
+	case None => () => ();
+	case Some(Pair(p, r)) => {
+	  val args = values(p);
+	  () => concurrent.ops.spawn(r(args))
+	}
+      }
+
+  }
+
+  /////////////////// SIGNALS /////////////////////////
+
+  abstract class Signal (join: Join) {
+    type C;
+    val queue = new Queue[C];
+    def tryReduction(x: C): unit = {
+      val continuation = join synchronized {
+	queue.enqueue(x);
+	join.tryMatch
+      };
+      continuation()
+    }
+  }
+
+  abstract class Asynchr(join: Join) extends Signal(join) {
+    def send(x: C): unit = tryReduction(x);
+  }
+
+  abstract class Synchr[a](join: Join) extends Signal(join) {
+    type C <: SyncVar[a];
+    def send(x: C): a = {
+      tryReduction(x);
+      x.get
+    }
+  }
+
+}
+
+/* Example: References. (It does not work because of bugs in the compiler)
+
+import concurrent.jolib._;
+import concurrent.SyncVar;
+
+class Ref(init: int) extends Join {
+
+  object get extends Synchr[int](this) { case class C() extends SyncVar[int]; }
+  object set extends Synchr[unit](this) { case class C(x: int) extends SyncVar[unit]; }
+  object state extends Asynchr(this) { case class C(x: int); }
+
+  rules (
+    Pair(List(get, state), { case List(g @ get.C(), state.C(x) ) => { g.set(x); state.send(state.C(x)) } }),
+    Pair(List(set, state), { case List(s @ set.C(x), state.C(y) ) => { s.set(()); state.send(state.C(x)) } })
+  );
+
+  state.send(state.C(init));
+
+  def Get: int = get.send(get.C());
+  def Set(x: int): unit = set.send(set.C(x));
+}
+*/
+