2 files changed, 55 insertions, 4 deletions

diff --git a/src/actors/scala/Reactions.scala b/src/actors/scala/Reactions.scala
new file mode 100755
index 0000000000..041cc793bd
--- /dev/null
+++ b/src/actors/scala/Reactions.scala
@@ -0,0 +1,54 @@
+package scala
+
+/** An enclosing trait for reactions.
+ *  Examples of reactions are: actor.receive's, event.handle's, etc
+ *  @param m The input type of a Reaction; typically the type of messages or events.
+ */
+trait Reactions[m] {
+
+  /** The partial function underlying a reaction. Note that this is formulated
+   *  in CPS style.
+   */
+  type Re[r] = PartialFunction[m, (r => unit) => unit]
+
+  /** Activate the given partial function `f', for instance by reading
+   *  a message or waiting for an event, and applying `f' to the result.
+   */
+  def activate[r](f: Re[r]): (r => unit) => unit
+
+  /** The class of reactions
+   *  @param r     The type of values returned by the reaction.
+   *               (More precisely, the type of values passed to its continuation)
+   *  @param fun   The partial function underlying a reaction
+   */
+  class Reaction[+r](private val fun: Re[r]) extends Responder[r] {
+
+    def respond(k: r => unit): unit = activate(fun)(k)
+
+    override def map[s](f: r => s) = new Reaction[s] (
+      fun andThen {
+        result: ((r => unit) => unit) =>
+          k: (s => unit) => result((x: r) => k(f(x)))
+      }
+    )
+
+    def flatMap[s](f: r => Reaction[s]) = new Reaction[s] (
+      fun andThen {
+        result: ((r => unit) => unit) =>
+          k: (s => unit) => result((x: r) => f(x).respond(k))
+      }
+    )
+
+    override def filter(p: r => boolean) = new Reaction[r] (
+      fun andThen {
+        result: ((r => unit) => unit) =>
+          k: (r => unit) => result((x: r) => if (p(x)) k(x) else ())
+      }
+    )
+
+    def orElse[r1 >: r](that: Reaction[r1]) = new Reaction[r1] (
+      this.fun orElse that.fun
+    )
+  }
+}
+
diff --git a/src/actors/scala/actors/multi/TimerThread.scala b/src/actors/scala/actors/multi/TimerThread.scala
index fc1c2162da..436b27354f 100644
--- a/src/actors/scala/actors/multi/TimerThread.scala
+++ b/src/actors/scala/actors/multi/TimerThread.scala
@@ -25,10 +25,7 @@ case class Signal()
 object TimerThread extends AnyRef with Runnable {
   case class WakedActor(actor: MailBox, time: long, reason: String) extends Ordered[WakedActor] {
     var valid = true
-    def compare [b >: WakedActor <% Ordered[b]](that: b): int = that match {
-      case that2: WakedActor => -(this.time compare that2.time)
-      case _ => error("not comparable")
-    }
+    def compare (that: WakedActor): int = -(this.time compare that.time)
   }
 
   var queue = new PriorityQueue[WakedActor]