a fast, functional PartialFunction implementation

runtime.AbstractPartialFunction provides a default implementation
for the new-style partial function. In principle this class is only
subclassed by compiler-generated partial functions arising from matches.

Either
 - the apply method (old-style partialfun) or
 - the applyOrElse method (current scheme)
must be overridden, and the isDefinedAt method implemented.
The applyOrElse method implementation is provided to ease the
transition from the old scheme, since starr still generates
old-style PartialFunctions, but locker's library has the
new AbstractPartialFunction.

Thus, this implementation is intended as a drop-in replacement for the
old partial function, and does not require changes to the compiler.
(compiler patches, both for old and new-style pattern matching, follow)

- runtime.AbstractPartialFunction is based on PartialFunction.WithDefault
Original version of FunctionWithDefault by Odersky
(http://article.gmane.org/gmane.comp.lang.scala.internals/4032)
- better performance for OrElse#applyOrElse, OrElse#lift, PF.cond
- new combinator methods: PF#run, PF#runWith, PF.apply

authored by @pavelpavlov, refactored by @adriaanm, review by @paulp

3 files changed, 9 insertions, 7 deletions

diff --git a/src/actors/scala/actors/Actor.scala b/src/actors/scala/actors/Actor.scala
index aab533ae8d..bc9bbc6ef0 100644
--- a/src/actors/scala/actors/Actor.scala
+++ b/src/actors/scala/actors/Actor.scala
@@ -1,3 +1,5 @@
+
+
 /*                     __                                               *\
 **     ________ ___   / /  ___     Scala API                            **
 **    / __/ __// _ | / /  / _ |    (c) 2005-2011, LAMP/EPFL             **
@@ -246,8 +248,8 @@ object Actor extends Combinators {
     rawSelf.react(new RecursiveProxyHandler(rawSelf, f))
 
   private class RecursiveProxyHandler(a: InternalReplyReactor, f: PartialFunction[Any, Unit])
-          extends scala.runtime.AbstractPartialFunction[Any, Unit] {
-    def _isDefinedAt(m: Any): Boolean =
+          extends PartialFunction[Any, Unit] {
+    def isDefinedAt(m: Any): Boolean =
       true // events are immediately removed from the mailbox
     def apply(m: Any) {
       if (f.isDefinedAt(m)) f(m)
@@ -404,5 +406,5 @@ trait Actor extends InternalActor with ReplyReactor {
     this
   }
 
-}
+  }
 
diff --git a/src/actors/scala/actors/Future.scala b/src/actors/scala/actors/Future.scala
index eec43013d3..735c13190b 100644
--- a/src/actors/scala/actors/Future.scala
+++ b/src/actors/scala/actors/Future.scala
@@ -200,8 +200,8 @@ object Futures {
     Actor.timer.schedule(timerTask, timeout)
 
     def awaitWith(partFuns: Seq[PartialFunction[Any, Pair[Int, Any]]]) {
-      val reaction: PartialFunction[Any, Unit] = new scala.runtime.AbstractPartialFunction[Any, Unit] {
-        def _isDefinedAt(msg: Any) = msg match {
+      val reaction: PartialFunction[Any, Unit] = new PartialFunction[Any, Unit] {
+        def isDefinedAt(msg: Any) = msg match {
           case TIMEOUT => true
           case _ => partFuns exists (_ isDefinedAt msg)
         }
diff --git a/src/actors/scala/actors/Reactor.scala b/src/actors/scala/actors/Reactor.scala
index 8fc7578344..206a97d97c 100644
--- a/src/actors/scala/actors/Reactor.scala
+++ b/src/actors/scala/actors/Reactor.scala
@@ -38,8 +38,8 @@ private[actors] object Reactor {
     }
   }
 
-  val waitingForNone: PartialFunction[Any, Unit] = new scala.runtime.AbstractPartialFunction[Any, Unit] {
-    def _isDefinedAt(x: Any) = false
+  val waitingForNone: PartialFunction[Any, Unit] = new PartialFunction[Any, Unit] {
+    def isDefinedAt(x: Any) = false
     def apply(x: Any) {}
   }
 }