From 0b98fa17637ef4c7cf8929467908aff43b6e9cd3 Mon Sep 17 00:00:00 2001
From: michelou <michelou@5e8d7ff9-d8ef-0310-90f0-a4852d11357a>
Date: Wed, 11 Jul 2007 14:52:34 +0000
Subject: [PATCH] added Stepan's patch ops/SyncVar

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@12271 5e8d7ff9-d8ef-0310-90f0-a4852d11357a
---
 docs/examples/actors/channels.scala        |  6 ++--
 src/library/scala/concurrent/SyncVar.scala | 33 +++++++++++++++++-----
 src/library/scala/concurrent/ops.scala     | 20 ++++++-------
 3 files changed, 39 insertions(+), 20 deletions(-)

diff --git a/docs/examples/actors/channels.scala b/docs/examples/actors/channels.scala
index 40ddeecbc..3c0dbf232 100644
--- a/docs/examples/actors/channels.scala
+++ b/docs/examples/actors/channels.scala
@@ -4,15 +4,15 @@ import scala.actors._
 import scala.actors.Actor._
 
 object channels extends Application {
-  case class Msg(ch1: Channel[int], ch2: Channel[String])
+  case class Msg(ch1: Channel[Int], ch2: Channel[String])
 
   val a = actor {
-    val Ch1 = new Channel[int]
+    val Ch1 = new Channel[Int]
     val Ch2 = new Channel[String]
 
     b ! Msg(Ch1, Ch2)
 
-    val ICh1 = Ch1.asInstanceOf[InputChannel[int]]
+    val ICh1 = Ch1.asInstanceOf[InputChannel[Int]]
     val ICh2 = Ch2.asInstanceOf[InputChannel[String]]
 
     react {
diff --git a/src/library/scala/concurrent/SyncVar.scala b/src/library/scala/concurrent/SyncVar.scala
index 9b852e4cb..413dc5dca 100644
--- a/src/library/scala/concurrent/SyncVar.scala
+++ b/src/library/scala/concurrent/SyncVar.scala
@@ -1,7 +1,7 @@
 /*                     __                                               *\
 **     ________ ___   / /  ___     Scala API                            **
-**    / __/ __// _ | / /  / _ |    (c) 2003-2006, LAMP/EPFL             **
-**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
 ** /____/\___/_/ |_/____/_/ | |                                         **
 **                          |/                                          **
 \*                                                                      */
@@ -14,24 +14,43 @@ package scala.concurrent
 
 /** The class <code>SyncVar</code> ...
  *
- *  @author  Martin Odersky
+ *  @author  Martin Odersky, Stepan Koltsov
  *  @version 1.0, 10/03/2003
  */
-class SyncVar[a] {
+class SyncVar[A] {
   private var isDefined: Boolean = false
-  private var value: a = _
+  private var value: A = _
+  private var exception: Option[Throwable] = None
 
   def get = synchronized {
     while (!isDefined) wait()
-    value
+    if (exception.isEmpty) value
+    else throw exception.get
   }
 
-  def set(x: a) = synchronized {
+  def set(x: A) = synchronized {
     value = x
     isDefined = true
+    exception = None
     notifyAll()
   }
 
+  private def setException(e: Throwable) = synchronized {
+    exception = Some(e)
+    isDefined = true
+    notifyAll()
+  }
+  
+  def setWithCatch(x: => A) = synchronized {
+    try {
+      this set x
+    } catch {
+      case e =>
+        this setException e
+        throw e
+    }
+  }
+
   def isSet: Boolean = synchronized {
     isDefined
   }
diff --git a/src/library/scala/concurrent/ops.scala b/src/library/scala/concurrent/ops.scala
index 365a4c895..b62f0df50 100644
--- a/src/library/scala/concurrent/ops.scala
+++ b/src/library/scala/concurrent/ops.scala
@@ -1,7 +1,7 @@
 /*                     __                                               *\
 **     ________ ___   / /  ___     Scala API                            **
-**    / __/ __// _ | / /  / _ |    (c) 2003-2006, LAMP/EPFL             **
-**  __\ \/ /__/ __ |/ /__/ __ |                                         **
+**    / __/ __// _ | / /  / _ |    (c) 2003-2007, LAMP/EPFL             **
+**  __\ \/ /__/ __ |/ /__/ __ |    http://scala-lang.org/               **
 ** /____/\___/_/ |_/____/_/ | |                                         **
 **                          |/                                          **
 \*                                                                      */
@@ -16,7 +16,7 @@ import java.lang.Thread
 
 /** The object <code>ops</code> ...
  *
- *  @author  Martin Odersky
+ *  @author  Martin Odersky, Stepan Koltsov
  *  @version 1.0, 12/03/2003
  */
 object ops {
@@ -33,9 +33,9 @@ object ops {
    *  @param p ...
    *  @return  ...
    */
-  def future[a](p: => a): () => a = {
-    val result = new SyncVar[a]
-    spawn { result set p }
+  def future[A](p: => A): () => A = {
+    val result = new SyncVar[A]
+    spawn { result setWithCatch p }
     () => result.get
   }
 
@@ -44,9 +44,9 @@ object ops {
    *  @param yp ...
    *  @return   ...
    */
-  def par[a, b](xp: => a, yp: => b): (a, b) = {
-    val y = new SyncVar[b]
-    spawn { y set yp }
+  def par[A, B](xp: => A, yp: => B): (A, B) = {
+    val y = new SyncVar[B]
+    spawn { y setWithCatch yp }
     (xp, y.get)
   }
 
@@ -55,7 +55,7 @@ object ops {
    *  @param end   ...
    *  @param p     ...
    */
-  def replicate(start: Int, end: Int)(p: Int => Unit): Unit = {
+  def replicate(start: Int, end: Int)(p: Int => Unit) {
     if (start == end) 
       ()
     else if (start + 1 == end)