Changed signature on reduceLeft/Right per ticke...

Changed signature on reduceLeft/Right per ticket #721.

4 files changed, 18 insertions, 10 deletions

diff --git a/src/library/scala/Iterable.scala b/src/library/scala/Iterable.scala
index 9cf18f3b46..c52257e120 100644
--- a/src/library/scala/Iterable.scala
+++ b/src/library/scala/Iterable.scala
@@ -369,7 +369,7 @@ trait Iterable[+A] {
    *          <code>a<sub>0</sub>, a<sub>1</sub>, ..., a<sub>n</sub></code>.
    *  @throws Predef.UnsupportedOperationException if the iterable object is empty.
    */
-  def reduceLeft[B >: A](op: (B, B) => B): B = elements.reduceLeft(op)
+  def reduceLeft[B >: A](op: (B, A) => B): B = elements.reduceLeft(op)
 
 /** Combines the elements of this iterable object together using the binary
    *  operator <code>op</code>, from right to left
@@ -382,7 +382,7 @@ trait Iterable[+A] {
    *
    *  @throws Predef.UnsupportedOperationException if the iterator is empty.
    */
-  def reduceRight[B >: A](op: (B, B) => B): B = elements.reduceRight(op)
+  def reduceRight[B >: A](op: (A, B) => B): B = elements.reduceRight(op)
 
   /** Copy all elements to a given buffer
    *  @note Will not terminate for infinite-sized collections.
diff --git a/src/library/scala/IterableProxy.scala b/src/library/scala/IterableProxy.scala
index f20c3d25ca..1c51ca627a 100644
--- a/src/library/scala/IterableProxy.scala
+++ b/src/library/scala/IterableProxy.scala
@@ -44,8 +44,8 @@ trait IterableProxy[+A] extends Iterable[A] with Proxy {
   override def foldRight[B](z: B)(op: (A, B) => B): B = (self foldRight z)(op)
   override def /:[B](z: B)(op: (B, A) => B): B = (z /: self)(op)
   override def :\[B](z: B)(op: (A, B) => B): B = (self :\ z)(op)
-  override def reduceLeft[B >: A](op: (B, B) => B): B = self reduceLeft op
-  override def reduceRight[B >: A](op: (B, B) => B): B = self reduceRight op
+  override def reduceLeft[B >: A](op: (B, A) => B): B = self reduceLeft op
+  override def reduceRight[B >: A](op: (A, B) => B): B = self reduceRight op
   override def sameElements[B >: A](that: Iterable[B]): Boolean = self sameElements that
   override def copyToBuffer[B >: A](dest: Buffer[B]): Unit = self copyToBuffer dest
   override def toList: List[A] = self.toList
diff --git a/src/library/scala/Iterator.scala b/src/library/scala/Iterator.scala
index 1f75ba85aa..db6d682db0 100644
--- a/src/library/scala/Iterator.scala
+++ b/src/library/scala/Iterator.scala
@@ -505,7 +505,7 @@ trait Iterator[+A] {
    *  @throws Predef.UnsupportedOperationException if the iterator is empty.
    */
   @throws(classOf[UnsupportedOperationException])
-  def reduceLeft[B >: A](op: (B, B) => B): B = {
+  def reduceLeft[B >: A](op: (B, A) => B): B = {
     if (hasNext) foldLeft[B](next)(op)
     else throw new UnsupportedOperationException("empty.reduceLeft")
   }
@@ -521,7 +521,7 @@ trait Iterator[+A] {
    *  @throws Predef.UnsupportedOperationException if the iterator is empty.
    */
   @throws(classOf[UnsupportedOperationException])
-  def reduceRight[B >: A](op: (B, B) => B): B = {
+  def reduceRight[B >: A](op: (A, B) => B): B = {
     if (!hasNext) throw new UnsupportedOperationException("empty.reduceRight")
     val x = next
     if (hasNext) op(x, reduceRight(op))
diff --git a/src/library/scala/List.scala b/src/library/scala/List.scala
index b6086e2460..f87b034cde 100644
--- a/src/library/scala/List.scala
+++ b/src/library/scala/List.scala
@@ -1036,9 +1036,17 @@ sealed abstract class List[+A] extends Seq[A] {
    *          <code>a<sub>0</sub>, a<sub>1</sub>, ..., a<sub>n</sub></code>.
    *  @throws Predef.UnsupportedOperationException if the list is empty.
    */
-  override def reduceLeft[B >: A](f: (B, B) => B): B = this match {
+  override def reduceLeft[B >: A](f: (B, A) => B): B = this match {
     case Nil => throw new UnsupportedOperationException("Nil.reduceLeft")
-    case x :: xs => ((xs: List[B]) foldLeft (x: B))(f)
+    case x :: Nil => x
+    case x0 :: x1 :: xs =>
+      var acc : B = f(x0, x1)
+      var these : List[A] = xs
+      while (!these.isEmpty) {
+        acc = f(acc, these.head)
+        these = these.tail
+      }
+      acc
   }
 
   /** Combines the elements of this list together using the binary
@@ -1051,9 +1059,9 @@ sealed abstract class List[+A] extends Seq[A] {
    *
    *  @throws Predef.UnsupportedOperationException if the list is empty.
    */
-  override def reduceRight[B >: A](f: (B, B) => B): B = this match {
+  override def reduceRight[B >: A](f: (A, B) => B): B = this match {
     case Nil => throw new UnsupportedOperationException("Nil.reduceRight")
-    case x :: Nil => x: B
+    case x :: Nil => x
     case x :: xs => f(x, xs reduceRight f)
   }