From 9ff91b59862d7b734ae2515411c544e706637351 Mon Sep 17 00:00:00 2001
From: Sean McDirmid <sean.mcdirmid@gmail.com>
Date: Tue, 22 May 2007 13:56:08 +0000
Subject: Added by method to Range, made range configurable.

---
 src/library/scala/Iterator.scala |  5 +----
 src/library/scala/Range.scala    | 16 ++++++++++++----
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/library/scala/Iterator.scala b/src/library/scala/Iterator.scala
index f019357982..70f0b9516b 100644
--- a/src/library/scala/Iterator.scala
+++ b/src/library/scala/Iterator.scala
@@ -126,10 +126,7 @@ object Iterator {
    *  @param step  the increment value of the iterator (must be positive or negative)
    *  @return      the iterator with values in range <code>[start;end)</code>.
    */
- def range(start: Int, end: Int, step: Int): Range =
-   if      (start >= end && step > 0) new Range(0, 0, 1)
-   else if (start <= end && step < 0) new Range(0, 0, 1)
-   else new Range(start, end, step)
+ def range(start: Int, end: Int, step: Int): Range = new Range(start, end, step)
 
   /** Create an iterator with elements
    *  <code>e<sub>n+1</sub> = step(e<sub>n</sub>)</code>
diff --git a/src/library/scala/Range.scala b/src/library/scala/Range.scala
index 2fdef9a085..7da93d4afb 100644
--- a/src/library/scala/Range.scala
+++ b/src/library/scala/Range.scala
@@ -28,15 +28,17 @@ import Predef._
  *  @version 1.0, 01/05/2007
  */
 class Range(val start: Int, val end: Int, val step: Int) extends BufferedIterator[Int] {
-  assert(step != 0)
-  assert(if (step > 0) end >= start else end <= start)
+  if (step == 0) throw new Predef.IllegalArgumentException
   private var jdx = 0
 
+  /** create a new range with the start and end values of this range and a new <code>step</code> */
+  def by(step : Int) = new Range(start, end, step)
+
   override def peekList(sz : Int) : Seq[Int] = return new RandomAccessSeq.Projection[Int] {
     def length = Range.this.length - jdx
     def apply(idx : Int) = Range.this.apply(jdx + idx)
   }
-  override def hasNext = jdx < length
+  override def hasNext = if (step == 0) true else jdx < length
   override def next = {
     val ret = apply(jdx)
     jdx = jdx + 1
@@ -46,7 +48,13 @@ class Range(val start: Int, val end: Int, val step: Int) extends BufferedIterato
     def length = Range.this.length
     def apply(idx : Int) = Range.this.apply(idx)
   }
-  def length = {
+
+
+  def length : Int = {
+    if (this.step == 0) throw new Predef.UnsupportedOperationException
+    if (start < end && this.step < 0) return 0
+    if (start > end && this.step > 0) return 0
+
     val base = if (start < end) end - start
                else start - end
     assert(base >= 0)
-- 
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