List.transpose is now tailrecursive.

2 files changed, 9 insertions, 10 deletions

diff --git a/src/library/scala/List.scala b/src/library/scala/List.scala
index 537f649a8a..00b9112807 100644
--- a/src/library/scala/List.scala
+++ b/src/library/scala/List.scala
@@ -354,9 +354,15 @@ object List {
    *  @param xss the list of lists
    *  @return    the transposed list of lists
    */
-  def transpose[A](xss: List[List[A]]): List[List[A]] =
-    if (xss.head.isEmpty) List()
-    else (xss map (xs => xs.head)) :: transpose(xss map (xs => xs.tail))
+  def transpose[A](xss: List[List[A]]): List[List[A]] = {
+    val buf = new ListBuffer[List[A]]
+    var yss = xss
+    while (!yss.head.isEmpty) {
+      buf += (yss map (_.head))
+      yss = (yss map (_.tail))
+    }
+    buf.toList
+  }
 
   /** Lists with ordered elements are ordered
   implicit def list2ordered[a <% Ordered[a]](x: List[a]): Ordered[List[a]] = new Ordered[List[a]] {
diff --git a/src/library/scala/runtime/StringAdd.scala b/src/library/scala/runtime/StringAdd.scala
index a7da9a5d17..2ca64538d9 100644
--- a/src/library/scala/runtime/StringAdd.scala
+++ b/src/library/scala/runtime/StringAdd.scala
@@ -18,13 +18,6 @@ final class StringAdd(self: Any) {
 
   def +(other: String) = self.toString + other
 
-  /** Formats string according to given <code>locale</code> and
-   *  <code>format</code> string. Formatstrings are as for
-   *  <code>String.format</code> (@see java.lang.String.format)
-   */
-  def format(locale: java.util.Locale, format: String): String =
-    String.format(locale, format, Array(self.asInstanceOf[Object]))
-
   /** Formats string according to given <code>format</code> string.
    *  Format strings are as for <code>String.format</code>
    *  (@see java.lang.String.format).