Another exciting development in the world of -Y...

Another exciting development in the world of -Y options which I and
three other people will use. Today's is -Yrich-exceptions. Use it like
so:

  SOURCEPATH=/path/to/src scalac -Yrich-exceptions a.scala

In the repl, -Yrich-exceptions will cause lastException to be bound to
an Exceptional instead of old rusty Throwable. That spins up new powers:

  scala> Nil.head
  [Nil.head] (List.scala:389)
  (access lastException for the full trace)
  scala> lastException.show
  /* The repl internal portion of the stack trace is elided. */
  [Nil.head]
   386:   override def isEmpty = true
   387:   override def head: Nothing =
   388:     throw new NoSuchElementException("head of empty list")
  *389:   override def tail: List[Nothing] =
   390:     throw new UnsupportedOperationException("tail of empty list")
   391:   // Removal of equals method here might lead to an infinite recursion similar to IntMap.equals.
   392:   override def equals(that: Any) = that match {

  [line0.<init>] (<console>:6)
  [line0.<clinit>] (<console>:-1)

Also try "lastException.showTable" but this is getting a little long for
more excerpt. No review.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/io/Path.scala b/src/compiler/scala/tools/nsc/io/Path.scala
index 4373cc64a5..5d3fcee11e 100644
--- a/src/compiler/scala/tools/nsc/io/Path.scala
+++ b/src/compiler/scala/tools/nsc/io/Path.scala
@@ -1,5 +1,6 @@
 /* NSC -- new Scala compiler
  * Copyright 2005-2010 LAMP/EPFL
+ * @author Paul Phillips
  */
 
 package scala.tools.nsc
@@ -41,6 +42,21 @@ object Path {
   implicit def string2path(s: String): Path = apply(s)
   implicit def jfile2path(jfile: JFile): Path = apply(jfile)
 
+  def locateJarByClass(clazz: Class[_]): Option[File] = {
+    try Some(File(clazz.getProtectionDomain().getCodeSource().getLocation().toURI().getPath()))
+    catch { case _: Exception => None }
+  }
+  /** Walks upward from wherever the scala library jar is searching for
+   *  the given jar name.  This approach finds the scala library jar in the
+   *  release layout and in trunk builds going up from pack.
+   */
+  def locateJarByName(name: String): Option[File] = {
+    def toSrc(d: Directory) = d.dirs.toList map (_ / name)
+    def walk(d: Directory)  = d.parents flatMap toSrc find (_.isFile) map (_.toFile)
+
+    locateJarByClass(classOf[ScalaObject]) flatMap (x => walk(x.parent))
+  }
+
   // java 7 style, we don't use it yet
   // object AccessMode extends Enumeration("AccessMode") {
   //   val EXECUTE, READ, WRITE = Value