More repl work.

Hardened the repl against a bunch of erroneous conditions. Added a
:reset command which causes the repl to forget everything you have told
it. Added classloader tracing when repl tracing is enabled. :reset is
not that useful in its current form but it's the precursor to something
more interesting. No review.

1 files changed, 18 insertions, 0 deletions

diff --git a/test/files/run/repl-reset.scala b/test/files/run/repl-reset.scala
new file mode 100644
index 0000000000..95cc48b942
--- /dev/null
+++ b/test/files/run/repl-reset.scala
@@ -0,0 +1,18 @@
+import scala.tools.partest.ReplTest
+
+object Test extends ReplTest {
+  def code = """
+    |val x1 = 1
+    |val x2 = 2
+    |val x3 = 3
+    |case class BippyBungus()
+    |x1 + x2 + x3
+    |:reset
+    |x1 + x2 + x3
+    |val x1 = 4
+    |new BippyBungus
+    |class BippyBungus() { def f = 5 }
+    |{ new BippyBungus ; x1 }
+    |:javap BippyBungus
+  """.stripMargin
+}