From 82eaeed3b1bf3d4e9a6b4c4dedfeed0e603e56e7 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Tue, 31 May 2011 05:07:47 +0000
Subject: Created AbstractOrMissingHandler for the repl t...

Created AbstractOrMissingHandler for the repl trying to give better
error messages in the face of bytecode fatalities. No review.
---
 .../nsc/interpreter/AbstractOrMissingHandler.scala | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 src/compiler/scala/tools/nsc/interpreter/AbstractOrMissingHandler.scala

diff --git a/src/compiler/scala/tools/nsc/interpreter/AbstractOrMissingHandler.scala b/src/compiler/scala/tools/nsc/interpreter/AbstractOrMissingHandler.scala
new file mode 100644
index 0000000000..2f47685757
--- /dev/null
+++ b/src/compiler/scala/tools/nsc/interpreter/AbstractOrMissingHandler.scala
@@ -0,0 +1,41 @@
+/* NSC -- new Scala compiler
+ * Copyright 2005-2011 LAMP/EPFL
+ * @author  Paul Phillips
+ */
+
+package scala.tools.nsc
+package interpreter
+
+class AbstractOrMissingHandler[T](onError: String => Unit, value: T) extends PartialFunction[Throwable, T] {
+  def isDefinedAt(t: Throwable) = t match {
+    case _: AbstractMethodError     => true
+    case _: NoSuchMethodError       => true
+    case _: MissingRequirementError => true
+    case _: NoClassDefFoundError    => true
+    case _                          => false
+  }
+  def apply(t: Throwable) = t match {
+    case x @ (_: AbstractMethodError | _: NoSuchMethodError | _: NoClassDefFoundError) =>
+      onError("""
+        |Failed to initialize compiler: %s.
+        |This is most often remedied by a full clean and recompile.
+        |Otherwise, your classpath may continue bytecode compiled by
+        |different and incompatible versions of scala.
+        |""".stripMargin.format(x.getClass.getName split '.' last)
+      )
+      x.printStackTrace()
+      value
+    case x: MissingRequirementError =>
+      onError("""
+        |Failed to initialize compiler: %s not found.
+        |** Note that as of 2.8 scala does not assume use of the java classpath.
+        |** For the old behavior pass -usejavacp to scala, or if using a Settings
+        |** object programatically, settings.usejavacp.value = true.""".stripMargin.format(x.req)
+      )
+      value
+  }
+}
+
+object AbstractOrMissingHandler {
+  def apply[T]() = new AbstractOrMissingHandler[T](Console println _, null.asInstanceOf[T])
+}
-- 
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