Made -Xprompt more useful, less crashy and more...

Made -Xprompt more useful, less crashy and more open to showing you the
stack trace without aborting. For example, the following would resume
compilation after showing the trace.

  % scala -deprecation -Xprompt -nc -e 'case class Foo' foo.scala:1:
  warning: case classes without a parameter list have been deprecated;
  use either case objects or case classes with `()' as parameter list.
  case class Foo ^

  a)bort, s)tack, r)esume: s
  java.lang.Exception
    [...]
  	at scala.tools.nsc.ast.parser.Parsers$UnitParser.deprecationWarning(Parsers.scala:207)
  	at scala.tools.nsc.ast.parser.Parsers$Parser.paramClauses(Parsers.scala:2058)
  	at scala.tools.nsc.ast.parser.Parsers$Parser$$anonfun$classDef$1.apply(Parsers.scala:2557)
  	at scala.tools.nsc.ast.parser.Parsers$Parser$$anonfun$classDef$1.apply(Parsers.scala:2545)

No review.

1 files changed, 12 insertions, 18 deletions

diff --git a/src/compiler/scala/tools/nsc/reporters/ConsoleReporter.scala b/src/compiler/scala/tools/nsc/reporters/ConsoleReporter.scala
index a6e661c4b4..967b582f11 100644
--- a/src/compiler/scala/tools/nsc/reporters/ConsoleReporter.scala
+++ b/src/compiler/scala/tools/nsc/reporters/ConsoleReporter.scala
@@ -93,27 +93,21 @@ class ConsoleReporter(val settings: Settings, reader: BufferedReader, writer: Pr
       print(pos, msg, severity)
   }
 
-  def displayPrompt(): Unit = try {
-    var continue = true
-    while (continue) {
-      writer.print("r)esume, a)bort: ")
-      writer.flush()
-      var line = reader.readLine()
-      if (line ne null) {
-	      line = line.toLowerCase()
-	      if ("abort" startsWith line)
-          abort("user abort")
-	      if ("resume" startsWith line)
-	        continue = false
+  def displayPrompt(): Unit = {
+    writer.print("\na)bort, s)tack, r)esume: ")
+    writer.flush()
+    if (reader != null) {
+      val response = reader.read().asInstanceOf[Char].toLower
+      if (response == 'a' || response == 's') {
+        (new Exception).printStackTrace()
+        if (response == 'a')
+          sys exit 1
+
+        writer.print("\n")
+        writer.flush()
       }
     }
   }
-  catch {
-    case ex: IOException => {
-      ex.printStackTrace()
-      abort("input read error")
-    }
-  }
 
   private def abort(msg: String) = throw new Error(msg)
   override def flush() { writer.flush() }