src/Pure/General/exn.scala

--- a/src/Pure/General/exn.scala	Wed Apr 23 13:05:11 2014 +0200
+++ b/src/Pure/General/exn.scala	Wed Apr 23 13:28:32 2014 +0200
@@ -73,5 +73,11 @@
 
   def message(exn: Throwable): String =
     user_message(exn) getOrElse (if (is_interrupt(exn)) "Interrupt" else exn.toString)
+
+
+  /* TTY error message */
+
+  def error_message(msg: String): String = cat_lines(split_lines(msg).map("*** " + _))
+  def error_message(exn: Throwable): String = error_message(message(exn))
 }