diff -r 8611f1813fc9 -r 5ccdc8bf3849 src/Pure/General/markup.scala
--- a/src/Pure/General/markup.scala	Mon Jan 04 18:55:32 2010 +0100
+++ b/src/Pure/General/markup.scala	Mon Jan 04 18:56:36 2010 +0100
@@ -153,6 +153,7 @@
 
   /* interactive documents */
 
+  val ASSIGN = "assign"
   val EDIT = "edit"