tuned message;

--- a/src/Pure/Isar/isar_syn.ML	Sat Dec 08 22:07:22 2007 +0100
+++ b/src/Pure/Isar/isar_syn.ML	Sat Dec 08 22:28:27 2007 +0100
@@ -753,7 +753,7 @@
     (P.position P.string :|-- (fn (str, pos) =>
       (case OuterSyntax.parse pos str of
         [transition] => Scan.succeed (K transition)
-      | _ => Scan.fail_with (K "exactly one nested command expected"))
+      | _ => Scan.fail_with (K "exactly one command expected"))
       handle ERROR msg => Scan.fail_with (K ("malformed command\n" ^ msg))));