--- a/src/Pure/Isar/toplevel.ML Mon Jun 26 23:59:29 2000 +0200
+++ b/src/Pure/Isar/toplevel.ML Tue Jun 27 00:02:01 2000 +0200
@@ -420,7 +420,7 @@
| excur ((tr, f) :: trs) (st, res) =
(case apply false tr st of
Some (st', None) =>
- excur trs (st', f st' res handle exn =>
+ excur trs (st', transform_error (fn () => f st' res) () handle exn =>
raise EXCURSION_FAIL (exn, "Presentation failed.\n" ^ at_command tr))
| Some (st', Some exn_info) => raise EXCURSION_FAIL exn_info
| None => raise EXCURSION_FAIL (TERMINATE, at_command tr));