proof-ids-to-regexp: use regexp-opt, this seems reliable now.

1 files changed, 5 insertions, 2 deletions

diff --git a/generic/proof-syntax.el b/generic/proof-syntax.el
index a261af2f..6c04e111 100644
--- a/generic/proof-syntax.el
+++ b/generic/proof-syntax.el
@@ -15,8 +15,11 @@
 ;;; Code:
 
 (defsubst proof-ids-to-regexp (l)
-  "Maps a non-empty list of tokens `l' to a regexp matching any element."
-  (concat "\\_<\\(?:" (mapconcat 'identity l "\\|") "\\)\\_>"))
+  "Maps a non-empty list of tokens `l' to a regexp matching any element.
+Uses a regexp of the form \\_<...\\_>."
+  (concat "\\_<\\(?:" 
+	  (regexp-opt l) ; was: (mapconcat 'identity l "\\|") 
+	  "\\)\\_>"))
 
 (defsubst proof-anchor-regexp (e)
   "Anchor (\\`) and group the regexp E."