(nroff-mode): Set the SYNTAX-BEGIN part

of font-lock-defaults to backward-paragraph.

diff --git a/lisp/textmodes/nroff-mode.el b/lisp/textmodes/nroff-mode.el
index 8bd53920823a03f023a795f8f96758f9df67dfdf..07cf36a31cfbe1fa74407d4fcf844eb0a20241fe 100644 (file)
--- a/lisp/textmodes/nroff-mode.el
+++ b/lisp/textmodes/nroff-mode.el
@@ -113,7 +113,11 @@ closing requests for requests that are used in matched pairs."
     (modify-syntax-entry ?\n ">  1" nroff-mode-syntax-table))
   (set-syntax-table nroff-mode-syntax-table)
   (make-local-variable 'font-lock-defaults)
-  (setq font-lock-defaults '(nroff-font-lock-keywords nil t))
+  (setq font-lock-defaults
+       ;; SYNTAX-BEGIN is set to backward-paragraph to avoid slow-down
+       ;; near the end of large buffers due to searching to buffer's
+       ;; beginning.
+       '(nroff-font-lock-keywords nil t nil backward-paragraph))
   (setq local-abbrev-table nroff-mode-abbrev-table)
   (make-local-variable 'nroff-electric-mode)
   (setq nroff-electric-mode nil)