(help-xref-on-pp): Only add xref if the text is less than 5K.

diff --git a/lisp/help-mode.el b/lisp/help-mode.el
index 904d08f75192137c34e5372f6637305abf9d1621..03a711115dbcaee5118e78c43b95af129eeef392 100644 (file)
--- a/lisp/help-mode.el
+++ b/lisp/help-mode.el
@@ -443,31 +443,29 @@ See `help-make-xrefs'."
 ;;;###autoload
 (defun help-xref-on-pp (from to)
   "Add xrefs for symbols in `pp's output between FROM and TO."
-  (let ((ost (syntax-table)))
-    (unwind-protect
-       (save-excursion
-         (save-restriction
-           (set-syntax-table emacs-lisp-mode-syntax-table)
-           (narrow-to-region from to)
-           (goto-char (point-min))
-           (condition-case nil
-               (while (not (eobp))
-                 (cond
-                  ((looking-at "\"") (forward-sexp 1))
-                  ((looking-at "#<") (search-forward ">" nil 'move))
-                  ((looking-at "\\(\\(\\sw\\|\\s_\\)+\\)")
-                   (let* ((sym (intern-soft (match-string 1)))
-                          (type (cond ((fboundp sym) 'help-function)
-                                      ((or (memq sym '(t nil))
-                                           (keywordp sym))
-                                       nil)
-                                      ((and sym (boundp sym))
-                                       'help-variable))))
-                     (when type (help-xref-button 1 type sym)))
-                   (goto-char (match-end 1)))
-                  (t (forward-char 1))))
-             (error nil))))
-      (set-syntax-table ost))))
+  (if (> (- to from) 5000) nil
+    (with-syntax-table emacs-lisp-mode-syntax-table
+      (save-excursion
+       (save-restriction
+         (narrow-to-region from to)
+         (goto-char (point-min))
+         (condition-case nil
+             (while (not (eobp))
+               (cond
+                ((looking-at "\"") (forward-sexp 1))
+                ((looking-at "#<") (search-forward ">" nil 'move))
+                ((looking-at "\\(\\(\\sw\\|\\s_\\)+\\)")
+                 (let* ((sym (intern-soft (match-string 1)))
+                        (type (cond ((fboundp sym) 'help-function)
+                                    ((or (memq sym '(t nil))
+                                         (keywordp sym))
+                                     nil)
+                                    ((and sym (boundp sym))
+                                     'help-variable))))
+                   (when type (help-xref-button 1 type sym)))
+                 (goto-char (match-end 1)))
+                (t (forward-char 1))))
+           (error nil)))))))
 
 \f
 ;; Additional functions for (re-)creating types of help buffers.