1 files changed, 13 insertions, 0 deletions

diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index fa253e09771..f6a09eaba2c 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -109,6 +109,8 @@
   ;; because lisp-fill-paragraph should do the job.
   (make-local-variable 'adaptive-fill-mode)
   (setq adaptive-fill-mode nil)
+  (make-local-variable 'normal-auto-fill-function)
+  (setq normal-auto-fill-function 'lisp-mode-auto-fill)
   (make-local-variable 'indent-line-function)
   (setq indent-line-function 'lisp-indent-line)
   (make-local-variable 'indent-region-function)
@@ -362,6 +364,17 @@ With argument, insert value in current buffer after the defun."
       (max (if (bolp) 0 (1+ (current-column)))
            comment-column))))
 
+(defun lisp-mode-auto-fill ()
+  (if (> (current-column) (current-fill-column))
+      (if (save-excursion
+            (nth 4 (parse-partial-sexp (save-excursion
+                                         (beginning-of-defun)
+                                         (point))
+                                       (point))))
+          (do-auto-fill)
+        (let ((comment-start nil) (comment-start-skip nil))
+          (do-auto-fill)))))
+
 (defvar lisp-indent-offset nil "")
 (defvar lisp-indent-function 'lisp-indent-function "")