1 files changed, 37 insertions, 10 deletions

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index fd433f3456c..d9bf1e520d9 100644
--- a/lisp/textmodes/fill.el
+++ b/lisp/textmodes/fill.el
@@ -348,6 +348,8 @@ justification.  Fourth arg NOSQUEEZE non-nil means not to make spaces
 between words canonical before filling.  Fifth arg SQUEEZE-AFTER, if non-nil,
 means don't canonicalize spaces before that position.
 
+Return the fill-prefix used for filling.
+
 If `sentence-end-double-space' is non-nil, then period followed by one
 space does not end a sentence, so don't break a line there."
   (interactive (progn
@@ -670,7 +672,18 @@ space does not end a sentence, so don't break a line there."
         ;; Leave point after final newline.
         (goto-char (point-max)))
       (unless (eobp)
-        (forward-char 1)))))
+        (forward-char 1))
+      ;; Return the fill-prefix we used
+      fill-prefix)))
+
+(defsubst skip-line-prefix (prefix)
+  "If point is inside the string PREFIX at the beginning of line, move past it."
+  (when (and prefix
+             (< (- (point) (line-beginning-position)) (length prefix))
+             (save-excursion
+               (beginning-of-line)
+               (looking-at (regexp-quote prefix))))
+    (goto-char (match-end 0))))
 
 (defun fill-paragraph (arg)
   "Fill paragraph at or after point.  Prefix arg means justify as well.
@@ -679,7 +692,9 @@ space does not end a sentence, so don't break a line there.
 the variable `fill-column' controls the width for filling.
 
 If `fill-paragraph-function' is non-nil, we call it (passing our
-argument to it), and if it returns non-nil, we simply return its value."
+argument to it), and if it returns non-nil, we simply return its value.
+
+If `fill-paragraph-function' is nil, return the fill-prefix used for filling."
   (interactive (progn
                  (barf-if-buffer-read-only)
                  (list (if current-prefix-arg 'full))))
@@ -688,6 +703,8 @@ argument to it), and if it returns non-nil, we simply return its value."
                  fill-paragraph-function)
              (funcall function arg)))
       (let ((before (point))
+            ;; Fill prefix used for filling the paragraph
+            fill-pfx
             ;; If fill-paragraph is called recursively,
             ;; don't give fill-paragraph-function a second chance.
             fill-paragraph-function)
@@ -697,11 +714,17 @@ argument to it), and if it returns non-nil, we simply return its value."
           (let ((end (point))
                 (beg (progn (backward-paragraph) (point))))
             (goto-char before)
-            (if use-hard-newlines
-                ;; Can't use fill-region-as-paragraph, since this paragraph
-                ;; may still contain hard newlines.  See fill-region.
-                (fill-region beg end arg)
-              (fill-region-as-paragraph beg end arg)))))))
+            (setq fill-pfx 
+                  (if use-hard-newlines
+                      ;; Can't use fill-region-as-paragraph, since this
+                      ;; paragraph may still contain hard newlines.  See
+                      ;; fill-region.
+                      (fill-region beg end arg)
+                    (fill-region-as-paragraph beg end arg)))))
+        ;; See if point ended up inside the fill-prefix, and if so, move
+        ;; past it.
+        (skip-line-prefix fill-pfx)
+        fill-pfx)))
 
 (defun fill-region (from to &optional justify nosqueeze to-eop)
   "Fill each of the paragraphs in the region.
@@ -718,6 +741,8 @@ whitespace other than line breaks untouched, and fifth arg TO-EOP
 non-nil means to keep filling to the end of the paragraph (or next
 hard newline, if `use-hard-newlines' is on).
 
+Return the fill-prefix used for filling the last paragraph.
+
 If `sentence-end-double-space' is non-nil, then period followed by one
 space does not end a sentence, so don't break a line there."
   (interactive (progn
@@ -726,7 +751,7 @@ space does not end a sentence, so don't break a line there."
                        (if current-prefix-arg 'full))))
   (unless (memq justify '(t nil none full center left right))
     (setq justify 'full))
-  (let (end beg)
+  (let (end beg fill-pfx)
     (save-restriction
       (goto-char (max from to))
       (if to-eop
@@ -756,8 +781,10 @@ space does not end a sentence, so don't break a line there."
           (if (< (point) beg)
               (goto-char beg))
           (if (>= (point) initial)
-              (fill-region-as-paragraph (point) end justify nosqueeze)
-            (goto-char end)))))))
+              (setq fill-pfx
+                    (fill-region-as-paragraph (point) end justify nosqueeze))
+            (goto-char end))))
+      fill-pfx)))
 
 
 (defcustom default-justification 'left