(fill-nobreak-predicate): New variable.

(fill-region-as-paragraph): Obey fill-nobreak-predicate.

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index 08a285b2aaa0d10022cc00d7297e43e837883e83..eb1d2a9ef42d0bf3f2eb598301d13c1a819be016 100644 (file)
--- a/lisp/textmodes/fill.el
+++ b/lisp/textmodes/fill.el
@@ -247,6 +247,11 @@ act as a paragraph-separator."
                                           (concat result "a"))))
                  result)))))))
 
+(defvar fill-nobreak-predicate nil
+  "If non-nil, a predicate for recognizing places not to break a line.
+The predicate is called with no arguments, with point at the place
+to be tested.  If it returns t, fill commands do not break the line there.")
+
 (defun fill-region-as-paragraph (from to &optional justify
                                      nosqueeze squeeze-after)
   "Fill the region as one paragraph.
@@ -421,14 +426,17 @@ space does not end a sentence, so don't break a line there."
                ;; further fills will assume it ends a sentence.
                ;; If we now know it does not end a sentence,
                ;; avoid putting it at the end of the line.
-               (if sentence-end-double-space
-                   (while (and (> (point) (+ linebeg 2))
+               (while (or (and sentence-end-double-space
+                               (> (point) (+ linebeg 2))
                                (eq (preceding-char) ?\ )
                                (not (eq (following-char) ?\ ))
-                               (eq (char-after (- (point) 2)) ?\.))
-                     (forward-char -2)
-                     (if (re-search-backward " \\|\\c|.\\|.\\c|" linebeg 0)
-                         (forward-char 1))))
+                               (eq (char-after (- (point) 2)) ?\.)
+                               (progn (forward-char -2) t))
+                          (and fill-nobreak-predicate
+                               (funcall fill-nobreak-predicate)
+                               (goto-char (match-beginning 0))))
+                 (if (re-search-backward " \\|\\c|.\\|.\\c|" linebeg 0)
+                     (forward-char 1)))
                ;; If the left margin and fill prefix by themselves
                ;; pass the fill-column. or if they are zero
                ;; but we have no room for even one word,
@@ -450,7 +458,9 @@ space does not end a sentence, so don't break a line there."
                                           sentence-end-double-space
                                           (save-excursion (forward-char -1)
                                                           (and (looking-at "\\. ")
-                                                               (not (looking-at "\\.  ")))))))
+                                                               (not (looking-at "\\.  ")))))
+                                     (and fill-nobreak-predicate
+                                          (funcall fill-nobreak-predicate))))
                        ;; Find a breakable point while ignoring the
                        ;; following spaces.
                        (skip-chars-forward " \t")
@@ -495,7 +505,9 @@ space does not end a sentence, so don't break a line there."
                                           sentence-end-double-space
                                           (save-excursion (forward-char -1)
                                                           (and (looking-at "\\. ")
-                                                               (not (looking-at "\\.  ")))))))
+                                                               (not (looking-at "\\.  ")))))
+                                     (and fill-nobreak-predicate
+                                          (funcall fill-nobreak-predicate))))
                        ;; Find a breakable point while ignoring the
                        ;; following spaces.
                        (skip-chars-forward " \t")