(fill-nobreak-predicate): New variable.

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

1 files changed, 20 insertions, 8 deletions

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index 08a285b2aaa..eb1d2a9ef42 100644
--- 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")