(fill-region-as-paragraph): Don't find adaptive-fill-regexp

on first line of paragraph if it's a paragraph-separate line.
Don't look past the intended line.
(adaptive-fill-function): New variable.
(fill-region-as-paragraph): Use it.
(colon-double-space): New variable.
(canonically-space-region): Put two spaces after colon if necessary.

1 files changed, 18 insertions, 6 deletions

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index a384125db90..991ca8a1933 100644
--- a/lisp/textmodes/fill.el
+++ b/lisp/textmodes/fill.el
@@ -37,6 +37,9 @@ A value of nil means that any change in indentation starts a new paragraph.")
 (defconst sentence-end-double-space t
   "*Non-nil means a single space does not end a sentence.")
 
+(defconst colon-double-space nil
+  "*Non-nil means put two spaces after a colon when filling.")
+
 (defvar fill-paragraph-function nil
   "Mode-specific function to fill a paragraph.")
 
@@ -64,6 +67,10 @@ on the second line of a paragraph is used as the standard indentation
 for the paragraph.  If the paragraph has just one line, the indentation
 is taken from that line.")
 
+(defun adaptive-fill-function nil
+  "*Function to call to choose a fill prefix for a paragraph.
+This function is used when `adaptive-fill-regexp' does not match.")
+
 (defun current-fill-column ()
   "Return the fill-column to use for this line.
 The fill-column to use for a buffer is stored in the variable `fill-column',
@@ -111,6 +118,8 @@ Remove indentation from each line."
             (skip-chars-backward " ]})\"'")
             (cond ((and sentence-end-double-space
                         (memq (preceding-char) '(?. ?? ?!)))  2)
+                  ((and colon-double-space
+                        (= (preceding-char) ?:))  2)
                   ((char-equal (preceding-char) ?\n)  0)
                   (t 1))))
        (match-end 0)))
@@ -187,12 +196,15 @@ space does not end a sentence, so don't break a line there."
               (if (>= (point) to)
                   (goto-char firstline)))
             (move-to-left-margin)
-            (let ((start (point)))
-              (re-search-forward adaptive-fill-regexp)
-              (setq fill-prefix (buffer-substring start (point)))
-              (set-text-properties 0 (length fill-prefix) nil
-                                   fill-prefix))
-            ))
+            (let ((start (point))
+                  (eol (save-excursion (end-of-line) (point)))
+                  temp)
+              (if (not (looking-at paragraph-start))
+                  (cond ((re-search-forward adaptive-fill-regexp nil t)
+                         (setq fill-prefix
+                               (buffer-substring-no-properties start (point))))
+                        ((setq temp (funcall adaptive-fill-function))
+                         (setq fill-prefix temp)))))))
 
       (save-restriction
         (goto-char from)