(fill-context-prefix): Fix criteria for first line,

and for second line; always fetch prefixes from both lines.

1 files changed, 50 insertions, 35 deletions

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index c3628be99f8..a769bd33616 100644
--- a/lisp/textmodes/fill.el
+++ b/lisp/textmodes/fill.el
@@ -1,6 +1,6 @@
 ;;; fill.el --- fill commands for Emacs
 
-;; Copyright (C) 1985, 86, 92, 94, 95, 1996 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 86, 92, 94, 95, 96, 1997 Free Software Foundation, Inc.
 
 ;; Keywords: wp
 
@@ -183,45 +183,60 @@ act as a paragraph-separator."
     (if (eolp) (forward-line 1))
     ;; Move to the second line unless there is just one.
     (let ((firstline (point))
+          first-line-prefix
           ;; Non-nil if we are on the second line.
           at-second
-          result)
+          second-line-prefix
+          start)
+      (move-to-left-margin)
+      (setq start (point))
+      (setq first-line-prefix
+            (cond ((looking-at paragraph-start) nil)
+                  ((and adaptive-fill-regexp (looking-at adaptive-fill-regexp))
+                   (buffer-substring-no-properties start (match-end 0)))
+                  (adaptive-fill-function (funcall adaptive-fill-function))))
       (forward-line 1)
       (if (>= (point) to)
           (goto-char firstline)
-        (setq at-second t))
-      (move-to-left-margin)
-      (let ((start (point)))
-        (setq result
-              (if (not (looking-at paragraph-start))
-                  (cond ((and adaptive-fill-regexp (looking-at adaptive-fill-regexp))
-                         (buffer-substring-no-properties start (match-end 0)))
-                        (adaptive-fill-function (funcall adaptive-fill-function)))))
-        (if at-second
-            ;; If we get a fill prefix from the second line,
-            ;; make sure it's on the first line too.
-            (and result
-                 (save-excursion
-                   (forward-line -1)
-                   (if (looking-at (regexp-quote result))
-                       result)))
-          ;; If we get a fill prefix from a one-line paragraph,
-          ;; maybe change it to whitespace,
-          ;; and check that it isn't a paragraph starter.
-          (if result
-              (progn
-                ;; If RESULT comes from the first line,
-                ;; see if it seems reasonable to use for all lines.
-                ;; If not, replace it with whitespace.
-                (or (and first-line-regexp
-                         (string-match first-line-regexp result))
-                    (and comment-start-skip
-                         (string-match comment-start-skip result))
-                    (setq result (make-string (string-width result) ?\ )))
-                ;; But either way, reject it if it indicates
-                ;; the start of a paragraph.
-                (if (not (eq 0 (string-match paragraph-start result)))
-                    result))))))))
+        (setq at-second t)
+        (move-to-left-margin)
+        (setq start (point))
+        (setq second-line-prefix
+              (cond ((looking-at paragraph-start) nil)
+                    ((and adaptive-fill-regexp (looking-at adaptive-fill-regexp))
+                     (buffer-substring-no-properties start (match-end 0)))
+                    (adaptive-fill-function (funcall adaptive-fill-function)))))
+      (if at-second
+          ;; If we get a fill prefix from the second line,
+          ;; make sure it or something compatible is on the first line too.
+          (and second-line-prefix
+               (if (or (string-match (regexp-quote second-line-prefix)
+                                     first-line-prefix)
+                       (and (string-match "[ \t]" second-line-prefix)
+                            (>= (string-width first-line-prefix)
+                                (string-width second-line-prefix))))
+                     second-line-prefix))
+        ;; If we get a fill prefix from a one-line paragraph,
+        ;; maybe change it to whitespace,
+        ;; and check that it isn't a paragraph starter.
+        (if first-line-prefix
+            (let ((result
+                   ;; If first-line-prefix comes from the first line,
+                   ;; see if it seems reasonable to use for all lines.
+                   ;; If not, replace it with whitespace.
+                   (if (or (and first-line-regexp
+                                (string-match first-line-regexp
+                                              first-line-prefix))
+                           (and comment-start-skip
+                                (string-match comment-start-skip
+                                              first-line-prefix)))
+                       first-line-prefix
+                     (make-string (string-width first-line-prefix) ?\ ))))
+              ;; But either way, reject it if it indicates the start
+              ;; of a paragraph when text follows it.
+              (if (not (eq 0 (string-match paragraph-start
+                                           (concat result "a"))))
+                  result))))))))
 
 (defun fill-region-as-paragraph (from to &optional justify
                                       nosqueeze squeeze-after)