(rmail-summary-next-same-subject): New command.

(rmail-summary-previous-same-subject): Likewise.
(rmail-summary-mode-map): Add bindings for C-c C-n and C-c C-p.

diff --git a/lisp/mail/rmailsum.el b/lisp/mail/rmailsum.el
index 70ab33e7216ab6aeb2eb27947df93255919d5e56..bb8060c54428778a5d8e7181f61fde76054f84ef 100644 (file)
--- a/lisp/mail/rmailsum.el
+++ b/lisp/mail/rmailsum.el
@@ -1,6 +1,6 @@
 ;;; rmailsum.el --- make summary buffers for the mail reader
 
-;; Copyright (C) 1985, 1993, 1994 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 1993, 1994, 1995 Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: mail
@@ -429,6 +429,64 @@ With prefix argument N moves backward N messages with these labels."
   (save-excursion
     (set-buffer rmail-buffer)
     (rmail-previous-labeled-message n labels)))
+
+(defun rmail-summary-next-same-subject (n)
+  "Go to the next message in the summary having the same subject.
+With prefix argument N, do this N times.
+If N is negative, go backwards."
+  (interactive "p")
+  (let (subject search-regexp  i found
+       (forward (> n 0)))
+    (save-excursion
+      (set-buffer rmail-buffer)
+      (setq subject (mail-fetch-field "Subject"))
+      (setq search-regexp (concat "^Subject: *\\(Re: *\\)?"
+                                 (regexp-quote subject)
+                                 "\n"))
+      (setq i rmail-current-message))
+    (if (string-match "Re:[ \t]*" subject)
+       (setq subject (substring subject (match-end 0))))
+    (save-excursion
+      (while (and (/= n 0)
+                 (if forward
+                     (not (eobp))
+                   (not (bobp))))
+       (let (done)
+         (while (and (not done)
+                     (if forward
+                         (not (eobp))
+                       (not (bobp))))
+           ;; Advance thru summary.
+           (forward-line (if forward 1 -1))
+           ;; Get msg number of this line.
+           (setq i (string-to-int
+                    (buffer-substring (point)
+                                      (min (point-max) (+ 5 (point))))))
+           ;; See if that msg has desired subject.
+           (save-excursion
+             (set-buffer rmail-buffer)
+             (save-restriction
+               (widen)
+               (goto-char (rmail-msgbeg i))
+               (search-forward "\n*** EOOH ***\n")
+               (let ((beg (point)) end)
+                 (search-forward "\n\n")
+                 (setq end (point))
+                 (goto-char beg)
+                 (setq done (re-search-forward search-regexp end t))))))
+         (if done (setq found i)))
+       (setq n (if forward (1- n) (1+ n)))))
+    (if found
+       (rmail-summary-goto-msg found)
+      (error "No %s message with same subject"
+            (if forward "following" "previous")))))
+
+(defun rmail-summary-previous-same-subject (n)
+  "Go to the previous message in the summary having the same subject.
+With prefix argument N, do this N times.
+If N is negative, go forwards instead."
+  (interactive "p")
+  (rmail-summary-next-same-subject (- n)))
 \f
 ;; Delete and undelete summary commands.
 
@@ -667,6 +725,8 @@ Commands for sorting the summary:
   (define-key rmail-summary-mode-map " "      'rmail-summary-scroll-msg-up)
   (define-key rmail-summary-mode-map "\177"   'rmail-summary-scroll-msg-down)
   (define-key rmail-summary-mode-map "?"      'describe-mode)
+  (define-key rmail-summary-mode-map "\C-c\C-n" 'rmail-summary-next-same-subject)
+  (define-key rmail-summary-mode-map "\C-c\C-p" 'rmail-summary-previous-same-subject)
   (define-key rmail-summary-mode-map "\C-c\C-s\C-d"
     'rmail-summary-sort-by-date)
   (define-key rmail-summary-mode-map "\C-c\C-s\C-s"