Moving between headers in message-mode

[Emanuel Berg]

Hello all. I wrote this tonight. The purpose is defined in the
docstring. It is supposed to be used in message-mode. I haven't
done much testing but it seems to work. If you have any
suggestions how to make it better, please tell me. Cheers.

;; separator
(setq mail-header-separator "---")
(set-face-attribute 'message-separator nil :foreground "black")

(defun do-nothing () "Do nothing." () )
(defun iterate-header (back)
  "Unless BACK, go to the next header input field:
either on the same line as the present point,
or the next header below.
If the field has a string, put point to the string's right;
if the field is empty, put point so that typing will set the header,
without any prior cursor movement.
If you move from a header which has data, that data is expanded if
found to be an `abbrev-mode' abbreviation (possibly setup in
~/.mailrc), without need for a whitespace.
If there are no headers left, `message-goto-body';
if already in the body, goto the topmost header.
If BACK, do the same, only in reverse direction."
  (interactive)
    (let ((position (point)))
      (goto-char (point-min))
      (search-forward mail-header-separator)
      (let ((separator-pos (point))
            (search-fun)
            (start-pos)
            (end-pos)
            (chars-forward-after-hit)
            (maybe-beginning-of-line))
        (if back
            (progn
              (setq search-fun 'search-backward)
              (setq start-pos separator-pos)
              (setq end-pos (point-min))
              (setq chars-forward-after-hit 2)
              (setq maybe-beginning-of-line 'beginning-of-line) )
            (progn
              (setq search-fun 'search-forward)
              (setq start-pos (point-min))
              (setq end-pos separator-pos)
              (setq chars-forward-after-hit 1)
              (setq maybe-beginning-of-line 'do-nothing) ))
        (if (< position separator-pos)
            (progn
              (goto-char position)
              (expand-abbrev) )
          (goto-char start-pos) )
        (funcall maybe-beginning-of-line)
        (if (not (funcall search-fun ":" end-pos t))
            (message-goto-body)
          (progn
            (forward-char chars-forward-after-hit)
            (end-of-line) )))))

(defun iterate-header-back ()
  "See `iterate-header'."
  (interactive)
  (iterate-header t) ) ; t = back (or up)

(defun iterate-header-next ()
  "See `iterate-header'."
  (interactive)
  (iterate-header nil) ) ; nil = forward (or down)

(define-key message-mode-map (kbd "TAB") 'iterate-header-next)
(define-key message-mode-map (kbd "<backtab>") 'iterate-header-back)

-- 
Emanuel Berg - programmer (hire me! CV below)
computer projects: http://user.it.uu.se/~embe8573
internet activity: http://home.student.uu.se/embe8573