Re: Annotation mode

["PT" <spamfilteraccount@gmail.com>]

Okay. I simply added the GNU license to the file. Hope it's enough.
I also fixed the bug reported by Enila Nero.

I don't intend to spend time improving the package, since it already
does what I want. If someone's interested in improving it it's up for
grabs.

I was a bit suprised Emacs didn't have something like this built in
given its 20 or so years of history. The concept seems fairly trivial
to me.


Here's the revised code. (The line beginning character in
re-search-forward is supposed to be a Ctrl-L if for some reason it
doesn't get through properly.)


;; annotate.el --- simple file annotation system
;;
;; Copyright (C) 2005  Free Software Foundation, Inc.
;;
;; This file is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This file is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;
;;
;; M-x annotate-file pops up a window where the annotation for the
;; current file can be edited. If the annotation window is left open
;; it always shows the annotation belonging to the current buffer.
;;
;;

;;; Code:

(defvar annotate-storage-file "~/.annotate"
  "File containing the stored annotations.")


(defvar annotate-current-buffer nil
  "The last buffer known to be the current one.")

(defvar annotate-window-configuration nil
  "The window configuration before the annoation buffer was
displayed.")


(defun annotate-file ()
  (interactive)
  (annotate-narrow-to-annotation)

  (setq annotate-window-configuration (current-window-configuration))
  (pop-to-buffer (get-file-buffer annotate-storage-file))

  (local-set-key (kbd "C-c C-c") 'annotate-finish)
  (message "Type C-c C-c to hide the annotation window.")

  (setq annotate-current-buffer 'nosuchbuffer)
  (ad-activate 'switch-to-buffer))


(defun annotate-narrow-to-annotation ()
  "Narrow the annotation buffer to the portion belonging to the file
associated
wit the current buffer.
If no annotation exists for the file a new section is created.

If the current buffer has no file associated with it then show a
warning message."
  (let* ((buffer (find-file-noselect annotate-storage-file))
         (file (buffer-file-name))
         (filename (if file
                        (expand-file-name file)
                      "nofile")))

    (with-current-buffer buffer
      (widen)
      (unless (equal filename (expand-file-name annotate-storage-file))
        (goto-char (point-min))
        (if (re-search-forward (concat "^\f " filename) nil t)
            (forward-line)
          (goto-char (point-min))
          (insert "\f " filename "\n\n")
          (forward-line -1))

        (let ((begin (point)))
          (if (re-search-forward "^\f" nil t)
              (progn (forward-line -1)
                     (end-of-line))
            (goto-char (point-max)))
          (narrow-to-region begin (point))
          (goto-char (point-min)))

        ;; prepare warning message if it does not exist yet
        (if (and (not file)
                 (= (point-min) (point-max)))
            (insert "The current buffer has no file associated with it,
"
                    "so it cannot have an annotation."))))))


(defadvice switch-to-buffer (after annotate-handle-buffer-change)
  (annotate-update-annotation-display))


(defun annotate-update-annotation-display ()
  "Synchronize the displayed annotation to the current buffer if the
annotation
window is visible. Otherwise cancel current buffer monitoring."
  (if (get-buffer-window  (let ((buffer (get-file-buffer
annotate-storage-file)))
                            (or buffer
                                (find-file-noselect
annotate-storage-file))))
      (unless (equal (current-buffer) annotate-current-buffer)
        (setq annotate-current-buffer (current-buffer))
        (annotate-narrow-to-annotation))

    (ad-deactivate 'switch-to-buffer)))


(defun annotate-finish ()
  "Hide the annotation buffer and restore previous window
configuration."
  (interactive)
  (set-window-configuration annotate-window-configuration)
  (with-current-buffer (get-file-buffer annotate-storage-file)
    (widen)
    (save-buffer)))


(provide 'annotate)
;;; annotate.el ends here