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eec82323 | 1 | ;;; gnus-undo.el --- minor mode for undoing in Gnus |
16409b0b | 2 | |
b6c2d8c6 | 3 | ;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, |
d7a0267c | 4 | ;; 2005, 2006, 2007 Free Software Foundation, Inc. |
eec82323 | 5 | |
6748645f | 6 | ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> |
eec82323 LMI |
7 | ;; Keywords: news |
8 | ||
9 | ;; This file is part of GNU Emacs. | |
10 | ||
11 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
12 | ;; it under the terms of the GNU General Public License as published by | |
5a9dffec | 13 | ;; the Free Software Foundation; either version 3, or (at your option) |
eec82323 LMI |
14 | ;; any later version. |
15 | ||
16 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
17 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | ;; GNU General Public License for more details. | |
20 | ||
21 | ;; You should have received a copy of the GNU General Public License | |
22 | ;; along with GNU Emacs; see the file COPYING. If not, write to the | |
3a35cf56 LK |
23 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
24 | ;; Boston, MA 02110-1301, USA. | |
eec82323 LMI |
25 | |
26 | ;;; Commentary: | |
27 | ||
28 | ;; This package allows arbitrary undoing in Gnus buffers. As all the | |
29 | ;; Gnus buffers aren't very text-oriented (what is in the buffers is | |
6748645f | 30 | ;; just some arbitrary representation of the actual data), normal Emacs |
eec82323 LMI |
31 | ;; undoing doesn't work at all for Gnus. |
32 | ;; | |
33 | ;; This package works by letting Gnus register functions for reversing | |
34 | ;; actions, and then calling these functions when the user pushes the | |
35 | ;; `undo' key. As with normal `undo', there it is possible to set | |
36 | ;; undo boundaries and so on. | |
37 | ;; | |
38 | ;; Internally, the undo sequence is represented by the | |
39 | ;; `gnus-undo-actions' list, where each element is a list of functions | |
40 | ;; to be called, in sequence, to undo some action. (An "action" is a | |
41 | ;; collection of functions.) | |
42 | ;; | |
43 | ;; For instance, a function for killing a group will call | |
44 | ;; `gnus-undo-register' with a function that un-kills the group. This | |
45 | ;; package will put that function into an action. | |
46 | ||
47 | ;;; Code: | |
48 | ||
249ffa67 RS |
49 | (eval-when-compile (require 'cl)) |
50 | ||
eec82323 LMI |
51 | (require 'gnus-util) |
52 | (require 'gnus) | |
6748645f LMI |
53 | |
54 | (defgroup gnus-undo nil | |
55 | "Undoing in Gnus buffers." | |
56 | :group 'gnus) | |
57 | ||
58 | (defcustom gnus-undo-limit 2000 | |
59 | "The number of undoable actions recorded." | |
60 | :type 'integer | |
61 | :group 'gnus-undo) | |
eec82323 | 62 | |
6748645f LMI |
63 | (defcustom gnus-undo-mode nil |
64 | "Minor mode for undoing in Gnus buffers." | |
65 | :type 'boolean | |
66 | :group 'gnus-undo) | |
eec82323 | 67 | |
6748645f LMI |
68 | (defcustom gnus-undo-mode-hook nil |
69 | "Hook called in all `gnus-undo-mode' buffers." | |
70 | :type 'hook | |
71 | :group 'gnus-undo) | |
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72 | |
73 | ;;; Internal variables. | |
74 | ||
75 | (defvar gnus-undo-actions nil) | |
76 | (defvar gnus-undo-boundary t) | |
77 | (defvar gnus-undo-last nil) | |
78 | (defvar gnus-undo-boundary-inhibit nil) | |
79 | ||
80 | ;;; Minor mode definition. | |
81 | ||
82 | (defvar gnus-undo-mode-map nil) | |
83 | ||
84 | (unless gnus-undo-mode-map | |
85 | (setq gnus-undo-mode-map (make-sparse-keymap)) | |
86 | ||
87 | (gnus-define-keys gnus-undo-mode-map | |
16409b0b GM |
88 | "\M-\C-_" gnus-undo |
89 | "\C-_" gnus-undo | |
90 | "\C-xu" gnus-undo | |
91 | ;; many people are used to type `C-/' on X terminals and get `C-_'. | |
92 | [(control /)] gnus-undo)) | |
eec82323 LMI |
93 | |
94 | (defun gnus-undo-make-menu-bar () | |
a8151ef7 | 95 | ;; This is disabled for the time being. |
eec82323 | 96 | (when nil |
a8151ef7 LMI |
97 | (define-key-after (current-local-map) [menu-bar file gnus-undo] |
98 | (cons "Undo" 'gnus-undo-actions) | |
99 | [menu-bar file whatever]))) | |
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100 | |
101 | (defun gnus-undo-mode (&optional arg) | |
102 | "Minor mode for providing `undo' in Gnus buffers. | |
103 | ||
104 | \\{gnus-undo-mode-map}" | |
105 | (interactive "P") | |
106 | (set (make-local-variable 'gnus-undo-mode) | |
107 | (if (null arg) (not gnus-undo-mode) | |
108 | (> (prefix-numeric-value arg) 0))) | |
109 | (set (make-local-variable 'gnus-undo-actions) nil) | |
110 | (set (make-local-variable 'gnus-undo-boundary) t) | |
111 | (when gnus-undo-mode | |
112 | ;; Set up the menu. | |
113 | (when (gnus-visual-p 'undo-menu 'menu) | |
114 | (gnus-undo-make-menu-bar)) | |
01c52d31 | 115 | (add-minor-mode 'gnus-undo-mode "" gnus-undo-mode-map) |
23f87bed | 116 | (gnus-make-local-hook 'post-command-hook) |
eec82323 | 117 | (add-hook 'post-command-hook 'gnus-undo-boundary nil t) |
6748645f | 118 | (gnus-run-hooks 'gnus-undo-mode-hook))) |
eec82323 LMI |
119 | |
120 | ;;; Interface functions. | |
121 | ||
122 | (defun gnus-disable-undo (&optional buffer) | |
123 | "Disable undoing in the current buffer." | |
124 | (interactive) | |
125 | (save-excursion | |
126 | (when buffer | |
127 | (set-buffer buffer)) | |
128 | (gnus-undo-mode -1))) | |
129 | ||
130 | (defun gnus-undo-boundary () | |
131 | "Set Gnus undo boundary." | |
132 | (if gnus-undo-boundary-inhibit | |
133 | (setq gnus-undo-boundary-inhibit nil) | |
134 | (setq gnus-undo-boundary t))) | |
135 | ||
a8151ef7 LMI |
136 | (defun gnus-undo-force-boundary () |
137 | "Set Gnus undo boundary." | |
138 | (setq gnus-undo-boundary-inhibit nil | |
139 | gnus-undo-boundary t)) | |
140 | ||
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141 | (defun gnus-undo-register (form) |
142 | "Register FORMS as something to be performed to undo a change. | |
143 | FORMS may use backtick quote syntax." | |
144 | (when gnus-undo-mode | |
145 | (gnus-undo-register-1 | |
146 | `(lambda () | |
147 | ,form)))) | |
148 | ||
149 | (put 'gnus-undo-register 'lisp-indent-function 0) | |
150 | (put 'gnus-undo-register 'edebug-form-spec '(body)) | |
151 | ||
152 | (defun gnus-undo-register-1 (function) | |
153 | "Register FUNCTION as something to be performed to undo a change." | |
154 | (when gnus-undo-mode | |
155 | (cond | |
156 | ;; We are on a boundary, so we create a new action. | |
157 | (gnus-undo-boundary | |
158 | (push (list function) gnus-undo-actions) | |
159 | (setq gnus-undo-boundary nil)) | |
160 | ;; Prepend the function to an old action. | |
161 | (gnus-undo-actions | |
162 | (setcar gnus-undo-actions (cons function (car gnus-undo-actions)))) | |
163 | ;; Initialize list. | |
164 | (t | |
165 | (setq gnus-undo-actions (list (list function))))) | |
6748645f LMI |
166 | ;; Limit the length of the undo list. |
167 | (let ((next (nthcdr gnus-undo-limit gnus-undo-actions))) | |
168 | (when next | |
169 | (setcdr next nil))) | |
170 | ;; We are not at a boundary... | |
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171 | (setq gnus-undo-boundary-inhibit t))) |
172 | ||
173 | (defun gnus-undo (n) | |
174 | "Undo some previous changes in Gnus buffers. | |
175 | Repeat this command to undo more changes. | |
176 | A numeric argument serves as a repeat count." | |
177 | (interactive "p") | |
178 | (unless gnus-undo-mode | |
179 | (error "Undoing is not enabled in this buffer")) | |
180 | (message "%s" last-command) | |
181 | (when (or (not (eq last-command 'gnus-undo)) | |
182 | (not gnus-undo-last)) | |
183 | (setq gnus-undo-last gnus-undo-actions)) | |
184 | (let ((action (pop gnus-undo-last))) | |
185 | (unless action | |
186 | (error "Nothing further to undo")) | |
187 | (setq gnus-undo-actions (delq action gnus-undo-actions)) | |
188 | (setq gnus-undo-boundary t) | |
01c52d31 | 189 | (mapc 'funcall action))) |
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190 | |
191 | (provide 'gnus-undo) | |
192 | ||
ab5796a9 | 193 | ;;; arch-tag: 0d787bc7-787d-499a-837f-211d2cb07f2e |
eec82323 | 194 | ;;; gnus-undo.el ends here |