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eec82323 | 1 | ;;; gnus-undo.el --- minor mode for undoing in Gnus |
16409b0b GM |
2 | |
3 | ;; Copyright (C) 1996, 1997, 1998, 1999, 2000 | |
4 | ;; 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 | |
13 | ;; the Free Software Foundation; either version 2, or (at your option) | |
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 | |
23 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
24 | ;; Boston, MA 02111-1307, USA. | |
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 | (require 'custom) |
54 | ||
55 | (defgroup gnus-undo nil | |
56 | "Undoing in Gnus buffers." | |
57 | :group 'gnus) | |
58 | ||
59 | (defcustom gnus-undo-limit 2000 | |
60 | "The number of undoable actions recorded." | |
61 | :type 'integer | |
62 | :group 'gnus-undo) | |
eec82323 | 63 | |
6748645f LMI |
64 | (defcustom gnus-undo-mode nil |
65 | "Minor mode for undoing in Gnus buffers." | |
66 | :type 'boolean | |
67 | :group 'gnus-undo) | |
eec82323 | 68 | |
6748645f LMI |
69 | (defcustom gnus-undo-mode-hook nil |
70 | "Hook called in all `gnus-undo-mode' buffers." | |
71 | :type 'hook | |
72 | :group 'gnus-undo) | |
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73 | |
74 | ;;; Internal variables. | |
75 | ||
76 | (defvar gnus-undo-actions nil) | |
77 | (defvar gnus-undo-boundary t) | |
78 | (defvar gnus-undo-last nil) | |
79 | (defvar gnus-undo-boundary-inhibit nil) | |
80 | ||
81 | ;;; Minor mode definition. | |
82 | ||
83 | (defvar gnus-undo-mode-map nil) | |
84 | ||
85 | (unless gnus-undo-mode-map | |
86 | (setq gnus-undo-mode-map (make-sparse-keymap)) | |
87 | ||
88 | (gnus-define-keys gnus-undo-mode-map | |
16409b0b GM |
89 | "\M-\C-_" gnus-undo |
90 | "\C-_" gnus-undo | |
91 | "\C-xu" gnus-undo | |
92 | ;; many people are used to type `C-/' on X terminals and get `C-_'. | |
93 | [(control /)] gnus-undo)) | |
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94 | |
95 | (defun gnus-undo-make-menu-bar () | |
a8151ef7 | 96 | ;; This is disabled for the time being. |
eec82323 | 97 | (when nil |
a8151ef7 LMI |
98 | (define-key-after (current-local-map) [menu-bar file gnus-undo] |
99 | (cons "Undo" 'gnus-undo-actions) | |
100 | [menu-bar file whatever]))) | |
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101 | |
102 | (defun gnus-undo-mode (&optional arg) | |
103 | "Minor mode for providing `undo' in Gnus buffers. | |
104 | ||
105 | \\{gnus-undo-mode-map}" | |
106 | (interactive "P") | |
107 | (set (make-local-variable 'gnus-undo-mode) | |
108 | (if (null arg) (not gnus-undo-mode) | |
109 | (> (prefix-numeric-value arg) 0))) | |
110 | (set (make-local-variable 'gnus-undo-actions) nil) | |
111 | (set (make-local-variable 'gnus-undo-boundary) t) | |
112 | (when gnus-undo-mode | |
113 | ;; Set up the menu. | |
114 | (when (gnus-visual-p 'undo-menu 'menu) | |
115 | (gnus-undo-make-menu-bar)) | |
a8151ef7 | 116 | (gnus-add-minor-mode 'gnus-undo-mode "" gnus-undo-mode-map) |
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117 | (make-local-hook 'post-command-hook) |
118 | (add-hook 'post-command-hook 'gnus-undo-boundary nil t) | |
6748645f | 119 | (gnus-run-hooks 'gnus-undo-mode-hook))) |
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120 | |
121 | ;;; Interface functions. | |
122 | ||
123 | (defun gnus-disable-undo (&optional buffer) | |
124 | "Disable undoing in the current buffer." | |
125 | (interactive) | |
126 | (save-excursion | |
127 | (when buffer | |
128 | (set-buffer buffer)) | |
129 | (gnus-undo-mode -1))) | |
130 | ||
131 | (defun gnus-undo-boundary () | |
132 | "Set Gnus undo boundary." | |
133 | (if gnus-undo-boundary-inhibit | |
134 | (setq gnus-undo-boundary-inhibit nil) | |
135 | (setq gnus-undo-boundary t))) | |
136 | ||
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137 | (defun gnus-undo-force-boundary () |
138 | "Set Gnus undo boundary." | |
139 | (setq gnus-undo-boundary-inhibit nil | |
140 | gnus-undo-boundary t)) | |
141 | ||
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142 | (defun gnus-undo-register (form) |
143 | "Register FORMS as something to be performed to undo a change. | |
144 | FORMS may use backtick quote syntax." | |
145 | (when gnus-undo-mode | |
146 | (gnus-undo-register-1 | |
147 | `(lambda () | |
148 | ,form)))) | |
149 | ||
150 | (put 'gnus-undo-register 'lisp-indent-function 0) | |
151 | (put 'gnus-undo-register 'edebug-form-spec '(body)) | |
152 | ||
153 | (defun gnus-undo-register-1 (function) | |
154 | "Register FUNCTION as something to be performed to undo a change." | |
155 | (when gnus-undo-mode | |
156 | (cond | |
157 | ;; We are on a boundary, so we create a new action. | |
158 | (gnus-undo-boundary | |
159 | (push (list function) gnus-undo-actions) | |
160 | (setq gnus-undo-boundary nil)) | |
161 | ;; Prepend the function to an old action. | |
162 | (gnus-undo-actions | |
163 | (setcar gnus-undo-actions (cons function (car gnus-undo-actions)))) | |
164 | ;; Initialize list. | |
165 | (t | |
166 | (setq gnus-undo-actions (list (list function))))) | |
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167 | ;; Limit the length of the undo list. |
168 | (let ((next (nthcdr gnus-undo-limit gnus-undo-actions))) | |
169 | (when next | |
170 | (setcdr next nil))) | |
171 | ;; We are not at a boundary... | |
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172 | (setq gnus-undo-boundary-inhibit t))) |
173 | ||
174 | (defun gnus-undo (n) | |
175 | "Undo some previous changes in Gnus buffers. | |
176 | Repeat this command to undo more changes. | |
177 | A numeric argument serves as a repeat count." | |
178 | (interactive "p") | |
179 | (unless gnus-undo-mode | |
180 | (error "Undoing is not enabled in this buffer")) | |
181 | (message "%s" last-command) | |
182 | (when (or (not (eq last-command 'gnus-undo)) | |
183 | (not gnus-undo-last)) | |
184 | (setq gnus-undo-last gnus-undo-actions)) | |
185 | (let ((action (pop gnus-undo-last))) | |
186 | (unless action | |
187 | (error "Nothing further to undo")) | |
188 | (setq gnus-undo-actions (delq action gnus-undo-actions)) | |
189 | (setq gnus-undo-boundary t) | |
190 | (while action | |
191 | (funcall (pop action))))) | |
192 | ||
193 | (provide 'gnus-undo) | |
194 | ||
195 | ;;; gnus-undo.el ends here |