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eec82323 | 1 | ;;; gnus-undo.el --- minor mode for undoing in Gnus |
16409b0b | 2 | |
ba318903 | 3 | ;; Copyright (C) 1996-2014 Free Software Foundation, Inc. |
eec82323 | 4 | |
6748645f | 5 | ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> |
eec82323 LMI |
6 | ;; Keywords: news |
7 | ||
8 | ;; This file is part of GNU Emacs. | |
9 | ||
5e809f55 | 10 | ;; GNU Emacs is free software: you can redistribute it and/or modify |
eec82323 | 11 | ;; it under the terms of the GNU General Public License as published by |
5e809f55 GM |
12 | ;; the Free Software Foundation, either version 3 of the License, or |
13 | ;; (at your option) any later version. | |
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14 | |
15 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
16 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
5e809f55 | 17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
eec82323 LMI |
18 | ;; GNU General Public License for more details. |
19 | ||
20 | ;; You should have received a copy of the GNU General Public License | |
5e809f55 | 21 | ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. |
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22 | |
23 | ;;; Commentary: | |
24 | ||
25 | ;; This package allows arbitrary undoing in Gnus buffers. As all the | |
26 | ;; Gnus buffers aren't very text-oriented (what is in the buffers is | |
6748645f | 27 | ;; just some arbitrary representation of the actual data), normal Emacs |
eec82323 LMI |
28 | ;; undoing doesn't work at all for Gnus. |
29 | ;; | |
30 | ;; This package works by letting Gnus register functions for reversing | |
31 | ;; actions, and then calling these functions when the user pushes the | |
32 | ;; `undo' key. As with normal `undo', there it is possible to set | |
33 | ;; undo boundaries and so on. | |
34 | ;; | |
35 | ;; Internally, the undo sequence is represented by the | |
36 | ;; `gnus-undo-actions' list, where each element is a list of functions | |
37 | ;; to be called, in sequence, to undo some action. (An "action" is a | |
38 | ;; collection of functions.) | |
39 | ;; | |
40 | ;; For instance, a function for killing a group will call | |
41 | ;; `gnus-undo-register' with a function that un-kills the group. This | |
42 | ;; package will put that function into an action. | |
43 | ||
44 | ;;; Code: | |
45 | ||
249ffa67 | 46 | (eval-when-compile (require 'cl)) |
d029b5d2 KY |
47 | (eval-when-compile |
48 | (when (featurep 'xemacs) | |
49 | (require 'easy-mmode))) ; for `define-minor-mode' | |
249ffa67 | 50 | |
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51 | (require 'gnus-util) |
52 | (require 'gnus) | |
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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 | 63 | (defcustom gnus-undo-mode nil |
bbf52f1e SM |
64 | ;; FIXME: This is a buffer-local minor mode which requires running |
65 | ;; code upon activation/deactivation, so defining it as a defcustom | |
66 | ;; doesn't seem very useful: setting it to non-nil via Customize | |
67 | ;; probably won't do the right thing. | |
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68 | "Minor mode for undoing in Gnus buffers." |
69 | :type 'boolean | |
70 | :group 'gnus-undo) | |
eec82323 | 71 | |
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72 | (defcustom gnus-undo-mode-hook nil |
73 | "Hook called in all `gnus-undo-mode' buffers." | |
74 | :type 'hook | |
75 | :group 'gnus-undo) | |
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76 | |
77 | ;;; Internal variables. | |
78 | ||
79 | (defvar gnus-undo-actions nil) | |
80 | (defvar gnus-undo-boundary t) | |
81 | (defvar gnus-undo-last nil) | |
82 | (defvar gnus-undo-boundary-inhibit nil) | |
83 | ||
84 | ;;; Minor mode definition. | |
85 | ||
bbf52f1e SM |
86 | (defvar gnus-undo-mode-map |
87 | (let ((map (make-sparse-keymap))) | |
88 | (gnus-define-keys map | |
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) | |
94 | map)) | |
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95 | |
96 | (defun gnus-undo-make-menu-bar () | |
a8151ef7 | 97 | ;; This is disabled for the time being. |
eec82323 | 98 | (when nil |
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99 | (define-key-after (current-local-map) [menu-bar file gnus-undo] |
100 | (cons "Undo" 'gnus-undo-actions) | |
101 | [menu-bar file whatever]))) | |
eec82323 | 102 | |
bbf52f1e | 103 | (define-minor-mode gnus-undo-mode |
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104 | "Minor mode for providing `undo' in Gnus buffers. |
105 | ||
106 | \\{gnus-undo-mode-map}" | |
bbf52f1e | 107 | :keymap gnus-undo-mode-map |
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108 | (set (make-local-variable 'gnus-undo-actions) nil) |
109 | (set (make-local-variable 'gnus-undo-boundary) t) | |
110 | (when gnus-undo-mode | |
111 | ;; Set up the menu. | |
112 | (when (gnus-visual-p 'undo-menu 'menu) | |
113 | (gnus-undo-make-menu-bar)) | |
23f87bed | 114 | (gnus-make-local-hook 'post-command-hook) |
bbf52f1e | 115 | (add-hook 'post-command-hook 'gnus-undo-boundary nil t))) |
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116 | |
117 | ;;; Interface functions. | |
118 | ||
119 | (defun gnus-disable-undo (&optional buffer) | |
120 | "Disable undoing in the current buffer." | |
121 | (interactive) | |
122 | (save-excursion | |
123 | (when buffer | |
124 | (set-buffer buffer)) | |
125 | (gnus-undo-mode -1))) | |
126 | ||
127 | (defun gnus-undo-boundary () | |
128 | "Set Gnus undo boundary." | |
129 | (if gnus-undo-boundary-inhibit | |
130 | (setq gnus-undo-boundary-inhibit nil) | |
131 | (setq gnus-undo-boundary t))) | |
132 | ||
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133 | (defun gnus-undo-force-boundary () |
134 | "Set Gnus undo boundary." | |
135 | (setq gnus-undo-boundary-inhibit nil | |
136 | gnus-undo-boundary t)) | |
137 | ||
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138 | (defun gnus-undo-register (form) |
139 | "Register FORMS as something to be performed to undo a change. | |
140 | FORMS may use backtick quote syntax." | |
141 | (when gnus-undo-mode | |
142 | (gnus-undo-register-1 | |
143 | `(lambda () | |
144 | ,form)))) | |
145 | ||
146 | (put 'gnus-undo-register 'lisp-indent-function 0) | |
147 | (put 'gnus-undo-register 'edebug-form-spec '(body)) | |
148 | ||
149 | (defun gnus-undo-register-1 (function) | |
150 | "Register FUNCTION as something to be performed to undo a change." | |
151 | (when gnus-undo-mode | |
152 | (cond | |
153 | ;; We are on a boundary, so we create a new action. | |
154 | (gnus-undo-boundary | |
155 | (push (list function) gnus-undo-actions) | |
156 | (setq gnus-undo-boundary nil)) | |
157 | ;; Prepend the function to an old action. | |
158 | (gnus-undo-actions | |
159 | (setcar gnus-undo-actions (cons function (car gnus-undo-actions)))) | |
160 | ;; Initialize list. | |
161 | (t | |
162 | (setq gnus-undo-actions (list (list function))))) | |
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163 | ;; Limit the length of the undo list. |
164 | (let ((next (nthcdr gnus-undo-limit gnus-undo-actions))) | |
165 | (when next | |
166 | (setcdr next nil))) | |
167 | ;; We are not at a boundary... | |
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168 | (setq gnus-undo-boundary-inhibit t))) |
169 | ||
170 | (defun gnus-undo (n) | |
171 | "Undo some previous changes in Gnus buffers. | |
172 | Repeat this command to undo more changes. | |
173 | A numeric argument serves as a repeat count." | |
174 | (interactive "p") | |
175 | (unless gnus-undo-mode | |
176 | (error "Undoing is not enabled in this buffer")) | |
177 | (message "%s" last-command) | |
178 | (when (or (not (eq last-command 'gnus-undo)) | |
179 | (not gnus-undo-last)) | |
180 | (setq gnus-undo-last gnus-undo-actions)) | |
181 | (let ((action (pop gnus-undo-last))) | |
182 | (unless action | |
183 | (error "Nothing further to undo")) | |
184 | (setq gnus-undo-actions (delq action gnus-undo-actions)) | |
185 | (setq gnus-undo-boundary t) | |
01c52d31 | 186 | (mapc 'funcall action))) |
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187 | |
188 | (provide 'gnus-undo) | |
189 | ||
190 | ;;; gnus-undo.el ends here |