1;;; gnus-undo.el --- minor mode for undoing in Gnus 2 3;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 4;; 2005, 2006, 2007 Free Software Foundation, Inc. 5 6;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org> 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., 51 Franklin Street, Fifth Floor, 24;; Boston, MA 02110-1301, 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 30;; just some arbitrary representation of the actual data), normal Emacs 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 49(eval-when-compile (require 'cl)) 50 51(require 'gnus-util) 52(require 'gnus) 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) 63 64(defcustom gnus-undo-mode nil 65 "Minor mode for undoing in Gnus buffers." 66 :type 'boolean 67 :group 'gnus-undo) 68 69(defcustom gnus-undo-mode-hook nil 70 "Hook called in all `gnus-undo-mode' buffers." 71 :type 'hook 72 :group 'gnus-undo) 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 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 95(defun gnus-undo-make-menu-bar () 96 ;; This is disabled for the time being. 97 (when nil 98 (define-key-after (current-local-map) [menu-bar file gnus-undo] 99 (cons "Undo" 'gnus-undo-actions) 100 [menu-bar file whatever]))) 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)) 116 (gnus-add-minor-mode 'gnus-undo-mode "" gnus-undo-mode-map) 117 (gnus-make-local-hook 'post-command-hook) 118 (add-hook 'post-command-hook 'gnus-undo-boundary nil t) 119 (gnus-run-hooks 'gnus-undo-mode-hook))) 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))) 136 137(defun gnus-undo-force-boundary () 138 "Set Gnus undo boundary." 139 (setq gnus-undo-boundary-inhibit nil 140 gnus-undo-boundary t)) 141 142(defun gnus-undo-register (form) 143 "Register FORMS as something to be performed to undo a change. 144FORMS 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))))) 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... 172 (setq gnus-undo-boundary-inhibit t))) 173 174(defun gnus-undo (n) 175 "Undo some previous changes in Gnus buffers. 176Repeat this command to undo more changes. 177A 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;;; arch-tag: 0d787bc7-787d-499a-837f-211d2cb07f2e 196;;; gnus-undo.el ends here 197