| 1 | ;;; novice.el --- handling of disabled commands ("novice mode") for Emacs. |
| 2 | |
| 3 | ;; Copyright (C) 1985, 1986, 1987, 1994 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Maintainer: FSF |
| 6 | ;; Keywords: internal, help |
| 7 | |
| 8 | ;; This file is part of GNU Emacs. |
| 9 | |
| 10 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
| 11 | ;; it under the terms of the GNU General Public License as published by |
| 12 | ;; the Free Software Foundation; either version 2, or (at your option) |
| 13 | ;; any later version. |
| 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 |
| 17 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 18 | ;; GNU General Public License for more details. |
| 19 | |
| 20 | ;; You should have received a copy of the GNU General Public License |
| 21 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
| 22 | ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
| 23 | ;; Boston, MA 02111-1307, USA. |
| 24 | |
| 25 | ;;; Commentary: |
| 26 | |
| 27 | ;; This mode provides a hook which is, by default, attached to various |
| 28 | ;; putatively dangerous commands in a (probably futile) attempt to |
| 29 | ;; prevent lusers from shooting themselves in the feet. |
| 30 | |
| 31 | ;;; Code: |
| 32 | |
| 33 | ;; This function is called (by autoloading) |
| 34 | ;; to handle any disabled command. |
| 35 | ;; The command is found in this-command |
| 36 | ;; and the keys are returned by (this-command-keys). |
| 37 | |
| 38 | ;;;###autoload |
| 39 | (setq disabled-command-hook 'disabled-command-hook) |
| 40 | |
| 41 | ;;;###autoload |
| 42 | (defun disabled-command-hook (&rest ignore) |
| 43 | (let (char) |
| 44 | (save-window-excursion |
| 45 | (with-output-to-temp-buffer "*Help*" |
| 46 | (let ((keys (this-command-keys))) |
| 47 | (if (or (eq (aref keys 0) |
| 48 | (if (stringp keys) |
| 49 | (aref "\M-x" 0) |
| 50 | ?\M-x)) |
| 51 | (and (>= (length keys) 2) |
| 52 | (eq (aref keys 0) meta-prefix-char) |
| 53 | (eq (aref keys 1) ?x))) |
| 54 | (princ "You have invoked the disabled command ") |
| 55 | (princ "You have typed ") |
| 56 | (princ (key-description keys)) |
| 57 | (princ ", invoking disabled command "))) |
| 58 | (princ this-command) |
| 59 | (princ ":\n") |
| 60 | ;; Print any special message saying why the command is disabled. |
| 61 | (if (stringp (get this-command 'disabled)) |
| 62 | (princ (get this-command 'disabled))) |
| 63 | (princ (or (condition-case () |
| 64 | (documentation this-command) |
| 65 | (error nil)) |
| 66 | "<< not documented >>")) |
| 67 | ;; Keep only the first paragraph of the documentation. |
| 68 | (save-excursion |
| 69 | (set-buffer "*Help*") |
| 70 | (goto-char (point-min)) |
| 71 | (if (search-forward "\n\n" nil t) |
| 72 | (delete-region (1- (point)) (point-max)) |
| 73 | (goto-char (point-max)))) |
| 74 | (princ "\n\n") |
| 75 | (princ "You can now type |
| 76 | Space to try the command just this once, |
| 77 | but leave it disabled, |
| 78 | Y to try it and enable it (no questions if you use it again), |
| 79 | N to do nothing (command remains disabled).") |
| 80 | (save-excursion |
| 81 | (set-buffer standard-output) |
| 82 | (help-mode))) |
| 83 | (message "Type y, n or Space: ") |
| 84 | (let ((cursor-in-echo-area t)) |
| 85 | (while (not (memq (setq char (downcase (read-char))) |
| 86 | '(? ?y ?n))) |
| 87 | (ding) |
| 88 | (message "Please type y, n or Space: ")))) |
| 89 | (if (= char ?y) |
| 90 | (if (and user-init-file |
| 91 | (not (string= "" user-init-file)) |
| 92 | (y-or-n-p "Enable command for future editing sessions also? ")) |
| 93 | (enable-command this-command) |
| 94 | (put this-command 'disabled nil))) |
| 95 | (if (/= char ?n) |
| 96 | (call-interactively this-command)))) |
| 97 | |
| 98 | ;;;###autoload |
| 99 | (defun enable-command (command) |
| 100 | "Allow COMMAND to be executed without special confirmation from now on. |
| 101 | The user's .emacs file is altered so that this will apply |
| 102 | to future sessions." |
| 103 | (interactive "CEnable command: ") |
| 104 | (put command 'disabled nil) |
| 105 | (save-excursion |
| 106 | (set-buffer (find-file-noselect |
| 107 | (substitute-in-file-name user-init-file))) |
| 108 | (goto-char (point-min)) |
| 109 | (if (search-forward (concat "(put '" (symbol-name command) " ") nil t) |
| 110 | (delete-region |
| 111 | (progn (beginning-of-line) (point)) |
| 112 | (progn (forward-line 1) (point)))) |
| 113 | ;; Explicitly enable, in case this command is disabled by default |
| 114 | ;; or in case the code we deleted was actually a comment. |
| 115 | (goto-char (point-max)) |
| 116 | (insert "\n(put '" (symbol-name command) " 'disabled nil)\n") |
| 117 | (save-buffer))) |
| 118 | |
| 119 | ;;;###autoload |
| 120 | (defun disable-command (command) |
| 121 | "Require special confirmation to execute COMMAND from now on. |
| 122 | The user's .emacs file is altered so that this will apply |
| 123 | to future sessions." |
| 124 | (interactive "CDisable command: ") |
| 125 | (if (not (commandp command)) |
| 126 | (error "Invalid command name `%s'" command)) |
| 127 | (put command 'disabled t) |
| 128 | (save-excursion |
| 129 | (set-buffer (find-file-noselect |
| 130 | (substitute-in-file-name user-init-file))) |
| 131 | (goto-char (point-min)) |
| 132 | (if (search-forward (concat "(put '" (symbol-name command) " ") nil t) |
| 133 | (delete-region |
| 134 | (progn (beginning-of-line) (point)) |
| 135 | (progn (forward-line 1) (point)))) |
| 136 | (goto-char (point-max)) |
| 137 | (insert "\n(put '" (symbol-name command) " 'disabled t)\n") |
| 138 | (save-buffer))) |
| 139 | |
| 140 | ;;; novice.el ends here |