| 1 | ;;; novice.el --- handling of disabled commands ("novice mode") for Emacs |
| 2 | |
| 3 | ;; Copyright (C) 1985-1987, 1994, 2001-2014 Free Software Foundation, |
| 4 | ;; Inc. |
| 5 | |
| 6 | ;; Maintainer: FSF |
| 7 | ;; Keywords: internal, help |
| 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 3 of the License, or |
| 14 | ;; (at your option) 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. If not, see <http://www.gnu.org/licenses/>. |
| 23 | |
| 24 | ;;; Commentary: |
| 25 | |
| 26 | ;; This mode provides a hook which is, by default, attached to various |
| 27 | ;; putatively dangerous commands in a (probably futile) attempt to |
| 28 | ;; prevent lusers from shooting themselves in the feet. |
| 29 | |
| 30 | ;;; Code: |
| 31 | |
| 32 | ;; This function is called (by autoloading) |
| 33 | ;; to handle any disabled command. |
| 34 | ;; The command is found in this-command |
| 35 | ;; and the keys are returned by (this-command-keys). |
| 36 | |
| 37 | ;;;###autoload |
| 38 | (define-obsolete-variable-alias 'disabled-command-hook |
| 39 | 'disabled-command-function "22.1") |
| 40 | ;;;###autoload |
| 41 | (defvar disabled-command-function 'disabled-command-function |
| 42 | "Function to call to handle disabled commands. |
| 43 | If nil, the feature is disabled, i.e., all commands work normally.") |
| 44 | |
| 45 | ;; It is ok here to assume that this-command is a symbol |
| 46 | ;; because we won't get called otherwise. |
| 47 | ;;;###autoload |
| 48 | (defun disabled-command-function (&optional cmd keys) |
| 49 | (unless cmd (setq cmd this-command)) |
| 50 | (unless keys (setq keys (this-command-keys))) |
| 51 | (let (char) |
| 52 | (save-window-excursion |
| 53 | (with-output-to-temp-buffer "*Disabled Command*" ;; (help-buffer) |
| 54 | (if (or (eq (aref keys 0) |
| 55 | (if (stringp keys) |
| 56 | (aref "\M-x" 0) |
| 57 | ?\M-x)) |
| 58 | (and (>= (length keys) 2) |
| 59 | (eq (aref keys 0) meta-prefix-char) |
| 60 | (eq (aref keys 1) ?x))) |
| 61 | (princ (format "You have invoked the disabled command %s.\n" cmd)) |
| 62 | (princ (format "You have typed %s, invoking disabled command %s.\n" |
| 63 | (key-description keys) cmd))) |
| 64 | ;; Print any special message saying why the command is disabled. |
| 65 | (if (stringp (get cmd 'disabled)) |
| 66 | (princ (get cmd 'disabled)) |
| 67 | (princ "It is disabled because new users often find it confusing.\n") |
| 68 | (princ "Here's the first part of its description:\n\n") |
| 69 | ;; Keep only the first paragraph of the documentation. |
| 70 | (with-current-buffer "*Disabled Command*" ;; standard-output |
| 71 | (goto-char (point-max)) |
| 72 | (let ((start (point))) |
| 73 | (save-excursion |
| 74 | (princ (or (condition-case () |
| 75 | (documentation cmd) |
| 76 | (error nil)) |
| 77 | "<< not documented >>"))) |
| 78 | (if (search-forward "\n\n" nil t) |
| 79 | (delete-region (match-beginning 0) (point-max))) |
| 80 | (goto-char (point-max)) |
| 81 | (indent-rigidly start (point) 3)))) |
| 82 | (princ "\n\nDo you want to use this command anyway?\n\n") |
| 83 | (princ "You can now type |
| 84 | y to try it and enable it (no questions if you use it again). |
| 85 | n to cancel--don't try the command, and it remains disabled. |
| 86 | SPC to try the command just this once, but leave it disabled. |
| 87 | ! to try it, and enable all disabled commands for this session only.") |
| 88 | ;; Redundant since with-output-to-temp-buffer will do it anyway. |
| 89 | ;; (with-current-buffer standard-output |
| 90 | ;; (help-mode)) |
| 91 | ) |
| 92 | (fit-window-to-buffer (get-buffer-window "*Disabled Command*")) |
| 93 | (message "Type y, n, ! or SPC (the space bar): ") |
| 94 | (let ((cursor-in-echo-area t)) |
| 95 | (while (progn (setq char (read-event)) |
| 96 | (or (not (numberp char)) |
| 97 | (not (memq (downcase char) |
| 98 | '(?! ?y ?n ?\s ?\C-g))))) |
| 99 | (ding) |
| 100 | (message "Please type y, n, ! or SPC (the space bar): ")))) |
| 101 | (setq char (downcase char)) |
| 102 | (pcase char |
| 103 | (?\C-g (setq quit-flag t)) |
| 104 | (?! (setq disabled-command-function nil)) |
| 105 | (?y |
| 106 | (if (and user-init-file |
| 107 | (not (string= "" user-init-file)) |
| 108 | (y-or-n-p "Enable command for future editing sessions also? ")) |
| 109 | (enable-command cmd) |
| 110 | (put cmd 'disabled nil)))) |
| 111 | (or (char-equal char ?n) |
| 112 | (call-interactively cmd)))) |
| 113 | |
| 114 | (defun en/disable-command (command disable) |
| 115 | (unless (commandp command) |
| 116 | (error "Invalid command name `%s'" command)) |
| 117 | (put command 'disabled disable) |
| 118 | (let ((init-file user-init-file) |
| 119 | (default-init-file |
| 120 | (if (eq system-type 'ms-dos) "~/_emacs" "~/.emacs"))) |
| 121 | (unless init-file |
| 122 | (if (or (file-exists-p default-init-file) |
| 123 | (and (eq system-type 'windows-nt) |
| 124 | (file-exists-p "~/_emacs"))) |
| 125 | ;; Started with -q, i.e. the file containing |
| 126 | ;; enabled/disabled commands hasn't been read. Saving |
| 127 | ;; settings there would overwrite other settings. |
| 128 | (error "Saving settings from \"emacs -q\" would overwrite existing customizations")) |
| 129 | (setq init-file default-init-file) |
| 130 | (if (and (not (file-exists-p init-file)) |
| 131 | (eq system-type 'windows-nt) |
| 132 | (file-exists-p "~/_emacs")) |
| 133 | (setq init-file "~/_emacs"))) |
| 134 | (with-current-buffer (find-file-noselect |
| 135 | (substitute-in-file-name init-file)) |
| 136 | (goto-char (point-min)) |
| 137 | (if (search-forward (concat "(put '" (symbol-name command) " ") nil t) |
| 138 | (delete-region |
| 139 | (progn (beginning-of-line) (point)) |
| 140 | (progn (forward-line 1) (point)))) |
| 141 | ;; Explicitly enable, in case this command is disabled by default |
| 142 | ;; or in case the code we deleted was actually a comment. |
| 143 | (goto-char (point-max)) |
| 144 | (unless (bolp) (newline)) |
| 145 | (insert "(put '" (symbol-name command) " 'disabled " |
| 146 | (symbol-name disable) ")\n") |
| 147 | (save-buffer)))) |
| 148 | |
| 149 | ;;;###autoload |
| 150 | (defun enable-command (command) |
| 151 | "Allow COMMAND to be executed without special confirmation from now on. |
| 152 | COMMAND must be a symbol. |
| 153 | This command alters the user's .emacs file so that this will apply |
| 154 | to future sessions." |
| 155 | (interactive "CEnable command: ") |
| 156 | (en/disable-command command nil)) |
| 157 | |
| 158 | ;;;###autoload |
| 159 | (defun disable-command (command) |
| 160 | "Require special confirmation to execute COMMAND from now on. |
| 161 | COMMAND must be a symbol. |
| 162 | This command alters your init file so that this choice applies to |
| 163 | future sessions." |
| 164 | (interactive "CDisable command: ") |
| 165 | (en/disable-command command t)) |
| 166 | |
| 167 | (provide 'novice) |
| 168 | |
| 169 | ;;; novice.el ends here |