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|
;;; novice.el --- handling of disabled commands ("novice mode") for Emacs.
;; Copyright (C) 1985, 1986, 1987, 1994 Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: internal, help
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to
;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
;;; Commentary:
;; This mode provides a hook which is, by default, attached to various
;; putatively dangerous commands in a (probably futile) attempt to
;; prevent lusers from shooting themselves in the feet.
;;; Code:
;; This function is called (by autoloading)
;; to handle any disabled command.
;; The command is found in this-command
;; and the keys are returned by (this-command-keys).
;;;###autoload
(setq disabled-command-hook 'disabled-command-hook)
;;;###autoload
(defun disabled-command-hook (&rest ignore)
(let (char)
(save-window-excursion
(with-output-to-temp-buffer "*Help*"
(let ((keys (this-command-keys)))
(if (or (eq (aref keys 0)
(if (stringp keys)
(aref "\M-x" 0)
?\M-x))
(and (>= (length keys) 2)
(eq (aref keys 0) meta-prefix-char)
(eq (aref keys 1) ?x)))
(princ "You have invoked the disabled command ")
(princ "You have typed ")
(princ (key-description keys))
(princ ", invoking disabled command ")))
(princ this-command)
(princ ":\n")
;; Print any special message saying why the command is disabled.
(if (stringp (get this-command 'disabled))
(princ (get this-command 'disabled)))
(princ (or (condition-case ()
(documentation this-command)
(error nil))
"<< not documented >>"))
;; Keep only the first paragraph of the documentation.
(save-excursion
(set-buffer "*Help*")
(goto-char (point-min))
(if (search-forward "\n\n" nil t)
(delete-region (1- (point)) (point-max))
(goto-char (point-max))))
(princ "\n\n")
(princ "You can now type
Space to try the command just this once,
but leave it disabled,
Y to try it and enable it (no questions if you use it again),
N to do nothing (command remains disabled).")
(save-excursion
(set-buffer standard-output)
(help-mode)))
(message "Type y, n or Space: ")
(let ((cursor-in-echo-area t))
(while (not (memq (setq char (downcase (read-char)))
'(? ?y ?n)))
(ding)
(message "Please type y, n or Space: "))))
(if (= char ?y)
(if (and user-init-file
(not (string= "" user-init-file))
(y-or-n-p "Enable command for future editing sessions also? "))
(enable-command this-command)
(put this-command 'disabled nil)))
(if (/= char ?n)
(call-interactively this-command))))
;;;###autoload
(defun enable-command (command)
"Allow COMMAND to be executed without special confirmation from now on.
The user's .emacs file is altered so that this will apply
to future sessions."
(interactive "CEnable command: ")
(put command 'disabled nil)
(save-excursion
(set-buffer (find-file-noselect
(substitute-in-file-name user-init-file)))
(goto-char (point-min))
(if (search-forward (concat "(put '" (symbol-name command) " ") nil t)
(delete-region
(progn (beginning-of-line) (point))
(progn (forward-line 1) (point))))
;; Explicitly enable, in case this command is disabled by default
;; or in case the code we deleted was actually a comment.
(goto-char (point-max))
(insert "\n(put '" (symbol-name command) " 'disabled nil)\n")
(save-buffer)))
;;;###autoload
(defun disable-command (command)
"Require special confirmation to execute COMMAND from now on.
The user's .emacs file is altered so that this will apply
to future sessions."
(interactive "CDisable command: ")
(if (not (commandp command))
(error "Invalid command name `%s'" command))
(put command 'disabled t)
(save-excursion
(set-buffer (find-file-noselect
(substitute-in-file-name user-init-file)))
(goto-char (point-min))
(if (search-forward (concat "(put '" (symbol-name command) " ") nil t)
(delete-region
(progn (beginning-of-line) (point))
(progn (forward-line 1) (point))))
(goto-char (point-max))
(insert "\n(put '" (symbol-name command) " 'disabled t)\n")
(save-buffer)))
;;; novice.el ends here
|
