| 1 | ;;; rot13.el --- display a buffer in rot13. |
| 2 | |
| 3 | ;; Copyright (C) 1988 Free Software Foundation, Inc. |
| 4 | |
| 5 | ;; Author: Howard Gayle: |
| 6 | ;; Maintainer: FSF |
| 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 |
| 22 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 23 | |
| 24 | ;; Commentary: |
| 25 | |
| 26 | ;; The single entry point, `rot13-other-window', oerforms a Caesar cipher |
| 27 | ;; encrypt/decrypt on the current buffer and displays the result in another |
| 28 | ;; window. Rot13 encryption is sometimes used on USENET as a read-at-yur- |
| 29 | ;; own-risk wrapper for material some might consider offensive, such as |
| 30 | ;; ethnic humor. |
| 31 | ;; |
| 32 | ;; Written by Howard Gayle. See case-table.el for details. |
| 33 | ;; This hack is mainly to show off the char table stuff. |
| 34 | |
| 35 | ;;; Code: |
| 36 | |
| 37 | (defvar rot13-display-table |
| 38 | (let ((table (make-display-table)) |
| 39 | (i 0)) |
| 40 | (while (< i 26) |
| 41 | (aset table (+ i ?a) (vector (+ (% (+ i 13) 26) ?a))) |
| 42 | (aset table (+ i ?A) (vector (+ (% (+ i 13) 26) ?A))) |
| 43 | (setq i (1+ i))) |
| 44 | table) |
| 45 | "Char table for rot 13 display.") |
| 46 | |
| 47 | ;;;###autoload |
| 48 | (defun rot13-other-window () |
| 49 | "Display current buffer in rot 13 in another window." |
| 50 | (interactive) |
| 51 | (let ((w (display-buffer (current-buffer) t))) |
| 52 | (set-window-display-table w rot13-display-table))) |
| 53 | |
| 54 | (provide 'rot13) |
| 55 | |
| 56 | ;;; rot13.el ends here |