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1 | ;;; rot13.el --- display a buffer in rot13. |
2 | ||
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3 | ;; Copyright (C) 1988 Free Software Foundation, Inc. |
4 | ||
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5 | ;; Author: Howard Gayle: |
6 | ;; Maintainer: FSF | |
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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 | |
e5167999 | 12 | ;; the Free Software Foundation; either version 2, or (at your option) |
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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 | ||
e5167999 | 24 | ;; Commentary: |
3b4a6e27 | 25 | |
716e9939 | 26 | ;; The single entry point, `rot13-other-window', performs a Caesar cipher |
d9ecc911 | 27 | ;; encrypt/decrypt on the current buffer and displays the result in another |
716e9939 | 28 | ;; window. Rot13 encryption is sometimes used on USENET as a read-at-your- |
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29 | ;; own-risk wrapper for material some might consider offensive, such as |
30 | ;; ethnic humor. | |
31 | ;; | |
716e9939 | 32 | ;; Written by Howard Gayle. |
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33 | ;; This hack is mainly to show off the char table stuff. |
34 | ||
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35 | ;;; Code: |
36 | ||
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37 | (defvar rot13-display-table |
38 | (let ((table (make-display-table)) | |
39 | (i 0)) | |
40 | (while (< i 26) | |
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41 | (aset table (+ i ?a) (vector (+ (% (+ i 13) 26) ?a))) |
42 | (aset table (+ i ?A) (vector (+ (% (+ i 13) 26) ?A))) | |
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43 | (setq i (1+ i))) |
44 | table) | |
45 | "Char table for rot 13 display.") | |
46 | ||
8931b34a | 47 | ;;;###autoload |
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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) | |
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55 | |
56 | ;;; rot13.el ends here |