lisp/play/dissociate.el

   1 ;; Scramble text amusingly for Emacs.
   2 ;; Copyright (C) 1985 Free Software Foundation, Inc.
   3
   4 ;; This file is part of GNU Emacs.
   5
   6 ;; GNU Emacs is free software; you can redistribute it and/or modify
   7 ;; it under the terms of the GNU General Public License as published by
   8 ;; the Free Software Foundation; either version 1, or (at your option)
   9 ;; any later version.
  10
  11 ;; GNU Emacs is distributed in the hope that it will be useful,
  12 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 ;; GNU General Public License for more details.
  15
  16 ;; You should have received a copy of the GNU General Public License
  17 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  18 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  19
  20
  21 ;;;###autoload
  22 (defun dissociated-press (&optional arg)
  23   "Dissociate the text of the current buffer.
  24 Output goes in buffer named *Dissociation*,
  25 which is redisplayed each time text is added to it.
  26 Every so often the user must say whether to continue.
  27 If ARG is positive, require ARG chars of continuity.
  28 If ARG is negative, require -ARG words of continuity.
  29 Default is 2."
  30   (interactive "P")
  31   (setq arg (if arg (prefix-numeric-value arg) 2))
  32   (let* ((inbuf (current-buffer))
  33          (outbuf (get-buffer-create "*Dissociation*"))
  34          (move-function (if (> arg 0) 'forward-char 'forward-word))
  35          (move-amount (if (> arg 0) arg (- arg)))
  36          (search-function (if (> arg 0) 'search-forward 'word-search-forward))
  37          (last-query-point 0))
  38     (switch-to-buffer outbuf)
  39     (erase-buffer)
  40     (while
  41       (save-excursion
  42         (goto-char last-query-point)
  43         (vertical-motion (- (window-height) 4))
  44         (or (= (point) (point-max))
  45             (and (progn (goto-char (point-max))
  46                         (y-or-n-p "Continue dissociation? "))
  47                  (progn
  48                    (message "")
  49                    (recenter 1)
  50                    (setq last-query-point (point-max))
  51                    t))))
  52       (let (start end)
  53         (save-excursion
  54          (set-buffer inbuf)
  55          (setq start (point))
  56          (if (eq move-function 'forward-char)
  57              (progn
  58                (setq end (+ start (+ move-amount (random 16))))
  59                (if (> end (point-max))
  60                    (setq end (+ 1 move-amount (random 16))))
  61                (goto-char end))
  62            (funcall move-function
  63                     (+ move-amount (random 16))))
  64          (setq end (point)))
  65         (let ((opoint (point)))
  66           (insert-buffer-substring inbuf start end)
  67           (save-excursion
  68            (goto-char opoint)
  69            (end-of-line)
  70            (and (> (current-column) fill-column)
  71                 (do-auto-fill)))))
  72       (save-excursion
  73        (set-buffer inbuf)
  74        (if (eobp)
  75            (goto-char (point-min))
  76          (let ((overlap
  77                 (buffer-substring (prog1 (point)
  78                                          (funcall move-function
  79                                                   (- move-amount)))
  80                                   (point))))
  81            (let (ranval)
  82              (while (< (setq ranval (random)) 0))
  83              (goto-char (1+ (% ranval (1- (point-max))))))
  84            (or (funcall search-function overlap nil t)
  85                (let ((opoint (point)))
  86                  (goto-char 1)
  87                  (funcall search-function overlap opoint t))))))
  88       (sit-for 0))))