lisp/play/spook.el

   1 ;;; spook.el --- spook phrase utility for overloading the NSA line eater
   2
   3 ;; Copyright (C) 1988 Free Software Foundation, Inc.
   4
   5 ;; Maintainer: FSF
   6 ;; Keywords: games
   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 ; Steve Strassmann (straz@media-lab.media.mit.edu) didn't write
  27 ; this, and even if he did, he really didn't mean for you to use it
  28 ; in an anarchistic way.
  29 ; May 1987
  30
  31 ; To use this:
  32 ;  Make sure you have the variable SPOOK-PHRASES-FILE pointing to
  33 ;  a valid phrase file. Phrase files are in the same format as
  34 ;  zippy's yow.lines (ITS-style LINS format).
  35 ;  Strings are terminated by ascii 0 characters. Leading whitespace ignored.
  36 ;  Everything up to the first \000 is a comment.
  37 ;
  38 ;  Just before sending mail, do M-x spook.
  39 ;  A number of phrases will be inserted into your buffer, to help
  40 ;  give your message that extra bit of attractiveness for automated
  41 ;  keyword scanners.
  42
  43 ;;; Code:
  44
  45 ; Variables
  46 (defvar spook-phrases-file (concat data-directory "spook.lines")
  47    "Keep your favorite phrases here.")
  48
  49 (defvar spook-phrase-default-count 15
  50    "Default number of phrases to insert")
  51
  52 (defvar spook-vector nil
  53   "Important phrases for NSA mail-watchers")
  54
  55 ; Randomize the seed in the random number generator.
  56 (random t)
  57
  58 ; Call this with M-x spook.
  59 (defun spook ()
  60   "Adds that special touch of class to your outgoing mail."
  61   (interactive)
  62   (if (null spook-vector)
  63       (setq spook-vector (snarf-spooks)))
  64   (shuffle-vector spook-vector)
  65   (let ((start (point)))
  66     (insert ?\n)
  67     (spook1 (min (- (length spook-vector) 1) spook-phrase-default-count))
  68     (insert ?\n)
  69     (fill-region-as-paragraph start (point) nil)))
  70
  71 (defun spook1 (arg)
  72   "Inserts a spook phrase ARG times."
  73   (cond ((zerop arg) t)
  74         (t (insert (aref spook-vector arg))
  75            (insert " ")
  76            (spook1 (1- arg)))))
  77
  78 (defun snarf-spooks ()
  79   "Reads in the phrase file"
  80   (message "Checking authorization...")
  81   (save-excursion
  82     (let ((buf (generate-new-buffer "*spook*"))
  83           (result '()))
  84       (set-buffer buf)
  85       (insert-file-contents (expand-file-name spook-phrases-file))
  86       (search-forward "\0")
  87       (while (progn (skip-chars-forward " \t\n\r\f") (not (eobp)))
  88         (let ((beg (point)))
  89           (search-forward "\0")
  90           (setq result (cons (buffer-substring beg (1- (point)))
  91                              result))))
  92       (kill-buffer buf)
  93       (message "Checking authorization... Approved.")
  94       (setq spook-vector (apply 'vector result)))))
  95
  96 (defun pick-random (n)
  97   "Returns a random number from 0 to N-1 inclusive."
  98   (% (logand 0777777 (random)) n))
  99
 100 ; Thanks to Ian G Batten <BattenIG@CS.BHAM.AC.UK>
 101 ; [of the University of Birmingham Computer Science Department]
 102 ; for the iterative version of this shuffle.
 103 ;
 104 (defun shuffle-vector (vector)
 105   "Randomly permute the elements of VECTOR (all permutations equally likely)"
 106   (let ((i 0)
 107         j
 108         temp
 109         (len (length vector)))
 110     (while (< i len)
 111       (setq j (+ i (pick-random (- len i))))
 112       (setq temp (aref vector i))
 113       (aset vector i (aref vector j))
 114       (aset vector j temp)
 115       (setq i (1+ i))))
 116   vector)
 117
 118 ;;; spook.el ends here