lisp/play/cookie1.el

   1 ;;; cookie1.el --- retrieve random phrases from fortune cookie files
   2
   3 ;; Copyright (C) 1993 Free Software Foundation, Inc.
   4
   5 ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
   6 ;; Maintainer: FSF
   7 ;; Keywords: games, extensions
   8 ;; Created: Mon Mar 22 17:06:26 1993
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software; you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation; either version 2, or (at your option)
  15 ;; any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  24 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  25 ;; Boston, MA 02111-1307, USA.
  26
  27 ;;; Commentary:
  28
  29 ;; Support for random cookie fetches from phrase files, used for such
  30 ;; critical applications as emulating Zippy the Pinhead and confounding
  31 ;; the NSA Trunk Trawler.
  32 ;;
  33 ;; The two entry points are `cookie' and `cookie-insert'.  The helper
  34 ;; function `shuffle-vector' may be of interest to programmers.
  35 ;;
  36 ;; The code expects phrase files to be in one of two formats:
  37 ;;
  38 ;; * ITS-style LINS format (strings terminated by ASCII 0 characters,
  39 ;; leading whitespace ignored).
  40 ;;
  41 ;; * UNIX fortune file format (quotes terminated by %% on a line by itself).
  42 ;;
  43 ;; Everything up to the first delimiter is treated as a comment.  Other
  44 ;; formats could be supported by adding alternates to the regexp
  45 ;; `cookie-delimiter'.
  46 ;;
  47 ;; strfile(1) is the program used to compile the files for fortune(6).
  48 ;; In order to achieve total compatibility with strfile(1), cookie files
  49 ;; should start with two consecutive delimiters (and no comment).
  50 ;;
  51 ;; This code derives from Steve Strassman's 1987 spook.el package, but
  52 ;; has been generalized so that it supports multiple simultaneous
  53 ;; cookie databases and fortune files.  It is intended to be called
  54 ;; from other packages such as yow.el and spook.el.
  55 ;;
  56 ;; TO DO: teach cookie-snarf to auto-detect ITS PINS or UNIX fortune(6)
  57 ;; format and do the right thing.
  58
  59 ;;; Code:
  60
  61 ; Randomize the seed in the random number generator.
  62 (random t)
  63
  64 (defconst cookie-delimiter "\n%%\n\\|\n%\n\\|\0"
  65   "Delimiter used to separate cookie file entries.")
  66
  67 (defvar cookie-cache (make-vector 511 0)
  68   "Cache of cookie files that have already been snarfed.")
  69
  70 ;;;###autoload
  71 (defun cookie (phrase-file startmsg endmsg)
  72   "Return a random phrase from PHRASE-FILE.
  73 When the phrase file is read in, display STARTMSG at the beginning
  74 of load, ENDMSG at the end."
  75   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  76     (shuffle-vector cookie-vector)
  77     (aref cookie-vector 1)))
  78
  79 ;;;###autoload
  80 (defun cookie-insert (phrase-file &optional count startmsg endmsg)
  81   "Insert random phrases from PHRASE-FILE; COUNT of them.
  82 When the phrase file is read in, display STARTMSG at the beginning
  83 of load, ENDMSG at the end."
  84   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  85     (shuffle-vector cookie-vector)
  86     (let ((start (point)))
  87       (insert ?\n)
  88       (cookie1 (min (- (length cookie-vector) 1) (or count 1)) cookie-vector)
  89       (insert ?\n)
  90       (fill-region-as-paragraph start (point) nil))))
  91
  92 (defun cookie1 (arg cookie-vec)
  93   "Inserts a cookie phrase ARG times."
  94   (cond ((zerop arg) t)
  95         (t (insert (aref cookie-vec arg))
  96            (insert " ")
  97            (cookie1 (1- arg) cookie-vec))))
  98
  99 ;;;###autoload
 100 (defun cookie-snarf (phrase-file startmsg endmsg)
 101   "Reads in the PHRASE-FILE, returns it as a vector of strings.
 102 Emit STARTMSG and ENDMSG before and after.  Caches the result; second
 103 and subsequent calls on the same file won't go to disk."
 104   (let ((sym (intern-soft phrase-file cookie-cache)))
 105     (and sym (not (equal (symbol-function sym)
 106                          (nth 5 (file-attributes phrase-file))))
 107          (yes-or-no-p (concat phrase-file
 108                               " has changed.  Read new contents? "))
 109          (setq sym nil))
 110     (if sym
 111         (symbol-value sym)
 112       (setq sym (intern phrase-file cookie-cache))
 113       (message "%s" startmsg)
 114       (save-excursion
 115         (let ((buf (generate-new-buffer "*cookie*"))
 116               (result nil))
 117           (set-buffer buf)
 118           (fset sym (nth 5 (file-attributes phrase-file)))
 119           (insert-file-contents (expand-file-name phrase-file))
 120           (re-search-forward cookie-delimiter)
 121           (while (progn (skip-chars-forward " \t\n\r\f") (not (eobp)))
 122             (let ((beg (point)))
 123               (re-search-forward cookie-delimiter)
 124               (setq result (cons (buffer-substring beg (match-beginning 0))
 125                                  result))))
 126           (kill-buffer buf)
 127           (message "%s" endmsg)
 128           (set sym (apply 'vector result)))))))
 129
 130 (defun read-cookie (prompt phrase-file startmsg endmsg &optional require-match)
 131   "Prompt with PROMPT and read with completion among cookies in PHRASE-FILE.
 132 STARTMSG and ENDMSG are passed along to `cookie-snarf'.
 133 Optional fifth arg REQUIRE-MATCH non-nil forces a matching cookie."
 134   ;; Make sure the cookies are in the cache.
 135   (or (intern-soft phrase-file cookie-cache)
 136       (cookie-snarf phrase-file startmsg endmsg))
 137   (completing-read prompt
 138                    (let ((sym (intern phrase-file cookie-cache)))
 139                      ;; We cache the alist form of the cookie in a property.
 140                      (or (get sym 'completion-alist)
 141                          (let* ((alist nil)
 142                                 (vec (cookie-snarf phrase-file
 143                                                    startmsg endmsg))
 144                                 (i (length vec)))
 145                            (while (> (setq i (1- i)) 0)
 146                              (setq alist (cons (list (aref vec i)) alist)))
 147                            (put sym 'completion-alist alist))))
 148                    nil require-match nil nil))
 149
 150 ; Thanks to Ian G Batten <BattenIG@CS.BHAM.AC.UK>
 151 ; [of the University of Birmingham Computer Science Department]
 152 ; for the iterative version of this shuffle.
 153 ;
 154 ;;;###autoload
 155 (defun shuffle-vector (vector)
 156   "Randomly permute the elements of VECTOR (all permutations equally likely)."
 157   (let ((i 0)
 158         j
 159         temp
 160         (len (length vector)))
 161     (while (< i len)
 162       (setq j (+ i (random (- len i))))
 163       (setq temp (aref vector i))
 164       (aset vector i (aref vector j))
 165       (aset vector j temp)
 166       (setq i (1+ i))))
 167   vector)
 168
 169 (provide 'cookie1)
 170
 171 ;;; cookie1.el ends here