lisp/play/cookie1.el

   1 ;;; cookie1.el --- retrieve random phrases from fortune cookie files
   2
   3 ;; Copyright (C) 1993, 2001, 2002, 2003, 2004, 2005,
   4 ;;   2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Author: Eric S. Raymond <esr@snark.thyrsus.com>
   7 ;; Maintainer: FSF
   8 ;; Keywords: games, extensions
   9 ;; Created: Mon Mar 22 17:06:26 1993
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 3, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  26 ;; Boston, MA 02110-1301, USA.
  27
  28 ;;; Commentary:
  29
  30 ;; Support for random cookie fetches from phrase files, used for such
  31 ;; critical applications as emulating Zippy the Pinhead and confounding
  32 ;; the NSA Trunk Trawler.
  33 ;;
  34 ;; The two entry points are `cookie' and `cookie-insert'.  The helper
  35 ;; function `shuffle-vector' may be of interest to programmers.
  36 ;;
  37 ;; The code expects phrase files to be in one of two formats:
  38 ;;
  39 ;; * ITS-style LINS format (strings terminated by ASCII 0 characters,
  40 ;; leading whitespace ignored).
  41 ;;
  42 ;; * UNIX fortune file format (quotes terminated by %% on a line by itself).
  43 ;;
  44 ;; Everything up to the first delimiter is treated as a comment.  Other
  45 ;; formats could be supported by adding alternates to the regexp
  46 ;; `cookie-delimiter'.
  47 ;;
  48 ;; strfile(1) is the program used to compile the files for fortune(6).
  49 ;; In order to achieve total compatibility with strfile(1), cookie files
  50 ;; should start with two consecutive delimiters (and no comment).
  51 ;;
  52 ;; This code derives from Steve Strassman's 1987 spook.el package, but
  53 ;; has been generalized so that it supports multiple simultaneous
  54 ;; cookie databases and fortune files.  It is intended to be called
  55 ;; from other packages such as yow.el and spook.el.
  56 ;;
  57 ;; TO DO: teach cookie-snarf to auto-detect ITS PINS or UNIX fortune(6)
  58 ;; format and do the right thing.
  59
  60 ;;; Code:
  61
  62 ; Randomize the seed in the random number generator.
  63 (random t)
  64
  65 (defconst cookie-delimiter "\n%%\n\\|\n%\n\\|\0"
  66   "Delimiter used to separate cookie file entries.")
  67
  68 (defvar cookie-cache (make-vector 511 0)
  69   "Cache of cookie files that have already been snarfed.")
  70
  71 ;;;###autoload
  72 (defun cookie (phrase-file startmsg endmsg)
  73   "Return a random phrase from PHRASE-FILE.
  74 When the phrase file is read in, display STARTMSG at the beginning
  75 of load, ENDMSG at the end."
  76   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  77     (shuffle-vector cookie-vector)
  78     (aref cookie-vector 0)))
  79
  80 ;;;###autoload
  81 (defun cookie-insert (phrase-file &optional count startmsg endmsg)
  82   "Insert random phrases from PHRASE-FILE; COUNT of them.
  83 When the phrase file is read in, display STARTMSG at the beginning
  84 of load, ENDMSG at the end."
  85   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  86     (shuffle-vector cookie-vector)
  87     (let ((start (point)))
  88       (insert ?\n)
  89       (cookie1 (min (- (length cookie-vector) 1) (or count 1)) cookie-vector)
  90       (insert ?\n)
  91       (fill-region-as-paragraph start (point) nil))))
  92
  93 (defun cookie1 (arg cookie-vec)
  94   "Inserts a cookie phrase ARG times."
  95   (cond ((zerop arg) t)
  96         (t (insert (aref cookie-vec arg))
  97            (insert " ")
  98            (cookie1 (1- arg) cookie-vec))))
  99
 100 ;;;###autoload
 101 (defun cookie-snarf (phrase-file startmsg endmsg)
 102   "Reads in the PHRASE-FILE, returns it as a vector of strings.
 103 Emit STARTMSG and ENDMSG before and after.  Caches the result; second
 104 and subsequent calls on the same file won't go to disk."
 105   (let ((sym (intern-soft phrase-file cookie-cache)))
 106     (and sym (not (equal (symbol-function sym)
 107                          (nth 5 (file-attributes phrase-file))))
 108          (yes-or-no-p (concat phrase-file
 109                               " has changed.  Read new contents? "))
 110          (setq sym nil))
 111     (if sym
 112         (symbol-value sym)
 113       (setq sym (intern phrase-file cookie-cache))
 114       (message "%s" startmsg)
 115       (save-excursion
 116         (let ((buf (generate-new-buffer "*cookie*"))
 117               (result nil))
 118           (set-buffer buf)
 119           (fset sym (nth 5 (file-attributes phrase-file)))
 120           (insert-file-contents (expand-file-name phrase-file))
 121           (re-search-forward cookie-delimiter)
 122           (while (progn (skip-chars-forward " \t\n\r\f") (not (eobp)))
 123             (let ((beg (point)))
 124               (re-search-forward cookie-delimiter)
 125               (setq result (cons (buffer-substring beg (match-beginning 0))
 126                                  result))))
 127           (kill-buffer buf)
 128           (message "%s" endmsg)
 129           (set sym (apply 'vector result)))))))
 130
 131 (defun read-cookie (prompt phrase-file startmsg endmsg &optional require-match)
 132   "Prompt with PROMPT and read with completion among cookies in PHRASE-FILE.
 133 STARTMSG and ENDMSG are passed along to `cookie-snarf'.
 134 Optional fifth arg REQUIRE-MATCH non-nil forces a matching cookie."
 135   ;; Make sure the cookies are in the cache.
 136   (or (intern-soft phrase-file cookie-cache)
 137       (cookie-snarf phrase-file startmsg endmsg))
 138   (completing-read prompt
 139                    (let ((sym (intern phrase-file cookie-cache)))
 140                      ;; We cache the alist form of the cookie in a property.
 141                      (or (get sym 'completion-alist)
 142                          (let* ((alist nil)
 143                                 (vec (cookie-snarf phrase-file
 144                                                    startmsg endmsg))
 145                                 (i (length vec)))
 146                            (while (> (setq i (1- i)) 0)
 147                              (setq alist (cons (list (aref vec i)) alist)))
 148                            (put sym 'completion-alist alist))))
 149                    nil require-match nil nil))
 150
 151 ; Thanks to Ian G Batten <BattenIG@CS.BHAM.AC.UK>
 152 ; [of the University of Birmingham Computer Science Department]
 153 ; for the iterative version of this shuffle.
 154 ;
 155 ;;;###autoload
 156 (defun shuffle-vector (vector)
 157   "Randomly permute the elements of VECTOR (all permutations equally likely)."
 158   (let ((i 0)
 159         j
 160         temp
 161         (len (length vector)))
 162     (while (< i len)
 163       (setq j (+ i (random (- len i))))
 164       (setq temp (aref vector i))
 165       (aset vector i (aref vector j))
 166       (aset vector j temp)
 167       (setq i (1+ i))))
 168   vector)
 169
 170 (provide 'cookie1)
 171
 172 ;; arch-tag: 4a8a8712-df6a-4f34-b030-108a1b47f9f2
 173 ;;; cookie1.el ends here