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, 2009, 2010 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 of the License, or
  16 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  25
  26 ;;; Commentary:
  27
  28 ;; Support for random cookie fetches from phrase files, used for such
  29 ;; critical applications as emulating Zippy the Pinhead and confounding
  30 ;; the NSA Trunk Trawler.
  31 ;;
  32 ;; The two entry points are `cookie' and `cookie-insert'.  The helper
  33 ;; function `shuffle-vector' may be of interest to programmers.
  34 ;;
  35 ;; The code expects phrase files to be in one of two formats:
  36 ;;
  37 ;; * ITS-style LINS format (strings terminated by ASCII 0 characters,
  38 ;; leading whitespace ignored).
  39 ;;
  40 ;; * UNIX fortune file format (quotes terminated by %% on a line by itself).
  41 ;;
  42 ;; Everything up to the first delimiter is treated as a comment.  Other
  43 ;; formats could be supported by adding alternates to the regexp
  44 ;; `cookie-delimiter'.
  45 ;;
  46 ;; strfile(1) is the program used to compile the files for fortune(6).
  47 ;; In order to achieve total compatibility with strfile(1), cookie files
  48 ;; should start with two consecutive delimiters (and no comment).
  49 ;;
  50 ;; This code derives from Steve Strassman's 1987 spook.el package, but
  51 ;; has been generalized so that it supports multiple simultaneous
  52 ;; cookie databases and fortune files.  It is intended to be called
  53 ;; from other packages such as yow.el and spook.el.
  54
  55 ;;; Code:
  56
  57 ; Randomize the seed in the random number generator.
  58 (random t)
  59
  60 (defconst cookie-delimiter "\n%%\n\\|\n%\n\\|\0"
  61   "Delimiter used to separate cookie file entries.")
  62
  63 (defvar cookie-cache (make-vector 511 0)
  64   "Cache of cookie files that have already been snarfed.")
  65
  66 ;;;###autoload
  67 (defun cookie (phrase-file startmsg endmsg)
  68   "Return a random phrase from PHRASE-FILE.
  69 When the phrase file is read in, display STARTMSG at the beginning
  70 of load, ENDMSG at the end."
  71   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  72     (shuffle-vector cookie-vector)
  73     (aref cookie-vector 0)))
  74
  75 ;;;###autoload
  76 (defun cookie-insert (phrase-file &optional count startmsg endmsg)
  77   "Insert random phrases from PHRASE-FILE; COUNT of them.
  78 When the phrase file is read in, display STARTMSG at the beginning
  79 of load, ENDMSG at the end."
  80   (let ((cookie-vector (cookie-snarf phrase-file startmsg endmsg)))
  81     (shuffle-vector cookie-vector)
  82     (let ((start (point)))
  83       (insert ?\n)
  84       (cookie1 (min (- (length cookie-vector) 1) (or count 1)) cookie-vector)
  85       (insert ?\n)
  86       (fill-region-as-paragraph start (point) nil))))
  87
  88 (defun cookie1 (arg cookie-vec)
  89   "Inserts a cookie phrase ARG times."
  90   (cond ((zerop arg) t)
  91         (t (insert (aref cookie-vec arg))
  92            (insert " ")
  93            (cookie1 (1- arg) cookie-vec))))
  94
  95 ;;;###autoload
  96 (defun cookie-snarf (phrase-file startmsg endmsg)
  97   "Reads in the PHRASE-FILE, returns it as a vector of strings.
  98 Emit STARTMSG and ENDMSG before and after.  Caches the result; second
  99 and subsequent calls on the same file won't go to disk."
 100   (let ((sym (intern-soft phrase-file cookie-cache)))
 101     (and sym (not (equal (symbol-function sym)
 102                          (nth 5 (file-attributes phrase-file))))
 103          (yes-or-no-p (concat phrase-file
 104                               " has changed.  Read new contents? "))
 105          (setq sym nil))
 106     (if sym
 107         (symbol-value sym)
 108       (setq sym (intern phrase-file cookie-cache))
 109       (message "%s" startmsg)
 110       (save-excursion
 111         (let ((buf (generate-new-buffer "*cookie*"))
 112               (result nil))
 113           (set-buffer buf)
 114           (fset sym (nth 5 (file-attributes phrase-file)))
 115           (insert-file-contents (expand-file-name phrase-file))
 116           (re-search-forward cookie-delimiter)
 117           (while (progn (skip-chars-forward " \t\n\r\f") (not (eobp)))
 118             (let ((beg (point)))
 119               (re-search-forward cookie-delimiter)
 120               (setq result (cons (buffer-substring beg (match-beginning 0))
 121                                  result))))
 122           (kill-buffer buf)
 123           (message "%s" endmsg)
 124           (set sym (apply 'vector result)))))))
 125
 126 (defun read-cookie (prompt phrase-file startmsg endmsg &optional require-match)
 127   "Prompt with PROMPT and read with completion among cookies in PHRASE-FILE.
 128 STARTMSG and ENDMSG are passed along to `cookie-snarf'.
 129 Optional fifth arg REQUIRE-MATCH non-nil forces a matching cookie."
 130   ;; Make sure the cookies are in the cache.
 131   (or (intern-soft phrase-file cookie-cache)
 132       (cookie-snarf phrase-file startmsg endmsg))
 133   (completing-read prompt
 134                    (let ((sym (intern phrase-file cookie-cache)))
 135                      ;; We cache the alist form of the cookie in a property.
 136                      (or (get sym 'completion-alist)
 137                          (let* ((alist nil)
 138                                 (vec (cookie-snarf phrase-file
 139                                                    startmsg endmsg))
 140                                 (i (length vec)))
 141                            (while (>= (setq i (1- i)) 0)
 142                              (setq alist (cons (list (aref vec i)) alist)))
 143                            (put sym 'completion-alist alist))))
 144                    nil require-match nil nil))
 145
 146 ; Thanks to Ian G Batten <BattenIG@CS.BHAM.AC.UK>
 147 ; [of the University of Birmingham Computer Science Department]
 148 ; for the iterative version of this shuffle.
 149 ;
 150 ;;;###autoload
 151 (defun shuffle-vector (vector)
 152   "Randomly permute the elements of VECTOR (all permutations equally likely)."
 153   (let ((i 0)
 154         j
 155         temp
 156         (len (length vector)))
 157     (while (< i len)
 158       (setq j (+ i (random (- len i))))
 159       (setq temp (aref vector i))
 160       (aset vector i (aref vector j))
 161       (aset vector j temp)
 162       (setq i (1+ i))))
 163   vector)
 164
 165 (provide 'cookie1)
 166
 167 ;; arch-tag: 4a8a8712-df6a-4f34-b030-108a1b47f9f2
 168 ;;; cookie1.el ends here