code.delx.au - gnu-emacs-elpa/blob - chess-tutorial.el

   1 ;;; chess-tutorial.el --- A simple chess training display
   2
   3 ;; Copyright (C) 2002, 2004, 2014  Free Software Foundation, Inc.
   4
   5 ;; Author: John Wiegley <johnw@gnu.org>
   6 ;; Maintainer: Mario Lang <mlang@delysid.org>
   7 ;; Keywords: games
   8
   9 ;; This program is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; This program is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;; `M-x chess-tutorial' implements a simple knight movement exercise.
  25 ;; The objective is to take all pawns on the chessboard without moving to a
  26 ;; square which is attacked by a queen.
  27
  28 ;;; Code:
  29
  30 (require 'chess)
  31 (require 'chess-display)
  32 (require 'chess-game)
  33 (require 'chess-message)
  34
  35 (chess-message-catalog 'english
  36   '((queen-would-take . "The queen would take your knight!")
  37     (congratulations  . "Congratulations!")
  38     (knight-1-done    . "Goal: take all the pawns, without letting the queen take your knight")
  39     (cannot-take-queen . "You cannot take the queen")))
  40
  41 (defun chess-tutorial-knight-1 (game _ignore event &rest _args)
  42   (if (eq event 'move)
  43       (let ((position (chess-game-pos game)))
  44         (if (null (chess-pos-search position ?p))
  45             (chess-message 'congratulations)
  46           (cond
  47            ((chess-search-position position
  48                                    (car (chess-pos-search position ?N)) ?q)
  49             (let ((chess-display-handling-event nil))
  50               (chess-game-undo game 1))
  51             (chess-error 'queen-would-take))
  52            ((not (chess-pos-search position ?q))
  53             (let ((chess-display-handling-event nil))
  54               (chess-game-undo game 1))
  55             (chess-error 'cannot-take-queen)))))))
  56
  57 ;;;###autoload
  58 (defun chess-tutorial ()
  59   "A simple chess training display."
  60   (interactive)
  61   (with-current-buffer (chess-create-display t)
  62     (chess-module-set-leader nil)
  63     (chess-display-set-from-fen "8/3p1p/2p3p/4q/2p3p/3p1p/8/N w - -")
  64     (chess-game-add-hook (chess-display-game nil) 'chess-tutorial-knight-1)
  65     (setq chess-pos-always-white t)
  66     (chess-display-popup nil)
  67     (chess-message 'knight-1-done)))
  68
  69 (provide 'chess-tutorial)
  70
  71 ;;; chess-tutorial.el ends here