lisp/play/solitaire.el

   1 ;;; solitaire.el --- game of solitaire in Emacs Lisp
   2
   3 ;; Copyright (C) 1994, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
   4 ;;   2009, 2010, 2011  Free Software Foundation, Inc.
   5
   6 ;; Author: Jan Schormann <Jan.Schormann@rechen-gilde.de>
   7 ;; Created: Fri afternoon, Jun  3,  1994
   8 ;; Keywords: games
   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 3 of the License, or
  15 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; This mode is for playing a well-known game of solitaire
  28 ;; in which you jump pegs across other pegs.
  29
  30 ;; The game itself is somehow self-explanatory.  Read the help text to
  31 ;; solitaire, and try it.
  32
  33 ;;; Code:
  34
  35 (defgroup solitaire nil
  36   "Game of Solitaire."
  37   :prefix "solitaire-"
  38   :group 'games)
  39
  40 (defcustom solitaire-mode-hook nil
  41   "Hook to run upon entry to Solitaire."
  42   :type 'hook
  43   :group 'solitaire)
  44
  45 (defvar solitaire-mode-map
  46   (let ((map (make-sparse-keymap)))
  47     (suppress-keymap map t)
  48
  49     (define-key map "\C-f" 'solitaire-right)
  50     (define-key map "\C-b" 'solitaire-left)
  51     (define-key map "\C-p" 'solitaire-up)
  52     (define-key map "\C-n" 'solitaire-down)
  53     (define-key map "\r" 'solitaire-move)
  54     (define-key map [remap undo] 'solitaire-undo)
  55     (define-key map " " 'solitaire-do-check)
  56     (define-key map "q" 'quit-window)
  57
  58     (define-key map [right] 'solitaire-right)
  59     (define-key map [left] 'solitaire-left)
  60     (define-key map [up] 'solitaire-up)
  61     (define-key map [down] 'solitaire-down)
  62
  63     (define-key map [S-right] 'solitaire-move-right)
  64     (define-key map [S-left]  'solitaire-move-left)
  65     (define-key map [S-up]    'solitaire-move-up)
  66     (define-key map [S-down]  'solitaire-move-down)
  67
  68     (define-key map [kp-6] 'solitaire-right)
  69     (define-key map [kp-4] 'solitaire-left)
  70     (define-key map [kp-8] 'solitaire-up)
  71     (define-key map [kp-2] 'solitaire-down)
  72     (define-key map [kp-5] 'solitaire-center-point)
  73
  74     (define-key map [S-kp-6] 'solitaire-move-right)
  75     (define-key map [S-kp-4] 'solitaire-move-left)
  76     (define-key map [S-kp-8] 'solitaire-move-up)
  77     (define-key map [S-kp-2] 'solitaire-move-down)
  78
  79     (define-key map [kp-enter] 'solitaire-move)
  80     (define-key map [kp-0] 'solitaire-undo)
  81
  82     ;; spoil it with s ;)
  83     (define-key map [?s] 'solitaire-solve)
  84
  85     ;;  (define-key map [kp-0] 'solitaire-hint) - Not yet provided ;)
  86     map)
  87   "Keymap for playing Solitaire.")
  88
  89 ;; Solitaire mode is suitable only for specially formatted data.
  90 (put 'solitaire-mode 'mode-class 'special)
  91
  92 (define-derived-mode solitaire-mode nil "Solitaire"
  93   "Major mode for playing Solitaire.
  94 To learn how to play Solitaire, see the documentation for function
  95 `solitaire'.
  96 \\<solitaire-mode-map>
  97 The usual mnemonic keys move the cursor around the board; in addition,
  98 \\[solitaire-move] is a prefix character for actually moving a stone on the board."
  99   (setq truncate-lines t)
 100   (setq show-trailing-whitespace nil))
 101
 102 (defvar solitaire-stones 0
 103   "Counter for the stones that are still there.")
 104
 105 (defvar solitaire-center nil
 106   "Center of the board.")
 107
 108 (defvar solitaire-start nil
 109   "Upper left corner of the board.")
 110
 111 (defvar solitaire-start-x nil)
 112 (defvar solitaire-start-y nil)
 113
 114 (defvar solitaire-end nil
 115   "Lower right corner of the board.")
 116
 117 (defvar solitaire-end-x nil)
 118 (defvar solitaire-end-y nil)
 119
 120 (defcustom solitaire-auto-eval t
 121   "Non-nil means check for possible moves after each major change.
 122 This takes a while, so switch this on if you like to be informed when
 123 the game is over, or off, if you are working on a slow machine."
 124   :type 'boolean
 125   :group 'solitaire)
 126
 127 (defconst solitaire-valid-directions
 128   '(solitaire-left solitaire-right solitaire-up solitaire-down))
 129
 130 ;;;###autoload
 131 (defun solitaire (arg)
 132   "Play Solitaire.
 133
 134 To play Solitaire, type \\[solitaire].
 135 \\<solitaire-mode-map>
 136 Move around the board using the cursor keys.
 137 Move stones using \\[solitaire-move] followed by a direction key.
 138 Undo moves using \\[solitaire-undo].
 139 Check for possible moves using \\[solitaire-do-check].
 140 \(The variable `solitaire-auto-eval' controls whether to automatically
 141 check after each move or undo.)
 142
 143 What is Solitaire?
 144
 145 I don't know who invented this game, but it seems to be rather old and
 146 its origin seems to be northern Africa.  Here's how to play:
 147 Initially, the board will look similar to this:
 148
 149         Le Solitaire
 150         ============
 151
 152                 o   o   o
 153
 154                 o   o   o
 155
 156         o   o   o   o   o   o   o
 157
 158         o   o   o   .   o   o   o
 159
 160         o   o   o   o   o   o   o
 161
 162                 o   o   o
 163
 164                 o   o   o
 165
 166 Let's call the o's stones and the .'s holes.  One stone fits into one
 167 hole.  As you can see, all holes but one are occupied by stones.  The
 168 aim of the game is to get rid of all but one stone, leaving that last
 169 one in the middle of the board if you're cool.
 170
 171 A stone can be moved if there is another stone next to it, and a hole
 172 after that one.  Thus there must be three fields in a row, either
 173 horizontally or vertically, up, down, left or right, which look like
 174 this:  o  o  .
 175
 176 Then the first stone is moved to the hole, jumping over the second,
 177 which therefore is taken away.  The above thus `evaluates' to:  .  .  o
 178
 179 That's all.  Here's the board after two moves:
 180
 181                 o   o   o
 182
 183                 .   o   o
 184
 185         o   o   .   o   o   o   o
 186
 187         o   .   o   o   o   o   o
 188
 189         o   o   o   o   o   o   o
 190
 191                 o   o   o
 192
 193                 o   o   o
 194
 195 Pick your favourite shortcuts:
 196
 197 \\{solitaire-mode-map}"
 198
 199   (interactive "P")
 200   (switch-to-buffer "*Solitaire*")
 201   (solitaire-mode)
 202   (setq buffer-read-only t)
 203   (setq solitaire-stones 32)
 204   (solitaire-insert-board)
 205   (solitaire-build-modeline)
 206   (goto-char (point-max))
 207   (setq solitaire-center (search-backward "."))
 208   (setq buffer-undo-list (list (point)))
 209   (set-buffer-modified-p nil))
 210
 211 (defun solitaire-build-modeline ()
 212   (setq mode-line-format
 213         (list "" "---" 'mode-line-buffer-identification
 214               (if (< 1 solitaire-stones)
 215                   (format "--> There are %d stones left <--" solitaire-stones)
 216                 "------")
 217               'global-mode-string "   %[(" 'mode-name 'minor-mode-alist "%n"
 218               ")%]-%-"))
 219   (force-mode-line-update))
 220
 221 (defun solitaire-insert-board ()
 222   (let* ((buffer-read-only nil)
 223          (w (window-width))
 224          (h (window-height))
 225          (hsep (cond ((> w 26) "   ")
 226                      ((> w 20) " ")
 227                      (t "")))
 228          (vsep (cond ((> h 17) "\n\n")
 229                      (t "\n")))
 230          (indent (make-string (/ (- w 7 (* 6 (length hsep))) 2) ?\s)))
 231     (erase-buffer)
 232     (insert (make-string (/ (- h 7 (if (> h 12) 3 0)
 233                                (* 6 (1- (length vsep)))) 2) ?\n))
 234     (when (or (string= vsep "\n\n") (> h 12))
 235       (insert (format "%sLe Solitaire\n" indent))
 236       (insert (format "%s============\n\n" indent)))
 237     (insert indent)
 238     (setq solitaire-start (point))
 239     (setq solitaire-start-x (current-column))
 240     (setq solitaire-start-y (solitaire-current-line))
 241     (insert (format " %s %so%so%so%s" hsep hsep hsep hsep vsep))
 242     (insert (format "%s %s %so%so%so%s" indent hsep hsep hsep hsep vsep))
 243     (insert (format "%so%so%so%so%so%so%so%s" indent hsep hsep hsep hsep hsep hsep vsep))
 244     (insert (format "%so%so%so%s" indent hsep hsep hsep))
 245     (setq solitaire-center (point))
 246     (insert (format ".%so%so%so%s" hsep hsep hsep vsep))
 247     (insert (format "%so%so%so%so%so%so%so%s" indent hsep hsep hsep hsep hsep hsep vsep))
 248     (insert (format "%s %s %so%so%so%s" indent hsep hsep hsep hsep vsep))
 249     (insert (format "%s %s %so%so%so%s %s " indent hsep hsep hsep hsep hsep hsep))
 250     (setq solitaire-end (point))
 251     (setq solitaire-end-x (current-column))
 252     (setq solitaire-end-y (solitaire-current-line))))
 253
 254 (defun solitaire-right ()
 255   (interactive)
 256   (let ((start (point)))
 257     (forward-char)
 258     (while (= ?\s (following-char))
 259       (forward-char))
 260     (when (or (= 0 (following-char))
 261               (= ?\s (following-char))
 262               (= ?\n (following-char)))
 263       (goto-char start))))
 264
 265 (defun solitaire-left ()
 266   (interactive)
 267   (let ((start (point)))
 268     (backward-char)
 269     (while (= ?\s (following-char))
 270       (backward-char))
 271     (when (or (= 0 (preceding-char))
 272               (= ?\s (following-char))
 273               (= ?\n (following-char)))
 274       (goto-char start))))
 275
 276 (defun solitaire-up ()
 277   (interactive)
 278   (let ((start (point))
 279         (c (current-column)))
 280     (forward-line -1)
 281     (move-to-column c)
 282     (while (and (= ?\n (following-char))
 283                 (forward-line -1)
 284                 (move-to-column c)
 285                 (not (bolp))))
 286     (when (or (= 0 (preceding-char))
 287               (= ?\s (following-char))
 288               (= ?\= (following-char))
 289               (= ?\n (following-char)))
 290       (goto-char start))))
 291
 292 (defun solitaire-down ()
 293   (interactive)
 294   (let ((start (point))
 295         (c (current-column)))
 296     (forward-line 1)
 297     (move-to-column c)
 298     (while (and (= ?\n (following-char))
 299                 (forward-line 1)
 300                 (move-to-column c)
 301                 (not (eolp))))
 302     (when (or (= 0 (following-char))
 303               (= ?\s (following-char))
 304               (= ?\n (following-char)))
 305       (goto-char start))))
 306
 307 (defun solitaire-center-point ()
 308   (interactive)
 309   (goto-char solitaire-center))
 310
 311 (defun solitaire-move-right () (interactive) (solitaire-move '[right]))
 312 (defun solitaire-move-left () (interactive) (solitaire-move '[left]))
 313 (defun solitaire-move-up () (interactive) (solitaire-move '[up]))
 314 (defun solitaire-move-down () (interactive) (solitaire-move '[down]))
 315
 316 (defun solitaire-possible-move (movesymbol)
 317   "Check if a move is possible from current point in the specified direction.
 318 MOVESYMBOL specifies the direction.
 319 Returns either a string, indicating cause of contraindication, or a
 320 list containing three numbers: starting field, skipped field (from
 321 which a stone will be taken away) and target."
 322
 323   (save-excursion
 324     (if (memq movesymbol solitaire-valid-directions)
 325         (let ((start (point))
 326               (skip (progn (funcall movesymbol) (point)))
 327               (target (progn (funcall movesymbol) (point))))
 328           (if (= skip target)
 329               "Off Board!"
 330             (if (or (/= ?o (char-after start))
 331                     (/= ?o (char-after skip))
 332                     (/= ?. (char-after target)))
 333                 "Wrong move!"
 334               (list start skip target))))
 335       "Not a valid direction")))
 336
 337 (defun solitaire-move (dir)
 338   "Pseudo-prefix command to move a stone in Solitaire."
 339   (interactive "kMove where? ")
 340   (let* ((class (solitaire-possible-move (lookup-key solitaire-mode-map dir)))
 341          (buffer-read-only nil))
 342     (if (stringp class)
 343         (error class)
 344       (let ((start (car class))
 345             (skip (car (cdr class)))
 346             (target (car (cdr (cdr class)))))
 347         (goto-char start)
 348         (delete-char 1)
 349         (insert ?.)
 350         (goto-char skip)
 351         (delete-char 1)
 352         (insert ?.)
 353         (goto-char target)
 354         (delete-char 1)
 355         (insert ?o)
 356         (goto-char target)
 357         (setq solitaire-stones (1- solitaire-stones))
 358         (solitaire-build-modeline)
 359         (if solitaire-auto-eval (solitaire-do-check))))))
 360
 361 (defun solitaire-undo (arg)
 362   "Undo a move in Solitaire."
 363   (interactive "P")
 364   (let ((buffer-read-only nil))
 365     (undo arg))
 366   (save-excursion
 367     (setq solitaire-stones
 368           (let ((count 0))
 369             (goto-char solitaire-end)
 370             (while (search-backward "o" solitaire-start 'done)
 371               (and (>= (current-column) solitaire-start-x)
 372                    (<= (current-column) solitaire-end-x)
 373                    (>= (solitaire-current-line) solitaire-start-y)
 374                    (<= (solitaire-current-line) solitaire-end-y)
 375                    (setq count (1+ count))))
 376             count)))
 377   (solitaire-build-modeline)
 378   (when solitaire-auto-eval (solitaire-do-check)))
 379
 380 (defun solitaire-check ()
 381   (save-excursion
 382     (if (= 1 solitaire-stones)
 383         0
 384       (goto-char solitaire-end)
 385       (let ((count 0))
 386         (while (search-backward "o" solitaire-start 'done)
 387           (and (>= (current-column) solitaire-start-x)
 388                (<= (current-column) solitaire-end-x)
 389                (>= (solitaire-current-line) solitaire-start-y)
 390                (<= (solitaire-current-line) solitaire-end-y)
 391                (mapc
 392                 (lambda (movesymbol)
 393                   (when (listp (solitaire-possible-move movesymbol))
 394                     (setq count (1+ count))))
 395                 solitaire-valid-directions)))
 396         count))))
 397
 398 (defun solitaire-do-check (&optional arg)
 399   "Check for any possible moves in Solitaire."
 400   (interactive "P")
 401   (let ((moves (solitaire-check)))
 402     (cond ((= 1 solitaire-stones)
 403            (message "Yeah! You made it! Only the King is left!"))
 404           ((zerop moves)
 405            (message "Sorry, no more possible moves."))
 406           ((= 1 moves)
 407            (message "There is one possible move."))
 408           (t (message "There are %d possible moves." moves)))))
 409
 410 (defun solitaire-current-line ()
 411   "Return the vertical position of point.
 412 Seen in info on text lines."
 413   (+ (count-lines (point-min) (point))
 414      (if (= (current-column) 0) 1 0)
 415      -1))
 416
 417 ;; And here's the spoiler:)
 418 (defun solitaire-solve ()
 419   "Spoil Solitaire by solving the game for you - nearly ...
 420 ... stops with five stones left ;)"
 421   (interactive)
 422   (when (< solitaire-stones 32)
 423     (error "Cannot solve game in progress"))
 424   (let ((allmoves [up up S-down up left left S-right up up left S-down
 425                       up up right right S-left down down down S-up up
 426                       S-down down down down S-up left left down
 427                       S-right left left up up S-down right right right
 428                       S-left left S-right right right right S-left
 429                       right down down S-up down down left left S-right
 430                       up up up S-down down S-up up up up S-down up
 431                       right right S-left down right right down S-up
 432                       left left left S-right right S-left down down
 433                       left S-right S-up S-left S-left S-down S-right
 434                       up S-right left left])
 435         ;; down down S-up left S-right
 436         ;; right S-left
 437         (solitaire-auto-eval nil))
 438     (solitaire-center-point)
 439     (mapc (lambda (op)
 440             (when (memq op '(S-left S-right S-up S-down))
 441               (sit-for 0.2))
 442             (execute-kbd-macro (vector op))
 443             (when (memq op '(S-left S-right S-up S-down))
 444               (sit-for 0.4)))
 445           allmoves))
 446   (solitaire-do-check))
 447
 448 (provide 'solitaire)
 449
 450 ;;; solitaire.el ends here