lisp/play/solitaire.el

   1 ;;; solitaire.el --- game of solitaire in Emacs Lisp
   2
   3 ;; Copyright (C) 1994, 2001-2012  Free Software Foundation, Inc.
   4
   5 ;; Author: Jan Schormann <Jan.Schormann@rechen-gilde.de>
   6 ;; Created: Fri afternoon, Jun  3,  1994
   7 ;; Keywords: games
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; This mode is for playing a well-known game of solitaire
  27 ;; in which you jump pegs across other pegs.
  28
  29 ;; The game itself is somehow self-explanatory.  Read the help text to
  30 ;; solitaire, and try it.
  31
  32 ;;; Code:
  33
  34 (defgroup solitaire nil
  35   "Game of Solitaire."
  36   :prefix "solitaire-"
  37   :group 'games)
  38
  39 (defcustom solitaire-mode-hook nil
  40   "Hook to run upon entry to Solitaire."
  41   :type 'hook
  42   :group 'solitaire)
  43
  44 (defvar solitaire-mode-map
  45   (let ((map (make-sparse-keymap)))
  46     (set-keymap-parent map special-mode-map)
  47
  48     (define-key map "\C-f" 'solitaire-right)
  49     (define-key map "\C-b" 'solitaire-left)
  50     (define-key map "\C-p" 'solitaire-up)
  51     (define-key map "\C-n" 'solitaire-down)
  52     (define-key map "\r" 'solitaire-move)
  53     (define-key map [remap undo] 'solitaire-undo)
  54     (define-key map " " 'solitaire-do-check)
  55
  56     (define-key map [right] 'solitaire-right)
  57     (define-key map [left] 'solitaire-left)
  58     (define-key map [up] 'solitaire-up)
  59     (define-key map [down] 'solitaire-down)
  60
  61     (define-key map [S-right] 'solitaire-move-right)
  62     (define-key map [S-left]  'solitaire-move-left)
  63     (define-key map [S-up]    'solitaire-move-up)
  64     (define-key map [S-down]  'solitaire-move-down)
  65
  66     (define-key map [kp-6] 'solitaire-right)
  67     (define-key map [kp-4] 'solitaire-left)
  68     (define-key map [kp-8] 'solitaire-up)
  69     (define-key map [kp-2] 'solitaire-down)
  70     (define-key map [kp-5] 'solitaire-center-point)
  71
  72     (define-key map [S-kp-6] 'solitaire-move-right)
  73     (define-key map [S-kp-4] 'solitaire-move-left)
  74     (define-key map [S-kp-8] 'solitaire-move-up)
  75     (define-key map [S-kp-2] 'solitaire-move-down)
  76
  77     (define-key map [kp-enter] 'solitaire-move)
  78     (define-key map [kp-0] 'solitaire-undo)
  79
  80     ;; spoil it with s ;)
  81     (define-key map [?s] 'solitaire-solve)
  82
  83     ;;  (define-key map [kp-0] 'solitaire-hint) - Not yet provided ;)
  84     map)
  85   "Keymap for playing Solitaire.")
  86
  87 ;; Solitaire mode is suitable only for specially formatted data.
  88 (put 'solitaire-mode 'mode-class 'special)
  89
  90 (define-derived-mode solitaire-mode special-mode "Solitaire"
  91   "Major mode for playing Solitaire.
  92 To learn how to play Solitaire, see the documentation for function
  93 `solitaire'.
  94 \\<solitaire-mode-map>
  95 The usual mnemonic keys move the cursor around the board; in addition,
  96 \\[solitaire-move] is a prefix character for actually moving a stone on the board."
  97   (setq truncate-lines t)
  98   (setq show-trailing-whitespace nil))
  99
 100 (defvar solitaire-stones 0
 101   "Counter for the stones that are still there.")
 102
 103 (defvar solitaire-center nil
 104   "Center of the board.")
 105
 106 (defvar solitaire-start nil
 107   "Upper left corner of the board.")
 108
 109 (defvar solitaire-start-x nil)
 110 (defvar solitaire-start-y nil)
 111
 112 (defvar solitaire-end nil
 113   "Lower right corner of the board.")
 114
 115 (defvar solitaire-end-x nil)
 116 (defvar solitaire-end-y nil)
 117
 118 (defcustom solitaire-auto-eval t
 119   "Non-nil means check for possible moves after each major change.
 120 This takes a while, so switch this on if you like to be informed when
 121 the game is over, or off, if you are working on a slow machine."
 122   :type 'boolean
 123   :group 'solitaire)
 124
 125 (defconst solitaire-valid-directions
 126   '(solitaire-left solitaire-right solitaire-up solitaire-down))
 127
 128 ;;;###autoload
 129 (defun solitaire (_arg)
 130   "Play Solitaire.
 131
 132 To play Solitaire, type \\[solitaire].
 133 \\<solitaire-mode-map>
 134 Move around the board using the cursor keys.
 135 Move stones using \\[solitaire-move] followed by a direction key.
 136 Undo moves using \\[solitaire-undo].
 137 Check for possible moves using \\[solitaire-do-check].
 138 \(The variable `solitaire-auto-eval' controls whether to automatically
 139 check after each move or undo.)
 140
 141 What is Solitaire?
 142
 143 I don't know who invented this game, but it seems to be rather old and
 144 its origin seems to be northern Africa.  Here's how to play:
 145 Initially, the board will look similar to this:
 146
 147         Le Solitaire
 148         ============
 149
 150                 o   o   o
 151
 152                 o   o   o
 153
 154         o   o   o   o   o   o   o
 155
 156         o   o   o   .   o   o   o
 157
 158         o   o   o   o   o   o   o
 159
 160                 o   o   o
 161
 162                 o   o   o
 163
 164 Let's call the o's stones and the .'s holes.  One stone fits into one
 165 hole.  As you can see, all holes but one are occupied by stones.  The
 166 aim of the game is to get rid of all but one stone, leaving that last
 167 one in the middle of the board if you're cool.
 168
 169 A stone can be moved if there is another stone next to it, and a hole
 170 after that one.  Thus there must be three fields in a row, either
 171 horizontally or vertically, up, down, left or right, which look like
 172 this:  o  o  .
 173
 174 Then the first stone is moved to the hole, jumping over the second,
 175 which therefore is taken away.  The above thus `evaluates' to:  .  .  o
 176
 177 That's all.  Here's the board after two moves:
 178
 179                 o   o   o
 180
 181                 .   o   o
 182
 183         o   o   .   o   o   o   o
 184
 185         o   .   o   o   o   o   o
 186
 187         o   o   o   o   o   o   o
 188
 189                 o   o   o
 190
 191                 o   o   o
 192
 193 Pick your favorite shortcuts:
 194
 195 \\{solitaire-mode-map}"
 196
 197   (interactive "P")
 198   (switch-to-buffer "*Solitaire*")
 199   (let ((inhibit-read-only t))
 200     (solitaire-mode)
 201     (setq buffer-read-only t)
 202     (setq solitaire-stones 32)
 203     (solitaire-insert-board)
 204     (solitaire-build-modeline)
 205     (goto-char (point-max))
 206     (setq solitaire-center (search-backward "."))
 207     (setq buffer-undo-list (list (point)))))
 208
 209 (defun solitaire-build-modeline ()
 210   (setq mode-line-format
 211         (list "" "---" 'mode-line-buffer-identification
 212               (if (< 1 solitaire-stones)
 213                   (format "--> There are %d stones left <--" solitaire-stones)
 214                 "------")
 215               'global-mode-string "   %[(" 'mode-name 'minor-mode-alist "%n"
 216               ")%]-%-"))
 217   (force-mode-line-update))
 218
 219 (defun solitaire-insert-board ()
 220   (let* ((buffer-read-only nil)
 221          (w (window-width))
 222          (h (window-height))
 223          (hsep (cond ((> w 26) "   ")
 224                      ((> w 20) " ")
 225                      (t "")))
 226          (vsep (cond ((> h 17) "\n\n")
 227                      (t "\n")))
 228          (indent (make-string (/ (- w 7 (* 6 (length hsep))) 2) ?\s)))
 229     (erase-buffer)
 230     (insert (make-string (/ (- h 7 (if (> h 12) 3 0)
 231                                (* 6 (1- (length vsep)))) 2) ?\n))
 232     (when (or (string= vsep "\n\n") (> h 12))
 233       (insert (format "%sLe Solitaire\n" indent))
 234       (insert (format "%s============\n\n" indent)))
 235     (insert indent)
 236     (setq solitaire-start (point))
 237     (setq solitaire-start-x (current-column))
 238     (setq solitaire-start-y (solitaire-current-line))
 239     (insert (format " %s %so%so%so%s" hsep hsep hsep hsep vsep))
 240     (insert (format "%s %s %so%so%so%s" indent hsep hsep hsep hsep vsep))
 241     (insert (format "%so%so%so%so%so%so%so%s" indent hsep hsep hsep hsep hsep hsep vsep))
 242     (insert (format "%so%so%so%s" indent hsep hsep hsep))
 243     (setq solitaire-center (point))
 244     (insert (format ".%so%so%so%s" hsep hsep hsep vsep))
 245     (insert (format "%so%so%so%so%so%so%so%s" indent hsep hsep hsep hsep hsep hsep vsep))
 246     (insert (format "%s %s %so%so%so%s" indent hsep hsep hsep hsep vsep))
 247     (insert (format "%s %s %so%so%so%s %s " indent hsep hsep hsep hsep hsep hsep))
 248     (setq solitaire-end (point))
 249     (setq solitaire-end-x (current-column))
 250     (setq solitaire-end-y (solitaire-current-line))))
 251
 252 (defun solitaire-right ()
 253   (interactive)
 254   (let ((start (point)))
 255     (forward-char)
 256     (while (= ?\s (following-char))
 257       (forward-char))
 258     (when (or (= 0 (following-char))
 259               (= ?\s (following-char))
 260               (= ?\n (following-char)))
 261       (goto-char start))))
 262
 263 (defun solitaire-left ()
 264   (interactive)
 265   (let ((start (point)))
 266     (backward-char)
 267     (while (= ?\s (following-char))
 268       (backward-char))
 269     (when (or (= 0 (preceding-char))
 270               (= ?\s (following-char))
 271               (= ?\n (following-char)))
 272       (goto-char start))))
 273
 274 (defun solitaire-up ()
 275   (interactive)
 276   (let ((start (point))
 277         (c (current-column)))
 278     (forward-line -1)
 279     (move-to-column c)
 280     (while (and (= ?\n (following-char))
 281                 (forward-line -1)
 282                 (move-to-column c)
 283                 (not (bolp))))
 284     (when (or (= 0 (preceding-char))
 285               (= ?\s (following-char))
 286               (= ?\= (following-char))
 287               (= ?\n (following-char)))
 288       (goto-char start))))
 289
 290 (defun solitaire-down ()
 291   (interactive)
 292   (let ((start (point))
 293         (c (current-column)))
 294     (forward-line 1)
 295     (move-to-column c)
 296     (while (and (= ?\n (following-char))
 297                 (forward-line 1)
 298                 (move-to-column c)
 299                 (not (eolp))))
 300     (when (or (= 0 (following-char))
 301               (= ?\s (following-char))
 302               (= ?\n (following-char)))
 303       (goto-char start))))
 304
 305 (defun solitaire-center-point ()
 306   (interactive)
 307   (goto-char solitaire-center))
 308
 309 (defun solitaire-move-right () (interactive) (solitaire-move '[right]))
 310 (defun solitaire-move-left () (interactive) (solitaire-move '[left]))
 311 (defun solitaire-move-up () (interactive) (solitaire-move '[up]))
 312 (defun solitaire-move-down () (interactive) (solitaire-move '[down]))
 313
 314 (defun solitaire-possible-move (movesymbol)
 315   "Check if a move is possible from current point in the specified direction.
 316 MOVESYMBOL specifies the direction.
 317 Returns either a string, indicating cause of contraindication, or a
 318 list containing three numbers: starting field, skipped field (from
 319 which a stone will be taken away) and target."
 320
 321   (save-excursion
 322     (if (memq movesymbol solitaire-valid-directions)
 323         (let ((start (point))
 324               (skip (progn (funcall movesymbol) (point)))
 325               (target (progn (funcall movesymbol) (point))))
 326           (if (= skip target)
 327               "Off Board!"
 328             (if (or (/= ?o (char-after start))
 329                     (/= ?o (char-after skip))
 330                     (/= ?. (char-after target)))
 331                 "Wrong move!"
 332               (list start skip target))))
 333       "Not a valid direction")))
 334
 335 (defun solitaire-move (dir)
 336   "Pseudo-prefix command to move a stone in Solitaire."
 337   (interactive "kMove where? ")
 338   (let* ((class (solitaire-possible-move (lookup-key solitaire-mode-map dir)))
 339          (buffer-read-only nil))
 340     (if (stringp class)
 341         (error class)
 342       (let ((start (car class))
 343             (skip (car (cdr class)))
 344             (target (car (cdr (cdr class)))))
 345         (goto-char start)
 346         (delete-char 1)
 347         (insert ?.)
 348         (goto-char skip)
 349         (delete-char 1)
 350         (insert ?.)
 351         (goto-char target)
 352         (delete-char 1)
 353         (insert ?o)
 354         (goto-char target)
 355         (setq solitaire-stones (1- solitaire-stones))
 356         (solitaire-build-modeline)
 357         (if solitaire-auto-eval (solitaire-do-check))))))
 358
 359 (defun solitaire-undo (arg)
 360   "Undo a move in Solitaire."
 361   (interactive "P")
 362   (let ((buffer-read-only nil))
 363     (undo arg))
 364   (save-excursion
 365     (setq solitaire-stones
 366           (let ((count 0))
 367             (goto-char solitaire-end)
 368             (while (search-backward "o" solitaire-start 'done)
 369               (and (>= (current-column) solitaire-start-x)
 370                    (<= (current-column) solitaire-end-x)
 371                    (>= (solitaire-current-line) solitaire-start-y)
 372                    (<= (solitaire-current-line) solitaire-end-y)
 373                    (setq count (1+ count))))
 374             count)))
 375   (solitaire-build-modeline)
 376   (when solitaire-auto-eval (solitaire-do-check)))
 377
 378 (defun solitaire-check ()
 379   (save-excursion
 380     (if (= 1 solitaire-stones)
 381         0
 382       (goto-char solitaire-end)
 383       (let ((count 0))
 384         (while (search-backward "o" solitaire-start 'done)
 385           (and (>= (current-column) solitaire-start-x)
 386                (<= (current-column) solitaire-end-x)
 387                (>= (solitaire-current-line) solitaire-start-y)
 388                (<= (solitaire-current-line) solitaire-end-y)
 389                (mapc
 390                 (lambda (movesymbol)
 391                   (when (listp (solitaire-possible-move movesymbol))
 392                     (setq count (1+ count))))
 393                 solitaire-valid-directions)))
 394         count))))
 395
 396 (defun solitaire-do-check (&optional _arg)
 397   "Check for any possible moves in Solitaire."
 398   (interactive "P")
 399   (let ((moves (solitaire-check)))
 400     (cond ((= 1 solitaire-stones)
 401            (message "Yeah! You made it! Only the King is left!"))
 402           ((zerop moves)
 403            (message "Sorry, no more possible moves."))
 404           ((= 1 moves)
 405            (message "There is one possible move."))
 406           (t (message "There are %d possible moves." moves)))))
 407
 408 (defun solitaire-current-line ()
 409   "Return the vertical position of point.
 410 Seen in info on text lines."
 411   (+ (count-lines (point-min) (point))
 412      (if (= (current-column) 0) 1 0)
 413      -1))
 414
 415 ;; And here's the spoiler:)
 416 (defun solitaire-solve ()
 417   "Spoil Solitaire by solving the game for you - nearly ...
 418 ... stops with five stones left ;)"
 419   (interactive)
 420   (when (< solitaire-stones 32)
 421     (error "Cannot solve game in progress"))
 422   (let ((allmoves [up up S-down up left left S-right up up left S-down
 423                       up up right right S-left down down down S-up up
 424                       S-down down down down S-up left left down
 425                       S-right left left up up S-down right right right
 426                       S-left left S-right right right right S-left
 427                       right down down S-up down down left left S-right
 428                       up up up S-down down S-up up up up S-down up
 429                       right right S-left down right right down S-up
 430                       left left left S-right right S-left down down
 431                       left S-right S-up S-left S-left S-down S-right
 432                       up S-right left left])
 433         ;; down down S-up left S-right
 434         ;; right S-left
 435         (solitaire-auto-eval nil))
 436     (solitaire-center-point)
 437     (mapc (lambda (op)
 438             (when (memq op '(S-left S-right S-up S-down))
 439               (sit-for 0.2))
 440             (execute-kbd-macro (vector op))
 441             (when (memq op '(S-left S-right S-up S-down))
 442               (sit-for 0.4)))
 443           allmoves))
 444   (solitaire-do-check))
 445
 446 (provide 'solitaire)
 447
 448 ;;; solitaire.el ends here