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1 ;;; gomoku.el --- Gomoku game between you and Emacs
3 ;; Copyright (C) 1988, 1994, 1996 Free Software Foundation, Inc.
5 ;; Author: Philippe Schnoebelen <phs@lsv.ens-cachan.fr>
6 ;; Adapted-By: ESR, Daniel Pfeiffer <occitan@esperanto.org>
7 ;; Keywords: games
9 ;; This file is part of GNU Emacs.
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 2, or (at your option)
14 ;; any later version.
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.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs; see the file COPYING. If not, write to the
23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
24 ;; Boston, MA 02111-1307, USA.
26 ;;; Commentary:
28 ;; RULES:
29 ;;
30 ;; Gomoku is a game played between two players on a rectangular board. Each
31 ;; player, in turn, marks a free square of its choice. The winner is the first
32 ;; one to mark five contiguous squares in any direction (horizontally,
33 ;; vertically or diagonally).
34 ;;
35 ;; I have been told that, in "The TRUE Gomoku", some restrictions are made
36 ;; about the squares where one may play, or else there is a known forced win
37 ;; for the first player. This program has no such restriction, but it does not
38 ;; know about the forced win, nor do I. Furthermore, you probably do not know
39 ;; it yourself :-).
42 ;; There are two main places where you may want to customize the program: key
43 ;; bindings and board display. These features are commented in the code. Go
44 ;; and see.
47 ;; HOW TO USE:
48 ;;
49 ;; The command "M-x gomoku" displays a
50 ;; board, the size of which depends on the size of the current window. The
51 ;; size of the board is easily modified by giving numeric arguments to the
52 ;; gomoku command and/or by customizing the displaying parameters.
53 ;;
54 ;; Emacs plays when it is its turn. When it is your turn, just put the cursor
55 ;; on the square where you want to play and hit RET, or X, or whatever key you
56 ;; bind to the command gomoku-human-plays. When it is your turn, Emacs is
57 ;; idle: you may switch buffers, read your mail, ... Just come back to the
58 ;; *Gomoku* buffer and resume play.
61 ;; ALGORITHM:
62 ;;
63 ;; The algorithm is briefly described in section "THE SCORE TABLE". Some
64 ;; parameters may be modified if you want to change the style exhibited by the
65 ;; program.
67 ;;; Code:
68 \f
70 "Gomoku game between you and Emacs."
73 ;;;
74 ;;; GOMOKU MODE AND KEYMAP.
75 ;;;
77 "If non-nil, its value is called on entry to Gomoku mode.
78 One useful value to include is `turn-on-font-lock' to highlight the pieces."
88 ;; Key bindings for cursor motion.
110 ;; Key bindings for entering Human moves.
122 (define-key gomoku-mode-map [down-mouse-1] 'gomoku-click)
123 (define-key gomoku-mode-map [drag-mouse-1] 'gomoku-click)
124 (define-key gomoku-mode-map [mouse-1] 'gomoku-click)
125 (define-key gomoku-mode-map [down-mouse-2] 'gomoku-click)
126 (define-key gomoku-mode-map [mouse-2] 'gomoku-mouse-play)
127 (define-key gomoku-mode-map [drag-mouse-2] 'gomoku-mouse-play)
129 (substitute-key-definition 'previous-line 'gomoku-move-up
130 gomoku-mode-map (current-global-map))
131 (substitute-key-definition 'next-line 'gomoku-move-down
132 gomoku-mode-map (current-global-map))
133 (substitute-key-definition 'beginning-of-line 'gomoku-beginning-of-line
134 gomoku-mode-map (current-global-map))
135 (substitute-key-definition 'end-of-line 'gomoku-end-of-line
136 gomoku-mode-map (current-global-map))
137 (substitute-key-definition 'undo 'gomoku-human-takes-back
138 gomoku-mode-map (current-global-map))
139 (substitute-key-definition 'advertised-undo 'gomoku-human-takes-back
140 gomoku-mode-map (current-global-map)))
142 (defvar gomoku-emacs-won ()
143 "For making font-lock use the winner's face for the line.")
145 (defcustom gomoku-font-lock-O-face
146 (if window-system
147 (list (facemenu-get-face 'fg:red) 'bold))
148 "*Face to use for Emacs' O."
149 :type '(repeat face)
150 :group 'gomoku)
152 (defcustom gomoku-font-lock-X-face
153 (if window-system
154 (list (facemenu-get-face 'fg:green) 'bold))
155 "*Face to use for your X."
156 :type '(repeat face)
157 :group 'gomoku)
159 (defvar gomoku-font-lock-keywords
160 '(("O" . gomoku-font-lock-O-face)
161 ("X" . gomoku-font-lock-X-face)
163 gomoku-font-lock-O-face
164 gomoku-font-lock-X-face)))
165 "*Font lock rules for Gomoku.")
167 (put 'gomoku-mode 'front-sticky
168 (put 'gomoku-mode 'rear-nonsticky '(intangible)))
169 (put 'gomoku-mode 'intangible 1)
171 (defun gomoku-mode ()
172 "Major mode for playing Gomoku against Emacs.
173 You and Emacs play in turn by marking a free square. You mark it with X
174 and Emacs marks it with O. The winner is the first to get five contiguous
175 marks horizontally, vertically or in diagonal.
179 Other useful commands:
181 Entry to this mode calls the value of `gomoku-mode-hook' if that value
182 is non-nil. One interesting value is `turn-on-font-lock'."
183 (interactive)
184 (setq major-mode 'gomoku-mode
185 mode-name "Gomoku")
186 (gomoku-display-statistics)
187 (use-local-map gomoku-mode-map)
188 (make-local-variable 'font-lock-defaults)
189 (setq font-lock-defaults '(gomoku-font-lock-keywords t))
190 (toggle-read-only t)
191 (run-hooks 'gomoku-mode-hook))
192 \f
193 ;;;
194 ;;; THE BOARD.
195 ;;;
197 ;; The board is a rectangular grid. We code empty squares with 0, X's with 1
198 ;; and O's with 6. The rectangle is recorded in a one dimensional vector
199 ;; containing padding squares (coded with -1). These squares allow us to
200 ;; detect when we are trying to move out of the board. We denote a square by
201 ;; its (X,Y) coords, or by the INDEX corresponding to them in the vector. The
202 ;; leftmost topmost square has coords (1,1) and index gomoku-board-width + 2.
203 ;; Similarly, vectors between squares may be given by two DX, DY coords or by
204 ;; one DEPL (the difference between indexes).
206 (defvar gomoku-board-width nil
207 "Number of columns on the Gomoku board.")
209 (defvar gomoku-board-height nil
210 "Number of lines on the Gomoku board.")
212 (defvar gomoku-board nil
213 "Vector recording the actual state of the Gomoku board.")
215 (defvar gomoku-vector-length nil
216 "Length of gomoku-board vector.")
218 (defvar gomoku-draw-limit nil
219 ;; This is usually set to 70% of the number of squares.
220 "After how many moves will Emacs offer a draw?")
223 (defun gomoku-xy-to-index (x y)
224 "Translate X, Y cartesian coords into the corresponding board index."
225 (+ (* y gomoku-board-width) x y))
227 (defun gomoku-index-to-x (index)
228 "Return corresponding x-coord of board INDEX."
229 (% index (1+ gomoku-board-width)))
231 (defun gomoku-index-to-y (index)
232 "Return corresponding y-coord of board INDEX."
233 (/ index (1+ gomoku-board-width)))
235 (defun gomoku-init-board ()
236 "Create the gomoku-board vector and fill it with initial values."
237 (setq gomoku-board (make-vector gomoku-vector-length 0))
238 ;; Every square is 0 (i.e. empty) except padding squares:
239 (let ((i 0) (ii (1- gomoku-vector-length)))
240 (while (<= i gomoku-board-width) ; The squares in [0..width] and in
241 (aset gomoku-board i -1) ; [length - width - 1..length - 1]
242 (aset gomoku-board ii -1) ; are padding squares.
243 (setq i (1+ i)
244 ii (1- ii))))
245 (let ((i 0))
246 (while (< i gomoku-vector-length)
247 (aset gomoku-board i -1) ; and also all k*(width+1)
248 (setq i (+ i gomoku-board-width 1)))))
249 \f
250 ;;;
251 ;;; THE SCORE TABLE.
252 ;;;
254 ;; Every (free) square has a score associated to it, recorded in the
255 ;; GOMOKU-SCORE-TABLE vector. The program always plays in the square having
256 ;; the highest score.
258 (defvar gomoku-score-table nil
259 "Vector recording the actual score of the free squares.")
262 ;; The key point point about the algorithm is that, rather than considering
263 ;; the board as just a set of squares, we prefer to see it as a "space" of
264 ;; internested 5-tuples of contiguous squares (called qtuples).
265 ;;
266 ;; The aim of the program is to fill one qtuple with its O's while preventing
267 ;; you from filling another one with your X's. To that effect, it computes a
268 ;; score for every qtuple, with better qtuples having better scores. Of
269 ;; course, the score of a qtuple (taken in isolation) is just determined by
270 ;; its contents as a set, i.e. not considering the order of its elements. The
271 ;; highest score is given to the "OOOO" qtuples because playing in such a
272 ;; qtuple is winning the game. Just after this comes the "XXXX" qtuple because
273 ;; not playing in it is just loosing the game, and so on. Note that a
274 ;; "polluted" qtuple, i.e. one containing at least one X and at least one O,
275 ;; has score zero because there is no more any point in playing in it, from
276 ;; both an attacking and a defending point of view.
277 ;;
278 ;; Given the score of every qtuple, the score of a given free square on the
279 ;; board is just the sum of the scores of all the qtuples to which it belongs,
280 ;; because playing in that square is playing in all its containing qtuples at
281 ;; once. And it is that function which takes into account the internesting of
282 ;; the qtuples.
283 ;;
284 ;; This algorithm is rather simple but anyway it gives a not so dumb level of
285 ;; play. It easily extends to "n-dimensional Gomoku", where a win should not
286 ;; be obtained with as few as 5 contiguous marks: 6 or 7 (depending on n !)
287 ;; should be preferred.
290 ;; Here are the scores of the nine "non-polluted" configurations. Tuning
291 ;; these values will change (hopefully improve) the strength of the program
292 ;; and may change its style (rather aggressive here).
294 (defconst nil-score 7 "Score of an empty qtuple.")
295 (defconst Xscore 15 "Score of a qtuple containing one X.")
296 (defconst XXscore 400 "Score of a qtuple containing two X's.")
297 (defconst XXXscore 1800 "Score of a qtuple containing three X's.")
298 (defconst XXXXscore 100000 "Score of a qtuple containing four X's.")
299 (defconst Oscore 35 "Score of a qtuple containing one O.")
300 (defconst OOscore 800 "Score of a qtuple containing two O's.")
301 (defconst OOOscore 15000 "Score of a qtuple containing three O's.")
302 (defconst OOOOscore 800000 "Score of a qtuple containing four O's.")
304 ;; These values are not just random: if, given the following situation:
305 ;;
306 ;; . . . . . . . O .
307 ;; . X X a . . . X .
308 ;; . . . X . . . X .
309 ;; . . . X . . . X .
310 ;; . . . . . . . b .
311 ;;
312 ;; you want Emacs to play in "a" and not in "b", then the parameters must
313 ;; satisfy the inequality:
314 ;;
315 ;; 6 * XXscore > XXXscore + XXscore
316 ;;
317 ;; because "a" mainly belongs to six "XX" qtuples (the others are less
318 ;; important) while "b" belongs to one "XXX" and one "XX" qtuples. Other
319 ;; conditions are required to obtain sensible moves, but the previous example
320 ;; should illustrate the point. If you manage to improve on these values,
321 ;; please send me a note. Thanks.
324 ;; As we chose values 0, 1 and 6 to denote empty, X and O squares, the
325 ;; contents of a qtuple are uniquely determined by the sum of its elements and
326 ;; we just have to set up a translation table.
328 (defconst gomoku-score-trans-table
329 (vector nil-score Xscore XXscore XXXscore XXXXscore 0
330 Oscore 0 0 0 0 0
331 OOscore 0 0 0 0 0
332 OOOscore 0 0 0 0 0
333 OOOOscore 0 0 0 0 0
334 0)
335 "Vector associating qtuple contents to their score.")
338 ;; If you do not modify drastically the previous constants, the only way for a
339 ;; square to have a score higher than OOOOscore is to belong to a "OOOO"
340 ;; qtuple, thus to be a winning move. Similarly, the only way for a square to
341 ;; have a score between XXXXscore and OOOOscore is to belong to a "XXXX"
342 ;; qtuple. We may use these considerations to detect when a given move is
343 ;; winning or loosing.
345 (defconst gomoku-winning-threshold OOOOscore
346 "Threshold score beyond which an Emacs move is winning.")
348 (defconst gomoku-loosing-threshold XXXXscore
349 "Threshold score beyond which a human move is winning.")
352 (defun gomoku-strongest-square ()
353 "Compute index of free square with highest score, or nil if none."
354 ;; We just have to loop other all squares. However there are two problems:
355 ;; 1/ The SCORE-TABLE only gives correct scores to free squares. To speed
356 ;; up future searches, we set the score of padding or occupied squares
357 ;; to -1 whenever we meet them.
358 ;; 2/ We want to choose randomly between equally good moves.
359 (let ((score-max 0)
360 (count 0) ; Number of equally good moves
361 (square (gomoku-xy-to-index 1 1)) ; First square
362 (end (gomoku-xy-to-index gomoku-board-width gomoku-board-height))
363 best-square score)
364 (while (<= square end)
365 (cond
366 ;; If score is lower (i.e. most of the time), skip to next:
367 ((< (aref gomoku-score-table square) score-max))
368 ;; If score is better, beware of non free squares:
369 ((> (setq score (aref gomoku-score-table square)) score-max)
370 (if (zerop (aref gomoku-board square)) ; is it free ?
371 (setq count 1 ; yes: take it !
372 best-square square
373 score-max score)
374 (aset gomoku-score-table square -1))) ; no: kill it !
375 ;; If score is equally good, choose randomly. But first check freeness:
376 ((not (zerop (aref gomoku-board square)))
377 (aset gomoku-score-table square -1))
378 ((zerop (random (setq count (1+ count))))
379 (setq best-square square
380 score-max score)))
381 (setq square (1+ square))) ; try next square
382 best-square))
383 \f
384 ;;;
385 ;;; INITIALIZING THE SCORE TABLE.
386 ;;;
388 ;; At initialization the board is empty so that every qtuple amounts for
389 ;; nil-score. Therefore, the score of any square is nil-score times the number
390 ;; of qtuples that pass through it. This number is 3 in a corner and 20 if you
391 ;; are sufficiently far from the sides. As computing the number is time
392 ;; consuming, we initialize every square with 20*nil-score and then only
393 ;; consider squares at less than 5 squares from one side. We speed this up by
394 ;; taking symmetry into account.
395 ;; Also, as it is likely that successive games will be played on a board with
396 ;; same size, it is a good idea to save the initial SCORE-TABLE configuration.
398 (defvar gomoku-saved-score-table nil
399 "Recorded initial value of previous score table.")
401 (defvar gomoku-saved-board-width nil
402 "Recorded value of previous board width.")
404 (defvar gomoku-saved-board-height nil
405 "Recorded value of previous board height.")
408 (defun gomoku-init-score-table ()
409 "Create the score table vector and fill it with initial values."
410 (if (and gomoku-saved-score-table ; Has it been stored last time ?
411 (= gomoku-board-width gomoku-saved-board-width)
412 (= gomoku-board-height gomoku-saved-board-height))
413 (setq gomoku-score-table (copy-sequence gomoku-saved-score-table))
414 ;; No, compute it:
415 (setq gomoku-score-table
416 (make-vector gomoku-vector-length (* 20 nil-score)))
417 (let (i j maxi maxj maxi2 maxj2)
418 (setq maxi (/ (1+ gomoku-board-width) 2)
419 maxj (/ (1+ gomoku-board-height) 2)
420 maxi2 (min 4 maxi)
421 maxj2 (min 4 maxj))
422 ;; We took symmetry into account and could use it more if the board
423 ;; would have been square and not rectangular !
424 ;; In our case we deal with all (i,j) in the set [1..maxi2]*[1..maxj] U
425 ;; [maxi2+1..maxi]*[1..maxj2]. Maxi2 and maxj2 are used because the
426 ;; board may well be less than 8 by 8 !
427 (setq i 1)
428 (while (<= i maxi2)
429 (setq j 1)
430 (while (<= j maxj)
431 (gomoku-init-square-score i j)
432 (setq j (1+ j)))
433 (setq i (1+ i)))
434 (while (<= i maxi)
435 (setq j 1)
436 (while (<= j maxj2)
437 (gomoku-init-square-score i j)
438 (setq j (1+ j)))
439 (setq i (1+ i))))
440 (setq gomoku-saved-score-table (copy-sequence gomoku-score-table)
441 gomoku-saved-board-width gomoku-board-width
442 gomoku-saved-board-height gomoku-board-height)))
444 (defun gomoku-nb-qtuples (i j)
445 "Return the number of qtuples containing square I,J."
446 ;; This function is complicated because we have to deal
447 ;; with ugly cases like 3 by 6 boards, but it works.
448 ;; If you have a simpler (and correct) solution, send it to me. Thanks !
449 (let ((left (min 4 (1- i)))
450 (right (min 4 (- gomoku-board-width i)))
451 (up (min 4 (1- j)))
452 (down (min 4 (- gomoku-board-height j))))
453 (+ -12
454 (min (max (+ left right) 3) 8)
455 (min (max (+ up down) 3) 8)
456 (min (max (+ (min left up) (min right down)) 3) 8)
457 (min (max (+ (min right up) (min left down)) 3) 8))))
459 (defun gomoku-init-square-score (i j)
460 "Give initial score to square I,J and to its mirror images."
461 (let ((ii (1+ (- gomoku-board-width i)))
462 (jj (1+ (- gomoku-board-height j)))
463 (sc (* (gomoku-nb-qtuples i j) (aref gomoku-score-trans-table 0))))
464 (aset gomoku-score-table (gomoku-xy-to-index i j) sc)
465 (aset gomoku-score-table (gomoku-xy-to-index ii j) sc)
466 (aset gomoku-score-table (gomoku-xy-to-index i jj) sc)
467 (aset gomoku-score-table (gomoku-xy-to-index ii jj) sc)))
468 \f
469 ;;;
470 ;;; MAINTAINING THE SCORE TABLE.
471 ;;;
473 ;; We do not provide functions for computing the SCORE-TABLE given the
474 ;; contents of the BOARD. This would involve heavy nested loops, with time
475 ;; proportional to the size of the board. It is better to update the
476 ;; SCORE-TABLE after each move. Updating needs not modify more than 36
477 ;; squares: it is done in constant time.
479 (defun gomoku-update-score-table (square dval)
480 "Update score table after SQUARE received a DVAL increment."
481 ;; The board has already been updated when this function is called.
482 ;; Updating scores is done by looking for qtuples boundaries in all four
483 ;; directions and then calling update-score-in-direction.
484 ;; Finally all squares received the right increment, and then are up to
485 ;; date, except possibly for SQUARE itself if we are taking a move back for
486 ;; its score had been set to -1 at the time.
487 (let* ((x (gomoku-index-to-x square))
488 (y (gomoku-index-to-y square))
489 (imin (max -4 (- 1 x)))
490 (jmin (max -4 (- 1 y)))
491 (imax (min 0 (- gomoku-board-width x 4)))
492 (jmax (min 0 (- gomoku-board-height y 4))))
493 (gomoku-update-score-in-direction imin imax
494 square 1 0 dval)
495 (gomoku-update-score-in-direction jmin jmax
496 square 0 1 dval)
497 (gomoku-update-score-in-direction (max imin jmin) (min imax jmax)
498 square 1 1 dval)
499 (gomoku-update-score-in-direction (max (- 1 y) -4
500 (- x gomoku-board-width))
501 (min 0 (- x 5)
502 (- gomoku-board-height y 4))
503 square -1 1 dval)))
505 (defun gomoku-update-score-in-direction (left right square dx dy dval)
506 "Update scores for all squares in the qtuples starting between the LEFTth
507 square and the RIGHTth after SQUARE, along the DX, DY direction, considering
508 that DVAL has been added on SQUARE."
509 ;; We always have LEFT <= 0, RIGHT <= 0 and DEPL > 0 but we may very well
510 ;; have LEFT > RIGHT, indicating that no qtuple contains SQUARE along that
511 ;; DX,DY direction.
512 (cond
513 ((> left right)) ; Quit
514 (t ; Else ..
515 (let (depl square0 square1 square2 count delta)
516 (setq depl (gomoku-xy-to-index dx dy)
517 square0 (+ square (* left depl))
518 square1 (+ square (* right depl))
519 square2 (+ square0 (* 4 depl)))
520 ;; Compute the contents of the first qtuple:
521 (setq square square0
522 count 0)
523 (while (<= square square2)
524 (setq count (+ count (aref gomoku-board square))
525 square (+ square depl)))
526 (while (<= square0 square1)
527 ;; Update the squares of the qtuple beginning in SQUARE0 and ending
528 ;; in SQUARE2.
529 (setq delta (- (aref gomoku-score-trans-table count)
530 (aref gomoku-score-trans-table (- count dval))))
531 (cond ((not (zerop delta)) ; or else nothing to update
532 (setq square square0)
533 (while (<= square square2)
534 (if (zerop (aref gomoku-board square)) ; only for free squares
535 (aset gomoku-score-table square
536 (+ (aref gomoku-score-table square) delta)))
537 (setq square (+ square depl)))))
538 ;; Then shift the qtuple one square along DEPL, this only requires
539 ;; modifying SQUARE0 and SQUARE2.
540 (setq square2 (+ square2 depl)
541 count (+ count (- (aref gomoku-board square0))
542 (aref gomoku-board square2))
543 square0 (+ square0 depl)))))))
544 \f
545 ;;;
546 ;;; GAME CONTROL.
547 ;;;
549 ;; Several variables are used to monitor a game, including a GAME-HISTORY (the
550 ;; list of all (SQUARE . PREVSCORE) played) that allows to take moves back
551 ;; (anti-updating the score table) and to compute the table from scratch in
552 ;; case of an interruption.
554 (defvar gomoku-game-in-progress nil
555 "Non-nil if a game is in progress.")
557 (defvar gomoku-game-history nil
558 "A record of all moves that have been played during current game.")
560 (defvar gomoku-number-of-moves nil
561 "Number of moves already played in current game.")
563 (defvar gomoku-number-of-human-moves nil
564 "Number of moves already played by human in current game.")
566 (defvar gomoku-emacs-played-first nil
567 "Non-nil if Emacs played first.")
569 (defvar gomoku-human-took-back nil
570 "Non-nil if Human took back a move during the game.")
572 (defvar gomoku-human-refused-draw nil
573 "Non-nil if Human refused Emacs offer of a draw.")
575 (defvar gomoku-emacs-is-computing nil
576 ;; This is used to detect interruptions. Hopefully, it should not be needed.
577 "Non-nil if Emacs is in the middle of a computation.")
580 (defun gomoku-start-game (n m)
581 "Initialize a new game on an N by M board."
582 (setq gomoku-emacs-is-computing t) ; Raise flag
583 (setq gomoku-game-in-progress t)
584 (setq gomoku-board-width n
585 gomoku-board-height m
586 gomoku-vector-length (1+ (* (+ m 2) (1+ n)))
587 gomoku-draw-limit (/ (* 7 n m) 10))
588 (setq gomoku-emacs-won nil
589 gomoku-game-history nil
590 gomoku-number-of-moves 0
591 gomoku-number-of-human-moves 0
592 gomoku-emacs-played-first nil
593 gomoku-human-took-back nil
594 gomoku-human-refused-draw nil)
595 (gomoku-init-display n m) ; Display first: the rest takes time
596 (gomoku-init-score-table) ; INIT-BOARD requires that the score
597 (gomoku-init-board) ; table be already created.
598 (setq gomoku-emacs-is-computing nil))
600 (defun gomoku-play-move (square val &optional dont-update-score)
601 "Go to SQUARE, play VAL and update everything."
602 (setq gomoku-emacs-is-computing t) ; Raise flag
603 (cond ((= 1 val) ; a Human move
604 (setq gomoku-number-of-human-moves (1+ gomoku-number-of-human-moves)))
605 ((zerop gomoku-number-of-moves) ; an Emacs move. Is it first ?
606 (setq gomoku-emacs-played-first t)))
607 (setq gomoku-game-history
608 (cons (cons square (aref gomoku-score-table square))
609 gomoku-game-history)
610 gomoku-number-of-moves (1+ gomoku-number-of-moves))
611 (gomoku-plot-square square val)
612 (aset gomoku-board square val) ; *BEFORE* UPDATE-SCORE !
613 (if dont-update-score nil
614 (gomoku-update-score-table square val) ; previous val was 0: dval = val
615 (aset gomoku-score-table square -1))
616 (setq gomoku-emacs-is-computing nil))
618 (defun gomoku-take-back ()
619 "Take back last move and update everything."
620 (setq gomoku-emacs-is-computing t)
621 (let* ((last-move (car gomoku-game-history))
622 (square (car last-move))
623 (oldval (aref gomoku-board square)))
624 (if (= 1 oldval)
625 (setq gomoku-number-of-human-moves (1- gomoku-number-of-human-moves)))
626 (setq gomoku-game-history (cdr gomoku-game-history)
627 gomoku-number-of-moves (1- gomoku-number-of-moves))
628 (gomoku-plot-square square 0)
629 (aset gomoku-board square 0) ; *BEFORE* UPDATE-SCORE !
630 (gomoku-update-score-table square (- oldval))
631 (aset gomoku-score-table square (cdr last-move)))
632 (setq gomoku-emacs-is-computing nil))
633 \f
634 ;;;
635 ;;; SESSION CONTROL.
636 ;;;
638 (defvar gomoku-number-of-emacs-wins 0
639 "Number of games Emacs won in this session.")
641 (defvar gomoku-number-of-human-wins 0
642 "Number of games you won in this session.")
644 (defvar gomoku-number-of-draws 0
645 "Number of games already drawn in this session.")
648 (defun gomoku-terminate-game (result)
649 "Terminate the current game with RESULT."
650 (message
651 (cond
652 ((eq result 'emacs-won)
653 (setq gomoku-number-of-emacs-wins (1+ gomoku-number-of-emacs-wins))
654 (cond ((< gomoku-number-of-moves 20)
655 "This was a REALLY QUICK win.")
656 (gomoku-human-refused-draw
657 "I won... Too bad you refused my offer of a draw !")
658 (gomoku-human-took-back
659 "I won... Taking moves back will not help you !")
660 ((not gomoku-emacs-played-first)
661 "I won... Playing first did not help you much !")
662 ((and (zerop gomoku-number-of-human-wins)
663 (zerop gomoku-number-of-draws)
664 (> gomoku-number-of-emacs-wins 1))
665 "I'm becoming tired of winning...")
666 ("I won.")))
667 ((eq result 'human-won)
668 (setq gomoku-number-of-human-wins (1+ gomoku-number-of-human-wins))
669 (concat "OK, you won this one."
670 (cond
671 (gomoku-human-took-back
672 " I, for one, never take my moves back...")
673 (gomoku-emacs-played-first
674 ".. so what ?")
675 (" Now, let me play first just once."))))
676 ((eq result 'human-resigned)
677 (setq gomoku-number-of-emacs-wins (1+ gomoku-number-of-emacs-wins))
678 "So you resign. That's just one more win for me.")
679 ((eq result 'nobody-won)
680 (setq gomoku-number-of-draws (1+ gomoku-number-of-draws))
681 (concat "This is a draw. "
682 (cond
683 (gomoku-human-took-back
684 "I, for one, never take my moves back...")
685 (gomoku-emacs-played-first
686 "Just chance, I guess.")
687 ("Now, let me play first just once."))))
688 ((eq result 'draw-agreed)
689 (setq gomoku-number-of-draws (1+ gomoku-number-of-draws))
690 (concat "Draw agreed. "
691 (cond
692 (gomoku-human-took-back
693 "I, for one, never take my moves back...")
694 (gomoku-emacs-played-first
695 "You were lucky.")
696 ("Now, let me play first just once."))))
697 ((eq result 'crash-game)
698 "Sorry, I have been interrupted and cannot resume that game...")))
699 (gomoku-display-statistics)
700 ;;(ding)
701 (setq gomoku-game-in-progress nil))
703 (defun gomoku-crash-game ()
704 "What to do when Emacs detects it has been interrupted."
705 (setq gomoku-emacs-is-computing nil)
706 (gomoku-terminate-game 'crash-game)
707 (sit-for 4) ; Let's see the message
708 (gomoku-prompt-for-other-game))
709 \f
710 ;;;
711 ;;; INTERACTIVE COMMANDS.
712 ;;;
714 ;;;###autoload
715 (defun gomoku (&optional n m)
716 "Start a Gomoku game between you and Emacs.
717 If a game is in progress, this command allow you to resume it.
718 If optional arguments N and M are given, an N by M board is used.
719 If prefix arg is given for N, M is prompted for.
721 You and Emacs play in turn by marking a free square. You mark it with X
722 and Emacs marks it with O. The winner is the first to get five contiguous
723 marks horizontally, vertically or in diagonal.
725 You play by moving the cursor over the square you choose and hitting
728 (interactive (if current-prefix-arg
729 (list (prefix-numeric-value current-prefix-arg)
730 (eval (read-minibuffer "Height: ")))))
731 (gomoku-switch-to-window)
732 (cond
733 (gomoku-emacs-is-computing
734 (gomoku-crash-game))
735 ((or (not gomoku-game-in-progress)
736 (<= gomoku-number-of-moves 2))
737 (let ((max-width (gomoku-max-width))
738 (max-height (gomoku-max-height)))
739 (or n (setq n max-width))
740 (or m (setq m max-height))
741 (cond ((< n 1)
742 (error "I need at least 1 column"))
743 ((< m 1)
744 (error "I need at least 1 row"))
745 ((> n max-width)
746 (error "I cannot display %d columns in that window" n)))
747 (if (and (> m max-height)
748 (not (eq m gomoku-saved-board-height))
749 ;; Use EQ because SAVED-BOARD-HEIGHT may be nil
750 (not (y-or-n-p (format "Do you really want %d rows " m))))
751 (setq m max-height)))
752 (message "One moment, please...")
753 (gomoku-start-game n m)
754 (if (y-or-n-p "Do you allow me to play first ")
755 (gomoku-emacs-plays)
756 (gomoku-prompt-for-move)))
757 ((y-or-n-p "Shall we continue our game ")
758 (gomoku-prompt-for-move))
759 (t
760 (gomoku-human-resigns))))
762 (defun gomoku-emacs-plays ()
763 "Compute Emacs next move and play it."
764 (interactive)
765 (gomoku-switch-to-window)
766 (cond
767 (gomoku-emacs-is-computing
768 (gomoku-crash-game))
769 ((not gomoku-game-in-progress)
770 (gomoku-prompt-for-other-game))
771 (t
772 (message "Let me think...")
773 (let (square score)
774 (setq square (gomoku-strongest-square))
775 (cond ((null square)
776 (gomoku-terminate-game 'nobody-won))
777 (t
778 (setq score (aref gomoku-score-table square))
779 (gomoku-play-move square 6)
780 (cond ((>= score gomoku-winning-threshold)
781 (setq gomoku-emacs-won t) ; for font-lock
782 (gomoku-find-filled-qtuple square 6)
783 (gomoku-terminate-game 'emacs-won))
784 ((zerop score)
785 (gomoku-terminate-game 'nobody-won))
786 ((and (> gomoku-number-of-moves gomoku-draw-limit)
787 (not gomoku-human-refused-draw)
788 (gomoku-offer-a-draw))
789 (gomoku-terminate-game 'draw-agreed))
790 (t
791 (gomoku-prompt-for-move)))))))))
793 ;; For small square dimensions this is approximate, since though measured in
794 ;; pixels, event's (X . Y) is a character's top-left corner.
795 (defun gomoku-click (click)
796 "Position at the square where you click."
797 (interactive "e")
798 (and (windowp (posn-window (setq click (event-end click))))
799 (numberp (posn-point click))
800 (select-window (posn-window click))
801 (setq click (posn-col-row click))
802 (gomoku-goto-xy
803 (min (max (/ (+ (- (car click)
804 gomoku-x-offset
805 1)
806 (window-hscroll)
807 gomoku-square-width
808 (% gomoku-square-width 2)
809 (/ gomoku-square-width 2))
810 gomoku-square-width)
811 1)
812 gomoku-board-width)
813 (min (max (/ (+ (- (cdr click)
814 gomoku-y-offset
815 1)
816 (let ((inhibit-point-motion-hooks t))
817 (count-lines 1 (window-start)))
818 gomoku-square-height
819 (% gomoku-square-height 2)
820 (/ gomoku-square-height 2))
821 gomoku-square-height)
822 1)
823 gomoku-board-height))))
825 (defun gomoku-mouse-play (click)
826 "Play at the square where you click."
827 (interactive "e")
828 (if (gomoku-click click)
829 (gomoku-human-plays)))
831 (defun gomoku-human-plays ()
832 "Signal to the Gomoku program that you have played.
833 You must have put the cursor on the square where you want to play.
834 If the game is finished, this command requests for another game."
835 (interactive)
836 (gomoku-switch-to-window)
837 (cond
838 (gomoku-emacs-is-computing
839 (gomoku-crash-game))
840 ((not gomoku-game-in-progress)
841 (gomoku-prompt-for-other-game))
842 (t
843 (let (square score)
844 (setq square (gomoku-point-square))
845 (cond ((null square)
846 (error "Your point is not on a square. Retry !"))
847 ((not (zerop (aref gomoku-board square)))
848 (error "Your point is not on a free square. Retry !"))
849 (t
850 (setq score (aref gomoku-score-table square))
851 (gomoku-play-move square 1)
852 (cond ((and (>= score gomoku-loosing-threshold)
853 ;; Just testing SCORE > THRESHOLD is not enough for
854 ;; detecting wins, it just gives an indication that
855 ;; we confirm with GOMOKU-FIND-FILLED-QTUPLE.
856 (gomoku-find-filled-qtuple square 1))
857 (gomoku-terminate-game 'human-won))
858 (t
859 (gomoku-emacs-plays)))))))))
861 (defun gomoku-human-takes-back ()
862 "Signal to the Gomoku program that you wish to take back your last move."
863 (interactive)
864 (gomoku-switch-to-window)
865 (cond
866 (gomoku-emacs-is-computing
867 (gomoku-crash-game))
868 ((not gomoku-game-in-progress)
869 (message "Too late for taking back...")
870 (sit-for 4)
871 (gomoku-prompt-for-other-game))
872 ((zerop gomoku-number-of-human-moves)
873 (message "You have not played yet... Your move ?"))
874 (t
875 (message "One moment, please...")
876 ;; It is possible for the user to let Emacs play several consecutive
877 ;; moves, so that the best way to know when to stop taking back moves is
878 ;; to count the number of human moves:
879 (setq gomoku-human-took-back t)
880 (let ((number gomoku-number-of-human-moves))
881 (while (= number gomoku-number-of-human-moves)
882 (gomoku-take-back)))
883 (gomoku-prompt-for-move))))
885 (defun gomoku-human-resigns ()
886 "Signal to the Gomoku program that you may want to resign."
887 (interactive)
888 (gomoku-switch-to-window)
889 (cond
890 (gomoku-emacs-is-computing
891 (gomoku-crash-game))
892 ((not gomoku-game-in-progress)
893 (message "There is no game in progress"))
894 ((y-or-n-p "You mean, you resign ")
895 (gomoku-terminate-game 'human-resigned))
896 ((y-or-n-p "You mean, we continue ")
897 (gomoku-prompt-for-move))
898 (t
899 (gomoku-terminate-game 'human-resigned)))) ; OK. Accept it
900 \f
901 ;;;
902 ;;; PROMPTING THE HUMAN PLAYER.
903 ;;;
905 (defun gomoku-prompt-for-move ()
906 "Display a message asking for Human's move."
907 (message (if (zerop gomoku-number-of-human-moves)
908 "Your move ? (move to a free square and hit X, RET ...)"
909 "Your move ?"))
910 ;; This may seem silly, but if one omits the following line (or a similar
911 ;; one), the cursor may very well go to some place where POINT is not.
912 (save-excursion (set-buffer (other-buffer))))
914 (defun gomoku-prompt-for-other-game ()
915 "Ask for another game, and start it."
916 (if (y-or-n-p "Another game ")
917 (gomoku gomoku-board-width gomoku-board-height)
918 (message "Chicken !")))
920 (defun gomoku-offer-a-draw ()
921 "Offer a draw and return T if Human accepted it."
922 (or (y-or-n-p "I offer you a draw. Do you accept it ")
923 (not (setq gomoku-human-refused-draw t))))
924 \f
925 ;;;
926 ;;; DISPLAYING THE BOARD.
927 ;;;
929 ;; You may change these values if you have a small screen or if the squares
930 ;; look rectangular, but spacings SHOULD be at least 2 (MUST BE at least 1).
932 (defconst gomoku-square-width 4
933 "*Horizontal spacing between squares on the Gomoku board.")
935 (defconst gomoku-square-height 2
936 "*Vertical spacing between squares on the Gomoku board.")
938 (defconst gomoku-x-offset 3
939 "*Number of columns between the Gomoku board and the side of the window.")
941 (defconst gomoku-y-offset 1
942 "*Number of lines between the Gomoku board and the top of the window.")
945 (defun gomoku-max-width ()
946 "Largest possible board width for the current window."
947 (1+ (/ (- (window-width (selected-window))
948 gomoku-x-offset gomoku-x-offset 1)
949 gomoku-square-width)))
951 (defun gomoku-max-height ()
952 "Largest possible board height for the current window."
953 (1+ (/ (- (window-height (selected-window))
954 gomoku-y-offset gomoku-y-offset 2)
955 ;; 2 instead of 1 because WINDOW-HEIGHT includes the mode line !
956 gomoku-square-height)))
958 (defun gomoku-point-y ()
959 "Return the board row where point is."
960 (let ((inhibit-point-motion-hooks t))
961 (1+ (/ (- (count-lines 1 (point)) gomoku-y-offset (if (bolp) 0 1))
962 gomoku-square-height))))
964 (defun gomoku-point-square ()
965 "Return the index of the square point is on."
966 (let ((inhibit-point-motion-hooks t))
967 (gomoku-xy-to-index (1+ (/ (- (current-column) gomoku-x-offset)
968 gomoku-square-width))
969 (gomoku-point-y))))
971 (defun gomoku-goto-square (index)
972 "Move point to square number INDEX."
973 (gomoku-goto-xy (gomoku-index-to-x index) (gomoku-index-to-y index)))
975 (defun gomoku-goto-xy (x y)
976 "Move point to square at X, Y coords."
977 (let ((inhibit-point-motion-hooks t))
978 (goto-line (+ 1 gomoku-y-offset (* gomoku-square-height (1- y)))))
979 (move-to-column (+ gomoku-x-offset (* gomoku-square-width (1- x)))))
981 (defun gomoku-plot-square (square value)
982 "Draw 'X', 'O' or '.' on SQUARE depending on VALUE, leave point there."
983 (or (= value 1)
984 (gomoku-goto-square square))
985 (let ((inhibit-read-only t)
986 (inhibit-point-motion-hooks t))
987 (insert-and-inherit (cond ((= value 1) ?X)
988 ((= value 6) ?O)
989 (?.)))
990 (and window-system
991 (zerop value)
992 (put-text-property (1- (point)) (point) 'mouse-face 'highlight))
993 (delete-char 1)
994 (backward-char 1))
995 (sit-for 0)) ; Display NOW
997 (defun gomoku-init-display (n m)
998 "Display an N by M Gomoku board."
999 (buffer-disable-undo (current-buffer))
1000 (let ((inhibit-read-only t)
1001 (point 1) opoint
1002 (intangible t)
1003 (i m) j x)
1004 ;; Try to minimize number of chars (because of text properties)
1005 (setq tab-width
1006 (if (zerop (% gomoku-x-offset gomoku-square-width))
1007 gomoku-square-width
1008 (max (/ (+ (% gomoku-x-offset gomoku-square-width)
1009 gomoku-square-width 1) 2) 2)))
1010 (erase-buffer)
1011 (newline gomoku-y-offset)
1012 (while (progn
1013 (setq j n
1014 x (- gomoku-x-offset gomoku-square-width))
1015 (while (>= (setq j (1- j)) 0)
1017 (current-column))
1018 tab-width))
1019 (insert-char ? (- x (current-column)))
1020 (if (setq intangible (not intangible))
1021 (put-text-property point (point) 'intangible 2))
1022 (and (zerop j)
1023 (= i (- m 2))
1024 (progn
1025 (while (>= i 3)
1026 (append-to-buffer (current-buffer) opoint (point))
1027 (setq i (- i 2)))
1028 (goto-char (point-max))))
1029 (setq point (point))
1030 (insert ?.)
1031 (if window-system
1032 (put-text-property point (point)
1033 'mouse-face 'highlight)))
1034 (> (setq i (1- i)) 0))
1035 (if (= i (1- m))
1036 (setq opoint point))
1038 (or (eq (char-after 1) ?.)
1039 (put-text-property 1 2 'point-entered
1040 (lambda (x x) (if (bobp) (forward-char)))))
1041 (or intangible
1042 (put-text-property point (point) 'intangible 2))
1043 (put-text-property point (point) 'point-entered
1044 (lambda (x x) (if (eobp) (backward-char))))
1045 (put-text-property (point-min) (point) 'category 'gomoku-mode))
1046 (gomoku-goto-xy (/ (1+ n) 2) (/ (1+ m) 2)) ; center of the board
1047 (sit-for 0)) ; Display NOW
1049 (defun gomoku-display-statistics ()
1050 "Obnoxiously display some statistics about previous games in mode line."
1051 ;; We store this string in the mode-line-process local variable.
1052 ;; This is certainly not the cleanest way out ...
1053 (setq mode-line-process
1054 (format ": Won %d, lost %d%s"
1055 gomoku-number-of-human-wins
1056 gomoku-number-of-emacs-wins
1057 (if (zerop gomoku-number-of-draws)
1058 ""
1059 (format ", drew %d" gomoku-number-of-draws))))
1060 (force-mode-line-update))
1062 (defun gomoku-switch-to-window ()
1063 "Find or create the Gomoku buffer, and display it."
1064 (interactive)
1065 (let ((buff (get-buffer "*Gomoku*")))
1066 (if buff ; Buffer exists:
1067 (switch-to-buffer buff) ; no problem.
1068 (if gomoku-game-in-progress
1069 (gomoku-crash-game)) ; buffer has been killed or something
1070 (switch-to-buffer "*Gomoku*") ; Anyway, start anew.
1071 (gomoku-mode))))
1072 \f
1073 ;;;
1074 ;;; CROSSING WINNING QTUPLES.
1075 ;;;
1077 ;; When someone succeeds in filling a qtuple, we draw a line over the five
1078 ;; corresponding squares. One problem is that the program does not know which
1079 ;; squares ! It only knows the square where the last move has been played and
1080 ;; who won. The solution is to scan the board along all four directions.
1082 (defun gomoku-find-filled-qtuple (square value)
1083 "Return T if SQUARE belongs to a qtuple filled with VALUEs."
1084 (or (gomoku-check-filled-qtuple square value 1 0)
1085 (gomoku-check-filled-qtuple square value 0 1)
1086 (gomoku-check-filled-qtuple square value 1 1)
1087 (gomoku-check-filled-qtuple square value -1 1)))
1089 (defun gomoku-check-filled-qtuple (square value dx dy)
1090 "Return T if SQUARE belongs to a qtuple filled with VALUEs along DX, DY."
1091 (let ((a 0) (b 0)
1092 (left square) (right square)
1093 (depl (gomoku-xy-to-index dx dy)))
1094 (while (and (> a -4) ; stretch tuple left
1095 (= value (aref gomoku-board (setq left (- left depl)))))
1096 (setq a (1- a)))
1097 (while (and (< b (+ a 4)) ; stretch tuple right
1098 (= value (aref gomoku-board (setq right (+ right depl)))))
1099 (setq b (1+ b)))
1100 (cond ((= b (+ a 4)) ; tuple length = 5 ?
1101 (gomoku-cross-qtuple (+ square (* a depl)) (+ square (* b depl))
1102 dx dy)
1103 t))))
1105 (defun gomoku-cross-qtuple (square1 square2 dx dy)
1106 "Cross every square between SQUARE1 and SQUARE2 in the DX, DY direction."
1107 (save-excursion ; Not moving point from last square
1108 (let ((depl (gomoku-xy-to-index dx dy))
1109 (inhibit-read-only t)
1110 (inhibit-point-motion-hooks t))
1111 ;; WARNING: this function assumes DEPL > 0 and SQUARE2 > SQUARE1
1112 (while (/= square1 square2)
1113 (gomoku-goto-square square1)
1114 (setq square1 (+ square1 depl))
1115 (cond
1116 ((= dy 0) ; Horizontal
1117 (forward-char 1)
1118 (insert-char ?- (1- gomoku-square-width) t)
1119 (delete-region (point) (progn
1121 (point))))
1122 ((= dx 0) ; Vertical
1123 (let ((n 1)
1124 (column (current-column)))
1125 (while (< n gomoku-square-height)
1126 (setq n (1+ n))
1127 (forward-line 1)
1128 (indent-to column)
1129 (insert-and-inherit ?|))))
1130 ((= dx -1) ; 1st Diagonal
1131 (indent-to (prog1 (- (current-column) (/ gomoku-square-width 2))
1132 (forward-line (/ gomoku-square-height 2))))
1133 (insert-and-inherit ?/))
1134 (t ; 2nd Diagonal
1135 (indent-to (prog1 (+ (current-column) (/ gomoku-square-width 2))
1136 (forward-line (/ gomoku-square-height 2))))
1138 (sit-for 0)) ; Display NOW
1139 \f
1140 ;;;
1141 ;;; CURSOR MOTION.
1142 ;;;
1143 ;; previous-line and next-line don't work right with intangible newlines
1144 (defun gomoku-move-down ()
1145 "Move point down one row on the Gomoku board."
1146 (interactive)
1147 (if (< (gomoku-point-y) gomoku-board-height)
1148 (next-line gomoku-square-height)))
1150 (defun gomoku-move-up ()
1151 "Move point up one row on the Gomoku board."
1152 (interactive)
1153 (if (> (gomoku-point-y) 1)
1154 (previous-line gomoku-square-height)))
1156 (defun gomoku-move-ne ()
1157 "Move point North East on the Gomoku board."
1158 (interactive)
1159 (gomoku-move-up)
1160 (forward-char))
1162 (defun gomoku-move-se ()
1163 "Move point South East on the Gomoku board."
1164 (interactive)
1165 (gomoku-move-down)
1166 (forward-char))
1168 (defun gomoku-move-nw ()
1169 "Move point North West on the Gomoku board."
1170 (interactive)
1171 (gomoku-move-up)
1172 (backward-char))
1174 (defun gomoku-move-sw ()
1175 "Move point South West on the Gomoku board."
1176 (interactive)
1177 (gomoku-move-down)
1178 (backward-char))
1180 (defun gomoku-beginning-of-line ()
1181 "Move point to first square on the Gomoku board row."
1182 (interactive)
1183 (move-to-column gomoku-x-offset))
1185 (defun gomoku-end-of-line ()
1186 "Move point to last square on the Gomoku board row."
1187 (interactive)
1188 (move-to-column (+ gomoku-x-offset
1189 (* gomoku-square-width (1- gomoku-board-width)))))
1191 (provide 'gomoku)
1193 ;;; gomoku.el ends here