diff options
| -rw-r--r-- | chess-ai.el | 38 |
1 files changed, 27 insertions, 11 deletions
diff --git a/chess-ai.el b/chess-ai.el index 9847fca..f530a19 100644 --- a/chess-ai.el +++ b/chess-ai.el @@ -19,17 +19,21 @@ ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, ;; Boston, MA 02111-1307, USA. -;;; Commentary: - -;; BUGS: Opponent moves are not displayed on the board! But they are announced -;; and shown in the mode-line, strange! - ;;; Code: (require 'chess-common) (require 'chess-pos) (require 'chess-ply) +(defgroup chess-ai () + "A simple chess engine written in elisp." + :group 'chess) + +(defcustom chess-ai-depth 2 + "*The depth used to prune the search tree." + :group 'chess-ai + :type 'integer) + (defvar chess-pawn-value 100) (defvar chess-knight-value 300) (defvar chess-bishop-value 300) @@ -38,6 +42,7 @@ (defvar chess-king-value 10000) (defun chess-eval-static (position) + "Find the static score for POSITION." (assert (vectorp position)) (let ((v 0) (status (chess-pos-status position))) @@ -62,6 +67,9 @@ ((= piece ?n) (decf v chess-knight-value))))))))) (defun chess-ai-eval (position depth alpha beta &optional line) + "Evaluate POSITION using a simple AlphaBeta search algorithm using at most +DEPTH plies." + ;; TBD: We do far too much consing (if (= depth 0) (cons (chess-eval-static position) line) (let ((plies (chess-legal-plies @@ -82,19 +90,23 @@ ret)))) (defun chess-ai-best-move (position depth &optional func) + "Find the best move for POSITION using `chess-ai-eval' with DEPTH. +Returns (VALUE . LIST-OF-PLIES) where + VALUE is the evaluated score of the move and + LIST-OF-PLIES is the list of plies which were actually found." (let ((res (chess-ai-eval position depth -100000 100000))) (cons (car res) (if (functionp func) (mapcar func (nreverse (cdr res))) (nreverse (cdr res)))))) +;; TBD: It is somewhat strange that we need to define this variable. (defvar chess-ai-regexp-alist nil) (defun chess-ai-handler (game event &rest args) (unless chess-engine-handling-event (cond ((eq event 'initialize) - (setq chess-engine-process t) (setq chess-engine-opponent-name "Emacs AI") t) @@ -105,11 +117,15 @@ (when (= 1 (chess-game-index game)) (chess-game-set-tag game "White" chess-full-name) (chess-game-set-tag game "Black" chess-engine-opponent-name)) - - (if (chess-game-over-p game) - (chess-game-set-data game 'active nil)) - (let ((bm (chess-ai-best-move (chess-engine-position nil) 2))) - (funcall chess-engine-response-handler 'move (cadr bm)))) + (when (chess-game-over-p game) + (chess-game-set-data game 'active nil))) + + ((eq event 'post-move) + (unless (chess-game-over-p game) + (let (chess-display-handling-event) + (funcall chess-engine-response-handler + 'move (cadr (chess-ai-best-move (chess-engine-position nil) + chess-ai-depth)))))) (t (apply 'chess-common-handler game event args))))) |