diff options
Diffstat (limited to 'chess-pos.el')
| -rw-r--r-- | chess-pos.el | 49 |
1 files changed, 48 insertions, 1 deletions
diff --git a/chess-pos.el b/chess-pos.el index ae06c26..e8ab392 100644 --- a/chess-pos.el +++ b/chess-pos.el @@ -405,6 +405,26 @@ in order to execute faster." (defvaralias 'chess-king-directions 'chess-queen-directions "The directions a king is allowed to move to.") +(defconst chess-sliding-white-piece-directions + (list (list chess-direction-north ?R ?Q) + (list chess-direction-northeast ?B ?Q) + (list chess-direction-east ?R ?Q) + (list chess-direction-southeast ?B ?Q) + (list chess-direction-south ?R ?Q) + (list chess-direction-southwest ?B ?Q) + (list chess-direction-west ?R ?Q) + (list chess-direction-northwest ?B ?Q))) + +(defconst chess-sliding-black-piece-directions + (list (list chess-direction-north ?r ?q) + (list chess-direction-northeast ?b ?q) + (list chess-direction-east ?r ?q) + (list chess-direction-southeast ?b ?q) + (list chess-direction-south ?r ?q) + (list chess-direction-southwest ?b ?q) + (list chess-direction-west ?r ?q) + (list chess-direction-northwest ?b ?q))) + (defsubst chess-next-index (index direction) "Create a new INDEX from an old one, by advancing it in DIRECTION. @@ -842,7 +862,34 @@ If NO-CASTLING is non-nil, do not consider castling moves." ;; from any piece movement. This is useful for testing whether a ;; king is in check, for example. ((memq piece '(t nil)) - (dolist (p (if piece '(?P ?R ?N ?B ?Q ?K) '(?p ?r ?n ?b ?q ?k))) + (dolist (dir-type (if piece + chess-sliding-white-piece-directions + chess-sliding-black-piece-directions)) + ;; up the current file + (let ((dir (car dir-type))) + (setq pos (chess-next-index target dir)) + (while pos + (let ((pos-piece (chess-pos-piece position pos))) + (if (memq pos-piece (cdr dir-type)) + (progn + (chess--add-candidate pos) + (setq pos nil)) + (setq pos (and (eq pos-piece ? ) (chess-next-index pos dir)))))))) + ;; test whether the rook can move to the target by castling + (if (and (not no-castling)) + (let (rook) + (if (and (= target (if color ?\075 ?\005)) + (setq rook (chess-pos-can-castle position + (if color ?K ?k))) + (chess-ply-castling-changes position)) + (chess--add-candidate rook) + (if (and (= target (if color ?\073 ?\003)) + (setq rook (chess-pos-can-castle position + (if color ?Q ?q))) + (chess-ply-castling-changes position t)) + (chess--add-candidate rook))))) + + (dolist (p (if piece '(?P ?N ?K) '(?p ?n ?k))) (mapc 'chess--add-candidate (chess-search-position position target p check-only)))) |