diff options
Diffstat (limited to 'chess-pos.el')
| -rw-r--r-- | chess-pos.el | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/chess-pos.el b/chess-pos.el index e8ab392..0725036 100644 --- a/chess-pos.el +++ b/chess-pos.el @@ -459,7 +459,7 @@ If the new index is not on the board, nil is returned." (defsubst chess-pos-search (position piece-or-color) "Look on POSITION anywhere for PIECE-OR-COLOR, returning all coordinates. If PIECE-OR-COLOR is t for white or nil for black, any piece of that -color will do." +color will do. See also `chess-pos-search*'." (cl-assert (vectorp position)) (cl-assert (memq piece-or-color '(t nil ? ?K ?Q ?N ?B ?R ?P ?k ?q ?n ?b ?r ?p))) @@ -469,6 +469,20 @@ color will do." (push i found))) found)) +(defsubst chess-pos-search* (position &rest pieces) + "Look on POSITION for any of PIECES. +The result is an alist where `car' of an entry is the piece and `cdr' is +a list of the indices that piece can be found at. Pieces which did not appear +in POSITION at all will be present in the resulting alist, but the `cdr' of +their entry will be nil." + (let ((alist (mapcar #'list pieces))) + (dotimes (index 64) + (let ((piece (chess-pos-piece position index))) + (unless (eq piece ? ) + (let ((candidates (assq piece alist))) + (when candidates (push index (cdr candidates))))))) + alist)) + (defsubst chess-pos-set-king-index (position color index) "Set the known index of the king on POSITION for COLOR, to INDEX. It is never necessary to call this function." @@ -865,7 +879,6 @@ If NO-CASTLING is non-nil, do not consider castling moves." (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 @@ -875,19 +888,19 @@ If NO-CASTLING is non-nil, do not consider castling moves." (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)) + (unless 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 ?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))))) + (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 |