diff options
Diffstat (limited to 'chess-ply.el')
| -rw-r--r-- | chess-ply.el | 91 |
1 files changed, 50 insertions, 41 deletions
diff --git a/chess-ply.el b/chess-ply.el index 8d25cce..a506b79 100644 --- a/chess-ply.el +++ b/chess-ply.el @@ -212,30 +212,30 @@ maneuver." (setq new-changes (chess-ply-castling-changes position long (car changes)))) - (setcdr ply new-changes)))) - - (when (= piece (if color ?P ?p)) - ;; is this a pawn move to the ultimate rank? if so, and - ;; we haven't already been told, ask for the piece to - ;; promote it to - (when (and (not (memq :promote changes)) - (= (if color 0 7) - (chess-index-rank (cadr changes)))) - ;; This does not always clear ALL input events - (discard-input) (sit-for 0) (sleep-for 0 1) - (discard-input) - (unless chess-ply-allow-interactive-query - (chess-error 'ambiguous-promotion)) - (let ((new-piece (if (yes-or-no-p - (chess-string 'pawn-promote-query)) - ?Q ?N))) - (nconc changes (list :promote (upcase new-piece))))) - - ;; is this an en-passant capture? - (if (= (or (chess-pos-en-passant position) 100) - (or (chess-incr-index (cadr changes) - (if color 1 -1) 0) 200)) - (nconc changes (list :en-passant)))) + (setcdr ply new-changes))) + + (when (eq piece (if color ?P ?p)) + ;; is this a pawn move to the ultimate rank? if so, and + ;; we haven't already been told, ask for the piece to + ;; promote it to + (when (and (not (memq :promote changes)) + (= (if color 0 7) + (chess-index-rank (cadr changes)))) + ;; This does not always clear ALL input events + (discard-input) (sit-for 0) (sleep-for 0 1) + (discard-input) + (unless chess-ply-allow-interactive-query + (chess-error 'ambiguous-promotion)) + (let ((new-piece (if (yes-or-no-p + (chess-string 'pawn-promote-query)) + ?Q ?N))) + (nconc changes (list :promote (upcase new-piece))))) + + ;; is this an en-passant capture? + (when (let ((ep (chess-pos-en-passant position))) + (when ep + (eq ep (funcall (if color #'+ #'-) (cadr changes) 8)))) + (nconc changes (list :en-passant))))) ;; we must determine whether this ply results in a check, ;; checkmate or stalemate @@ -249,7 +249,7 @@ maneuver." (next-color (not color)) (king (chess-pos-king-index next-pos next-color)) (in-check (catch 'in-check - (chess-search-position next-pos king color t)))) + (chess-search-position next-pos king color t t)))) ;; first, see if the moves leaves the king in check. ;; This is tested by seeing if any of the opponent's ;; pieces can reach the king in the position that will @@ -359,6 +359,7 @@ position object passed in." (upcase (or piece (chess-pos-piece position (cadr (memq :index keywords)))))) + (ep (when (eq test-piece ?P) (chess-pos-en-passant position))) pos plies file) ;; since we're looking for moves of a particular piece, do a ;; more focused search @@ -382,27 +383,35 @@ position object passed in." ;; 1 or 2 when moving (the most complex piece, actually) ((= test-piece ?P) (let* ((bias (if color -1 1)) - (ahead (chess-incr-index candidate bias 0)) - (2ahead (chess-incr-index candidate (if color -2 2) 0))) + (ahead (chess-next-index candidate (if color + chess-direction-north + chess-direction-south))) + (2ahead (when ahead (chess-next-index ahead (if color + chess-direction-north + chess-direction-south))))) (when (chess-pos-piece-p position ahead ? ) - (chess-ply--add bias 0 ahead) + (chess-ply--add nil nil ahead) (if (and (= (if color 6 1) (chess-index-rank candidate)) 2ahead (chess-pos-piece-p position 2ahead ? )) - (chess-ply--add (if color -2 2) 0 2ahead))) - (when (setq pos (chess-incr-index candidate bias -1)) + (chess-ply--add nil nil 2ahead))) + (when (setq pos (chess-next-index candidate + (if color + chess-direction-northeast + chess-direction-southwest))) (if (chess-pos-piece-p position pos (not color)) - (chess-ply--add nil nil pos)) - ;; check for en passant capture toward queenside - (if (= (or (chess-pos-en-passant position) 100) - (or (chess-incr-index pos (if color 1 -1) 0) 200)) - (chess-ply--add nil nil pos))) - (when (setq pos (chess-incr-index candidate bias 1)) + (chess-ply--add nil nil pos) + ;; check for en passant capture toward kingside + (when (and ep (= ep (funcall (if color #'+ #'-) pos 8))) + (chess-ply--add nil nil pos)))) + (when (setq pos (chess-next-index candidate + (if color + chess-direction-northwest + chess-direction-southeast))) (if (chess-pos-piece-p position pos (not color)) - (chess-ply--add nil nil pos)) - ;; check for en passant capture toward kingside - (if (= (or (chess-pos-en-passant position) 100) - (or (chess-incr-index pos (if color 1 -1) 0) 200)) - (chess-ply--add nil nil pos))))) + (chess-ply--add nil nil pos) + ;; check for en passant capture toward queenside + (when (and ep (eq ep (funcall (if color #'+ #'-) pos 8))) + (chess-ply--add nil nil pos)))))) ;; the rook, bishop and queen are the easiest; just look along ;; rank and file and/or diagonal for the nearest pieces! |