diff options
Diffstat (limited to 'chess-ply.el')
| -rw-r--r-- | chess-ply.el | 67 |
1 files changed, 41 insertions, 26 deletions
diff --git a/chess-ply.el b/chess-ply.el index 7e44a04..22e22d7 100644 --- a/chess-ply.el +++ b/chess-ply.el @@ -44,7 +44,6 @@ ;;; Code: -(require 'cl) (require 'chess-pos) (defgroup chess-ply nil @@ -158,19 +157,25 @@ maneuver." (chess-ply-create-castle position long))) (setcdr ply new-changes)))) - ;; 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 - (if (and (= piece (if color ?P ?p)) - (not (memq :promote changes)) - (= (if color 0 7) (chess-index-rank (cadr changes)))) - (let ((new-piece (completing-read - "Promote pawn to queen/rook/knight/bishop? " - chess-piece-name-table nil t "queen"))) - (setq new-piece - (cdr (assoc new-piece chess-piece-name-table))) - (if color - (setq new-piece (upcase new-piece))) - (nconc changes (list :promote new-piece)))) + (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 + (if (and (not (memq :promote changes)) + (= (if color 0 7) (chess-index-rank (cadr changes)))) + (let ((new-piece (completing-read + "Promote pawn to queen/rook/knight/bishop? " + chess-piece-name-table nil t "queen"))) + (setq new-piece + (cdr (assoc new-piece chess-piece-name-table))) + (if color + (setq new-piece (upcase new-piece))) + (nconc changes (list :promote 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)))) (unless (or (memq :check changes) (memq :checkmate changes) @@ -258,9 +263,10 @@ criteria." (let* ((piece (cadr (memq :piece keywords))) (color (if piece (< piece ?a) (chess-pos-side-to-move position))) - (test-piece (if piece (upcase piece) - (chess-pos-piece position - (cadr (memq :index keywords))))) + (test-piece + (upcase (or piece + (chess-pos-piece position + (cadr (memq :index keywords)))))) pos plies file) ;; since we're looking for moves of a particular piece, do a ;; more focused search @@ -289,12 +295,20 @@ criteria." (if (and (= (if color 6 1) (chess-index-rank candidate)) (chess-pos-piece-p position 2ahead ? )) (chess-ply--add (if color -2 2) 0))) - (if (and (setq pos (chess-incr-index candidate bias -1)) - (chess-pos-piece-p position pos (not color))) - (chess-ply--add nil nil pos)) - (if (and (setq pos (chess-incr-index candidate bias 1)) - (chess-pos-piece-p position pos (not color))) - (chess-ply--add nil nil pos)))) + (when (setq pos (chess-incr-index candidate bias -1)) + (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)) + (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))))) ;; the rook, bishop and queen are the easiest; just look along ;; rank and file and/or diagonal for the nearest pieces! @@ -302,7 +316,7 @@ criteria." (dolist (dir (cond ((= test-piece ?R) '( (-1 0) - (0 -1) (0 1) + (0 -1) (0 1) (1 0))) ((= test-piece ?B) '((-1 -1) (-1 1) @@ -354,8 +368,9 @@ criteria." (chess-pos-piece-p position pos (not color)))) (chess-ply--add nil nil pos)))) - (t (error "Unrecognized piece identifier")))) - plies)))) + (t (chess-error 'piece-unrecognized)))) + + (delq nil plies))))) (provide 'chess-ply) |