diff options
Diffstat (limited to 'chess-pos.el')
| -rw-r--r-- | chess-pos.el | 94 |
1 files changed, 78 insertions, 16 deletions
diff --git a/chess-pos.el b/chess-pos.el index 92cf5c4..592f4d2 100644 --- a/chess-pos.el +++ b/chess-pos.el @@ -1,4 +1,4 @@ -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; +;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ;; Routines for manipulating chess positions ;; @@ -326,6 +326,68 @@ in order to execute faster." (chess-rf-to-index (+ (chess-index-rank index) rank-move) (+ (chess-index-file index) file-move))) +(defconst chess-pos-address-index + (apply #'vector + (append (make-list 20 nil) + (cl-loop for rank from 0 to 7 + nconc (nconc (list nil) + (cl-loop for index + from (* rank 8) + to (+ 7 (* rank 8)) + collect index) + (list nil))) + (make-list 20 nil))) + "Map square addresses to square indices.") + +(defconst chess-pos-index-address + (let ((addresses ())) + (dotimes (r 8) + (cl-loop for i from (+ (* (1+ r) 10) 11) to (+ 7 (+ (* (1+ r) 10) 11)) + do (push i addresses))) + (apply #'vector (nreverse addresses))) + "Map square indices to square addresses.") + +(defconst chess-direction-northwest -11) +(defconst chess-direction-north-northwest -21) +(defconst chess-direction-north -10) +(defconst chess-direction-north-northeast -19) +(defconst chess-direction-northeast -9) +(defconst chess-direction-east-northeast -8) +(defconst chess-direction-east 1) +(defconst chess-direction-east-southeast 12) +(defconst chess-direction-southeast 11) +(defconst chess-direction-south-southeast 21) +(defconst chess-direction-south 10) +(defconst chess-direction-south-southwest 19) +(defconst chess-direction-southwest 9) +(defconst chess-direction-west-southwest 8) +(defconst chess-direction-west -1) +(defconst chess-direction-west-northwest -12) + +(defun chess-next-index (index direction) + "Create a new INDEX from an old one, by advancing it in DIRECTION. +DIRECTION should be one of +`chess-direction-north' (white pawns, rooks, queens and kings), +`chess-direction-north-northeast' (knights), +`chess-direction-northeast' (bishops, queens and kings), +`chess-direction-east-northeast' (knights), +`chess-direction-east' (rooks, queens and kings), +`chess-direction-east-southeast' (knights), +`chess-direction-southeast' (bishops, queens and kings), +`chess-direction-south-southeast' (knights), +`chess-direction-south' (black pawns, rooks, queens and kings), +`chess-direction-south-southwest' (knights), +`chess-direction-southwest' (bishops, queens and kings), +`chess-direction-west-southwest' (knights), +`chess-direction-west' (rooks, queens and kings), +`chess-direction-west-northwest' (knights), +`chess-direction-northwest' (bishops, queens and kings) or +`chess-direction-north-northwest' (knights). + +If the new index is not on the board, nil is returned." + (aref chess-pos-address-index + (+ (aref chess-pos-index-address index) direction))) + (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 @@ -778,26 +840,26 @@ If NO-CASTLING is non-nil, do not consider castling moves." ((memq test-piece '(?R ?B ?Q)) (dolist (dir (cond ((= test-piece ?R) - '( (-1 0) - (0 -1) (0 1) - (1 0))) + (list chess-direction-north + chess-direction-west chess-direction-east + chess-direction-south)) ((= test-piece ?B) - '((-1 -1) (-1 1) + (list chess-direction-northwest chess-direction-northeast - (1 -1) (1 1))) + chess-direction-southwest chess-direction-southeast)) ((= test-piece ?Q) - '((-1 -1) (-1 0) (-1 1) - (0 -1) (0 1) - (1 -1) (1 0) (1 1))))) + (list chess-direction-northwest chess-direction-north chess-direction-northeast + chess-direction-west chess-direction-east + chess-direction-southwest chess-direction-south chess-direction-southeast)))) ;; up the current file - (setq pos (apply 'chess-incr-index target dir)) + (setq pos (chess-next-index target dir)) (while pos (if (chess-pos-piece-p position pos piece) (progn (chess--add-candidate pos) (setq pos nil)) (setq pos (and (chess-pos-piece-p position pos ? ) - (apply 'chess-incr-index pos dir))))) + (chess-next-index pos dir))))) ;; test whether the rook can move to the target by castling (if (and (= test-piece ?R) (not no-castling)) @@ -840,12 +902,12 @@ If NO-CASTLING is non-nil, do not consider castling moves." ;; the knight is a zesty little piece; there may be more than ;; one, but at only one possible square in each direction ((= test-piece ?N) - (dolist (dir '((-2 -1) (-2 1) - (-1 -2) (-1 2) - (1 -2) (1 2) - (2 -1) (2 1))) + (dolist (dir (list chess-direction-north-northeast chess-direction-east-northeast + chess-direction-east-southeast chess-direction-south-southeast + chess-direction-south-southwest chess-direction-west-southwest + chess-direction-west-northwest chess-direction-north-northwest)) ;; up the current file - (if (and (setq pos (apply 'chess-incr-index target dir)) + (if (and (setq pos (chess-next-index target dir)) (chess-pos-piece-p position pos piece)) (chess--add-candidate pos)))) |