diff options
| -rwxr-xr-x | examples/2048/2048 | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/examples/2048/2048 b/examples/2048/2048 index 0bda152..c7a3b8d 100755 --- a/examples/2048/2048 +++ b/examples/2048/2048 @@ -54,6 +54,11 @@ (define (enumerate lst) (zip (iota (length lst)) lst)) +(define (replace-at lst idx item) + (let-values (((f d) + (split-at lst idx))) + (append f (cons item (cdr d))))) + ;;; ;;; Game Board ;;; @@ -141,20 +146,15 @@ (define (random-tile) (list-ref '(2 4) (random 2))) -;; So gross. (define (board-insert board) (let ((x (random board-size)) (y (random board-size))) - (if (zero? (list-ref (list-ref board y) x)) - (append (take board y) - (let ((rows (drop board y))) - (cons (let ((cells (car rows))) - (append (take cells x) - (let ((rest (drop cells x))) - (cons (random-tile) - (cdr rest))))) - (cdr rows)))) - (board-insert board)))) + (let-values (((f d) + (split-at (list-ref board y) x))) + (if (zero? (car d)) + (replace-at board y + (append f (cons (random-tile) (cdr d)))) + (board-insert board))))) (define (board-find board n) (list? @@ -163,7 +163,7 @@ board))) (define (board-win? board) - (board-find (make-board) 2048)) + (board-find board 2048)) (define (board-lose? board) (define (full? row) |