2009-04-07から1日間の記事一覧
(define (delete-1 elt lis . options) (if (member elt lis) (let-optionals* options ((cmp-fn equal?)) (define (loop lis) (cond [(null? lis) '()] [(cmp-fn elt (car lis)) (cdr lis)] [else (cons (car lis) (loop (cdr lis)))])) (loop lis)) lis)) …