(define (string-split str sep)
  (if (null? (string->list str))
      '()
      (if (equal? (car (string->list str)) (string->list sep))
                     (string-split (list->string (cdr ( string->list str))) sep)
                     (list->string (append (string->list (string-split (list->string (cdr (string->list str))) sep)))))))
(string-split "x;y;z" ";")