(define-record ve-cell (vector index))  ; ve = vector element

(define make-cell
  (lambda (val)
    (make-ve-cell (vector val) 0)))

(define cell? ve-cell?)

(define cell-ref
  (lambda (cell)
    (vector-ref (ve-cell->vector cell)
                (ve-cell->index cell))))

(define cell-set!
  (lambda (cell val)
    (vector-set! (ve-cell->vector cell)
                 (ve-cell->index cell)
                 val)))

(define-record array-rep2 (elements))

(define make-array
  (lambda (length)
    (make-array-rep2 (make-vector length))))

(define array? array-rep2?)

(define array-length
  (lambda (array)
    (vector-length (array-rep2->elements array))))

(define array-cell
  (lambda (array index)
    (make-ve-cell (array-rep2->elements array)
                  index)))