;;;; Under Creative Commons Attribution-ShareAlike 4.0
;;;; International. See
;;;; <https://creativecommons.org/licenses/by-sa/4.0/>.

(define-module (net ricketyspace sicp two eight)
  #:use-module (net ricketyspace sicp two seven)
  #:export (sub-interval))

(define (sub-interval x y)
  (make-interval (- (lower-bound x) (lower-bound y))
                 (- (upper-bound x) (upper-bound y))))