1 12687dd9 2023-08-04 jrmu (define (make-posn x y)
 2 12687dd9 2023-08-04 jrmu   (local ((define x0 x)
 3 12687dd9 2023-08-04 jrmu           (define y0 y)
 4 12687dd9 2023-08-04 jrmu           (define (service-manager msg)
 5 12687dd9 2023-08-04 jrmu             (cond
 6 12687dd9 2023-08-04 jrmu               [(equal? msg 'x) x0]
 7 12687dd9 2023-08-04 jrmu               [(equal? msg 'y) y0]
 8 12687dd9 2023-08-04 jrmu               [(equal? msg 'set-x) (lambda (new-x) (set! x0 new-x))]
 9 12687dd9 2023-08-04 jrmu               [(equal? msg 'set-y) (lambda (new-y) (set! y0 new-y))])))
10 12687dd9 2023-08-04 jrmu     service-manager))