Following code makes an "integerclass" with an "add" method :

#lang racket
(define (integerclass x)
  (define (getx)  x)
  (define (setx! x_new) (set! x x_new))
  (define (add y)(integerclass (+ x (y 'getx))))
  (lambda (message . args)
    (case message
        ((getx)      (apply getx    args))
        ((setx!)     (apply setx!   args))
        ((add)       (apply add     args))
      (else (error "POINT: Unknown message ->" message)))))

(define (myprint x) (print x)(newline))
(define p1 (integerclass 1))
(myprint (p1 'getx))
(define p2 (integerclass 2))
(myprint (p2 'getx))
(define p3 (p1 'add p2))
(myprint (p3 'getx))

Question 1 : can this code be inproved, are there "better patterns" one can 
Question 2 : can i modify this code to use typed/racket. I tried but failed 
on the "apply" method in the code.

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