Lambda the Ultimate Object

オブジェクトとしてのlambda
  (define (make-person first-name last-name occupation age)
    (lambda (msg . args)
      (case msg
        ((get-full-name) (string-append first-name " " last-name))
        ((get-occupation) occupation)
        ((get-age) age)
        ((grow-older) (inc! age))
        ((change-occupation) (set! occupation (car args)))
        ((bear-child)
         (make-person (car args) last-name #f 0)))))