;; a person is a (make-person string famtree famtree list-of-person)
(define-struct person (name mother father kids))

;; a famtree is either
;; 'unknown, or
;; a person

;; a list-of-person is either
;; empty, or
;; (cons person list-of-person)

(define Bper (make-person "Brenda" 'unknown 'unknown empty))
(define Jper (make-person "Judy" Bper 'unknown empty))
(set-person-kids! Bper (list Jper))


;; add-child-to-mother: person string -> void
;; creates a person with the given name and the given person as its mother
;; EFFECT:  adds a child to the kids component of the given person
(define (add-child-to-mother mother childname)
  (set-person-kids! mother (cons (make-person childname mother 'unknown empty)
                                 (person-kids mother))))