;; The first three lines of this file were inserted by DrScheme. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-reader.ss" "lang")((modname lect06c-) (read-case-sensitive #t) (teachpacks ((lib "universe.ss" "teachpack" "2htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "universe.ss" "teachpack" "2htdp")))))
; data def'n:
; an anc-tree (ancestor tree) is:
; - 'unknown
; - (make-child [string] [int] [symbol] [anc-tree] [anc-tree])

(define-struct child (name yob eye ma pa))

; examples of data of anc-tree:
'unknown

(define lieselotte
  (make-child "Lieselotte" 1915 'green 'unknown 'unknown))

(define kristin
  (make-child "Kristin" 1943 'blue lieselotte 'unknown))

(define gordon
  (make-child "Gordon" 1938 'brown (make-child "Lois"   1899 'brown 'unknown 'uknown)
                                   (make-child "George" 1894 'blue  'unknown 'uknown)))

(define ian (make-child "Ian" 1966 'blue kristin gordon))
                           
                           


;; fun-for-anc-tree : anc-tree -->  ???
;;
;(define (fun-for-anc-tree anc)
;  (cond [(symbol? anc) ...]
;        [(child? anc)  ...(child-name anc)
;                       ...(child-yob anc)
;                       ...(child-eye anc)
;                       ...(fun-for-anc-tree (child-ma anc))
;                       ...(fun-for-anc-tree (child-pa anc))])

(define (size anc)
  (cond [(symbol? anc) 0]
        [(child? anc)  (+ (size (child-ma anc))
                          (size (child-pa anc))
                          1)]))

(check-expect (size 'unknown) 0)
(check-expect (size lieselotte) 1)
(check-expect (size kristin) 2)
(check-expect (size gordon) 3)
(check-expect (size ian) 6)


; rename-all : anc-tree string -> anc-tree
;
(define (rename-all anc newname)
  (cond [(symbol? anc) 'unknown]
        [(child? anc)
         (make-child newname
                     (child-yob anc)
                     (child-eye anc)
                     (rename-all (child-ma anc) newname)
                     (rename-all (child-pa anc) newname))]))


; Return all the children in a tree.
; get-all-children : anc-tree -> (listof child)

(define (get-all-children anc)
  (cond [(symbol? anc) empty]
        [(child? anc) (append 
                       (get-all-children (child-ma anc))
                       (list anc)
                       (get-all-children (child-pa anc)))])

; challenge: write my-append.
; (Hint: follow the template for a list,
;  but only take first/rest of arg1.)