;; 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-advanced-reader.ss" "lang")((modname lect04a) (read-case-sensitive #t) (teachpacks ((lib "world.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #t #t none #f ((lib "world.ss" "teachpack" "htdp")))))
#|
The steps of design recipe (taken from How to Design Programs).
1. Data Def'n
2. Examples of Data
3. Template for functions handling the data
4a Write function header
 b Write function comments
 c Write test cases
 d Write function body
   i.   a cond line for each variant of union data
   ii.  pull out fields for each line handling a struct
   iii. add natural-recursion call, if present.
5. run tests
|#



; Data Def'n:
; A treenode is:
; - 'unknown 
; - (make-person string num symbol treenode treenode)
(define-struct person (name year eye ma pa))


(define abe (make-person "Abe" 1920 'blue 'unknown 'unknown))
(define mona (make-person "Mona" 1929 'brown 'unknown 'unkown))
(make-person "homer" 1955 'brown 
             (make-person "Mona" 1929 'brown 'unknown 'unkown)
             (make-person "Abe" 1920 'blue 'unknown 'unknown))




(define jackie (make-person "Jackie" 1926 'brown 'unknown 'unknown))
(define marge (make-person "Marge" 1956 'blue jackie 'unknown))
(define homer (make-person "Homer" 1955 'brown mona abe))
(define bart (make-person "Bart" 1979 'brown homer marge))


#;(define (fun-for-tnode a-ft)
  (cond [(symbol? a-ft) ...]
        [(person? a-ft) (person-name a-ft) ...
                        (person-year a-ft) ...
                        (person-eye  a-ft) ...
                        (fun-for-tnode (person-ma   a-ft)) ...
                        (fun-for-tnode (person-pa   a-ft)) ...
                        ]))



;;;; Spent most of the hour discussing hw soln.

; find-all-name : (-> treenode string (list-of person))
;
(define (find-all-name  a-ft target-name)
  (cond [(symbol? a-ft) empty]
        [(person? a-ft) (if (string=? target-name (person-name a-ft))
                            (cons a-ft
                                  (append (find-all-name (person-ma   a-ft) target-name)
                                          (find-all-name (person-pa   a-ft) target-name)))
                            (append (find-all-name (person-ma   a-ft) target-name)
                                    (find-all-name (person-pa   a-ft) target-name)))]))


(check-expect (find-all-name 'unknown "Beatrix")
              empty)
(check-expect (find-all-name homer "Beatrix")
              empty)
(check-expect (find-all-name homer "Homer")
              (list homer))