;; The first three lines of this file were inserted by DrRacket. They record metadata
;; about the language level of this file in a form that our tools can easily process.
#reader(lib "htdp-intermediate-lambda-reader.ss" "lang")((modname lect03a) (read-case-sensitive #t) (teachpacks ((lib "universe.ss" "teachpack" "2htdp") (lib "image.ss" "teachpack" "2htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "universe.ss" "teachpack" "2htdp") (lib "image.ss" "teachpack" "2htdp")))))
;;;;; lect03a.rkt


;;; Code from last time:

;;; Since we're handling data that can be integer OR character,
;;; we'll use "cond", which is like if-else-if:
#;(define (func-for-c-ranks a-cr)
    (cond [(integer?   a-cr) ...]
          [(character? a-cr) ...]))



;;; In bridge:
;;; you assign "bridge values" to card-ranks:
;;; most cards are 0, but jack is 1, queen is 2, king is 3, ace is 4.


;;; test cases (write 'em first!)
(check-expect (crank-bridge-value 5) 0)
(check-expect (crank-bridge-value 'queen) 2)

; crank-value :  c-rank -> int
; compute the bridge-playing value for a given c-rank.
(define (crank-bridge-value a-cr)
  (cond [(integer? a-cr)  0]
        [(symbol?  a-cr)  (cond [(symbol=? a-cr 'jack)   1]
                                [(symbol=? a-cr 'queen)  2]
                                [(symbol=? a-cr 'king)   3]
                                [(symbol=? a-cr 'ace)    4])]))

(check-expect (crank->string 5) "5")
(check-expect (crank->string 10) "10")
(check-expect (crank->string 'queen) "Q")

; crank->string : c-rank -> string
;
(define (crank->string a-cr)
    (cond [(integer?   a-cr) (number->string a-cr)]
          [(symbol? a-cr) 
           (string 
            (char-upcase 
             (string-ref (symbol->string a-cr) 0)))]))


; A c-rank is either:
;    - an integer (2..10)
; or - a symbol ('jack, 'queen, 'king, 'ace)

; OPTIONAL:
; Btw, we can write:
; crank? ANY -> boolean
;
(define (crank? any) (or (and (integer? any) (<= 2 any 10)) 
                         (symbol? any)))



;
; The design recipe:
;   http://htdp.org/2003-09-26/Book/curriculum-Z-H-7.html#node_sec_4.4
; --- per (abstract) data type:
; - data def'n
; - examples of data
; - template (case analysis)
; --- per function:
; - contract, purpose, header
; - test-cases (check-expect)
; - complete function-body
;   - case analysis (cond-questions, 1 per data variant)
;   - answer for each cases
; - run the tests (trivial)


;;;;;;;;;;;;;;;;; Next stage: define-struct  (product type)
;
; Example:

(define-struct card (rank suit))
; rank : card-rank
; suit : symbol


(make-card 4 'spades)


#|  The corresponding Java:

class Card {
  CRank rank;
  String suit;
  }


... new Card( 4, "hearts" ) ...
|#




; When I define-struct, racket creates four functions for me:
;   make-card  -- constructor
;   card-rank  -- accessor
;   card-suit  -- accessor
;   card?      -- predicate



; have-a-heart : c-rank -> card
; Return a card of the given rank, in hearts.

(check-expect (have-a-heart 3)
              (make-card 3 'hearts))
(check-expect (have-a-heart 'jack)
              (make-card 'jack 'hearts))

#|  In Java:
    Card haveAHeart( CardRank aCr ) {
        return new Card(aCr, "hearts");
        }
|#
;
(define (have-a-heart  a-cr)
  (make-card a-cr 'hearts))

(check-expect (have-a-heart 5) 
              (make-card 5 'hearts))
(check-expect (have-a-heart 'queen)
              (make-card 'queen 'hearts))






; turn-to-spades: Given a card, return a new card of the same rank, and suit 'spades.
;

; turn-to-spades : card -> card
(define (turn-to-spades a-card)
  ;...(card-rank a-card)... ; type: card-rank
  ;...(card-suit a-card)... ; type: symbol
  (make-card (card-rank a-card) 'spades)
  )

(check-expect (turn-to-spades (make-card 7 'hearts))
              (make-card 7 'spades))
(check-expect (turn-to-spades (make-card 7 'spades))
              (make-card 7 'spades))




; inventory

; card>?


; card<=?