person.rkt

#lang racket

(require 2htdp/image)
(require test-engine/racket-tests)

(struct person (name year-born fav-color))
(define CURRENT-YEAR 2014)

(define andrew (person "Andrew" 1989 (color 20 90 200 255)))
(define derp (person "Derp" 1901 (color 232 121 204 255)))
(define baby (person "Baby" 2013 'green))

; person -> number
; the age (in years) of the given person
(define (person-age p)
  (- CURRENT-YEAR (person-year-born p)))

; tests for our person-age function
(check-expect (person-age baby) 1)
(check-expect (person-age andrew) 25)

; person -> string
; a friendly greeting for the given person
(define (say-hi p)
  (let* ([age (person-age p)]
        [year-label (if (> age 1) "years" "year")]
        [age-str (number->string age)])
  (string-append "Hi, "
                 (person-name p)
                 "! You are "
                 age-str
                 " "
                 year-label
                 " old.")))

; tests for our say-hi function
(check-expect (say-hi baby) "Hi, Baby! You are 1 year old.")
(check-expect (say-hi andrew) "Hi, Andrew! You are 25 years old.")

(define (hi-message p)
  (text/font (say-hi p) 24 (person-fav-color p) "Gill Sans" 'swiss 'normal 'bold #f))

(hi-message andrew)
(hi-message derp)
(hi-message baby)

(define (trick-person p)
  (person (string-append (person-name p) "butt")
          (person-year-born p)
          (person-fav-color p)))

;(define people (list andrew derp baby))
;(map hi-message (map trick-person people))

(test)