;; 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-beginner-reader.ss" "lang")((modname lab5-given) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #f #t none #f () #f)))
(require 2htdp/image)
(require 2htdp/universe)
#|--- DATA DEFINITIONS ---|#
;;A Command is one of:
;; - 'move
;; - 'turn-left
;; - 'turn-right

;;A List-of-Commands (LOC) is one of:
;; - '()
;; - (cons Command LOC)

;;A Direction is one of:
;; - 'left
;; - 'right
;; - 'up
;; - 'down

;;A Turtle is a (make-turtle Direction Posn LOC)
(define-struct turtle (dir p loc))
; - where dir is the direction the turtle is facing
; - p is the current location of the turtle
; - and loc is the list of commands the turtle needs to follow

#|--- CONSTANTS ---|#
(define WIDTH 500)
(define HEIGHT 500)
(define BACKGROUND (empty-scene WIDTH HEIGHT))
(define TURTLE-UP (triangle 20 "solid" "forestgreen"))
(define TURTLE-LEFT (rotate 90 TURTLE-UP))
(define TURTLE-DOWN (rotate 90 TURTLE-LEFT))
(define TURTLE-RIGHT (rotate 90 TURTLE-DOWN))
(define CENTER (make-posn (/ WIDTH 2) (/ HEIGHT 2)))

#|--- FUNCTIONS ---|#
;;main : LOC -> Turtle
;;Simulate a turtle following these commands
(define (main all-commands)
  (big-bang (make-turtle 'up CENTER all-commands)
            [on-tick do-command]
            [to-draw draw-turtle]
            [stop-when out-of-commands?]))

;;do-command : Turtle -> Turtle
;;Do the first command in the list of commands
(define (do-command t) t) ;; FIX ME I'M A DUMMY HEADER

;;draw-turtle : Turtle -> Image
;;Renders the turtle on the background
(define (draw-turtle t) BACKGROUND) ;; FIX ME I'M A DUMMY HEADER

;;out-of-commands? : Turtle -> Boolean
;;Is the turtle out of commands?
(define (out-of-commands? t) #f) ;; FIX ME I'M A DUMMY HEADER