;; 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-advanced-reader.ss" "lang")((modname lecture_02) (read-case-sensitive #t) (teachpacks ()) (htdp-settings #(#t constructor repeating-decimal #t #t none #f ())))

;; Fold* is: (foldl fn base list)
;; Applies the fn recursively to all elements
;; foldl: (+ 4 (+ 3 (+ 2 (+ 1 10))))
(foldl + 10 (list 1 2 3 4))
;; foldr: (+ 1 (+ 2 (+ 3 (+ 4 0))))
(foldr + 0 (list 1 2 3 4))
;; Map is: [X -> Y] [Listof X] -> [Listof Y]
;; i.e. (map F (list x1 x2 x3)) ->
;;         (list (F x1) (F x2) (F x3))
(map (lambda (t) (+ t 5)) (list 1 2 3 4))

;; Examples of primitive data in racket
5
"test"
true
'nope

;; Compound data
(list 1 2 3)
;; A Rocket  is: (make-rocket String Posn Boolean)
(define-struct rocket (name pos landing?))

;; A Posn is: (make-posn Number Number)
(define-struct posn (x y))

;; Instantiation of structs (structs are very similar
;;   to classes)
(make-rocket 1 5 "hi")
(make-posn 1 2)