;;; Scheme Essentials language

;; Lists are written differently in results window:
(list 1 2 3) ;; the result written as (1 2 3)

;; #t and #f instead of true/false
(even? 7) ;; the result written as #f
(even? 6) ;; the result written as #t
;; true, false are not defined
#t
#f

;; null? instead of empty?, car and cdr instead of first and rest
empty
'() ;; another way of writing an empty list, also nil in some versions
;empty? ; not defined
(null? '())
;(first (list 1 2))
(car (list 1 2))
;(rest (list 1 2))
(cdr (list 2)) 

;; Fun with car and cdr (also available in other Scheme levels)
(cadr (list 1 2 3)) ;; (car (cdr (list 1 2 3))
(cddr (list 1 2 3)) ;; (cdr (cdr (list 1 2 3))
(cadddr (list 1 2 3 4 5 6 7 8)) ;; works up to 4 levels
;(cadar (list (list 1 2) (list 3 4))) ; what's this??