stdlib.scm

(define (caar x) (car (car x)))
(define (cadr x) (car (cdr x)))
(define (cdar x) (cdr (car x)))
(define (cddr x) (cdr (cdr x)))
(define (cadar x) (car (cdar x)))
	
; (define (fold f x xs)
;	(if (null? xs) x (fold f (f x (car xs)) (cdr xs))))

(define (reverse-impl xs acc)
	(if (null? xs)
		acc
		(reverse-impl (cdr xs) (cons (car xs) acc))))

(define (reverse xs)
	(reverse-native xs))
	;(reverse-impl xs '()))

(define (fold-list xs f)
	(reverse (fold f '() xs)))
	
;(define (length xs)
;	(fold (lambda (ct x) (+ ct 1)) 0 xs))

(define (append xs ys)
	(reverse
		(fold
			(lambda (acc x) (cons x acc))
			(reverse xs)
			ys)))

; (define (reverse xs)
;	(fold (lambda (tail x) (cons x tail)) '() xs))
	
(define (map f xs)
	(fold-list xs
		(lambda (acc x) (cons (f x) acc))))

(define (writeln x)
	(write x)
	(newline))

(define eof-object? null?)

(define (> a b) (< b a))