Find the last but one box of a list

	;; P02 (*) Find the last but one box of a list.
	;; Example:
	;; * (my-but-last '(a b c d))
	;; (C D)
	(define (my-but-last lst)
	(let ((revlis (reverse lst)))
	(cond
	((null? revlis) '())
	((< (length revlis) 3) lst)
	(else `(,(cadr revlis) ,(car revlis))))))

view raw p02.ss hosted with ❤ by GitHub