(defmacro while (a &rest b) `(do () ((not ,a)) . ,b))


(defun copyr (l)
(cond ((null l) nil)
(t (cons (car l) (copyr (cdr l))))))

(defun copyi0 (l)
(let ((result-head (list (car l))))
(do ((l (cdr l) (cdr l))
(result result-head (rplacd result (cons (car l) nil))))
((null l) result-head))))


(defun copyi2 (l) (let* ((l l) (result-head (list (car l)))
(result result-head))
(while (setq l (cdr l))
(setq result (rplacd result (cons (car l) nil))))
result-head))

(defun copyi4 (l)
(mapcar '(lambda(x)x) l))

(defun copyi3 (l)
(do((l l (cdr l)) (result nil (cons (car l) result))) ((null l) (nreverse result))))



(defun copyib (l) (if l (let* ((result (list (car l))))
(prog1 result (while (setq l (cdr l))
(setq result (rplacd result (cons (car l) nil))))))
)))))