;;; Timers

(defun start-timer ()
  (get-internal-real-time))

(defun stop-timer (timer)
  (/ (float (- (get-internal-real-time) timer))
     internal-time-units-per-second))

(defmacro timeit (func)
  `(let* ((timer (start-timer))
	  (rslt ,func))
     (format t "~a~%" (stop-timer timer))
     rslt))

;;; Imperative

(defun pipeline ()
  (let (buffer)
    (do ((k 1 (1+ k)))
	((= 100000 k))
      (let ((j (/ (* (1+ k) k) 2)))
	(if buffer
	    (let* ((i (pop buffer))
		   (r (/ (* i j)
			 (do ((x (max i j) y)
			      (y (min i j) (mod x y)))
			     ((= 0 y) x)))))
	      (dolist
		  (d (do ((x r (floor x 10))
			  (digits nil (cons (mod x 10) digits)))
			 ((= 0 x) digits)))
		(declare (ignore d))))
	    (push j buffer))))))

(timeit (dotimes (i 100) (pipeline)))