(require 'stdlib)

(defun fib (n)
  (if (<= n 2)
      1
    (+ (fib (- n 1)) (fib (- n 2)))))

(defmacro time (body)
  `(let ((start (current-utime))
         end)
     ,@body
     (setq end (current-utime))
     (puts (/ (- end start) 1000000.0))))

(time (fib 25))

;;(defun time (proc)
;;  (let ((start (current-utime)) end)
;;    (funcall proc)
;;    (setq end (current-utime))
;;    (/ (- end start) 1000000.0)))
;;
;;(do
;;    ((i 20 (+ i 1)))                    ; bindings: (var init step)
;;    ((= i 30))                          ; until
;;  (print (list i (time (lambda () (fib i))))))