How to get 10th Fibonacci number in Common Lisp

fibs.lisp

;; recur
(defun fib (i &optional (a 1) (b 0))
  (if (= i 1)
      a
      (fib (1- i) (+ a b) a)))
(fib 10)

;; do macro
(do ((i 1 (1+ i))
     (a 0 b)
     (b 1 (+ b a)))
    ((< 10 i) a))

;; loop macro
(loop for i from 1 to 10
      and a = 0 then b
      and b = 1 then (+ b a)
      finally (return a))