FizzBuzz in lisp

(defun fizzbuzz (start end)
  (let ((mod3 (= (rem start 3) 0)) (mod5 (= (rem start 5) 0)))
    (princ (cond
            ((and mod3 mod5) "FizzBuzz")
            (mod3 "Fizz")
            (mod5 "Buzz")
            (t start)))
    (princ #\newline)
    (unless (= start end) (fizzbuzz (+ start 1) end))))
(fizzbuzz 1 100)