(defmacro for (var start stop &body body)
  (let ((gstop (gensym)))
    `(do ((,var ,start (1+ ,var))
          (,gstop ,stop))
         ((> ,var ,gstop))
       ,@body)))

(defmacro in (obj &rest choices)
  (let ((insym (gensym)))
    `(let ((,insym ,obj))
       (or ,@(mapcar #'(lambda (c) `(eql ,insym ,c))
                     choices)))))

(defmacro avg (&rest args)
  `(/ (+ ,@args) ,(length args)))

(deftest test-macro-utilities ()
  (check
   (equalp (format t "1234") (for x 1 4 (princ x)))
   (equalp 't (in (car '(* 9 1 4 6)) '+ '- '*))
   (= '2 (avg 1 2 3))))