(defmacro if2 (cond1 cond2 both first second . neither)
  (let ((res1 (gensym))
        (res2 (gensym)))
    ^(let ((,res1 ,cond1)
           (,res2 ,cond2))
       (cond ((and ,res1 ,res2) ,both)
             (,res1             ,first)
             (,res2             ,second)
             (t                 ,*neither)))))