(defmacro switch (form &body clauses)
  (let ((end (gensym "END")))
    `(block NIL
       (tagbody
          (case ,form
            ,@(loop for clause in clauses
                    collect `(,(first clause) (go ,(first clause))))
            (T (go ,end)))
          ,@(loop for clause in clauses
                  append clause)
          ,end))))