(defcc <remove>
   [<as>] <remove> := <remove>;
   X <remove>;
   <e>;)

(defcc <as>
   a <as>;
   a;)

(compile (fn <remove>) [[a b] [a] [] 1 2 3])

(defcc <xs>
   [x x];)

(compile (fn <xs>) [[x x]])