;is the element a var symbol? i.e ?x ?y.. etc.
  (mac varsym? (x)
    `(and (is (type ,x) 'sym) (is ((string ,x) 0) #\?)))

  ;Are both elements varsyms? i.e ?x = ?y (?x . ?y)
  (mac tvs? (x y)
    `(and (varsym? (car ,x))(varsym? (car ,y))))

  ;is element x a varsym that hasn't been added to binds?
  (mac xvs? (x y binds)
    `(and (varsym? (car ,x))(~varsym? (car ,y))(no (assoc (car ,x) ,binds))))

  ;is element y a varsym that hasn't been added to binds?
  (mac yvs? (x y binds)
    `(and (varsym? (car ,y)) (~varsym? (car ,x))(no (assoc (car ,y) ,binds))))

  ;make bind i. e  ((?x . a)(?y . b))
  (mac mb (a b binds)
    `(push (cons (car ,a) (car ,b)) ,binds))

  (def match (x y)
    (let binds nil
      ((afn (x y)
        (if (or (no x) (no y)) binds ;lists are missing
          (if (iso x y) binds        ;list are the same
            (do
              (if (tvs? x y) (mb x y binds))
              (if (xvs? x y binds) (mb x y binds))
              (if (yvs? x y binds) (mb y x binds))	
            (self cdr.x cdr.y)))))
      x y)))

  (match '(p ?x b ?y a) '(p ?y b c a))
    ((?y . c) (?x . ?y))

  (match '(p ?x b ?y ?z) '(p ?y b c a))
    ((?z . a) (?y . c) (?x . ?y))

  (match '(a b c) '(a a a))
    nil     ... i.e nil bindings since there are no vars

  (match '(a b c) '(a b c)) 
    nil