anchor.diff:  	(->sym (third form))))
   
   (define-transform-rule (:with form)
  -  (let* ((lexenv-chain (cons :obj lexenv-chain))
  -	 (placeholder (copy-list lexenv-chain)))
  -    (push placeholder environments)
  +  (with-new-lexical-environment (env :obj)
       (list (js-intern (car form))
  -	  placeholder
  +	  env
   	  (transform-tree (second form))
   	  (transform-tree (third form)))))
   
  
positive.code: (in-package :js)
  
  
  (defparameter lexenv-chain nil)
  
  ;;
  (defun transform-tree (form)
    (cond ((null form) nil)
  	((atom form)
  
negative.code: 
  (defmacro define-transform-rule ((rule form) &body body)
    `(defmethod apply-transform-rule ((,(gensym) (eql ,rule)) ,form)
       (declare (special locals environments lexenv-chain toplevel))
       ,@body))
  
  (defgeneric apply-transform-rule (keyword form)
  