anchor.diff:  
   (defclass the-form (form)
     ((type :accessor type-of :initarg :type)
  -   (value :accessor value :initarg :value)))
  +   (value :accessor value-of :initarg :value)))
   
   (defwalker-handler the (form parent env)
     (with-form-object (the the-form :parent parent :source form
                                     :type (second form))
  -    (setf (value the) (walk-form (third form) the env))))
  +    (setf (value-of the) (walk-form (third form) the env))))
   
   ;;;; UNWIND-PROTECT
   
  
positive.code:     :accessor variable-name-of
      :initarg :variable-name)
     (value
      :accessor value
      :initarg :value)))
  
  (defwalker-handler setq (form parent env)
  
negative.code:           (ecase type
              (setq (with-form-object (setq setq-form :parent parent :source form
                                            :variable-name var)
                      (setf (value-of setq) (walk-form value setq env))))
              (setf (walk-form (first effective-code) parent env))))
          ;; multiple forms
          (with-form-object (progn progn-form :parent parent :source form)
  