anchor.diff:  
   (defmethod add-variable-ignore (environment symbol ignore)
     (make-instance 'variable-ignore
  +    :next environment
       :name symbol
       :ignore ignore))
   
  
positive.code: 
  (defmethod add-function-ignore (environment function-name ignore)
    (make-instance 'function-ignore
      :name function-name
      :ignore ignore))
  
  
negative.code: 
  (defmethod add-block (environment symbol)
    (make-instance 'block
      :next environment
      :name symbol
      :identity (gensym)))
  
  