anchor.diff:     #:find-block-in-lexenv
      #:find-tag-in-lexenv
   
  +   ;;;
  +   ;;; walker
  +   ;;;
      #:form
      #:walk-form
  -   #:make-walk-environment
  -   #:*walk-handlers*
  +   #:unwalk-form
  +   #:unwalk-forms
  +   #:unwalk-lambda-list
  +   #:macroexpand-all
  +   #:make-walkenv
      #:*warn-undefined*
  +
      #:undefined-reference
      #:undefined-variable-reference
      #:undefined-function-reference
      #:return-from-unknown-block
  +
      #:defwalker-handler
  +   #:defunwalker-handler
  +
      #:implicit-progn-mixin
      #:implicit-progn-with-declare-mixin
      #:binding-form-mixin
      #:declaration-form
      #:constant-form
  -   #:variable-reference
  -   #:local-variable-reference
  -   #:local-lexical-variable-reference
  -   #:free-variable-reference
  +   #:variable-reference-form
  +   #:lexical-variable-reference-form
  +   #:unwalked-lexical-variable-reference-form
  +   #:free-variable-reference-form
      #:application-form
  -   #:local-application-form
      #:lexical-application-form
  +   #:walked-lexical-application-form
  +   #:unwalked-lexical-application-form
      #:free-application-form
      #:lambda-application-form
      #:function-form
      #:lambda-function-form
      #:function-object-form
  -   #:local-function-object-form
  +   #:walked-lexical-function-object-form
      #:free-function-object-form
  -   #:lexical-function-object-form
  +   #:unwalked-lexical-function-object-form
      #:function-argument-form
      #:required-function-argument-form
      #:specialized-function-argument-form
  
positive.code: 
    (:export
  
     #:make-empty-lexenv
     #:macroexpand-all
  
     #:do-variables-in-lexenv
  
negative.code:    #:go-form
     #:the-form
     #:unwind-protect-form
  
     #:walk-lambda-list
     #:walk-implict-progn
     #:body
     #:cleanup-form
     #:code-of
     #:consequent
     #:declares
     #:default-value
  ;; #:else ; iterate
     #:enclosing-tagbody-of
     #:eval-when-times
     #:first-form
     #:func
     #:keyword-name
     #:name-of
     #:other-forms
     #:parent
     #:protected-form
     #:read-only-p
     #:result
     #:source
     #:specializer-of
     #:supplied-p-parameter
     #:tag
     #:target-block-of
     #:jump-target-of
     #:then
     ;;#:type-of
     #:value-of
     #:values-form
     #:variable-name-of
     #:vars-form
  
     ))
  