anchor.diff:     ;;; walker
      ;;;
      #:form
  +   #:walk-ast
      #:walk-form
      #:unwalk-form
      #:unwalk-forms
  
positive.code:    #:constant-form
     #:variable-reference-form
     #:lexical-variable-reference-form
     #:unwalked-lexical-variable-reference-form
     #:free-variable-reference-form
     #: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
     #:walked-lexical-function-object-form
     #:free-function-object-form
     #:unwalked-lexical-function-object-form
     #:function-argument-form
     #:required-function-argument-form
     #:specialized-function-argument-form
  
negative.code:    #:tag
     #:target-block-of
     #:jump-target-of
     #:then-of
     ;;#:type-of
     #:value-of
     #:values-form-of
     #:variable-name-of
     #:variables-form-of
  
     ))
  