anchor.diff:     #:the-form
      #:extract-argument-names
      #:walk-lambda-list
  -
  +   #:walk-implicit-progn
  +   #:arguments
  +   #:binds
  +   #:body
  +   #:cleanup-form
  +   #:code
  +   #:consequent
  +   #:declares
  +   #:default-value
  +;; #:else ; iterate
  +   #:enclosing-tagbody
  +   #:eval-when-times
  +   #:first-form
  +   #:func
  +   #:keyword-name
  +   #:name
  +   #:operator
  +   #:optimize-spec
  +   #:other-forms
  +   #:parent
  +   #:protected-form
  +   #:read-only-p
  +   #:result
  +   #:source
  +;; #:specializer ; closer-mop
  +   #:supplied-p-parameter
  +   #:tag
  +   #:target-block
  +   #:target-progn
  +   #:then
  +   #:type-form
  +   #:value
  +   #:values-form
  +   #:var
  +   #:vars-form
  +
  +   #:defunwalker-handler
      #:unwalk-form
  +   #:unwalk-forms
  +   #:unwalk-lambda-list
   
      #:to-cps
      #:with-call/cc
  
positive.code:    #:and-bind
     #:if2-bind
     #:aif2
  ;; #:while ;; iterate
     #:awhile
  ;; #:until ;; iterate
     #:it
     #:whichever
     #:xor
  
negative.code:    #:with-collector
     #:with-collectors
  
     #:form
     #:walk-form
     #:make-walk-env
     #:*walk-handlers*
  