anchor.diff:                             (&key
                               lambda-list
                               ((:first first-param) nil)
  -                            ((:required required-param-subset) nil)
  -                            ((:optional optional-param-subset) nil)
  -                            ((:keyword keyword-param-subset) nil)
  +                            ((:required required-subset) nil)
  +                            ((:optional optional-subset) nil)
  +                            ((:keyword key-subset) nil)
                               ((:other other-subset) nil)
                               ((:rest rest-param) nil)
                               )))
     ;; Ed. NB: See remarks about the design of this lambda list parser
  -  ;; model, in the COMPUTE-LAMBDA-SIGNATURE source form
  +  ;; model, in the PARSE-LAMBDA-SIGNATURE source form
   
     (first-param
  +   ;; FIXME: May actually be a LAMBDA-ELEMENT
      nil
  -   :type param
  +   :type #+NIL param #-NIL lambda-element
      :read-only t)
   
     (lambda-list
  
positive.code: 
  
  (declaim (ftype (function
                   (list &optional function)
                   (values lambda-signature &optional))
                  compute-lambda-signature))
  
  (defun compute-lambda-signature (lambda-list &optional other-handler)
    ;;
    ;; NB: OTHER-HANDLER - if provided, a function accepting three
    ;; arguments:
    ;;
    ;; - a lambda-list keyword symbol, or a symbol or list type PARAM
  
negative.code:    :type symbol
     :read-only t)
    (value-p-p
     ;; NB: To be construed as indicating that the value-p-name was
     ;; provided from evaluation of source forms, rather than being
     ;; initialized by default as in PARSE-LAMBDA-SIGNATURE
     ;; (May be removed in a subsequent changeset)
     nil
     :type boolean
     :read-only t))
  