anchor.diff:  
   ORDERED        boolean indicating whether the objects are ordered in the containers
                  (only for REFERENCE, LIST, VECTOR and REIFIED).
  +
  +
   OPTIONS        a list of (:keyword ...) options.
      (:DOCUMENTATION string)
   
  
positive.code:     (error "The association ~A needs at least two endpoints." name))
    (assert (= 2 (length endpoints)) ()
            "Sorry, associations with more than two endpoints such ~
             as ~A are not implemented yet." name)
    (let* ((link-parameters (generate-link-parameters endpoints))
           (link-arguments  (generate-link-arguments  endpoints))
           (types           (loop :for endpoint :in endpoints
  
negative.code:     "
  DO:            Decodes the multiplicity.
  MULTIPLICITY:  may be either an integer,  or a string designator
                 the form  \"*\" or \"MIN-MAX\" or \"MIN..MAX\".
                 (beware that the token 0..1 is a 'potential number').
  RETURN:        MIN; MAX"
      (multiple-value-bind (min max)
  