anchor.diff:      (%forward-ikeyword #'defsys:locate #'call-next-method
                          system-name definition-name :errorp errorp))
     (:method ((system-name symbol) definition-name &key (errorp t))
  -    (defsys:locate (defsys:locate 'defsys:system system-name)
  +    (defsys:locate (defsys:locate *root-system* system-name)
                      definition-name :errorp errorp))
  -  (:method ((system-name (eql 'defsys:system)) definition-name &key (errorp t))
  -    (declare (ignore errorp))
  -    *root-system*)
     (:method ((system defsys:hash-table-mixin) definition-name &key (errorp t))
       (declare (ignore errorp))
       (identity (gethash definition-name (slot-value system '%hash)))))
  
positive.code:     (%forward-ikeyword #'defsys:unbind #'call-next-method
                         system-name definition-name))
    (:method ((system-name symbol) definition-name)
      (defsys:unbind (defsys:locate 'defsys:system system-name)
                     definition-name))
    (:method ((system hash-table-mixin) definition-name)
      (setf (gethash definition-name (slot-value system '%hash)) nil)))
  
negative.code:   (:method ((system-name symbol) definition-name environment args
              &rest options &key &allow-other-keys)
      (apply #'defsys:expand-definition
             (defsys:locate *root-system* system-name)
             definition-name environment args options)))
  
  (defmacro defsys:define ((kind definition-name &body options)
  