anchor.diff:    (:method ((system-name symbol) definition-name environment args &rest options)
       (apply #'defsys:expand-definition
              (defsys:locate *root-system* system-name)
  -           definition-name environment args options)))
  +           definition-name environment args options))
  +  (:method ((system %root-system) name environment args &key)
  +    (declare (ignore environment))
  +    (destructuring-bind (class &rest args) args
  +      `(defsys:ensure ',(defsys:name system) ',name ',class ,@args))))
   
   (defmacro defsys:define ((kind definition-name &body options)
                            &body args &environment env)
  
positive.code:                    definition-name :errorp errorp))
    (:method ((system defsys:hash-table-mixin) definition-name &key (errorp t))
      (declare (ignore errorp))
      (identity (gethash definition-name (slot-value system '%hash)))))
  
  (defgeneric (setf defsys:locate) (new-definition system definition-name &key errorp)
    (:method (new-definition (system-name symbol) definition-name &key (errorp nil))
  
negative.code: (defclass defsys:standard-system (defsys:name-mixin defsys:hash-table-mixin defsys:system)
    ())
  
  (defclass %root-system (defsys:standard-system) ())
  
  (defvar *root-system* (make-instance '%root-system :name 'defsys:system))
  
  (defun defsys:root-system ()
    *root-system*)
  