Reference Objects
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    Reference objects were implemented mainly for internal and future use,
    but may be of use in applications.  A reference object refers to
    another object, in much the same way that two different variables in
    Clipper can refer to the same array (or object).  The difference is
    that a reference object can belong to a different class from the object
    it refers to - it can belong to any class in the superclass chain of
    the object it refers to.  A reference object can be obtained by sending
    the super message to an object.  For example:

        oRef := obj:super

    If obj belonged to a class which had an ancestor class, somewhere in
    its tree, called Rectangle, then the above message would result in a
    reference object, of class Rectangle,

    The expression obj:super returns a reference to obj which is
    'scoped' to the superclass of obj.  This reference can be stored in
    a variable, such as oRef in the example.  oRef and obj refer to the
    same object, but oRef will only handle messages belonging to obj's
    superclass.

    Note:

    Class(y) also returns a reference object if you send a message
    corresponding to the class name of an ancestor class to an object.
    This feature may not be supported in future versions of Class(y).