A method and system for implementing functions in a class that inherits an interface
and that inherits an implementing class which implements the interface. A forwarding
system adds to the class for each virtual function a forwarding implementation
of that virtual function. The forwarding implementation forwards its invocation
to the implementation of that the virtual function in the implementing class. The
forwarding system implements a special forwarding instruction that specifies the
interface and implementing class. A developer of a class that inherits the interface
and the implementing class inserts the forwarding instruction into the class definition.
When the forwarding system encounters such an instruction during compilation of
the class definition, the forwarding system provides an implementation of each
virtual function of the interface that forwards its invocation to a corresponding
virtual function in the implementing class. The forwarding system also forwards
virtual functions of any direct or indirect base interface of the interface to
the implementing class.
