Provides a function to conceal the type of an instance.
This class is a standard built-in class in the Rice language.
Instance that is created by declaration is still uninitialized.
The proxy type cannot initialize by the proxy type.
Operation to the proxy will be converted to the operation of the instance that is held.
Get a new instance of proxy class with initial value.
Return a proxy type instance that is initialized by the any instance.
Sets a new instance to the proxy.
It releases the reference of the caller instance and returns it to the uninitialized state.