RLS11 — The usage of ParameterValue class is not clear

First, it is hard to access the target Parameter from ParameterValueBase. Second, it is not clear whether we should provide a pointer to a real Parameter instance for ParameterValue::param attribute or use a clone. If clone, we should deallocate the memory (who do?) If not clone, we should not deallocate the memory. There is a possibility that the values of ParameterValue::val and ParameterValue::param.val are inconsistent. How about ParamterValue class to refer to the ID of Parameter instance not the instance itself?

Whether to use a pointer or cloned instance is an implementation issue and will
not be discussed here. As suggested, one way of implementation is to refer to
some ID of Parameter instance, such as the one inherited from
ISO19111::IO_IdentifiedObject. See issue 16201 for discussion on the
referencing system.
As for the two ‘val’ attributes, the actual values for each Attribute (or Parameter)
instance is held by Attribute.val. ParameterValueBase and inherited class
instances are used for passing the values to be set, typically through
InterfaceBase::setParameterValues() or to obtain the current values through
InterfaceBase::getParameterValues(). As this was not clearly stated in the
specification, we will add some more description.