Restrict inheritance to desired number of classes at compile-time

Question

We have a restriction that a class cannot act as a base-class for more than 7 classes. Is there a way to enforce the above rule at compile-time?

I am aware of Andre

Answer 1

Rather than cluttering the code with assertions, you might be able to use something like GCC-XML, which parses C++ source using the g++ compiler frontend and generates XML output. I expect that it would be reasonably straightforward to develop a tool that parses this output and checks for violations of the rule; this could then be integrated with source code check-in.

BTW, having base classes know about their descendants violates the Open-Closed Principle, meaning that it actually undercuts the usefulness of OO programming in general. The main reason for separating code into base classes and subclasses is so that the base class does not have to know about its subclasses -- this makes possible things like plugin packages delivered after installation.