can_be | CanBe allows you to track the type of your ActiveRecord | Web Framework library

I am using C++11, and was trying to set up a generic Handle class in my application, where it is sometimes possible to convert handles with different underlying types, but only if the underlying types are related as ancestor/descendant, otherwise attempts to convert should simply fail. I also need a function that will never fail that tells me if a conversion is even possible between the two types. In particular, I do not want the underlying type to try to do any conversion to types that are not within its own ancestry/descendant lines, so I was thinking if I defined a templated functor on a boolean that told me at compile time whether the types were related, and used template specialization to reject the conversion if they are not related, or to forward the conversion request to the underlying type if they are related. Each base class contains a templated conversion function that knows how to convert to each of the corresponding types in it hierarchy as well as a templated boolean function that indicates if such conversion is possible based on the internal states of the class instance.

What I put together looks like this: