Would it be better to make the pointer_plus_bits convertible to a boolean based on the value of the pointer being stored? This would allow it to be more like to a pointer being that you could, as many people do, put it inside of an if statement to check to see if its null.
No. One could argue that the bits should be evaluated to produce the Boolean result as easily as evaluating the pointer. There are two aspects in pointer_plus_bits and they shouldn't be obscured or conflated.
I strongly disagree with using views in the design of this data structure. It's not such a complex concept that you would need to explicitly decouple its concerns via views. You end up designing a pointer+bits that can't be used natively as a pointer or bits. The data structure is pointer_(plus_bits). First and foremost, I would expect its instances to model (at least some) Pointer semantics, which includes "if(p)" and not "if(pointer_view<...>(p))". Dereferencing the pointer returns the object being pointed at--although it could also return a pair with the object and extra bits, which might be kind of neat. Otherwise, I suspect that providing a small set of member functions to interact with the bitfield would be perfectly acceptable. Andrew Sutton andrew.n.sutton@gmail.com