What is the status of N2965 - std::bases and std::direct_bases?

Question

I'm writing a template which really needs to know about all the base classes of its parameter type. The std::bases trait proposed by N2965 is perfect for this, however I can't find any reliable information about its status.

Is this proposal still alive? If so, when might we be likely to see it, standardized? If not, are there any other proposals around that would provide this capability?

As a follow-up, g++ has the two N2965 traits available as std::tr2::bases and std::tr2::direct_bases. Are there any extensions for Clang and/or Intel that can provide equivalent functionality?

Araujo

This on its own is unlikely to go anywhere. When we start down this route, we'll surely also add other introspection/reflection facilities rather than singling out just one property (the base classes of something). – Lame

Answer 1

As far as I can tell this was rejected we can see this from N3296: C++ FCD Comment Status Rev 6 which has the following comment:

Paper n2965 was largely rejected after the last CD on the grounds there was no associated national body comment, so I am submitting a national body comment this time.

and the disposition ended up being:

REJECTED

There is no consensus to adopt this proposal at this time

We can find a comment from Jonathan Wakely which points us to the gcc patches email about implementing N2965 into gcc and he notes that there is no TR2 anymore.

I don't see any follow-up proposals for this

Diffusivity

Why? It was proposed, discussed and was rejected. You would say the same if every proposal, no matter how niche, was added without comment. – Leckie

> " on the grounds there was no associated national body comment" how in earth is this a valid reason for rejecting something ? – Stifling

@Jean-MichaëlCelerier - It's a matter of timing. At a point where the committee draft (CD) is already out on a formal review by the national bodies, the committee cannot add new material without a strong request from the voting nations. Apparently a single such request wasn't enough. – Cuttlefish