On Sun, Oct 27, 2013 at 1:35 PM, Jonathan Wakely
No proposal has reached WG21, I can't say whether anyone is working on one.
Ok.
I'm against the idea that every useful container needs to be in the standard, if you want a different set of trade-offs from the standard containers then use different containers, either from Boost, another library, or write your own.
I think I would have have the advice for most non-standard containers, but I strongly disagree in the case of flat_set, flat_map and stable_vector. The standard containers don't provide enough basic alternatives and, at least in my experience and experiences I've read online and discussed with other C++ devs, we end-up often getting back to std::vector for almost anything. Boost's flat_set and flat_map are preferable as default container than std::set/map in almost all cases I've been working on in the last 5 years (which include time I couldn't use these containers in practice). My understanding of the standard is that it should provide useful and widely used tools, like containers, which are then standard because everybody should use them by default. Adding these containers (stable_vector being discutable but I find it extremely useful too) in the standard library would, in my opinion, be a huge improvement both for performance vs simplicity reasons and for ease of education and choice: it's far simpler to just use something that is fundamentally a vector in all cases, but with the interface corresponding to the wanted manipulations, than to have to know the (wide and long to explain) differences between contiguous and node-based containers. Maybe I'm a bit biased by my specific projects, but they are of wide variety and I end up very often choosing flat_map/set instead of std::map/set simply because cases where it flat_* are what I really want occurs far more often than cases where std::set/map are what I really want. It looks like I'm not the only one praising these kind of containers: http://www.slashslash.info/2013/10/ode-to-a-flat-set/ At the time I'm writting this I'm not in the position to start working on a proposal, even if I'm really tempted (I also think I'm not a specialist so maybe I'm not legitimate for this). But I'm considering doing it in coming months when I'm done with other things.