state of libstdcxx_so_7-branch

[Benjamin Kosnik]

> Agreed. However, if you want to get a jump-start on rvalue references in 
> the library, I urge you to commit your changes to the cxx0x-branch. 
> There are some benefits to using the cxx0x-branch for these changes, 
> then merging to mainline when we can:
> 
>     (1) cxx0x-branch is tested completely in C++0x mode, so we get 
> better coverage for C++0x-specific changes.
>     (2) cxx0x-branch has rvalue references already integrated (as of 30 
> minutes ago...)
>     (3) cxx0x-branch gets nightly testing on Boost, where some 
> developers are experimenting with these features already

I think these are all pretty compelling reasons to use cxx0x branch 
instead of libstdcxx_so_7-branch.

> I don't know what to do about the libstdcxx_so_7 branch... AFAICT, the 
> cxx0x-branch hasn't done anything yet that breaks the ABI, so there are 
> certain advantages to keeping it from breaking the ABI. That said, some 
> C++0x changes will break the library ABI, so we might just be delaying 
> the inevitable...

Yes, and I'm just wondering if this means it's better to try and 
implement a "clean" C++0x library from the very beginning, with no 
hacks, one type_traits file, etc. I think dealing with a branch might be 
easier than dealing with obscured interfaces mashing the two together. 
(Especially if in the end, it turns out that doesn't give us a full 
solution for both.)

Perhaps I'm looking ahead too far, to where work progresses to the point 
of a concepts-enabled library. I see divergence growing, not shrinking 
over time. The divergence between C++0x and mainline will be much more 
substantial than say from gcc-4_1-branch to gcc-4_2-branch.

-benjamin