tr1::regex

[Benjamin Kosnik]

> Should I be working from HEAD or a branch for this?

HEAD is preferred, always, for development.

I don't think a branch specifically for the regex work in libstdc++ is
necessary. First, it just adds more work for you. Second, this stuff
should be pretty isolated, so it is by nature confined  to the <regex>
include file. 

Because it's so well-defined, I would think that you could even do your
development with gcc-4_2-branch if you don't want to play games with the
compiler churn on mainline at the moment. At set points, just make sure
it compiles with a snapshot of mainline, and post the patch. 

best,
-benjamin