I know, C++11 has many fancy features and all, and I'm all for its adoption too. But Boost also serves practical purpose, and if people can't use your library then that just limits its usefulness. So unless you trying to make some academic work here, the library should be more portable.
Seems an undue constraint on a new library to me.
Adding a new C++11 library harms no one that doesn't have have a C++11 compiler.
If you need a C++03 version of a C++11 only library and you feel it is not an unreasonable amount of work to provide you could just fork the library into your own github and do the backporting.
Whether this is good enough for Boost will be decided during the review and not by individual interests. Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu