boost::pfr

[xR3b0rn]

In the current beta release of boost, boost::pfr comes with a new feature for extracting the struct name from a given type. This way structopt could get rid of the library visit_struct and fully rely on boost::pfr. Or, since the new boost::pfr feature requries C++20, to still support older C++ standards , the current reflection mechanism might stay as fallback.