...one of the most highly
regarded and expertly designed C++ library projects in the
world. — Herb Sutter and Andrei
str is a lazy PolymorphicFunctionObject for converting a
xpressive::sub_match<> to a
std::basic_string<> in an xpressive semantic action.
// In header: <boost/xpressive/regex_actions.hpp> function< op::str >::type const str;