...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::xpressive::op::length
// In header: <boost/xpressive/regex_actions.hpp> struct length { // member classes/structs/unions template<typename Sig> struct result { }; template<typename This, typename Sub> struct result<This(Sub)> { }; // public member functions template<typename Sub> Sub::difference_type operator()(Sub const &) const; };