// In header: <boost/xpressive/regex_actions.hpp>


struct back {
  // member classes/structs/unions
  template<typename Sig> 
  struct result {
  };
  template<typename This, typename Sequence> 
  struct result<This(Sequence)> {
    // types
    typedef mpl::if_c< is_const< sequence_type >::value, typename sequence_type::const_reference, typename sequence_type::reference >::type type;

    // public member functions
    typedef UNREF(Sequence);
  };

  // public data members
  result< back(Sequence &)>::type operator();
};