// In header: <boost/log/utility/record_ordering.hpp>
template<typename ValueT, typename FunT = less> 
class attribute_value_ordering : private FunT {
public:
  // types
  typedef bool   result_type;  // Result type. 
  typedef ValueT value_type;   // Compared attribute value type. 
  // member classes/structs/unions
  struct l1_visitor {
    // types
    typedef void result_type;
    // construct/copy/destruct
    l1_visitor(attribute_value_ordering const &, record_view const &, bool &);
    // public member functions
    template<typename LeftT> result_type operator()(LeftT const &) const;
  };
  template<typename LeftT> 
  struct l2_visitor {
    // types
    typedef void result_type;
    // construct/copy/destruct
    l2_visitor(FunT const &, LeftT const &, bool &);
    // public member functions
    template<typename RightT> result_type operator()(RightT const &) const;
  };
  // construct/copy/destruct
  explicit attribute_value_ordering(attribute_name const &, 
                                    FunT const & = FunT());
  // public member functions
  result_type operator()(record_view const &, record_view const &) const;
};