template<typename date_type_, typename time_duration_type_, 
         unsigned int dst_start_offset_minutes = , 
         short dst_length_minutes = > 
class us_dst_rules {
public:
  // types
  typedef time_duration_type_                             time_duration_type;
  typedef date_type_                                      date_type;         
  typedef date_type::year_type                            year_type;         
  typedef date_type::calendar_type                        calendar_type;     
  typedef date_time::last_kday_of_month< date_type >      lkday;             
  typedef date_time::first_kday_of_month< date_type >     fkday;             
  typedef dst_calculator< date_type, time_duration_type > dstcalc;           

  // public static functions
  time_is_dst_result 
  local_is_dst(const date_type &, const time_duration_type &) ;
  bool is_dst_boundary_day(date_type) ;
  date_type local_dst_start_day(year_type) ;
  date_type local_dst_end_day(year_type) ;
  time_duration_type dst_offset() ;
};