71     join( DS1&& ds1, DS2&& ds2 )  in join()  argument
72     : m_ds1( std::forward<DS1>( ds1 ) )  in join()
83     join( DS1 const& ds1, DS2 const& ds2 )  in join()  argument
84     : m_ds1( ds1 )  in join()
126 operator+( DS1&& ds1, DS2&& ds2 )  in operator +()  argument
128     return join<DS1,DS2>( std::forward<DS1>( ds1 ),  std::forward<DS2>( ds2 ) );  in operator +()
131 operator+( DS1 const& ds1, DS2 const& ds2 )
133     return join<DS1,DS2>( ds1,  ds2 );
145 operator+( DS1&& ds1, DS2&& ds2 )  in operator +()  argument
147     return std::forward<DS1>(ds1) + data::make(std::forward<DS2>(ds2));  in operator +()
154 operator+( DS1 const& ds1, DS2 const& ds2 )  in operator +()  argument
156     return ds1 + data::make(ds2);  in operator +()
168 operator+( DS1&& ds1, DS2&& ds2 )  in operator +()  argument
170     return data::make(std::forward<DS1>(ds1)) + std::forward<DS2>(ds2);  in operator +()
177 operator+( DS1 const& ds1, DS2 const& ds2 )  in operator +()  argument
179     return data::make(ds1) + ds2;  in operator +()