[Boost-users] [Boost.MultiIndex] docs unclear for ey extractors

Hi! In http://boost.org/libs/multi_index/doc/advanced_topics.html #advanced_key_extractors I do not understand how the struct name_extractor comes to use and why I have to define it. IIUC the code snippet -------------------------------- typedef multi_index_container< employee *, indexed_by< ordered_non_unique<member<employee,std::string,&employee::name> > >

employee_set;

takes care of all what I need even without it - or do I have to define the struct to make this work? Markus