[Boost-users] [multi_index] How to iterate by user selected index

Hello, I'm looking for an easy way to iterate over a set by a user selected index. A little example: [code] struct Person { std::string name; std::string city; }; struct city{}; struct name{}; typedef multi_index_container< Person, indexed_by< ordered_unique< tag<name>, member >, ordered_non_unique< tag<city>, member >

person_set;

typedef Person::index<name>::type Person_by_name; typedef Person::index<city>::type Person_by_city; person_set persons; for(Person_by_name::iterator it = persons.get<name>().begin(); .....) {...} [/code] This for loop is hard-coded to iterate over the set sorted by name. How can I dynamically change the iterator used in this loop to let the user decide the sort criteria? Greetings, René