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

From: René Haber (rene.haber_at_[hidden])
Date: 2006-10-03 05:43:38

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<Person, std::string, &Person::name> >,
    ordered_non_unique< tag<city>, member<Person, std::string, 
&Person::city> >
  >
 > 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