[Boost-users] [MultiIndex] is it possible to create multi-key key-extractors?

Subject: [Boost-users] [MultiIndex] is it possible to create multi-key key-extractors?
From: Mostafa (mostafa_working_away_at_[hidden])
Date: 2010-08-08 09:05:06

Hi,

For the following struct:

struct Flower
{
   int type;
   string name;
   std::list<string> aliases;
};

I want to create a multiindexed container that indexes Flower objects by  
type, name, and aliases, where aliases is some iteratable collection of  
strings.  I just don't know if it's possible to create a multi-key  
key-extractor for aliases.  So far I've come up with the following:

typedef boost::multi_index_container<
   Flower,
   indexed_by<
     ordered_unique<
       member<Flower, int, &Flower::type>
     >,
     ordered_unique<
       member<Flower, string, &Flower::name>
     >,
     ordered_unique<
       //What goes here ... ?
     >
   >
> FlowerMngr;

Thanks,

-Mostafa