I have a class that requires a boost::variant containing shared pointers to various types as follows:

    template <typename ToySharedPtrVariant, typename ColorSharedPtrVariant>

    class ToyPicker {

       typedef std::pair<

         ToySharedPtrVariant, 

         ColorSharedPtrVariant 

       > toyAndColorPair;

       typedef std::map<

         std::string,

         std::vector< 

           toyAndColoPair 

         > 

       > stringToToyColorPairMap;

       // ... methods that use the defined types...

    }

This class currently requires template parameters of the following form to compile:

    ToyPicker<

               boost::variant<

                 boost::shared_ptr<ToyModel> 

               >,

               boost::variant<

                 boost::shared_ptr<BlueToy>,

                 boost::shared_ptr<RedToy>,

                 boost::shared_ptr<GreenToy> 

               > 

             > toyPicker;

How do I use an mpl list so that I can allow the following much simpler definition for users, then convert it into the one above inside my class?

    ToyPicker<

           boost::mpl::list<

             ToyModel

           >,

           boost::mpl::list<

             BlueToy,

             RedToy,

             GreenToy 

           > 

         > toyPicker;