Thanks a lot jeff! It did put me on the right track... This is the compilable version. Thanks & kind regards, Peter //------------------------------------------------------------- #include <boost/mpl/if.hpp> #include <boost/mpl/inherit.hpp> #include <boost/mpl/inherit_linearly.hpp> #include <boost/mpl/int.hpp> #include <boost/mpl/fold.hpp> #include <boost/mpl/pair.hpp> #include <boost/mpl/push_back.hpp> #include <boost/mpl/vector.hpp> #include <boost/multi_index_container.hpp> #include <boost/multi_index/indexed_by.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> namespace mpl = boost::mpl; namespace bmi = boost::multi_index; struct ATTR_1 {}; struct ATTR_2 {}; struct ATTR_3 {}; template <typename attrT> struct AttrTraits { typedef int type; }; template <typename AttrT> struct Attribute { typedef AttrTraits<AttrT> ATraits; typename ATraits::type value; }; template <typename AttrList> struct Object : public boost::mpl::inherit_linearly< AttrList, boost::mpl::inherit<boost::mpl::_1, Attribute<boost::mpl::_2> >
::type {};
struct unique {}; struct non_unique {}; template <typename T> struct is_unique : boost::false_type {}; template <> struct is_unique<unique> : boost::true_type {}; template <typename AttrT> struct GetUnique { typedef bmi::ordered_unique< bmi::tag<AttrT>, bmi::member< Attribute<AttrT>, typename AttrTraits<AttrT>::type, &Attribute<AttrT>::value
type;
}; template <typename AttrT> struct GetNonUnique { typedef bmi::ordered_non_unique< bmi::tag<AttrT>, bmi::member< Attribute<AttrT>, typename AttrTraits<AttrT>::type, &Attribute<AttrT>::value
type;
}; template<typename ObjectT, typename IndicesMap> struct ObjectContainer { typedef typename mpl::fold< IndicesMap, mpl::vector<>, mpl::if_< is_unique<mpl::first<mpl::_2> >, mpl::push_back< mpl::_1, GetUnique<mpl::second<mpl::_2> >
, mpl::push_back< mpl::_1, GetNonUnique<mpl::second<mpl::_2> >
::type IndexList;
typedef boost::multi_index_container<ObjectT, IndexList> Container_t; Container_t Container; }; int main() { typedef boost::mpl::vector< ATTR_1, ATTR_2, ATTR_3
AttributeList_1;
typedef Object<AttributeList_1> Object_1; typedef mpl::vector< mpl::pair<unique, ATTR_1>, mpl::pair<non_unique, ATTR_2>
Object_1_Indices;
ObjectContainer<Object_1, Object_1_Indices> Object1Container; Object_1 obj1; Object1Container.Container.get<ATTR_1>().insert(obj1); return 0; } //-------------------------------------------------------------