Please ignore my last message. I somehow accidentally sent it while still editing! I am trying to create a std::map from an mpl::map. I've been trying to figure out how to use mpl::for_each to accomplish this. The problem I have is that the runtime function is passed to for_each by value and returns void. All the examples I've seen for mpl::for_each involve printing and not creating any new objects. Here is the attempt I've made: // creates std::map<size_t,size_t> from mpl::map<size_t,size_t> template<typename TypeMap> struct MapMaker { typedef std::map<size_t, size_t> map_type; map_type func_map; MapMaker() { boost::mpl::for_each<TypeMap>(*this); } template<typename U> void operator()(U x) { func_map[U::first::value]=U::second::value; } func_type operator[](size_t i) { return func_map[i]; } }; typedef boost::mpl::map< boost::mpl::pair<boost::mpl::size_t<1>, boost::mpl::size_t<2> >, boost::mpl::pair<boost::mpl::size_t<2>, boost::mpl::size_t<24> >,

myMap;

int main() { MapMaker<myMap> m; size_t result = m[1]; } Of course this is a simplified version of what I'm really trying to do, which is create a map to function pointers. The problem is in the call to mpl::for_each in the MapMaker constructor. The std::map is created, but never returned. I've considered making func_map static, but that complicates things quite a bit, especially since MapMaker it is a class template. Luke Skelly