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