nvector

#include "boost/type_traits/declval.hpp"
#include "boost/foreach.hpp"
#include <vector>

template <int N, typename T>
struct NVector{
    typedef std::vector<typename NVector<N-1,T>::type> type;
};
template <typename T> struct NVector<1,T> {
    typedef std::vector<T> type;
};

template <typename T, typename Mapper>
struct MapResult {
    typedef decltype(boost::declval<Mapper>()(boost::declval<T>())) type;
};

template <typename T, typename Mapper>
struct MapResult<std::vector<T>, Mapper> {
    typedef std::vector<typename MapResult<T, Mapper>::type> type;
};

template <typename T, typename Mapper>
typename MapResult<T, Mapper>::type Map(T const& elem, Mapper&& mapper)
{
    return mapper(elem);
}

template <typename T, typename Mapper>
typename MapResult<std::vector<T>, Mapper>::type Map(std::vector<T> const& vector, Mapper&& mapper)
{
    MapResult<std::vector<T>, Mapper>::type  out;
    out.reserve(vector.size());
    BOOST_FOREACH(auto& v , vector)
        out.push_back(Map(v, mapper));
    return out;
}