Hi Eric, My semantic actions might look like +(name[push_back(ref(causeNames),as<std::string>(_) )]); My first question here is whether ref() is really necessary? In your example from the documentation, I can better understand it: [ ref(result)[s1] = as<int>(s2) ]; because you apply the [] operator to the result. But otherwise, is there any time you not want a reference stored? In my case above, couldn't the destructor of push_back() take a T& argumentment and construct a lazy reference from that? I also have another question: is it really necessary to write the as<std::string>(_) part of the semantic action? Can this type not be deduced from the template argument to push_back()? In my case it would simply be Container::value_type. If so, we would end up with the really slick looking +(name[push_back(causeNames)]); best regards -Thorsten