template<typename tag, typename... tags>
tk::grm::action<Store_back_back_back<tag, tags...>> struct

Convert and push back value to vector of back of vector of back of vector in state at position given by tags.

This struct and its apply function are used as a functor-like wrapper for calling the store_back_back_back member function of the underlying grammar stack, tk::Control::store_back_back_back.