light/user ================ *utility class for the cheapest form of (light) userdata* .. code-block:: cpp template struct user; template struct light; ``sol::user`` and ``sol::light`` are two utility classes that do not participate in the full :doc:`sol::usertype\` system. The goal of these classes is to provide the most minimal memory footprint and overhead for putting a single item and getting a single item out of Lua. ``sol::user``, when pushed into Lua, will create a thin, unnamed metatable for that instance specifically which will be for calling its destructor. ``sol::light`` specifically pushes a reference / pointer into Lua as a ``sol::type::lightuserdata``. If you feel that you do not need to have something participate in the full :doc:`usertype\` system, use the utility functions ``sol::make_user( ... )`` and ``sol::make_light( ... )`` to create these types and store them into Lua. You can get them off the Lua stack / out of the Lua system by using the same retrieval techniques on ``get`` and ``operator[]`` on tables and with stack operations. Both have implicit conversion operators to ``T*`` and ``T&``, so you can set them immediately to their respective pointer and reference types if you need them.