sol2/docs/source/tutorial/existing.rst
2016-04-11 02:15:06 -04:00

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integrating into existing code
==============================
If you're already using lua and you just want to use ``sol`` in some places, you can use ``state_view``:
.. code-block:: cpp
:linenos:
:caption: using state_view
:name: state-view-snippet
void something_in_my_system (lua_State* L) {
// start using Sol with a pre-existing system
sol::state_view lua(L); // non-owning
lua.script("print('bark bark bark!')");
sol::table expected_table(L); // get the table off the top of the stack
// start using it...
}
:doc:`sol::state_view<../api/state` is exactly like ``sol::state``, but it doesn't manage the lifetime of a ``lua_State*``. Therefore, you get all the goodies that come with a ``sol::state`` without any of the ownership implications. Sol has no initialization components that need to deliberately remain alive for the duration of the program. It's entirely self-containing and uses lua's garbage collectors and various implementation techniques to require no state C++-side. After you do that, all of the power of `Sol` is available to you, and then some!
Remember that Sol can be as lightweight as you want it: almost all of Sol's types take the ``lua_State*`` argument and then a second ``int index`` stack index argument, meaning you can use :doc:`tables<../api/table>`, :doc:`lua functions<../api/function>`, :doc:`coroutines<../api/coroutine>`, and other reference-derived objects that expose the proper constructor for your use. You can also set :doc:`usertypes<../api/usertype>` and other things you need without changing your entire architecture!