The most important class here is ``state_view``. This structure takes a ``lua_State*`` that was already created and gives you simple, easy access to Lua's interfaces without taking ownership. ``state`` derives from ``state_view``, inheriting all of this functionality, but has the additional purpose of creating a fresh ``lua_State*`` and managing its lifetime for you in the default constructor.
The majority of the members between ``state_view`` and :doc:`sol::table<table>` are identical, with added for this higher-level type. Therefore, all of the examples and notes in :doc:`sol::table<table>` apply here as well.
This enumeration details the various base libraries that come with Lua. See the `standard lua libraries`_ for details about the various standard libraries.
members
-------
..code-block:: cpp
:caption: function: open standard libraries/modules
These functions run the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It will not run isolated: any scripts or code run will affect code in the ``lua_State*`` the object uses as well (unless ``local`` is applied to a variable declaration, as specified by the Lua language). Code ran in this fashion is not isolated. If you need isolation, consider creating a new state or traditional Lua sandboxing techniques.
If your script returns a value, you can capture it from the returned :ref:`sol::function_result<function-result>`/:ref:`sol::protected_function_result<protected-function-result>`.
To handle errors when using the second overload, provide a callable function/object that takes a ``lua_State*`` as its first argument and a ``sol::protected_function_result`` as its second argument. Then, handle the errors any way you like:
..code-block:: cpp
:caption: running code safely
:name: state-script-safe
int main () {
sol::state lua;
// the default handler panics or throws, depending on your settings
auto result1 = lua.script("bad.code", &sol::default_on_error);
auto result2 = lua.script("123 bad.code", [](lua_State* L, sol::protected_function_result pfr) {
// pfr will contain things that went wrong, for either loading or executing the script
// the user can do whatever they like here, including throw. Otherwise,
// they need to return the protected_function_result
// You can also just return it, and let the call-site handle the error if necessary.
You can also pass a :doc:`sol::environment<environment>` to ``script``/``script_file`` to have the script have sandboxed / contained in a way inside of a state. This is useful for runnig multiple different "perspectives" or "views" on the same state, and even has fallback support. See the :doc:`sol::environment<environment>` documentation for more details.
These functions play a role similar to `luaL_requiref`_ except that they make this functionality available for loading a one-time script or a single file. The code here checks if a module has already been loaded, and if it has not, will either load / execute the file or execute the string of code passed in. If ``create_global`` is set to true, it will also link the name ``key`` to the result returned from the open function, the code or the file. Regardless or whether a fresh load happens or not, the returned module is given as a single :doc:`sol::object<object>` for you to use as you see fit.
Thanks to `Eric (EToreo) for the suggestion on this one`_!
These functions *load* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It will not run: it returns a ``load_result`` proxy that can be called to actually run the code, turned into a ``sol::function``, a ``sol::protected_function``, or some other abstraction. If it is called, it will run on the object's current ``lua_State*``: it is not isolated. If you need isolation, consider creating a new state or traditional Lua sandboxing techniques.
These functions *loads and performs* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It *will* run, and then return a ``protected_function_result`` proxy that can be examined for either an error or the return value.
Get either the global table or the Lua registry as a :doc:`sol::table<table>`, which allows you to modify either of them directly. Note that getting the global table from a ``state``/``state_view`` is usually unnecessary as it has all the exact same functions as a :doc:`sol::table<table>` anyhow.
Overrides the panic function Lua calls when something unrecoverable or unexpected happens in the Lua VM. Must be a function of the that matches the ``int(lua_State*)`` function signature.
Returns the amount of memory used *in bytes* by the Lua State.
..code-block:: cpp
:caption: function: collect_garbage
:name: collect-garbage
void collect_garbage();
Attempts to run the garbage collector. Note that this is subject to the same rules as the Lua API's collect_garbage function: memory may or may not be freed, depending on dangling references or other things, so make sure you don't have tables or other stack-referencing items currently alive or referenced that you want to be collected.
