How does one make an entire c++ class available to lua

[MoustacheSpy]

I am working on a little game library that includes a behaviour class that is supposed to handle the behaviour of certain objects. I am not sure how to implement this though.

I want to use lua to:
*)Control gameobjects
*)Control amatures and animations (for example someone could script a animation behaviour to always move the IK Bones down to the floor when playing a walk animation)

I am not very familliar with how lua works under the hood. All I know is that there is a lua "stack" on which I can push some functions and variables from c++. But in LUA there arent any classes, are there? Well then how can there be structures that interact with the c++ object below?

Also another problem I am facing is keeping this stuff dry. I need a way to use the behaviour class to control multiple types of OTHER objects. Normally this wouldnt be a problem with templates but since I also need to make different functions available to lua when a different class is passed, this doesnt seem possible. So do I need to write a seperate class for every object I want to control?

[c👌de_g🎷]

The closest thing to classes you'll see in the engine side of Lua is userdata. It can be affected by metatables like tables, but the core object is a pointer to actual data in C, and can't inherently be used as tables. For each class, you'll have to write a metatable and typeid for your userdata, then you push it to either the global environment or the registry. After this, you write Lua pushcfunc calls adding your C methods to the metatable and adapting the lua args for those methods.

In other words, you'll need Lua bindings for each class method -- you can't just push the entire class.

[drrs]

Lua is great but there are much more user-friendly scripting languages to implement into C++. I am a huge fan of AngelScript, it is a C-like scripting language and it is veryyyy easy to bind C++ objects to it (only real downside is that its slower than Lua but I haven't noticed it to be a problem).

You still have to bind each method/member but the C++ class and its data is directly exposed to the scripting language.

RegisterObjectType("InputManager", 0, asOBJ_REF | asOBJ_NOHANDLE);
RegisterGlobalProperty("InputManager input", GameEngineInterface::get()->inputManager());

RegisterObjectMethod("InputManager", "bool onActionPress(string)", asMETHOD(InputManager, isActionPressed), asCALL_THISCALL);
RegisterObjectMethod("InputManager", "bool onActionRelease(string)", asMETHOD(InputManager, isActionReleased), asCALL_THISCALL);

And in the script:

if (input.onActionPress("moveForward")) {
    // bla bla bla...
}