Injecting LuaObject structure

[ashtonmeuser]

Currently, the recommended way of adding a LuaObject class to the environment is to do state.Environment["Vector2"] = new Vector3();. This adds a full "instance" of the class as a Lua table. This includes non-static properties and methods.

In my opinion, the way "classes" are injected should further mirror C#. Perhaps a state.Environment.Inject(Vector3) or something similar. Instead of instantiating the class and adding this instance to the environment as a table, it should simply add all static methods and properties. The type can still be used as a LuaValue in that it can be passed to and received from Lua. But the e.g. x property and normalized method of the global Vector3 class in the README are really meaningless.

TL;DR: Provide a way to add only static properties and methods to Lua environment global table, mirroring the C# class interface.

For example, the Vector3 class in the README would expose the create method to Lua but not normalized.

[ashtonmeuser]

For more context, here's how I'm currently exposing my Vector2 class to Lua. Note that I'm using two LuaObject annotated classes, one for instance properties/methods, and the other for static properties/methods including initialization via Vector2.new(x, y). The static version is the only one injected into the Lua environment as a global "class" via state.Environment["Vector2"] = new LuaVector2Class();.

using UnityEngine;
using Lua;

[LuaObject]
public partial class LuaVector2
{
    public Vector2 vector;

    [LuaMember("x")]
    public float X { get => vector.x; set => vector.x = value; }

    [LuaMember("y")]
    public float Y { get => vector.y; set => vector.y = value; }

    public LuaVector2(Vector2 v) => vector = v;

    [LuaMember("normalized")]
    public LuaVector2 Normalized() => new LuaVector2(Vector2.Normalize(vector));

    [LuaMetamethod(LuaObjectMetamethod.Add)]
    public static LuaVector2 Add(LuaVector2 a, LuaVector2 b) => new LuaVector2(a.vector + b.vector);

    [LuaMetamethod(LuaObjectMetamethod.Sub)]
    public static LuaVector2 Sub(LuaVector2 a, LuaVector2 b) => new LuaVector2(a.vector - b.vector);

    [LuaMetamethod(LuaObjectMetamethod.ToString)]
    public override string ToString() => vector.ToString();
}

[LuaObject]
public partial class LuaVector2Class
{
    [LuaMember("new")]
    public static LuaVector2 New(float x, float y) => new LuaVector2(new Vector2(x, y));
}