C++ Integration and Assignments

["Marc Fascia" <m_fascia@...>]

Hi,

I am currently interfacing LUA with my game engine (C++) and the process is 
going rather smoothly but i've come across some issues I can't tackle all by 
myself :)

On the engine side, all objects share a common base class called Object 
which has a reflection system allowing to browse/access/invoke object fields 
and members at runtime (just like the C# or Java reflection system).

I want to manipulate these objects via Lua in a C++/OOP fashion. I managed 
to dereference sub objects by overloading the __index of my Object metatable 
and even call objects methods by overloading __call. These two hooks are 
very simple since they only need to query the reflection system for the 
right object field or method and return a pointer on an object via a 
lightuserdata or a closure on the needed method.

But when it come to assignments, I can't get some simple syntax :

C++:
	class Object
	{
		String * ToString();
		Object * Parse( String * str );
	};

	class Vector : public Object
	{
		Float X;
		Float Y;
		...
		Float SetNull();
	};

Lua:
	-- I want to write code like this
	v = new( "Vector" );
	v:SetNull();
	v.x = 0.2;	-- for now, i must write: 	v.x:Parse( CreateString( "0.2" ) );
	v.y = 1.5;	-- for now, i must write: 	v.y:Parse( CreateString( "1.5" ) );

	-- i need to hook to the assignment operation in order to correctly set 
v.x.

So basically what I want is a way to convert some lua values to a custom 
format when stumbling across code like "EngineObjectRef = LuaValue". Is this 
possible or do I need to work my integration differently ?

Many thanks in advance.

-Marc Fascia

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