Re: Lua, ToLua and object instances

[Waldemar Celes <celes@...>]

> I use ToLua to create the bindings for my C++ class A.
> I create an instance of this class in my C++ code.
> That instance is now visible to C++ but not to Lua.
> I then expose the instance to Lua; the instance is visible to both C++ and 
> Lua.
> Is the variable in Lua a reference to the C++ instance, or is it a 
> completely separate entity (instance)?

I am assuming that "expose the instance to Lua" is to pass its pointer to a 
Lua variable, right?
In that case, Lua has only a reference to the C++ instance.

> I delete the instance in C++. The variable still exists in Lua, but what 
> value does it have? I presume that the deletion doesn't automatically get 
> filtered to Lua. How would I deal with this?

You should take care of that. This problem also happens in C/C++ programs, 
when you have more
than one variable pointing to a single instance.


> 2)
> I create an instance of an object in Lua. The instance is only visible to 
> Lua and not C++.
> I delete the instance in Lua, and the C++ code is none the wiser that a 
> new instance ever existed.

well, the instance was created by the C++ constructor, but you have no C++ 
variable holding this instance.

-- waldemar