Re: individual globals for coroutines.

[David Morris-Oliveros <david@...>]

Ok. I've got it mostly implemented (rewriting a lot of stuff in the 
process), and there's a theoretical question that I've missed.

I set a new global's table for the new thread. That is, boiled down, this:

m_SubLuaState = lua_newthread( m_MasterLuaState );
int thread = lua_gettop( m_MasterLuaState);

lua_newtable( m_MasterLuaState );
int newGlobal = lua_gettop( m_MasterLuaState );

lua_setfenv( m_MasterLuaState, thread );

At that point, i believe, the subState's thread has a new globals. Now, 
if I try to get something from it, by using:

lua_getfield( m_SubLuaState, LUA_GLOBALSINDEX, "Something" );

Does LUA_GLOBALSINDEX refer to the real global, or to the new global 
that i just created? Or am i getting this all wrong?

Cheers!



Marcus Brown wrote:

> * David Morris-Oliveros <david@teambondi.com> on Mon, Oct 10, 2005:
>
>  
>
> > Hi,
> >
> > I'm on my next stage of integrating lua into our engine, and have come 
> > to a point where it would be wise to ask for advice.
> >
> > I want each coroutine to have their own individual global table. I know 
> > that you can do this by creating a new table, filling it with whatever 
> > you want, and doing a lua_setfenv().
> >
> > Now, when I bind my code into lua, i create all sorts of tables and 
> > cfunctions in the global table. I still want these new coroutines to be 
> > able access my bound tables and cfunctions.
> >
> >    
>
> I'm doing the same exact thing in our project - creating a seperate global
> namespace for threads with access to the real global table.
>
> Just create your thread's global table, and give it a metatable with the
> __index metamethod pointing to the global table:
>
>    namespace = setmetatable({}, {__index = _G})
>
> In C this would look something like:
>
>    lua_newtable(L);
>    int metatable = lua_gettop(L);
>
>    lua_pushvalue(L, LUA_GLOBALSINDEX);
>    lua_setfield(L, metatable, "__index");    /* {__index = _G} */
>
> Then set this as the metatable of your namespace.
>
> I believe this was mentioned in PIL, section 14.3.
>
>
>  

--
// David Morris-Oliveros
// Camera & Lua Coder
// Team Bondi


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