Re: Adding module+DLL to Lua for Windows (LfW)

[Joshua Jensen <jjensen@...>]

----- Original Message -----
From: Joshua Jensen
Date: 12/10/2009 11:12 AM
> ----- Original Message -----
> From: Roberto Ierusalimschy
> Date: 12/10/2009 10:50 AM
> > > What I would like to see (and experimented with once) is for Lua to 
> > > load
> > > the Lua module and call the luaopen_ function by passing in a structure
> > > of pointers to all the exported Lua functions.
> > >
> > > struct lua_Exports
> > > {
> > >      ...
> > >      void  (*lua_pushvalue) (lua_State *L, int idx);
> > > };
> > >
> > > int luaopen_mymodule(lua_State *L, lua_Exports *exports);
> > A variation of that idea is to have lua_Exports accessible via
> > lua_State, so that it does not need to be passed as an extra argument to
> > luaopen. (E.g., it may be the first pointer in lua_State.)
> I prefer the exports table being available in the lua_State.  I was 
> just trying to be explicit about my example for discussion's purposes.
Another thought with this... existing Lua modules can continue to 
compile like so:

lua.h:

#if LUA_BUILD_AS_DLL &&  LUA_LIB

    #if LUA_EXPORTS_GLOBALS_TABLE

        extern void (*lua_pushvalue)(lua_State *L, int idx);

    #else /* !LUA_EXPORTS_GLOBALS_TABLE */

        #define lua_pushvalue(L) (lua_exports((L))->lua_pushvalue((L)))

    #endif /* LUA_EXPORTS_GLOBALS_TABLE */

#else /* !(LUA_BUILD_AS_DLL &&  LUA_LIB) */

/* the standard lua.h */

#endif

If people use the new #define for their modules, they can take advantage 
of the "high performance" globals (one dereference less).  Otherwise, 
the existing modules just work as they have done with a minor 
performance decrease.

Josh