Re: setglobals and Lua 5.0

["Wim Couwenberg" <w.couwenberg@...>]

The second half of my previous reply (about the __index method) is plain
silly, sorry about that...  I found your earlier mail and will give it
another try...

Define a hook by:

static int zeus_func(lua_State *L);  /* defined below */

static int zeus_hook(lua_State *L)
/* in:  table, index
   out: closed zeus_func */
{
    lua_pushvalue(L, 2);  /* copy global name */
    lua_pushcclosure(L, zeus_func, 1);  /* bind it to zeus_func as upvalue
*/
    return 1;
}

And set it as __index method of the globals table:

lua_newtable(L);
lua_pushstring(L, "__index");
lua_pushcfunction(L, zeus_hook);
lua_settable(L, -3);
lua_setmetatable(L, LUA_GLOBALSINDEX);


Then if a global name "SomeName" is not defined, our hook will be called and
it returns zeus_func closed with "SomeName" as its first upvaue.  Now
zeus_func can look something like:

static int zeus_func(lua_State *L)
{
    /* push macro name (first upvalue)... */
    lua_pushvalue(L, lua_upvalueindex(1));

    /* check the macro name and do your thing... */
}


Bye,
Wim