RE: C++ binding

[Timothée VERROUIL <dreamothee@...>]

Thanls a lot, but i get this error :
PANIC: unprotected error in call to Lua API (attempt to index a string value),
Here's my code :

for each attribute I do the following :
lua_pushstring(L, attributeName)

lua_pushcclosure(L, DispatchAttribute, 1);
lua_setfield(L, -2, "__index");
lua_settable(L, iMetaTable);


> Date: Fri, 8 Apr 2011 04:59:38 -0400
> From: sean@conman.org
> To: lua-l@lists.lua.org
> Subject: Re: C++ binding
>
> It was thus said that the Great Timothée VERROUIL once stated:
> >
> > Thanks a lot :)
> > so I have to implemente __index as a function.
> > But how can I do that in C++ ???
>
> Same way you write the routines for the other metatable functions. As a
> function, __index (in Lua) will be called with two paramters, the first
> being the table (or userdata) and the second being the key. So, a
> hypothetical function might look like (and sorry this is in C; I don't use
> C++ but you should be able to translate this):
>
> static int foolua___index(lua_State *L)
> {
> foo_t *foo;
>
> foo = luaL_checkudata(L,1,FOOTYPE);
>
> /*------------------------------------------------
> ; okay, index is a string. Check what the index is
> ; and handle appropriately, pushing the appropriate
> ; values onto the stack.
> ;--------------------------------------------------*/
>
> if (lua_type(L,2) == LUA_TSTRING)
> {
>
> const char *key;
> size_t ksize;
>
> key = lua_tolstring(L,2,&ksize);
> if (strcmp(key,"myAttribute") == 0)
> {
> lua_pushnumber(L,foo->myAttribute);
> return 1;
> }
> if (strcmp(key,"myFunction") == 0)
> {
> lua_pushcfunction(L,foolua_myfunction);
> return 1;
> }
> /* and so on .. */
> }
>
> /*---------------------------------------------
> ; we've got a number as a key
> ;---------------------------------------------*/
>
> else if (lua_type(L,2) == LUA_TNUMBER)
> {
>
> int idx;
>
> idx = lua_tointeger(L,2);
> if (idx > foo->maxIndex)
> {
> lua_pushnil(L);
> return 1;
> }
> lua_pushnumber(L,foo->data[idx]);
> return 1;
> }
>
> /*--------------------------------------------------
> ; something else, like a LUA_TTABLE or LUA_TBOOLEAN
> ; was passed in as the key. If these make sense,
> ; handle them, otherwise, return nil.
> ;---------------------------------------------------*/
>
> lua_pushnil(L);
> return 1;
> }
>
>
> And when you initialize the metatable:
>
> lua_pushcfunction(L,foolua___index);
> lua_setfield(L,-2,"__index");
>
> -spc (Hope this helps)
>
>
>