Re: Possible 4.0Beta Bug??

[Edgar Toernig <froese@...>]

Hi,

>   // expect a table as only argument on the stack.
>   lua_pushnil(ls);  /* first key */
>   while (lua_next(ls, 1) != 0) {
>     /* `key' is at index -2 and `value' at index -1 */
>     printf("%s - %s - %s - %s\n",
>             lua_tostring(ls, -2), lua_type(ls, -2),
>             lua_tostring(ls, -1), lua_type(ls, -1));
>     lua_pop(ls, 1);  /* removes `value'; keeps `index' for next
> iteration */
>   }
[snipp] 
>
> Here's the Lua code:
> 
> t1 = {a=1, b=2, c=3, d=4, e=5}
> t2 = {'a', 'b', 'c', 'd', 'e', 'f'}
> 
> LuaCallMe(t1) -- OK
> LuaCallMe(t2) -- Error
> 
> Here's the output:
> a - string - 1 - number
> c - string - 3 - number
> b - string - 2 - number
> e - string - 5 - number
> d - string - 4 - number
> 1 - number - a - string
> error: invalid key for 'next

lua_tostring & co convert the data in place.  So, first
your printf-statement depends on the C-compiler (what is
evaluated first, lua_tostring or the corresponding lua_type?)
and second, the following lua_next will fail because it
can't find the old key - it's now a string.

Ciao, ET.