RE: toLua and luaSDL bug in SDL_Event management (it's a union typedef)

[Ariel Manzur <listas@...>]

At 10:24 AM 3/19/2004, you wrote:
> The problem IS that SDL_Event was binded as a struct ! And in the real code
> (SDL is a C library) the management of the SDL_Event type was made with
> implicit assertions about its "union nature". Now that it is binded as a
> struct, the fields which would have been are not updated anymore !

Yes they are.. the only reason why the union is binded as a struct is so 
that you can access the fields of the union from lua.. if you look a the 
code generated by tolua, you'll see that when you call 'e.type' the code is 
accessing 'e->type'.. tolua doesn't know/care whether those fields are in 
the same memory address or not.. The example you mention should look like 
this on lua:

if e.type == SDL_KEYDOWN or e.type == SDL_KEYUP then
        manage_key(e.key)
end

the actual problem will be that, because of a known bug, tolua++ (and 
tolua5) will assume that 'e.key' inherits from 'e', and will change to type 
of 'e' to 'e.key' after you access e.key.. That may limit the direct use of 
unions that contain usertype fields..


Ariel.
http://Anime.com.ar
snm