Re: [Wxlua-users] Possible coroutine fixes

[John L. <jla...@gm...>]

> I hardly understand the problem. I do understand that there are two
> lua_State at the same time.
> While there is only one wxLuaState.
> What would be the problem if there would be two wxLuaStates too?

Because the rest of the variables in the wxLuaStateRefData must be
shared between the two lua_States. You only know which lua_State you
want to use from lua calling the C function.

> And what would be the solution if the new lua_State became part of every
> new wxLuaState, and that
> was passed around using a Smart Pointer to it, instead of the current
> ref counting mechanism.
> If several lua_State need to share data, that can be done using a second
> Smart Pointer inside wxLuaState.

You still need a way to associate many lua_States with a single group
of data structures. I'm not sure how a smart pointer would help here.

> It will be cleared properly if all wxLuaStates's are released ( no more
> smart pointers to it ).
> I used hierarchies of smart pointers for storing drawing objects, and it
> works great.

Deletion is not so much a problem, I will look back at your smart
pointers. Another reason to have the wxObject ref mechanism is that
you can have a delayed construction, eg. make a wxLuaState a member of
a class and then Create it as necessary or not at all.

> What is exactly the reason you choose the current form of ref counting?

So that when you pass a wxLuaState to a wxLuaCallback (a handler for a
wxEvent) and then close the lua_State you want the wxLuaCallback to
know that the lua_State has been closed. It's a simple way to let
anyone who's given a wxLuaState that the lua_State is good or not. If
you just use pointers to the lua_State you have to track them all and
NULL them to avoid someone trying to use them. This can happen with
delayed window deletion in wxWidgets.

> I do not know how and why wxLua is organized as is yet, so don't get mad
> if i am talking nonsense ;-)

It's not too difficult, but there are some subtle intricacies.

Regards,
    John Labenski