[Wxlua-users] Possible coroutine fixes

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

There is a problem with coroutines currently. The issue is that when
lua creates a coroutine a new lua_State is created by lua and wxLua
correctly associates the new lua_State with the original wxLuaState so
that it can get the ref data (where the bindings and C++ variables are
stored). This is all fine, however when you try to run some lua code
in a coroutine, lua calls the function "int LUACALL
wxLua_lua_getTableFunc(lua_State *L)" to find out about a bound
function. It needs to look up the wxLuaState (for the ref data) and
though the proper ref data IS found, subsequent calls to functions
like wxLuaState::ttag use the lua_State of the wxLuaState and not the
coroutine one and so it fails.

Solutions:

a) Remove all the ttag and other functions from the wxLuaState and
make them standalone 'C' functions that only take a lua_State* L. This
would require that the wxLuaState (and it's ref data) would have to be
incessantly looked up, this is how it was previously.

b) Add a parameter lua_State* L =3D NULL to the end of functions like
ttag (and EVERY function that would be called by a 'C' function called
by lua) that would either use the given lua_State passed in if !NULL
or use the lua_State of the wxLuaState. This is easy to do, but may be
a little confusing.

c) Make the ref data, the C++ data for the lua_State itself ref data.
     wxLuaState : wxObject
        -> wxLuaStateRefData (the wxObjectRefData)
                members are lua_State* and wxLuaStateData
     wxLuaStateData : wxObject
        -> wxLuaStateDataRefData (the wxObjectRefData)
                members are the rest of what is currently in the
wxLuaStateRefData

So that if you do "wxLuaState wxlState(lua_State* L)" it finds the
wxLuaStateRefData for the given lua_State, but since the
wxLuaStateData is also ref counted two or more wxLuaStateRefData can
share the same data, which is what coroutines require.

d) Make wxLuaState NOT ref counted and keep a list of pointers to them
for looking them up from the lua_State*. As a member it would have a
ref counted wxLuaStateData class, similar to the one outlined above.

e) ?

I'd appreciate any thoughts on this. In my effort to make the
wxLuaState more robust, I missed this important detail.

Regards,
    John Labenski