Re: [Wxlua-users] namespace and static binding

[klaas.holwerda <kho...@xs...>]

John Labenski wrote:

>
>Ok, we can try to turn on debug info. I'll have to see if I can do it
>in the bakefiles? Do you know how?
>  
>
I am affraid not, but i think Franscesco knows it right away :-)

>
>Ok, so there really is a problem.
>  
>
Right, we need to find a solution for the static initalization classes.
And i think wxModule is oke to use, since i think the first wxLuaState 
will be defined by other classes which  are initiated after wxApp 
startup etc. 
Am i Right??

If this is the case, we only need to make sure all wxModule (one per 
binding  module ) is called before initating the first wxLuaState. And 
as far as i can see, no static initialisation class is needed.
I use wxModule like classes for stock object s, which is close to what 
we need.
Maybe we can simple generate the wxModule_bindX automatically?

>So, I got your email from Michael, I don't understand the first part.
>I guess I'm missing some of the lingo.
>  
>
I will read it once more, and already asked Michael to explain the first 
better.

>  
>
>>1. Rely on 0-initialization for 'first objects' and don't touch them
>>in their constructors (maybe use a special constructor for this). The
>>0 intialization of all objects is guaranteed to be finished before any
>>constructors are called. But of course the real constructor can be
>>called later at any time, so it must not touch e.g. the list head,
>>that might already have been valid data.
>>    
>>
>
>Can you give me an example?
>  
>
Asked that too.

>The second example of guaranteeing static var initialization works
>like this, right? We have no problem doing this and Michael says the
>only downside is code bloat, but we're not going to have very many of
>these, so that's not an issue. This can be easily automated in
>genwxluabind.lua.
>
>static wxLuaBinding* wxLua_GetMyBinding()
>{   static wxLuaMyBinding m_binding; return &m_binding; }
>  
>
I tried it now, and just defining such a function is not enough. ( i 
tried in header and source ).
The only thing which works is the next:
In header file:
extern wxart2d_Binding* wxLua_GetArt2DBinding();

In the binding .cpp file

wxart2d_Binding* wxLua_GetArt2DBinding()
{
    static wxart2d_Binding binding;
    binding.GetBindingList()->Append(&binding);
    return &binding;
}

In wxMyApp::OnInit()
{
        wxLua_GetArt2DBinding();
}

And this is essential how wxModule can work, and that has the advantage 
that the user is not responsible for calling the initilization himself, 
it is done automatically.
So finally i tried the next :

In the binding header:

class wxArt2DBindingModule : public wxModule
{
public:

    wxArt2DBindingModule() { m_intialized = false; }

    virtual bool OnInit();
    virtual void OnExit();

    bool IsInitialized() { return m_intialized; }

private:   

    DECLARE_DYNAMIC_CLASS(wxArt2DBindingModule)

    bool m_intialized;
};

In the binding source:

// 
----------------------------------------------------------------------------
// wxArt2DBindingModule
// 
----------------------------------------------------------------------------
IMPLEMENT_DYNAMIC_CLASS(wxArt2DBindingModule, wxModule)

bool wxArt2DBindingModule::OnInit()
{
    if ( !m_intialized )
    {
/* if we want failsave:

        // Initialize lower level modules first
        wxModuleList::compatibility_iterator node;
        for ( node = m_modules.GetFirst(); node; node = node->GetNext() )
        {
            wxLuaModule* wxluabase = wxDynamicCast( node->GetData(), 
wxLuaModule );
            if ( wxluabase && !wxluabase->IsInitialized() )
            {
                node->GetData()->Init();
            }
        }
*/
       

        static wxart2d_Binding binding;
        binding.GetBindingList()->Append(&binding);

        m_intialized = true;
    }

    return true;
}

void wxArt2DBindingModule::OnExit()
{
}

And guess what  it only works  ( means it is only linked in ) when i add 
my dummy
wxart2d_binding m_dummy somewhere in my main program code.
Or adding a "wxArt2DBindingModule dummy" works as well, anything that 
makes this library linked in , will do.

So maybe we  best do wxArt2DBindingModule, and a simple  macro like:
wxUSES_LUA_BINDING( wxArt2DBinding )

The first to make initialization work any way we want too. The second 
macro to be used by the user program to force linkage of that binding.

Klaas