Re: Replacing GTypeInterface instances.

[murrayc t-online de (Murray Cumming)]

On Fri, 2001-11-02 at 00:11, Havoc Pennington wrote:
> 
> murrayc t-online de (Murray Cumming) writes:
> > > IIRC the best solution that was reasonably transparent to C++ users
> > > involved dynamically generating proxy classes for C++ classes based on
> > > RTTI on the C++ class.
> > 
> > It would be nice to know why this might be necessary. I think that I can
> > see a way to do it just by replacing the vfunc table (the
> > GTypeInterface-derived struct instance) with our own.
> 
> You mean derive a proxy class, or poke in the existing class?

Ideally we would derive a proxy class, but I don't know how to do that.
With normal classes we can do this by calling g_object_new() with our
derived klass instead of the normal klass.

> >  i.e. you keep a hash from list of interfaces
> > > implemented to proxy class, and you yank the right proxy out of your
> > > hash on object construction. Or something.
> > 
> > Which would also require replacement of the GTypeInterface instance.
> > That's what I need to know how to do.
> 
> You just override the interface as you would in a subclass, right. I'm
> not sure we currently have any examples...

Can you give me a clue about how to do this? See above.

> > > You might be better off just requiring C++ users to put in some funky
> > > boilerplate, instead of trying to do it magically.
> > 
> > I don't think that it will be possible to make a C++ class implement a
> > C++/Glib interface just by inheritance. C++ coders will also need to
> > call
> > implements_interface(TreeModel::get_sometypething());
> > in the constructors of their C++ interface-implementing classes.
> 
> That's what I mean by "funky boilerplate"
> 
> The proxy hash I was describing is an attempt to avoid the funky
> boilerplate. If you feel OK requiring some boilerplate, there are many
> ways to do it, I don't think there's any big issue.

It will do for now. We can explore some smarter voodoo after we get this
working.

-- 
Murray Cumming
murrayc usa net
www.murrayc.com