Re: [ruby-gnome2-devel-en] rbbr is now available!

[Masao M. <mu...@hi...>]

Hi,

> > Ruby/GLib provides cool macros for other libraries which use GObject system.
> > They help you. See "How to implement Ruby-GNOME2" on our Website.
> > (http://ruby-gnome2.sourceforge.net/howto_gnome.html).
> >
> > Also many of hints are already existed in Ruby/GLib2 and Ruby/GTK2 source codes.
> > It may be better to study some classes in Ruby/GTK2 before you start your project.
> > #Especially the classes which inherited GLib::Object, GLib::Boxed directory is helpful.
> >
> ok, i haven't really dug deep into the whole GLib thing, but i am
> wondering why we need things such as GLib::Boxed. i mean when will we
> need it in Ruby? GLib::Boxed is apparently for wrapping C structs to
> GObjects right? and when is this useful from Ruby? am i missing
> something in the abstraction layers here?

Good question. But I may be not able to answer well in my poor English ...

GLib/GTK+ have three type of C Structure which make GLib/GTK+ classes.
#Of course there are some other classes like GSignal, GParamSpec.
#But I don't tell about them here.

1. GOBject subclasses - follow GType system.
2. GBoxed subclasses  - follow GType system.
3. others - not follow GType system.

GLib::Boxed is not GObject. Both of them follow GType system, but the
mechanism are quite different.

GObject is:
 - follow GType system.
 - have properties using GParamSpec.
 - reference counting.
 - have some other useful methods.
 - others:->.

GBoxed is:
 - follow GType system.
 - don't have parent classes.
 - provide copy()/free() but not reference counting.

So I think we can't merge them in a GObject or GBoxed.
We may be able to inherit both of them from common abstract class, but
I didn't think it's better way(I thought it was overdoing).

----
3. others which are not follow GType system
  We can implement them using Ruby's standard APIs, as Data_Make/Get_Struct.
But it is very complicated to implement with GType macros.
So we re-implemented these C structs as GBoxed object.
(It's very easy. implement copy, free, get_type and G*_TYPE_* macro. 
 See gtk/src/rbgdkgeometry.c and others).


The other side, Ruby users viewpoint,
GLib::Boxed, GLib::Object both have own methods. Usually it'll be used.
But sometimes you may need them.
#Usually abstract classes are not used necessarily by user, I think;->.


P.S.
"GLib::Boxed" may be bad name. Because it isn't native GBoxed only.
And general Ruby-GNOME2 users may be not able to understand 
why they are 'Boxed'.
The name may be changed something like "GLib::Data" in the future.
However, I think the priority is low for the moment.

Cheers,
Masao

-- 
.:% Masao Mutoh<mu...@hi...>