Re: object model

[Lars Clausen <lrclause cs uiuc edu>]

On 28 Oct 2003, saintiss gmx net wrote:
> Hi,
>
> I've got a quite general question here:
>
> I've noticed that inheritance is simulated by having an instance of the
> superclass as the first member...  But is there something like a checked
> type cast? i.e. where you'd get NULL if the pointer isn't of the right
> type or something? (an equivalent of dynamic_cast in C++ I mean)...

There's the standard GLib type operations.

> Also, I'm guessing there's something like polymorphism too... Is all this
> just written from scratch for Dia, or is this all part of a certain
> object model, like GObject? I'd think so, but then again it seems like
> Object doesn't inherit from GObject, so I'm a bit confused...

It doesn't though it really should.  We use the GTK type system, but
everything else is Dia-specific.  The renderers have been converted to
GObjects, but the regular objects remain strange.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| HÃrdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?