Date: Thu, 3 Jul 2003 16:49:31 +0200
From: Nicolas George <nicolas.george at ens.fr>
To: lablgtk at kaba.or.jp
Cc: Richard Jones <rich at annexia.org>
Subject: Re: containers & subclasses of widgets
Message-ID: <20030703144931.GA29657 at clipper.ens.fr>
Reply-To: lablgtk at kaba.or.jp
References: <20030703144222.GA15588 at redhat.com>
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Le quintidi 15 messidor, an CCXI, Richard Jones a =E9crit=A0:
> I guess this comes down to the strange type system used by LablGtk.

No, it has to do with static typing. The children of a container are
widgets, nothing more: they could be labels, input boxes, images,
anything. The static type system of Caml has no way to know that they
will be vboxes.

You could use the dynamic type checking facilities of Gtk+ to refine the
widget into a vbox, but I believe this is a bad style. If you need to do
something to some widget, do not rely on accessing it through its
parents: store it in a variable with a relevant name. This way you will
have reliable static typing, and your code will not break if you change
the layout of your widgets.

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