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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Access types as parameters
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Date: Mon, 20 Jul 2009 10:13:48 +0200
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Date: 2009-07-20T10:13:47+02:00
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On Sun, 19 Jul 2009 15:57:12 -0700 (PDT), rickduley wrote:

>> So it is best to avoid the first form unless you have a particular need for
>> dispatching on an access value (which won't happen here, because the
>> designated type is class-wide).
> 
> Why then does GtkAda consistently use the first form,

alas!

> i.e.:
> function My_Function (Thing : access My_Type'Class) return Positive;
> for an 'Initialize' function?

You mean 

   function My_Function (Thing : access Gtk_XXX_Record'Class)
      return Positive;

I think it should better be

   function My_Function (Thing : Gtk_XXX) return Positive;

since GtkAda has Gtk_XXX declared as access to every Gtk_XXX_Record'Class.

> It actually uses the form (this for Gtk.Button.Gtk_Button):
> procedure Initialize
>   (Button : access Gtk_Button_Record'Class;
>    Label  : UTF8_String);

Well, this is likely a design bug. Gtk_Object_Record should have been
limited controlled with Initialize inherited from
Ada.Finalization.Limited_Controlled.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de