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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Event mechanisms for GUI's
Newsgroups: comp.lang.ada
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Date: Thu, 19 Oct 2006 17:04:52 +0200
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Date: 2006-10-19T17:04:52+02:00
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On 19 Oct 2006 07:22:09 -0700, Lucretia wrote:

> But there are problems with this:
> 
> 1) use of multiple interfaces just to provide 1 "event handler" over
> the use of 1 listener interface which provides all "event handlers"
> which are specified as null procedures so that the user can override
> the ones (s)he is interested in.
> 
> 2) the user may forget to do the test (the Set_Bit_Mask call).

3) You cannot provide a default implementation for events, when those
handlers are interfaces.

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