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Subject: Re: [geda-user] Non-modal Dialogs
From: Edward Hennessy <ehennes AT sbcglobal DOT net>
In-Reply-To: <20130722222617.6c1528c1@Parasomnia.thuis.lan>
Date: Mon, 22 Jul 2013 16:24:03 -0700
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Bas,

Thank you for the article. Here is another pattern designed to improve
testability. It strives for the same philosophy, to remove logic from
the dialog box, but in a different way.

http://martinfowler.com/eaaDev/PresentationModel.html

The immediate problem I'm up against is identifying a mechanism for
property change notification.

For property change notification, I prefer gobject signals. However,
gobject is cumbersome and I'm not sure all developers would be onboard
with that direction.

The Humble Dialog Box implementation closely resembles the observer
pattern from the Gang of Four. This system would be another option.

I also need to look at the weak references already in the code. And of
course, there is also the callback function pointer. ;)

Cheers,
Ed

On Jul 22, 2013, at 1:26 PM, Bas Gieltjes <bas AT gieltjes DOT dds DOT nl> wrote:

> 
> Hello Edward,
> 
> See the attached paper "The Humble Dialog Box" by Michael Feathers that
> describes a dialog box implementation. The implementation separates the
> data (model) and view, when the data changes the dialog box is
> updated. I hope that the paper is not too object oriented.
> 
> You know how the current implementation of the dialog boxes and are
> better able to guess if the paper is a useful start. 
> 
>> Implementation of non-modal dialogs requires some form of property
>> change notification. This way, if an object property gets changed,
>> either through the GUI or scripting, the dialog box widgets stay in
>> sync with the value of the property. How should property change
>> notification be implemented in gschem/libgeda?
> 
> Bas
> -- 
> <TheHumbleDialogBox.pdf>