<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>Hi, <br>
</p>
<p>Below some important reflections based on the application of
PreferenceNG to DrGeo's preferences.<br>
</p>
<p>In the current PreferenceNG design (true as well for the legacy
preference design) we are not exploiting the full potential of the
category attribute.</p>
<p>Indeed, there is no logical reason we can't have two preferences
with the same name but under two different categories. In the
current design it is not possible.<br>
</p>
<p>This is a problem that could arise quickly when loading two
packages developed separately. The two developers may have both
declared a preference named #textColor.</p>
<p>In package 'Zork':<br>
</p>
<p><font face="monospace"><font color="#97082d"> PreferenceNG <br>
name: #textColor<br>
category: #Zork<br>
value: #red</font><br>
</font>
</p>
<font face="monospace">
</font>
<p>and package 'Zul':<br>
</p>
<p><font face="monospace" color="#97082d"> PreferenceNG <br>
name: #textColor<br>
category: #Zul<br>
value: #black</font><br>
</p>
<p>When both packages are installed, we have a preference name
clash.<br>
</p>
<p><br>
</p>
<p>Exploiting category as a preference domain could reduce the
complexity of preference name. Observe how these two preferences:<br>
</p>
<p><font face="monospace" color="#97082d"> PreferenceNG <br>
name: #DrGeoPointColor<br>
description: 'Default colour of a point.' translated <br>
category: #DrGeoPoint <br>
type: (DrGTypeColor with: #DrGeoPointColor)<br>
value: Color red<br>
</font></p>
<p><font face="monospace" color="#97082d"> PreferenceNG <br>
name: #DrGeoSegmentColor<br>
description: 'Default colour of a segment.' translated <br>
category: #DrGeoPoint <br>
type: (DrGTypeColor with: #DrGeoSegmentColor)<br>
value: Color black</font></p>
<p>could be better named as:<br>
</p>
<p><font face="monospace" color="#97082d"> PreferenceNG <br>
name: #color<br>
description: 'Default colour of a point.' translated <br>
category: #DrGeoPoint <br>
type: (DrGTypeColor with: #DrGeoPoint:color)<br>
value: Color red<br>
</font></p>
<p><font face="monospace" color="#97082d"> PreferenceNG <br>
name: #color<br>
description: 'Default colour of a segment.' translated <br>
category: #DrGeoSegment <br>
type: (DrGTypeColor with: #DrGeoSegment:color)<br>
value: Color black</font></p>
<p>In another email I will propose how to adapt the class and its
protocol.<br>
</p>
<p>Hilaire<br>
</p>
<pre class="moz-signature" cols="72">--
GNU Dr. Geo
<a class="moz-txt-link-freetext" href="http://drgeo.eu">http://drgeo.eu</a>
<a class="moz-txt-link-freetext" href="http://blog.drgeo.eu">http://blog.drgeo.eu</a></pre>
</body>
</html>