Dave Johnson

I am currently looking into various markup based / declarative languages such as SVG, XForms, MXML/Flex, XUL, XAML and Laszlo. These are all picking up steam to various degrees. I find it hard to imagine a Microsoft future without XAML (or Adobe without Flex for that matter) - though I suppose it is _possible_…

At any rate, the evolving declarative landscape is very interesting particularly since every language is similar to the next - so close in fact that they are really just a quick XSL Transformation away from each other. The question is which technology will be the trail blazer that defines the new landscape? To my way of thinking, the most important part of any of these declarative languages is data binding and that is where the war will be won.

Several of these technologies are W3C standards (SVG, XForms, XBL) while the others are being pushed by various companies / foundations such as Mozilla (XUL), Adobe (MXML/Flex), Microsoft (XAML) and Laszlo (Laszlo).

What I do like quite a bit on the W3C side of things is XBL - it seems pretty well thought out but there are still lingering questions that I need to get sorted. When looking at these different languages the first thing that I examine is how easy it is to create a simple lookup or listbox. So essentially consider some foreign key relationship between to sets of data such as a list of people records. In the user-interface you want to display their list of names while actually binding to the person’s ID. This is fairly easily achieved in XForms from what I have seen (when using select or select1), however, the other languages are a bit more ambiguous on these sorts of issues I find. Here is the snippit from XForms:

<select model=”cone” ref=”my:order”>
<label>Flavors</label>
<itemset model=”flavors” nodeset=”/my:flavors/my:flavor”>

<label ref=”my:description”/>
<value ref=”my:description”/>
</itemset>
</select>

Essentially by using the <value ref=”my:description”/> tag tells the XForms processor the xpath in the data source / model that the selected value should come from - which can be different from the label path.

If anyone can point me to some good examples in any of these languages I would love to see them!

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This entry was posted on Friday, December 30th, 2005 at 3:08 pm and is filed under Web2.0, AJAX, XML, Declarative Programming. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.