next gen XUL templates/RDF and Fresnel

Fresnel (see: http://simile.mit.edu/fresnel/) is an RDF query mechanism
that is part of MIT's SIMILE. It provides mechanisms over and above
those offered in SPARQL (builds on it) or the RDF query mechanism in
XUL templates. Fresnel's been much in discussion on the SIMILE mail
list over the last two weeks. For those not on that list, here's one
back and forth about Fresnel's relevance for XUL templates and their
RDF handling.

-------------------- me ----------------
I've been reading this mail group over the last two weeks with great
interest. After using the current generation of XUL templates to build
an RDF-driven display (see:
http://www.the325project.org/factlog/325Factlog.xul), I could see a lot
 of functionality described here and in the Fresnel spec that XUL
templates sorely lack.

I think that their main omission, besides the  lack of remote queries,
is support for wildcards and defaults - they  need a fallback to grab
all properties and use OWL labels to enable  compact but powerful
displays.
There's a new XUL template proposal (see:
http://wiki.mozilla.org/XUL:Templates_Plan), one that allows for a
variety of Query Processors. One could be a Fresnel Lens interpreter,
encompassing the tree construction and label handling that's had quite
an airing on this group recently. However, the proposal leaves the
builder - the part of the template that fills in XUL elements - largely
 as is. This isn't sufficient for Fresnel.

So what? Well, people could play around with Fresnel interpreters in
Firefox (I wrote up a crude list of things for a lite processor at
http://www.the325project.org/blogs/2005/04/simple-greedy-owl-based-
query.html) if, along with upgraded templates to handle a variety of
Query Processors,  came an enhanced template builder. This would help
XUL and so help Firefox and I think it would help Fresnel too. Has
anyone on the list looked at the XUL template spec?

-------------------------- reply from stefano --------------------

I had not and I'm very happy that you pointed me in that direction.

After a complete-but-not-super-detailed read, I see strong overlap in
the design methodology and partial (but very interesting!) overlap in
the functional capabilities.

I personally think that the mozilla folks used RDF for a long time but
never really got it, they use it as a sort of mergeable property files
on (big!) steroids. Their templates reflect that: they are pretty solid
on the UI side (actions, bindings, UI widgets and all that) but lacking
in the RDF selection and graph->tree generation (which doesn't surprise
me: you hit that wall only after a while).

If XUL templates were to support, say, XPath queries over a DOM (as
they
mention), then my vision of Fresnel would fit perfectly: fresnel would
do the graph selection and graph->DOM manipulation, and XUL templates +
mozilla will do the rest. Having a fresnel XPCOM component in mozilla
that does graph->tree rendering would be the only thing needed for this
to happen.

At the end of the day, XUL templates + mozilla achieve the exact same
functionality than velocity + servlet engine + HTML + CSS + javascript
+
web browser, so they reside in the same space of the workflow: right
after the bridging between graph-world and tree-world.

XUL templates, to me, represent a perfect example of why we should stop
illuding ourselves that we can declare everything people will need from
RDF presentation and just work to bridge existing solutions between the
two worlds.

-------------------------------------------------------------

Long and the short, if a XUL template upgrade were to fully enable
Fresnel and other query approaches, it would greatly enhance Firefox's
position as the semantic browser. Some changes to the current spec (an
enhanced result structure for instance) would be needed but it would be
worth it.