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Interesting experience: my foaf in RDFa

From: Ivan Herman <ivan@w3.org>
Date: Fri, 24 Aug 2007 12:38:42 +0200
Message-ID: <46CEB532.4030008@w3.org>
To: W3C RDFa task force <public-rdf-in-xhtml-tf@w3.org>
I decided to experiment with RDFa with a slightly more complex example.
I used to have my foaf file[1] only in RDF/XML, ie, edit it, update it,
etc, in that format. I now created an XHTML/RDFa version of it[2] and
from now on my intention to update [2] and generate [1] automatically
(as an extra bonus my non-informational URI[3] redirects to either the
html or the rdf file, depending on the HTTP request).

My foaf file is fairly complex, and it mixes a good number of namespaces
(I always used it as some sort of an experiment to express different
things). Putting it into RDFa was a bit of a challenge here and there,
but it was worth it. Some experiences:

- It works!  This is a really important point: I did not find any
construction in my previous foaf file that I could not express somehow.
And that is really important; it is a one-time evidence that we do have
something good here.

- It is an authoring challenge (this is not unlike microformats). Of
course, editing the file in a screen editor is possible but makes it a
bit difficult to follow and is error prone. The problem with a WSWYG
editor like Amaya is that editing the attributes is sometimes a bit
complicated. What you need is an editor that makes it easy to switch
between WYSWYG and source view but most of them mean moving to another
window and thereby loosing context. My best experience is with Adobe
GoLive which allows (in the WYSWG window) to have a pop up window on a
specific element with all the xml source editable. That helps a lot...

- It can be a bit convoluted sometimes. No real surprise there: if you
look at [2] you can see that I tried to incorporate some sioc statements
and turning that into RDFa was a bit complicated. Well, the sioc
statements themselves are convoluted....

This means that some of the RDF constructs become a bit unnatural in
HTML, if you want to add some humanly readable text to it. Which raises
a practical question. What if the author wants to keep some of what
he/she wants to express in RDF/XML and would like to 'bind' it to the
RDF extracted from HTML? My solution was to add a <link> statement with
rel="rdfs:seeAlso", but this relies on the RDF environment to understand
and interpret that.

Do not crucify me: maybe we should have (as some sort of a very edge
case advanced feature) some sort of an import mechanism. Something like

<link rel="rdfa-import" href="...."/>

which means that the end result should be the merge of the value of
@href and the extracted RDF. I am not sure... just raising the
possibility here...


[1] http://www.ivan-herman.net/foaf.rdf
[2] http://www.ivan-herman.net/foaf.html
[3] http://www.ivan-herman.net/Ivan_Herman

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Friday, 24 August 2007 10:38:42 UTC

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