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[Wow. The to/cc headers on this thread seem to be growing without upper
bound. Trimmed a bit for now]
Shelley Powers:
> >> Anyone know of an [RDF] vocabulary using reification?
Moi-meme:
> >I'm glad they're hard to find. If I saw an RDF vocab using
> >reification, I'd
> >steer very clear of it. I have a very firm policy of avoiding reification
> >like the plague.
> >I either use explicit blank nodes or (if I can relax interop
> >requirements),
> >4RDF statement context/scope annotations.
Danny Ayers:
> Now that's exactly the thing - apart from being of a nice toy for the
> theoreticians, reification should give us context/scope capability without
> having to relax any requirements. I've still not got far enough through the
> latest spec suite to see how any recent changes might have impacted on the
> potential for contexts, but some of the n3 stuff and Graham Klyne's work on
> contexts [1] and scoping [2] suggest that it should be possible with little
> (or no?) extension to the current specs.
>
> As I'm sure is the case in practice with 4RDF, contexts aren't particularly
> complicated in principle. They should be simple to do within the shared
> model. Very simple. Reification shouldn't be the 'big ugly' (as Shelley
> nicely put it) to be avoided by sensible developers, it should be a big
> friend.
I agree that proper context/scopes would be little work to add to core RDF, so
I have always wondered: why the complete avoidance of the issue in the specs?
This is a matter that almost every RDF implementor has had to rediscover
and/or reinvent. I would think a "standard" in development should take note
of this fact.
As for reification in RDF 1.0, it is B.A.D., to use Tim Bray's cheeky term.
It's B.A.D. from a model-theoretic point of view -- the lack of enforceable
relationship between the four statements generated by its reification and the
original statement itself makes it useless for a lot of the cases at which it
is aimed. It's B.A.D. from the implementation POV -- each reification bloats
the data store, or the implementation has to add a big-O-rder of magnitude to
typical query algorithmic complexity, unless one performs very dodgy tricks
with statement hashes and the like (dodgy because of the model-theoretic
failings of reification).
Thanks for the links, though, I'll reference them from my Akara page on 4Suite
RDF scopes.
--
Uche Ogbuji Fourthought, Inc.
http://uche.ogbuji.net http://4Suite.org http://fourthought.com
Python&XML column: 2. Introducing PyXML - http://www.xml.com/pub/a/2002/09/25/p
y.html
The Past, Present and Future of Web Services 1 - http://www.webservices.org/ind
ex.php/article/articleview/663/1/24/
The Past, Present and Future of Web Services 2 - 'http://www.webservices.org/in
dex.php/article/articleview/679/1/24/
Serenity through markup - http://adtmag.com/article.asp?id=6807
Tip: Using generators for XML processing - http://www-106.ibm.com/developerwork
s/xml/library/x-tipgenr.html
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