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Re: CURIEs vs. QNames

From: Jeremy Wong 黃泓量 <jeremy@miko.hk>
Date: Mon, 28 Nov 2005 23:58:03 +0800
Message-ID: <003301c5f434$85383fe0$0100a8c0@wongc63b9a507d>
To: "Mark Birbeck" <mark.birbeck@x-port.net>, "'Dan Connolly'" <connolly@w3.org>
Cc: <public-rdf-in-xhtml-tf@w3.org>


If CURIEs is really implemented, how can the user obtain the original URI? 
Or say at what layer the abbreviated URI be reverted into the original URI? 
At the level of SGML? XML? XHTML?

As my experience of implementing RDF/XML serializer, making use of entities 
(for abbreviating URI) requires extra processing cycles. The abbreviated URI 
does not look elegant sometimes. Not only extra processing cycles is a cost, 
but also memory consumption. Under this circumstance, it is not so common to 
have abbreviated URIs generated by computer programmes.

Before I had implemented my first RDF/XML serializer, it is really 
straightforward to produce abbreviated URIs, e.g. "&rdf;Property", by typing 
with my fingers. I really deemed that the abbreviated form of URIs was good. 
However, it was not so after I had finished my various implementations of 
RDF/XML serializer.

Jeremy Wong
----- Original Message ----- 
From: "Mark Birbeck" <mark.birbeck@x-port.net>
To: "'Dan Connolly'" <connolly@w3.org>
Cc: <public-rdf-in-xhtml-tf@w3.org>
Sent: Monday, November 28, 2005 11:14 PM
Subject: RE: CURIEs vs. QNames

> Dan,
>> I don't need a new standardized way to abbreviate URIs.
>> There's XML base, &entities; (ugh), relative URI references,
>> and even local short-hands that I can transform via
>> XSLT/GRDDL. So whoever "we" is, count me out.
> I'm not with you...are you saying that you are going to stop using in
> RDF/XML, SPARQL, or N3, the one mechanism you didn't mention, (so-called)
> QNames?
> Of course not. And I have to say, that's why this whole discussion is
> starting to get rather annoying!
> You see, I am proposing a *positive* solution, because my proposal
> *reserves* QNames for what they really are (a way of specifying
> namespace-qualified elements and attributes). For those situations where 
> we
> want to abbreviate URIs, my proposal suggests using something with a
> different name (CURIEs) and making it explicit that this is what we are
> doing.
> This is very different to the rather mixed up approach that we have at the
> moment, which glosses over what *real* QNames are, and clouds what exactly
> it is that is 'lifted' from the definition of QNames. We have XPath
> functions using 'QNames', XML Schema datatypes using 'QNames', alternative
> XForms appearance hints and submission types using 'QNames'...RDF/XML 
> using
> 'QNames'...SPARQL using 'QNames'...and so it goes on.
> Except...the problem is that *none* of these languages are really using
> QNames. Take SPARQL as a very good illustration (but by no means worse 
> than
> the others). In the latest WD [1] we have this example:
>  PREFIX  dc: <http://purl.org/dc/elements/1.1/>
>  PREFIX  : <http://example.org/book/>
>  SELECT  $title
>  WHERE   { :book1  dc:title  $title }
> How by any stretch of the definition is 'dc:title' a QName? It's neither 
> an
> XML element nor an XML attribute. It doesn't even have the merit that 
> XPath
> selectors have in that they are being run against an XML DOM which does 
> have
> elements and attributes! In the SPARQL case we have a query that is being
> run against a set of triples! So why is this abbreviation of a URI, that's
> being used in a non-XML language, to run queries against non-XML data 
> being
> described in terms of QNames?:
>  SPARQL provides an abbreviation mechanism for IRIs. Prefixes can be
> defined
>  and a QName-like syntax [14] provides shorter forms. Prefixes may be used
>  anywhere after they are declared; redefining a prefix causes the new
>  definition to be used from that point in the query syntax.
> There is not a single point of connection between this and QNames, so why
> call it "QName-like"?
> And that's where we get to the nub. Because people *want* this simplicity.
> It's an incredibly convenient way of expressing a URI, and although it has
> been 'misused', it has been 'misused' so much that there is significant
> mindshare in what it represents--people just 'know' what you mean when you
> express a URI in this more compact way, to the extent that very few people
> are aware of what it really means.
> And *that*, is my entire point. Let's leverage the mindshare, 'tidy up' 
> the
> current uses (i.e., keep QNames for what they were originally designed 
> for)
> and devise a new concept that "does what it says on the tin"--abbreviates
> URIs.
> Regards,
> Mark
> [1] http://www.w3.org/TR/2005/WD-rdf-sparql-query-20050721/
> Mark Birbeck
> x-port.net Ltd.
> e: Mark.Birbeck@x-port.net
> t: +44 (0) 20 7689 9232
> w: http://www.formsPlayer.com/
> Download our XForms processor from
> http://www.formsPlayer.com/
Received on Monday, 28 November 2005 15:59:08 UTC

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