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RE: CURIEs: A proposal

From: Misha Wolf <Misha.Wolf@reuters.com>
Date: Mon, 12 Jun 2006 22:10:30 +0100
To: www-tag@w3.org, public-rdf-in-xhtml-tf@w3.org, newsml-2@yahoogroups.com
Cc: Harry Halpin <hhalpin@ibiblio.org>
Message-id: <A29ADE959C70A1449470AA9A212F5D800203F84F@LONSMSXM06.emea.ime.reuters.com>

I'm concerned that people are incorrectly assuming that CURIEs 
address a single set of requirements.  On this mistaken foundation, 
various proposals are developed, which do not satisfy the full set 
of requirements.  I hope to respond to Harry's mail tomorrow.  In 
the meantime, please take a look at my presentation to the W3C AC, 
which summarises the News Industry's requirements:
and at my mail titled "CURIEs: A proposal":

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-----Original Message-----
From: public-rdf-in-xhtml-tf-request@w3.org [mailto:public-rdf-in-xhtml-tf-request@w3.org] On Behalf Of Harry Halpin
Sent: 09 June 2006 10:37
To: mark.birbeck@x-port.net
Cc: www-tag@w3.org; public-rdf-in-xhtml-tf@w3.org
Subject: Re: CURIEs: A proposal

I think Henry's pointing to the conceptual problem with making CURIEs a
"superset" of QNames.  Unlike CURIEs, QNames (at least as I've been able
to discover, correct me if I'm wrong - the spec just seems silent) do
not define an algorithm for converting an entire QName to a IRI, and by
"algorithm" we're not talking about anything fancy - but just
concatenating the namespace URI and the local name as strings, which is
what most processors do anyways - as pointed out by Borden [1] and
raised to the TAG [2], who seemed to be answer a sort of different
question in their finding.

Yet a processor can map (expanded name, local name)  like
(http://www.w3.org/1999/XSL/Transform,template) to an IRI by doing:


Or by doing:


And it seems both would be equally valid or invalid, depending on your

So by making CURIEs a superset of QNames is a bit difficult as long as
the QName (namespace prefix, local name)=>IRI construction is
unspecified. And so using the ":" for QNames and CURIEs means that given
any "x:y" element or attribute name one couldn't tell whether one meant
an IRI or a (namespace prefix, local name). So there seems to be two

1) Unspecified IRI construction for the entire (namespace prefix, local
name) a *bug* in QNames and should be corrected post-hoc by the CURIE
proposal. If this is the case, then CURIEs should use ":" and then make
themselves a superset of QNames.


2) Unspecified IRI construction in QNames is a *feature*  and so CURIEs
exist as a parallel standard, and so use [insert character besides ":"
here] in order to keep confusion between QNames and CURIEs at a minimum.

 My earlier post is that some communities (i.e. some of the microformat
people I talked to at WWW2006) mentioned that they would like another
character besides : for "namespaces in microformats." Next time I'll
just tell them to escape their colons :)

[1] http://www.openhealth.org/RDF/QNameQuagmire.html
[2] http://www.w3.org/2001/tag/issues.html#rdfmsQnameUriMapping-6


Harry Halpin,  University of Edinburgh 
http://www.ibiblio.org/hhalpin 6B522426

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Received on Monday, 12 June 2006 21:11:20 UTC

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