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RE: CURIEs: A proposal

From: Misha Wolf <Misha.Wolf@reuters.com>
Date: Tue, 13 Jun 2006 14:45:53 +0100
To: Harry Halpin <hhalpin@ibiblio.org>, www-tag@w3.org
Cc: public-rdf-in-xhtml-tf@w3.org, newsml-2@yahoogroups.com
Message-id: <A29ADE959C70A1449470AA9A212F5D800203FCC1@LONSMSXM06.emea.ime.reuters.com>

Hi Harry,

> 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.

I contest the assertion that there is some agreed rule for how to
obtain an IRI from the {prefix, suffix} of a CURIE.

> Yet a processor can map (expanded name, local name) like
> (http://www.w3.org/1999/XSL/Transform,template) to an IRI by doing:
> 
> http://www.w3.org/1999/XSL/Transformtemplate
> 
> Or by doing:
> 
> http://www.w3.org/1999/XSL/Transform#template
> 
> And it seems both would be equally valid or invalid, depending on
> your opinion.

If this is so, it should be fixed asap.

> 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.

This is not a problem, as the same is true for CURIEs.

> 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
> choices:
> 
> 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.

It is not a bug in QNames.

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

There is no difference between QNames and CURIEs in this matter.

> 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

Regards,
Misha
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Received on Tuesday, 13 June 2006 13:46:30 GMT

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