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RE: CURIEs: A proposal

From: Williams, Stuart \(HP Labs, Bristol\) <skw@hp.com>
Date: Mon, 5 Jun 2006 15:47:08 +0100
Message-ID: <DF5E364A470421429AE6DC96979A4F6FAA96BC@sdcexc04.emea.cpqcorp.net>
To: "Misha Wolf" <Misha.Wolf@reuters.com>, <www-tag@w3.org>
Cc: <public-rdf-in-xhtml-tf@w3.org>, <newsml-2@yahoogroups.com>

Hello Misha,

FWIW... a colleague suggested the use of '::'  to separate prefix from
suffix ie. prefix::suffix 

Rationale:
1) Visually/Syntactically distinct from QNames.
2) Appealingly similar in appearance to QNames.

Regarding 7(a-h) below: 
This seems to me to leave far too many things open for each language
using CURIEs to have to specify - making it difficult to conceive of
generic libraries for handling CURIEs. In particular:

7a) there should only be one set of syntactic constraints;
7b) see '::' suggestion above 
7d) *if* CURIEs are genuinely a compact way of writing a URI, there
should be a *single* mapping from a CURIE to a URI/IRI.
7e) should have a single answer... which probably (regrettably) means a
CURIE is a tuple of {prefix, suffix, prefixURI, compactedURI}
7f-g) seems like normal good practice with URIs applies any CURIE spec.
should remain silent.
7h) again surely a matter for generic URI/IRI syntax.

Fixing all of that would leave solely the matter of establish a
prefix=>URi mapping on a per language basis (7c), and I would hope there
would be a single approach for XML based languages - other non XML based
languages (N3 (and friends), SPARQL...) would have to define their own
mechanisms.

8b) seems troubling because it risks confusing a Qname with a CURIE.

Just my 2 cents.

Regards

Stuart
--


> -----Original Message-----
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] 
> On Behalf Of Misha Wolf
> Sent: 02 June 2006 19:14
> To: www-tag@w3.org
> Cc: public-rdf-in-xhtml-tf@w3.org; newsml-2@yahoogroups.com
> Subject: CURIEs: A proposal
> 
> 
> Hi folks,
> 
> A modest proposal, drawing on ideas from Mark, Henry, Tim, 
> Dan, Norm and others:
> 
> 1   We agree on a generic syntax and generic rules for Compact URIs 
>     (CURIEs) in attribute values.
> 
> 2   We agree that restricted syntaxes and rules will be (or have 
>     been) defined for specific purposes.   One such purpose is XML 
>     Namespaces and QNames.
> 
> 3   Groups within the W3C and elsewhere will define other restricted 
>     syntaxes and rules for their own purposes.
> 
> 4   The generic syntax for a CURIE in an attribute value will be:
>        <foo bar="prefix:suffix"/>
> 
> 5   The generic syntax for multiple CURIEs in an attribute value 
>     will (where permitted) be:
>        <foo bar="prefix1:suffix1 ... prefixN:suffixN"/>
> 
> 6   Both the prefix and the suffix may (in the generic case) be 
>     numeric.
> 
> 7   Each language must specify:
> 
> 7a  the syntactic constraints (if any) on the prefix and suffix.
> 
> 7b  how CURIEs and URIs are distinguished, eg through dedicated 
>     attributes or through a special syntax.
> 
> 7c  the mechanism for specifying the prefix-to-IRI mapping.  The 
>     mechanism may use information provided out-of-band.
> 
> 7d  whether and, if so, how the prefix and suffix are combined to 
>     form an IRI.
> 
> 7e  whether the prefix and suffix form a tuple or whether they are 
>     just a compact representation for an IRI.
> 
> 7f  whether the IRI mapped to the prefix is required to be 
>     dereferenceable.
> 
> 7g  whether the IRI built from the prefix and suffix (and, possibly, 
>     including also other building blocks) is required to be 
>     dereferenceable.
> 
> 7h  whether any fragment identifiers in these IRIs are required to 
>     be legal XML names.
> 
> 8   To avoid confusion with XML Namespaces and QNames:
> 
> 8a  The xmlns attribute is reserved for use with XML Namespaces and 
>     QNames.
> 
> 8b  If a prefix matches an xmlns declaration then the CURIE MUST be 
>     interpreted as a QName.
> 
> Misha
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Received on Monday, 5 June 2006 14:47:32 GMT

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