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Re: Turtle and CURIES

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Mon, 23 May 2011 15:57:49 +0100
Message-ID: <4DDA75ED.1040006@epimorphics.com>
To: public-rdf-wg@w3.org


On 23/05/11 14:53, David Wood wrote:
> Hi all,
>
> The TAG (or rather, the  AWWSW Task Group of the TAG) is (still |
> again) actively discussing http-range-14 and its relation to the
> definitions of URIs. [1]

Thanks for pointing it out.

>
> Section 5.2 of that document [2] states:
>
> [[ A null fragid precludes the use of qnames to abbreviate such URIs.
> (In particular it would not be possible to use them as predicate
> names in RDF/XML.) However, SPARQL, Turtle, and RDFa are being
> extended to admit CURIEs that include #, making this a newly
> attractive option. ]]

I can read this in two ways: the IRI that the CURIE represents can 
include a #, including null fragid, and so does not have the RDF/XML 
problem.

prefix ex: <http://example/ns#>
...
{ ex: ex: ex: }

Or that the syntax of CURIE can include a #. SPARQL is not being changed 
to include these - this area has not changed since SPARQL 1.0.

prefix ex: <http://example/>

{ ex:abc#def ex:ns# ex:#a }

which is illegal.



# is the comment character in SPARQL and Turtle.  (Could be changed to 
"<WS>#".)

> I have advised Jonathan Rees, the editor, that the RDF WG is leaning
> toward minimal changes in Turtle, but some form of Quartle may (or
> may not) follow.

SPARQL 1.1 Last Call is unchanged from SPARQL 1.0 in this area.

> If anyone thinks this changes their mind in relation to CURIE support
> in a standardized Turtle, this would be a good time to say so.

A CURIE is:

safe_curie  :=   '[' curie ']'
curie       :=   [ [ prefix ] ':' ] reference
prefix      :=   NCName
reference   :=   irelative-ref (as defined in IRI)

so Turtle's 'a' would match as would '123'

irelative-ref includes "?" and "@" and ":" (the last two via ipchar)

And '['  ']' have been used.

CURIE permits further restrictions - while Turtle may in spirit have 
CURIEs, we need to restrict in some way anyway.

	Andy

>
> Regards, Dave
>
> [1]  http://www.w3.org/2001/tag/awwsw/issue57/latest/ [2]
> http://www.w3.org/2001/tag/awwsw/issue57/latest/#suffix

	Andy
Received on Monday, 23 May 2011 14:58:20 GMT

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