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Re: [TF-PP] Document now in CVS

From: Ivan Herman <ivan@w3.org>
Date: Mon, 23 Nov 2009 12:01:53 +0100
Message-ID: <4B0A6BA1.2060408@w3.org>
To: Andy Seaborne <andy.seaborne@talis.com>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>
Hi Andy,

nobody reacted until now... But we should thank you in the first place!:-)

There is still a pending issue in my mind on whether property paths can
handle list elements properly or not. The issue I see is to be able to
query list elements in their 'natural' order.

I have digged up some mails from early discussions[1][2]. You
proposed[1] a scheme whereby

SELECT ?paper ?author
WHERE {
    ?paper ex:authors ?l .
    ?l rdf:rest*{?len}/rdf:first ?author .
}
SORTED BY ?len

(or something similar) would work to

would work to give back the author's list in list order. Orri had a more
complex scheme[2] in his mail...

I believe something like that is really necessary for '*' and '+';
handling lists is one of the big outstanding features in my view and not
handling them via paths would be a real shame...

Ivan


[1] http://lists.w3.org/Archives/Public/public-rdf-dawg/2009JanMar/0102.html
[2] http://lists.w3.org/Archives/Public/public-rdf-dawg/2009JanMar/0116.html


Andy Seaborne wrote:
> I've moved the document from the wiki into CVS, and used xmlspec.
> 
> http://www.w3.org/2009/sparql/docs/property-paths/Overview.xml
> 
> It does not look very nice - we need to settle on a "house style"
> (tables, examples, grammars) although I see something emerging in
> sparql.xsl.
> 
>     Andy
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
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Received on Monday, 23 November 2009 11:02:22 GMT

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