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RE: 9.1 Property Path Syntax

From: Nicholas Humfrey <Nicholas.Humfrey@bbc.co.uk>
Date: Tue, 14 Aug 2012 22:28:02 +0100
Message-ID: <79AEAFE5D84FB14B876861300FED97CF1B2CE5@bbcxues50.national.core.bbc.co.uk>
To: Andy Seaborne <andy.seaborne@epimorphics.com>, <public-rdf-dawg-comments@w3.org>
Thanks for clarifying Andy. It makes sense to me now.

Suggestions for clarifications:
* Provide a link from the description of property paths in section 9.1 to the definition of a SPARQL IRI in section 4.1.1.
* Give a property path example showing a IRI written in full. 

Thanks,

nick.



> From: Andy Seaborne [mailto:andy.seaborne@epimorphics.com]
> Sent: Tue 8/14/2012 4:28 PM
> To: public-rdf-dawg-comments@w3.org
> Subject: Re: 9.1 Property Path Syntax
>  
> Nick,
> 
> The syntax for IRIs is discussed in section 4.1.1.
> 
> http://www.w3.org/TR/sparql11-query/#QSynIRI
> 
> and there are some examples of writing equivalent IRIs.
> 
> This is not in the property path section as this is not specific to 
> property paths.
> 
> An IRI can be written in <...> form or a prefixed name - it's just 
> surface syntax and for execution purposes the expanded absolute IRI is 
> used.  There are no prefix names at execution time in SPARQL, only 
> absolute IRIs (the same is true of RDF).
> 
> Implementers need to treate prefix names as surface syntax for absolute 
> IRIs.
> 
>  > $names = $person->all('foaf:knows/foaf:name');
> 
> Somewhere EasyRdf needs to provide the prefix mapping for "foaf:" 
> because foaf:knows is just shorthand for
> <http://xmlns.com/foaf/0.1/knows> which is what will appear in the data 
> to be matched.
> 
> 	Andy
> 
> On 13/08/12 11:09, Nicholas Humfrey wrote:
> > Hello,
> >
> > I am looking at implementing a small subset of the SPARQL 1.1 Property Path
> > syntax in EasyRdf. Although it doesn't support SPARQL querying internally,
> > the property path syntax is useful for fetching values like this:
> > $names = $person->all('foaf:knows/foaf:name');
> >
> >
> > However I am finding the Property Path Syntax for an IRI is slightly
> > confusing:
> > "iri is either an IRI written in full or abbreviated by a prefixed name"
> >
> > How should implementers distinguish between an IRI and a property path?
> > Shouldn't a full IRI be enclosed in angle brackets?
> > <http://xmlns.com/foaf/0.1/knows>
> >
> > Hence property paths can only be used with prefixed names? I think an
> > example might help.
> >
> >
> > Thanks,
> >
> > nick.
> >

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Received on Tuesday, 14 August 2012 21:28:39 GMT

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