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Re: [TF-PP] Questions on Property Paths

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 9 Oct 2009 17:45:52 +0100
Cc: "public-rdf-dawg@w3.org Group" <public-rdf-dawg@w3.org>
Message-Id: <8AF94659-9437-492F-9C71-D7AC6935FB2F@garlik.com>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
On 9 Oct 2009, at 17:15, Seaborne, Andy wrote:
>
>> -----Original Message-----
>> From: public-rdf-dawg-request@w3.org [mailto:public-rdf-dawg-request@w3.org 
>> ]
>> On Behalf Of Steve Harris
>> Sent: 08 October 2009 12:50
>> To: public-rdf-dawg@w3.org Group
>> Subject: [TF-PP] Questions on Property Paths
>>
>> I've just read through the document Andy posted:
>> http://www.w3.org/2009/sparql/wiki/Design:PropertyPaths
>>  and I have a couple of questions:
>>
>> Is the () construct particularly useful? Without have tried it it  
>> does
>> seems like it might make the design much harder to implement that if
>> it was absent. Though I'd welcome evidence to the contrary.
>
> With foaf:knows, the foaf:Person is connected to another foaf:Person  
> by a single property.  Sometimes, the link from one resource to the  
> next is via two of more properties so
>
> ?x (:p/:q)+ ?y

OK, I can see that you can't do that without that syntax.

Do you have any feel for how much effort it was to do an implementation?

>> "Cycles in paths are possible and are handled." in any particular  
>> way?
>
> Rough wording. Cycles exist naturally so have to be handled but  
> that's an implementation issues.  It might be by tracking visited  
> nodes, or it might be just part of some algorithm. (e.g. Floyd- 
> Walshall does not have special cases for cycles).

OK, so you're not proposing any particular solution at this point?

- Steve
Received on Friday, 9 October 2009 16:46:29 GMT

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