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Re: [TF-PP] Possible starting points

From: Luke Wilson-Mawer <luke.wilson-mawer@garlik.com>
Date: Tue, 29 Sep 2009 12:59:27 +0100
Message-ID: <4AC1F69F.6080800@garlik.com>
To: "Seaborne, Andy" <andy.seaborne@hp.com>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>
Seaborne, Andy wrote:
> This is a request for your views on starting points for the property paths time permitting feature.  
> Please send +1/0/-1 for the options (which aren't meant to be mutually exclusive) or we might get telcon time.
> I've tried to list the main possibilities in terms of styles and approach as starting points: all have variations and areas of uncertainty (e.g. ordering of results).
> 1/ Property paths only mention IRIs or prefixed names.
> The most conservative choice. Still need to relate to entailment.
> 2/ Property paths with variables and IRIs or prefixed names.
> (issues include restriction of what can be asked a la ?p* discussion)
-1.  I think variables unlock a some really compelling features, but 
because property paths is a time permitting feature and variables 
introduce a fair amount of issues, I think it best to leave them out and 
concentrate on the core.  Perhaps implementors will solve some of these 
> 3/ With access to the length of the path matched
> Issues include how multiple paths between two nodes are handled (two lengths possible).
0.  I don't fully understand the issues that come from allowing access 
to the length of the path.
> 4/ With access to the path matched (path-valued variables is one possibility)
> Issues as 3 + what is a path value "datatype".
> For all of them: add an option to have
> 5/ A mechanism that will allow a variety of path matching schemes, and provide one such system.
> Roughly, this would involve defining syntax so various different approaches can at least use common syntax but choose from 1-4 as to what the WG describes in this round of standardization and show the relationship to the syntax. E.g having a PATH keyword idea in [1].
-1.  I don't see the advantage of having a common syntax.
> Then
> 6/ Do nothing in this round - too early to standardise.
-1.  Property paths have been implemented in a few places, and I think 
they add a lot of power to the language.  Even if we only standardise a 
rump,  I think it opens the door for more exciting features in the future.
> 	Andy
> http://www.w3.org/2009/sparql/wiki/TaskForce:PropertyPaths
> http://www.w3.org/2009/sparql/wiki/Feature:PropertyPaths
> [1] http://lists.w3.org/Archives/Public/public-rdf-dawg/2009JulSep/0315.html
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Received on Tuesday, 29 September 2009 12:00:03 UTC

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