- From: Luke Wilson-Mawer <luke.wilson-mawer@garlik.com>
- Date: Tue, 29 Sep 2009 12:59:27 +0100
- 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. > +1. > 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 problems. > 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 > > -------------------------------------------- > Hewlett-Packard Limited > Registered Office: Cain Road, Bracknell, Berks RG12 1HN > Registered No: 690597 England > >
Received on Tuesday, 29 September 2009 12:00:03 UTC