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Re: attempting to tackle ACTION-514

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Tue, 27 Sep 2011 15:13:40 +0100
Message-ID: <4E81DA14.9020201@epimorphics.com>
To: public-rdf-dawg@w3.org
One possibility is to define SERVICE algebra over the preceding pattern:

{ ?s ?p ?g .
   SERVICE ?g { ?s1 ?p1 ?o1 }
   ?s2 ?p2 ?o2 .
}

===>

(join
   (service ?g (bgp (?s1 ?p1 ?o1))
     (bgp (?s ?p ?g)))
   (?s2 ?p2 ?o2))

which puts a defined ?g into the service operation because the
"?s ?p ?g" is evaluted - then service part done.

c.f. FILTER
which works over a subpattern
c.f. OPTIONAL.
which combines the preceding pattern and the {} part into one operation.

	Andy
Received on Tuesday, 27 September 2011 14:14:20 GMT

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