- From: Ian Davis <iand@internetalchemy.org>
- Date: Wed, 18 Jan 2006 15:41:21 +0000
- To: andy.seaborne@hp.com
- CC: public-rdf-dawg-comments@w3.org
Thanks for the informative answer. I agree with the resolution. For email archive purposes, the key information I was missing is given here: http://www.w3.org/TR/2005/WD-rdf-sparql-query-20051123/#OptionalMatchingDefn It says: { optional { pattern } } is defined to be { } optional { pattern } It would be nice to put a little editorial prose in this section detailing the relevance, the explanation you give in your reply would be ideal: On 18/01/2006 10:09, Seaborne, Andy wrote: > The OPTIONAL operator is defined as a binary operator and it is > left-associative (the latter has been added since as it was unclear as > someone pointed out). > > So > { > ?x foaf:name ?name . > OPTIONAL { ?x foaf:homepage ?page . } > OPTIONAL { ?x foaf:workplaceHomepage ?page . } > } > > is (adding some braces): > { > { { ?x foaf:name ?name . } > OPTIONAL { ?x foaf:homepage ?page . } > } > OPTIONAL { ?x foaf:workplaceHomepage ?page . } > } > > that is, the second optional will operate on the matching of the of the > first. Thanks, Ian
Received on Wednesday, 18 January 2006 15:41:28 UTC