- From: Andy Seaborne <andy@apache.org>
- Date: Wed, 03 Jul 2013 15:49:09 +0100
- To: public-rdf-wg@w3.org
On 03/07/13 03:24, RDF Working Group Issue Tracker wrote: > RDF-ISSUE-137 (aligning-trig-and-sparql): Should TriG be a subset of > SPARQL Quad Pattern? [RDF TriG] > > http://www.w3.org/2011/rdf-wg/track/issues/137 > > Raised by: Sandro Hawke On product: RDF TriG > > (Raised as per discussion at 2013-06-26 meeting) > > TriG and SPARQL Quad Patterns *almost* overlap nicely, but there are > two syntactic differences that make the languages entirely disjoint. The description includes opinion. Please include all points of view. Some people (not me) have said they see it as a positive advantage -- evidence: different MIME types. -1 to the current description with opinion. > 1. SPARQL uses the GRAPH keyword before the graph name. Traditional > TriG doesn't. We agreed to include the GRAPH keyword as an "at > risk" feature, in parallel to PREFIX and BASE being "at risk". One > could argue that it automatically follows from accepting PREFIX and > BASE into Turtle that we accepted GRAPH into TriG. Disagree. > At very least > the spec should include it, marked at risk. > https://www.w3.org/2013/meeting/rdf-wg/2012-10-03#resolution_7 Noting the wording there "... the case-insensitive keyword "graph" MUST NOT appear before the name, in a name-graph pair ..." TriG was published April 2013 > > 2. SPARQL does not have curly braces around the default graph > triples (although it kind of looks like it, since it has them around > the whole quad pattern). > We decided that TriG would require them: > https://www.w3.org/2013/meeting/rdf-wg/2012-10-17#resolution_2 ... > but I don't think we were thinking about SPARQL compatibility at that > point. I was. I have raised this matter before. It is not new and that is why there is this resolution. (Also raised was N-Quads in TriG.) > Also, at that point, the same bytes parsed as Turtle and > TriG had different semantics, but since > https://www.w3.org/2013/meeting/rdf-wg/2013-06-12#resolution_2 they > now have the same semantics, so having overlapping syntaxes should be > okay. This conflicts with having simple parsing which is also a goal we have had since the beginning. It would require significant changes to many (all?) existing implementations of TriG parsers. significant => structural change to the parsers, not a single rule change. It is a divergence from Turtle. > PROPOSED: Make TriG (not counting prefix & base) be a subset of the > SPARQL quad pattern language, like Turtle is, by allowing (1) braces > around the default graph and (2) the GRAPH keyword. Explain that > this form is preferred for SPARQL alignment, but isn't handled by > older TriG parsers. "preferred" in (2) conflicts with 2012-10-03#resolution_7 Andy
Received on Wednesday, 3 July 2013 14:49:40 UTC