ISSUE-137: Should TriG be a subset of SPARQL Quad Pattern?

aligning-trig-and-sparql

Should TriG be a subset of SPARQL Quad Pattern?

State:

CLOSED

Product:

RDF TriG

Raised by:

Sandro Hawke

Opened on:

2013-07-03

Description:

(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.

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. At very least the spec should include it, marked at risk. https://www.w3.org/2013/meeting/rdf-wg/2012-10-03#resolution_7

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. 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.

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.

Related Actions Items:

No related actions

Related emails:

1. RDF WG teleconference record 10 July 2013 (from eric@w3.org on 2013-07-12)
2. "at risk" language for TriG sparql-alignment features (from sandro@w3.org on 2013-07-09)
3. Re: ACTION-278: grammar for TriG (from andy@apache.org on 2013-07-08)
4. Re: Some syntax tests for issue-137 (GRAPH + Turtle-in-TriG) (from gregg@greggkellogg.net on 2013-07-07)
5. Some syntax tests for issue-137 (GRAPH + Turtle-in-TriG) (from andy@apache.org on 2013-07-07)
6. Re: RDF-ISSUE-137 (aligning-trig-and-sparql): Should TriG be a subset of SPARQL Quad Pattern? [RDF TriG] (from andy@apache.org on 2013-07-03)
7. RDF-ISSUE-137 (aligning-trig-and-sparql): Should TriG be a subset of SPARQL Quad Pattern? [RDF TriG] (from sysbot+tracker@w3.org on 2013-07-03)

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