- From: Olaf Hartig <olaf.hartig@liu.se>
- Date: Tue, 3 Sep 2019 20:13:06 +0000
- To: "public-rdf-star@w3.org" <public-rdf-star@w3.org>
- CC: Richard Cyganiak <richard@cyganiak.de>
Hi Richard, On tisdag 3 september 2019 kl. 14:33:08 CEST Richard Cyganiak wrote: > [...] > >>> << <<:a :b :c>> :d :e >> :f :g . > >>> > >>> How would you represent this triple in the alternative serialization > >>> syntax that you have outlined? > >> > >> In my straw man syntax, this triple would be written as: > >> :a :b :c <<:d :e <<:f :g>> >>. > > > > Mmh. While I understand how this would work, I think that expressions of > > this form can be confusing as a serialization syntax for nested RDF* > > triples. I mean, this expression also looks like something that is > > nested, but the way this expression uses nesting is a very different one > > from the notion of nesting of triples that we have in abstract syntax of > > the RDF* data model. > > When you say this, you gloss over an important aspect of the RDF* data > model: the fact that the notation "<<:a :b :c>> :d :e" in Turtle* expresses > two triples, not one: > > ((:a :b :c) :d :e) > (:a :b :c) > > If the notation would only express the former triple, then there would > indeed be a clean and direct correspondence between concrete and abstract > syntax. > > But the notation also expresses the latter triple, and that aspect of the > abstract syntax is not hinted at in the concrete syntax at all. > In the alternative straw man syntax, one cannot write the expression for > the composite triple without first writing the expression for its inner > constituent triple: > :a :b :c <<:d :e>> > > This makes quite obvious that the ":a :b :c" triple is part of the graph > too. > > In that sense, the nesting in the alternative syntax captures the constraint > of the RDF* data model better than the nesting of Turtle*. That's a very good argument! However, the aspect of RDF* that you mention exists only when using RDF*/ SPARQL* in PG mode. It is not clear yet whether we end up with proposing only PG mode, or only SA mode, or maybe both as alternative options. Thanks, Olaf
Received on Tuesday, 3 September 2019 20:13:40 UTC