Re: Text about SPARQL-star built-in functions ready

Thanks James & Jeen for pointing that out. I created an issue for that:

https://github.com/w3c/rdf-star/issues/121

On 03/03/2021 00:21, Jeen Broekstra wrote:
>
>
> On Wed, 3 Mar 2021 at 08:57, James Anderson 
> <anderson.james.1955@gmail.com <mailto:anderson.james.1955@gmail.com>> 
> wrote:
>
>
>     > On 2021-03-02, at 21:34:20, Gregg Kellogg
>     <gregg@greggkellogg.net <mailto:gregg@greggkellogg.net>> wrote:
>     >
>     >> On Mar 2, 2021, at 12:09 PM, James Anderson
>     <anderson.james.1955@gmail.com
>     <mailto:anderson.james.1955@gmail.com>> wrote:
>     >>
>     >> good evening;
>     >>
>     >>> On 2021-03-02, at 18:56:40, Olaf Hartig <olaf.hartig@liu.se
>     <mailto:olaf.hartig@liu.se>> wrote:
>     >>>
>     >>> ...
>     >>>
>     >>> The changes are in Section 4.2 (SPARQL-star Grammar) and in
>     the new Section
>     >>> 4.4 (Function Definitions).
>     >>>
>     >>> As agreed during our telco last Friday, I will leave this PR
>     open for three
>     >>> days so that your can take a look at it and raise concerns (if
>     any). Unless
>     >>> anyone brings forward reasons that this PR should not be
>     merged, I will merge
>     >>> it on Friday afternoon (CET).
>     >>
>     >> i raise the concern, that the approach needs to comprehend
>     quads before it will be usable.
>     >
>     > I think this comment is more general than the specific functions
>     added. It would be useful to have some examples that use various
>     combinations of embedded triples, annotations, and these functions
>     within named graphs.
>
>     it would also be useful to know the consequences for paragraph
>     15.1 and section 17 of the sparql recommendation.
>
>
> In the interest of saving everybody's time trying to puzzle out what 
> these sections are about and how it relates to the topic under 
> discussion, I have done some homework. I'll ignore the earlier remark 
> about quads because I have no clue what is intended there or how it 
> fits in with the topic under discussion (the new functions).
>
> Section 15.1 is about establishing a partial ordering of RDF values 
> for the purpose of executing an ORDER BY clause. 
> See https://www.w3.org/TR/sparql11-query/#solutionModifiers 
> <https://www.w3.org/TR/sparql11-query/#solutionModifiers> . Although 
> it has no direct bearing on the introduction of these new functions, 
> there is a valid point here that we'll need to establish how RDF-star 
> triples fit into that partial ordering.
>
> For what it's worth, RDF4J has extended the partial ordering by adding 
> RDF-star triples at the end (behind RDF literals), and by comparing 
> two RDF-star triples by first comparing subject, then predicate, then 
> object to establish order.
>
> Section 17 is about expressions and value testing. See 
> https://www.w3.org/TR/sparql11-query/#expressions 
> <https://www.w3.org/TR/sparql11-query/#expressions>. What I'm 
> /guessing /mr. Anderson is referring to as needing examination is the 
> notion of RDFterm-equality 
> (seehttps://www.w3.org/TR/sparql11-query/#func-RDFterm-equal 
> <https://www.w3.org/TR/sparql11-query/#func-RDFterm-equal>). In 
> particular, it will need extending to explicitly state that two terms 
> are considered RDFterm-equal if they are both RDF-star triples and 
> those triples are equivalent under our predefined notion of 
> equivalence (which I assume would be most simply expressed in terms of 
> each of its constuent parts being RDFterm-equal, cf. 
> https://w3c.github.io/rdf-star/cg-spec/2021-02-18.html#dfn-rdf-star-terms 
> <https://w3c.github.io/rdf-star/cg-spec/2021-02-18.html#dfn-rdf-star-terms>). 
>
>
> Regards,
>
> Jeen
> -- 
> Dr Jeen Broekstra (he, him)
> /principal software engineer/
>
> jb@metaphacts.com <mailto:jb@metaphacts.com>
> www.metaphacts.com <https://www.metaphacts.com/>
>
> htps://www.metaphacts.com/ <https://www.metaphacts.com/>