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

On Wed, 3 Mar 2021 at 08:57, James Anderson <>

> > On 2021-03-02, at 21:34:20, Gregg Kellogg <>
> wrote:
> >
> >> On Mar 2, 2021, at 12:09 PM, James Anderson <
>> wrote:
> >>
> >> good evening;
> >>
> >>> On 2021-03-02, at 18:56:40, Olaf Hartig <> 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
<> . 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 What I'm *guessing *mr.
Anderson is referring to as needing examination is the notion of
RDFterm-equality (see 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.


Dr Jeen Broekstra (he, him)
*principal software engineer*

[image: htps://] <>

Received on Tuesday, 2 March 2021 23:21:28 UTC