GH-12 GH-13 basic specification of XML and JSON result formats

[abrokenjester]

Initial proposals for standardized representations of embedded triples as RDF terms in SPARQL JSON results format and SPARQL XML result format.

Feedback on both content and markup much appreciated (I am relatively new at ReSpec).

[abrokenjester]

Thanks again for the feedback @pchampin!

[gkellogg]

I think it’s automatically enabled for repos in the w3c group, just needs a .pr-preview.json file, similar to https://github.com/w3c/json-ld-syntax/blob/master/.pr-preview.json

It is/was temperamental, so look at https://github.com/apps/pr-preview for more.

[pchampin]

@gkellogg it did the trick, thanks :+1: Actually, it does not seem to work on PRs that previously existed, but that's not a problem as I have hand-created a preview for that one here: http://champin.net/tmp/rdf-star-pr39.html#query-result-formats

[hartig]

Questions related to this: Do we need/want new mime types for these two extended formats? Do we need/want to introduce another namespace for the extended XML schema?

I am just putting these questions here for the moment so that we don't forget them. We can certainly discuss these questions separately from the actual formats as proposed in this PR.

[pchampin]

@hartig I think we do need a new media type for these formats. We don't want an RDF-unaware client request an SPARQL endpoint, and choke on the results it gets from the server.

[hartig]

I have create a new issue to separate the discussion of the mime types for these results formats from the discussion of the formats themselves: #43

[hartig]

@pchampin before merging, please note that I added two editorial changes (see above)

[pchampin]

This was discussed in today's call https://w3c.github.io/rdf-star/Minutes/2020-11-27.html#item03

[afs]

"predicate" vs "property"

I don't have a strong opinion except to know which is clearer to people (and I don't know which that is and I switch between "predicate" and "property" for no obvious reason!). The only data points I have are:

• It is rdf:property.
• "The predicate itself is an IRI and denotes a property," See https://www.w3.org/TR/rdf11-concepts/#resources-and-statements which mostly uses "predicate".

[abrokenjester]

"predicate" vs "property"

I don't have a strong opinion except to know which is clearer to people (and I don't know which that is and I switch between "predicate" and "property" for no obvious reason!). The only data points I have are:

* It is `rdf:property`.

* "The predicate itself is an IRI and denotes a property," See https://www.w3.org/TR/rdf11-concepts/#resources-and-statements which mostly uses "predicate".

I personally have a slight preference for "predicate" mostly because I find it a more generic term than "property" ( YMMV), and because https://www.w3.org/TR/rdf11-concepts/#section-triples defines an RDF triple as:

An RDF triple consists of three components:

• the subject, which is an IRI or a blank node
• the predicate, which is an IRI
• the object, which is an IRI, a literal or a blank node

[pchampin]

@hartig I'll merge it now before conflicts appear, and apply your changes afterwards.