Re: Json-LD to N3?

Henry, all,

2 remarks:

- the problem you identified in Example 1 of VC-Core is indeed 
registered as an issue[1] , and should be fixed eventually

- the conversion from TriG / JSON-LD to N3 performed by Gregg's 
distiller is a non-standard interpretation of RDF datasets -- since RDF 
datasets have no standard semantics anyway. It assumes that the "name" 
of a named graph (IRI or blank node) actually denotes that graph (for 
some definition of "that graph") and therefore can be replaced, in N3, 
by the corresponding quoted graph. This is consistent with how JSON-LD 
is used in VC-core (and it aligns nicely with how this is serialized in 
JSON-LD, where the value of "poof", for example, is a JSON object 
representing the graph itself, not even requiring an explicit graph 
name) -- but this is not the only way one can use named graphs in RDF.

   best

[1] https://github.com/w3c/vc-data-model/issues/967


On 01/02/2023 11:12, Henry Story wrote:
>
>> On 1. Feb 2023, at 08:10, Patrick Hochstenbach <Patrick.Hochstenbach@UGent.be> wrote:
>>
>>> From: Henry Story <henry.story@bblfish.net>
>>> Date: Tuesday, 31 January 2023 at 20:59
>>> To: public-n3-dev@w3.org <public-n3-dev@w3.org>
>>> Subject: Json-LD to N3?
>>> Hi,
>>>
>>> I find Json-LD a bit opaque to read. Is there a way I can convert it to n3,
>>> so I can see clearly what the graphs are?
>>>
>>> I can use the json-ld playground to convert it to Nquads, but I could
>>> not see how to get nquads to n3 using eye.
>>>
>>> Henry
>>   I always use easyrdf.org for conversions:
>>   https://www.easyrdf.org/converter

>>   Patrick
> I am trying to convert the examples from the Verifiable Credentials Data Model spec such as
> https://www.w3.org/TR/vc-data-model/#example-a-simple-example-of-a-verifiable-credential

> so that I can clearly work out what is a quoted graph and what is not. That type
> of information is very much obscured by JSON-LD, even though it is essential to
> understanding claims.
>
> Easyrdf does not give me any output when I tried to convert the cleaned
> up Verifiable Claim example [1].
>
> Greg Kellog pointed me to his RDF distiller
> http://rdf.greggkellogg.net/distiller?command=serialize&format=jsonld&output_format=n3

>
> And that gives the n3 result as shown in the second snippet of [1]. That is consistent
> with the result given by first going through https://json-ld.org/playground/ and first
> converting to NQuads (third snipped in [1]) and then using distiller to convert nquads to n3.
>
> Interestingly both of those seem to reveal a problem with the first example json-ld, as it
> produces the following two triples in n3
>
>    <did:example:c276e12ec21ebfeb1f712ebc6f1> schema:name [], [] .
>
> But one can see quite clearly that the same is true in nquads.
> Greg Kellog suggested this may be a problem with ”value” and ”lang” fields not
> having been declared, and indeed when using the jsonld playground it helpfully
> suggests using @value and @language instead.  With that we then get the
> jsonld in [2] and the nquads and n3 conversions that go with it using distiller.
>
> Now I would have expected the graph to be signed to be quoted, and linked to by a
> signature. We seem to be having the opposite going on here.
>
> Henry
>
> [1] https://gist.github.com/bblfish/908145116b14486af9dd3460ce14b2c1

> [2] https://gist.github.com/bblfish/ab1b450c725674a4386cfc391b7e307b

>
>
>
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