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Re: JSON-LD Syntax request for FPWD via RDF WG

From: Gregg Kellogg <gregg@greggkellogg.net>
Date: Tue, 22 May 2012 12:54:55 -0400
To: Richard Cyganiak <richard.cyganiak@deri.org>
CC: Markus Lanthaler <markus.lanthaler@gmx.net>, "public-rdf-comments@w3.org" <public-rdf-comments@w3.org>
Message-ID: <8D78DCB3-B3F2-47A4-ABD0-5229CAAB928B@greggkellogg.net>
On May 22, 2012, at 9:02 AM, Markus Lanthaler wrote:

>> Is there a particular reason why the RDF mapping is in the API spec
>> rather than in the language spec?
> The syntax spec is targeted JSON-LD authors that don't necessarily have an
> RDF background. Furthermore it is not syntax but a transformation. We
> bundled all algorithms in the API spec.
>> Is the proposal that RDF-WG should take both the API spec and the
>> language spec to REC?
> Yes. The API spec is just not ready for prime time yet :-)

As Markus noted, at this point, it's only the Syntax spec that we're submitting. The API spec could potentially be done in a different group, when the time comes.

>> At first glance, these sections look great. I notice three things
>> though:
>> 1. I'd prefer if the algorithms were defined in terms of standard RDF
>> terminology (RDF graph, triple, IRI, etc.) rather than API interfaces
>> that use quite different terminology (array of Statements, Statement,
>> NamedNode, etc.)
> OK, I filed an issue for that [1]

The use of terms such as _Statement_ closely follows the RDF Interfaces spec [3] (Triple renamed to Statement), which has been dormant. I think it's reasonable that these terms echo definitions in RDF Concepts, but note that a Statement may be either a triple or a quad; triple seems too narrow for this. I don't believe the concepts doc discusses triples with a context.

For the context of the RDF WG, we could create a separate document describing the normative requirements for RDF transformations; we intentionally kept the discussion of RDF to a minimum in the Syntax document.

JSON-LD can pretty fully represent everything that can be represented in TriG, with the exception of lists containing other lists.

>> 2. Examples would be great.
> There are a couple of example in the syntax spec [2], don't know if you
> already saw them.

A good source of examples is the Test Suite [4], [5]. We should probably create links from the test suite to each individual test and result, to make them easier to access. The fact that manifests are all represented using JSON should make this a fairly easy thing to do within the HTML page itself, perhaps using the <script type="application/ld+json"> similar to that used in the Turtle spec.


>> 3. Is it possible to serialize an RDF graph into a "pretty" JSON-LD
>> document using a context? I presume the answer is "yes" and involves
>> Compaction of the basic serialized output.
> Yes, exactly either by compacting or by framing.
> [1] https://github.com/json-ld/json-ld.org/issues/125
> [2] http://json-ld.org/spec/latest/json-ld-syntax/#markup-examples
[3] http://www.w3.org/TR/2011/WD-rdf-interfaces-20110510/
[4] http://json-ld.org/test-suite/tests/fromRdf-manifest.jsonld
[5] http://json-ld.org/test-suite/tests/toRdf-manifest.jsonld

> --
> Markus Lanthaler
> @markuslanthaler
Received on Tuesday, 22 May 2012 16:56:11 UTC

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