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

From: Richard Cyganiak <richard@cyganiak.de>
Date: Tue, 22 May 2012 14:53:16 +0100
Cc: Manu Sporny <msporny@digitalbazaar.com>, RDF WG <public-rdf-wg@w3.org>, Linked JSON <public-linked-json@w3.org>
Message-Id: <4BFBCE0F-E139-4FFF-9E7D-435DA1B7500D@cyganiak.de>
To: Ivan Herman <ivan@w3.org>
On 22 May 2012, at 14:18, Ivan Herman wrote:
>> * Is JSON-LD an RDF serialization?
> 
> I think the best way of saying it is: it can be used as an RDF serialization, although applications may use it directly, too, without referring to RDF.

Ok.

>> * Given a JSON-LD document, how do I get an RDF graph from it?
> 
> The answer is that this is a bit hidden in the document though, when reading it, the conversion is fairly clear. But I agree is it not explicit. Manu, it may be worth having a separate section that makes that mapping absolutely explicit and formal.

This should be a normative section. The current spec doesn't normatively reference RDF.

>> * Given an RDF graph, how do I turn it into a JSON-LD document?
> 
> I think that if we get the previous issue done, that answers this question, too.

Ok. At the moment this isn't obvious at all. There seem to be many different ways of serializing the same RDF graph. I think this is potentially dangerous because (unlike in say Turtle) the triples are not necessarily obvious from the resulting JSON.

I think it would be great to:

1. document how to serialize an RDF graph, given a pre-defined context
2. document how to serialize an RDF graph without a context

In both cases, the more predictable the output, the better. This predictability is absolutely important. Without predictability, it would be the RDF/XML train wreck all over again, where you end up with something that isn't a good RDF serialization (because it hides the triples) and isn't a good XML format either (because there's a myriad ways of saying the same thing with different XML, so you can't use XML tools).

For the second case, I guess there would be bonus points for making the triples really obvious, even if it makes the JSON ugly. If you want pretty JSON, provide a context.

JSON-LD may already do all these things, but I find it hard to tell from the spec, as it apparently tries hard to avoid any association with RDF.

>> * Can any RDF graph be serialized as a JSON-LD document?
> 
> Yes.

Good.

Richard



> 
> B.t.w., just for the fun of it: the RDFa 1.1 distiller http://www.w3.org/2012/pyRdfa/ already has a JSON-LD serialization option (alongside RDF/XML and turtle).
> 
> Ivan
> 
> 
>> Best,
>> Richard
>> 
>> 
>> On 22 May 2012, at 05:19, Manu Sporny wrote:
>> 
>>> Last week, the Linked Data in JSON Community Group discussed whether or
>>> not we thought that JSON-LD was ready to be moved into the RDF WG for
>>> REC-track standardization:
>>> 
>>> http://json-ld.org/minutes/2012-05-15/#topic-1
>>> 
>>> There was consensus that the JSON-LD Syntax is finalized (as far as the
>>> CG is concerned). There may be one more change that we are considering,
>>> but that change would depend on feedback we get from this group. There
>>> will, of course, be plenty of opportunity to discuss changes to the spec
>>> in the RDF WG.
>>> 
>>> There is a date-stamped document that is available for review here:
>>> 
>>> http://json-ld.org/spec/ED/json-ld-syntax/20120522/
>>> 
>>> So, this is a request to place the JSON-LD Syntax specification on the
>>> W3C Recommendation track via the RDF Working Group. David, Guus - what
>>> are the next steps?
>>> 
>>> -- manu
>>> 
>>> -- 
>>> Manu Sporny (skype: msporny, twitter: manusporny)
>>> Founder/CEO - Digital Bazaar, Inc.
>>> blog: PaySwarm Website for Developers Launched
>>> http://digitalbazaar.com/2012/02/22/new-payswarm-alpha/
>>> 
>> 
>> 
> 
> 
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> FOAF: http://www.ivan-herman.net/foaf.rdf
> 
> 
> 
> 
> 
> 
Received on Tuesday, 22 May 2012 13:54:41 GMT

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