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Re: Updated JSON-LD spec to more closely align w/ RDF data model

From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
Date: Thu, 04 Jul 2013 04:34:28 -0700
Message-ID: <51D55DC4.8000501@gmail.com>
To: Markus Lanthaler <markus.lanthaler@gmx.net>
CC: 'RDF WG' <public-rdf-wg@w3.org>
Appendix A defines nothing in terms of anything related to RDF.  Its 
"normative" summary defines default graph, named graph, graph, edge, 
properties, nodes, IRI, blank node, blank node identifier, JSON-LD value, 
typed value, language-tagged string, and list and none of these definitions 
mention anything about RDF.   It is totally unnecessary to have all these 
redefinitions, even when there were real differences between the JSON-LD data 
model and definitions from RDF Concepts.

Consider, for example, the way that generalized RDF Datasets are now defined 
in RDF Concepts.   The JSON-LD data model could have been defined in an 
analogous manner all along, building on previous definitions instead of 
redoing them.


On 07/04/2013 03:41 AM, Markus Lanthaler wrote:
> On Thursday, July 04, 2013 11:51 AM, Peter F. Patel-Schneider wrote:
>> On 07/04/2013 12:59 AM, Markus Lanthaler wrote:
>>>> My changes to Appendix A were to turn this "should" into reality.
>>> In your proposal you write
>>>       JSON-LD is a serialization format for Linked Data based on JSON.
>>>       It is therefore important to distinguish between the syntax of
>>>       JSON-LD, which is defined by JSON [...] and the underlying data
>>>       model.
>>>       The data model underlying JSON-LD is RDF datasets as defined in
>>>       RDF 1.1 Concepts and Abstract Syntax [RDF-CONCEPTS], with the
>>>       following additions: ...
>>> [http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jun/0126.html]
>>> If it has additions, then it is not the same IMO. Do we agree on
>> that?
>> Sure, not the same, but ..
> OK, that's at least a starting point.
>>> I also can't really see a substantial difference from what the spec
>>> currently says:
>>>      JSON-LD is a serialization format for Linked Data based on JSON.
>>>      It is therefore important to distinguish between the syntax,
>>>      which is defined by JSON in [RFC4627], and the data model which
>>>      is an extension of the RDF data model [RDF11-CONCEPTS]. To ease
>>>      understanding for developers unfamiliar with the RDF model, the
>>>      following normative summary is provided: ...
>> ... there is a vast difference between being defined in terms
>> of RDF Datasets plus (now) one small addition and not being defined
>> in terms of RDF Datasets, even if the intent is to make things work
>> out the same.
> The terms which don't have a 1:1 mapping to RDF Concepts are:
>   - JSON-LD value: needed for native types (maps more or less to literal)
>   - typed value: a literal which is not a language-tagged string
>     (unfortunately no definition for this exists in Concepts, it should
>     probably be added; sending a separate mail in a minute)
>   - list: not mentioned in Concepts at all because they are not part
>     of the RDF data model but realized using a vocabulary
> All the others are exactly the same as in RDF Concepts so I can't really understand how you can say that it is "not being defined in terms of RDF Datasets"!?
>> Further, there is now generalized RDF Datasets, which
>> includes the addition.
> OK, you seem to argue that the difference stemming from native JSON types for booleans, numbers and arrays (lists) don't matter. Is that correct?
> --
> Markus Lanthaler
> @markuslanthaler
Received on Thursday, 4 July 2013 11:35:01 UTC

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