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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: Tue, 02 Jul 2013 05:10:09 -0700
Message-ID: <51D2C321.4010201@gmail.com>
To: Manu Sporny <msporny@digitalbazaar.com>
CC: RDF WG <public-rdf-wg@w3.org>
The thrust of the technical part of my comments was to base JSON-LD on the 
concepts defined in RDF Concepts, not just to say so, so the changes in 
Appendix A don't really address this part of my comments.  Appendix A still 
normatively defines everything about JSON-LD independently from the 
definitions of RDF triples, graphs, and datasets.

My proposal for Appendix A is given in
http://lists.w3.org/Archives/Public/public-rdf-wg/2013Jun/0126.html
I very much prefer this sort of basis to the one in the current editor's draft.

peter

On 06/30/2013 11:18 AM, Manu Sporny wrote:
> David Booth, Peter S.,
>
> There is a new time-stamped JSON-LD editor's draft that attempts to
> integrate all of the discussion related to RDF data model alignment
> we've had over the past several weeks:
>
> http://json-ld.org/spec/ED/json-ld/20130630/
>
> Diff-marked version is here:
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html
>
> Pay particular attention to the changes in these sections:
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#introduction
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#how-to-read-this-document
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#design-goals-and-rationale
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#data-model
>
> http://json-ld.org/spec/ED/json-ld/20130630/diff-20130411.html#relationship-to-rdf
>
> David, I think I've integrated everything we have consensus on in the
> JSON-LD CG. The only outstanding issue is what to do with blank node
> property skolemization.
>
> Peter, I hope the changes I made are in the right direction. I tried to
> not change the terminology that we use throughout the spec too greatly
> (because it would have negative cascading effects throughout all of the
> JSON-LD specs), while making it very clear that the data model in
> JSON-LD is an extension to the RDF data model.
>
> When I started editing the spec to apply each of your changes, my intent
> was to keep iterating until Appendix C was removed.
>
> The removal of the blank nodes as graph labels change went just fine.
>
> The blank node as property remains, because it is a difference between
> the two models
>
> Gregg thought that we could remove the sets/lists difference, but sets
> and lists aren't talked about at all in the RDF data model (in RDF
> Concepts). There is nothing to refer to and I couldn't think of a way of
> papering over this difference.
>
> I tried to align JSON numbers and JSON booleans with XML Schema, but the
> value spaces and lexical spaces don't match up. They are fundamentally
> different, so it's one more thing that I couldn't get rid of in the
> spec. There is now a note describing why this difference exists:
>
> """
> NOTE
> All JSON numbers and booleans can be mapped to XML Schema datatypes,
> which are built-in datatypes in the RDF model. Non-decimal JSON numbers
> map to xsd:integer and decimal numbers map to xsd:double. JSON numbers
> are described as extensions to the RDF data model because they combine
> the value space of xsd:integer and xsd:double into a single value space.
> JSON booleans may be mapped to XML Schema using the xsd:boolean
> datatype. JSON booleans are described as extensions to the RDF data
> model because, while they have the same value space, they omit the
> values of 0 and 1 from the lexical space.
> """
>
> As I mentioned on the call last week, it'll probably take us a couple of
> iterations to get something that both of you and the JSON-LD CG can live
> with, so please provide feedback and we'll go from there. We will
> discuss these changes on the call on Tuesday if either of you would like
> to join and discuss further.
>
> -- manu
>
Received on Tuesday, 2 July 2013 12:10:39 UTC

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