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RE: WA and JSON-LD default context

From: Hugo Manguinhas <Hugo.Manguinhas@europeana.eu>
Date: Mon, 9 May 2016 09:33:29 +0000
To: Robert Sanderson <azaroth42@gmail.com>
CC: public-openannotation <public-openannotation@w3.org>, "W3C Public Annotation List" <public-annotation@w3.org>
Message-ID: <6D0598B03E7E9848A4287E110919B4BA01192B6F@MBX-SRV-P200.wpakb.kb.nl>
Hi all,

Thanks a lot for all your help!

I guess my mistake was when reading the spec, I was assuming the RDFa behaviour and the last note regarding JSON-LD just skipped my attention... thanks Shane for pointing it out.

@Rob: in our case, we are still gathering/understanding the cases that could require an extension... we might include a context for a specific part of the annotation, or if we choose to define a "master" context for ourselves, we were thinking of replacing the context with "ours" and having it importing the WA one, just to keep it simple... would this last option be alright? I am assuming here that both JSON and RDF developers would be able to work with it, unless I am missing something...

Btw, about the WA JSON-LD context, I was wondering if it would be relevant to directly import the RDFa 1.1. default context from the WA context. I suspect this would lower the need to add an extension context for a great number of applications, at least the ones only requiring the prefix declarations...

Best regards,

From: Robert Sanderson [azaroth42@gmail.com]
Sent: 06 May 2016 20:45
Cc: Hugo Manguinhas; public-openannotation; W3C Public Annotation List
Subject: Re: WA and JSON-LD default context

In terms of extension of the context ... the latest drafts have some opinions about this:

Is that the way you were also thinking?

Thanks Hugo!


On Fri, May 6, 2016 at 11:35 AM, Shane McCarron <shane@spec-ops.io<mailto:shane@spec-ops.io>> wrote:
Just to be clear, [1] does NOT attempt to define a default context for JSON-LD.  It says:

The same list of prefixes have also been defined for JSON-LD as a JSON-LD Context<http://www.w3.org/TR/json-ld/#the-context> at the URI http://www.w3.org/2013/json-ld-context/rdfa11; JSON-LD users can use the @context key with that URI as a shorthand to use the same prefixes.

[1] https://www.w3.org/2011/rdfa-context/rdfa-1.1

On Fri, May 6, 2016 at 6:28 AM, Gregg Kellogg <gregg@greggkellogg.net<mailto:gregg@greggkellogg.net>> wrote:
On May 6, 2016, at 13:36, Ivan Herman <ivan@w3.org<mailto:ivan@w3.org>> wrote:

+Cc Gregg, who knows the answer better than I do. Note, however, that he is currently on vacations…

On 6 May 2016, at 12:12, Hugo Manguinhas <Hugo.Manguinhas@europeana.eu<mailto:Hugo.Manguinhas@europeana.eu>> wrote:

Hi all,

We have a question about JSON-LD that might be of interest to this group.

As part of our efforts to move forward towards more advanced modelling scenarios, we have been debating the need for a JSON-LD context for ourselves (extending the WA) to reduce the number of prefix declarations and eventually further simplify the labels by even removing the prefix as it is currently being done in WA spec.

While looking at the best practices we stumbled across the “RDFa Core Initial Context” [1] which also defines a default context for JSON-LD with a list of default prefixes. We were wondering if you might know how normative this specification is since it is not mentioned in the JSON-LD specification

It is not normative, afaik. (As opposed to the usage of the RDFa Initial Context.) I do not know whether tools implement it by default; I would not expect so.

There is no default initial context for JSON-LD. Best practice would be for the group to define one in their namespace (e.g., http://w3.org/ns/wa) in include within it prefixes you would like to be available, along with other appropriate term definitions. The CSVW group took this approach [1].

and if there is significant adoption (I guess that this is only critical for RDF engines). My understanding is that there should be still a way to explicitly state the default context (at least for back compatibility), either at the protocol level or context level.

I am not sure I understand the remark: of course, any JSON-LD can refer to that context, that is why it was created…

JSON-LD needs to explicitly reference one or more contexts, which may also be inline.


[1] http://w3.org/ns/csvw


Btw, with regards to WA specs (and also Open Annotation), and if this really happens to be normative, it might be relevant to make some note about it in both the model and protocol specs... or even explicitly import the default in the current WA context.

Looking forward to your feedback...

[1] https://www.w3.org/2011/rdfa-context/rdfa-1.1

Best regards,
Hugo Manguinhas
Technical R&D Coordinator

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Shane McCarron
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Rob Sanderson
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Received on Monday, 9 May 2016 09:41:09 UTC

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