Re: WA and JSON-LD default context

On May 6, 2016, at 13:36, Ivan Herman <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> 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.

Gregg

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

> Ivan
> 
>> 
>> 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
>>  
>> T: +31 (0)70 314 0998
>> M: 
>> E: hugo.manguinhas@europeana.eu
>> Skype: hugo.manguinhas
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> Ivan Herman, W3C 
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Received on Friday, 6 May 2016 13:14:10 UTC