W3C home > Mailing lists > Public > public-linked-json@w3.org > August 2011

Re: Issues with disjoint graph modelling

From: Manu Sporny <msporny@digitalbazaar.com>
Date: Sun, 28 Aug 2011 21:51:33 -0400
Message-ID: <4E5AF0A5.306@digitalbazaar.com>
To: Alexandre Passant <alex@seevl.net>
CC: Gregg Kellogg <gregg@kellogg-assoc.com>, "public-linked-json@w3.org" <public-linked-json@w3.org>
On 08/25/2011 02:11 PM, Alexandre Passant wrote:
>> Be it "@": [] or "@subject": [], much of these forms fall out of
>> the general processing rules, such that every call to process an
>> entity return a value that can be used as a subject. Otherwise, we
>> end up adding special cases, where.none are necessary.
> It was probably not clear - I'm not asking to add special cases, but
> just found confusing the use of @ / @subject where it does not
> define the subject of a triple. But that eventually works fine with
> overloading (that's how we've done it in [1] with the use of @data)

I know this might hurt a few brains, so apologies in advance... but we 
had considered this at one point for JSON-LD:

"@subject": ["#foo", "#bar", "#baz"],
"dc:creator": "http://example.com/people/bob"

which would generate the following triples:

<#foo> dc:creator <http://example.com/people/bob> .
<#bar> dc:creator <http://example.com/people/bob> .
<#baz> dc:creator <http://example.com/people/bob> .

That's not in the spec right now and we probably won't put it in the 1.0 
spec, but have reserved the pattern if people might find it useful in 
the future.

What we were really going for with "@subject" being a non-IRI value was 
supporting graph literals, like so:

    "@subject": { "foaf:name": "John Doe", "foaf:age": 34 },
    "dc:created": "2011-08-28"

This would generate the following graph, which includes a graph literal:

_:g1 {
    _:bnode1 foaf:name "John Doe" .
    _:bnode1 foaf:age 34 .
_:g1 dc:created "2011-08-28" .

>> The second form should be allowed, but as you point out, the first
>> form my be required to add an @context.
> It is probably good to add a warning in the spec. Something like
> "Warning: This alternative serialisation does not allow to specify a
> particular @context in the data file".

Where would you expect this warning to go in the spec, Alexandre?

-- manu

Manu Sporny (skype: msporny, twitter: manusporny)
Founder/CEO - Digital Bazaar, Inc.
blog: Building a Better World with Web Payments
Received on Monday, 29 August 2011 01:52:05 UTC

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