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Re: Named Graphs / Layers / Surfaces / Doohickies added to JSON-LD

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 30 Apr 2012 18:46:13 -0400
To: Manu Sporny <msporny@digitalbazaar.com>
Cc: RDF WG <public-rdf-wg@w3.org>
Message-ID: <1335825973.9663.969.camel@waldron>
On Mon, 2012-04-30 at 15:56 -0400, Manu Sporny wrote:
> Our intent when we started JSON-LD was to leave named graphs out of the
> spec. We were waiting on this group to finalize the modeling aspects of
> named graphs because we didn't want to do something counter to what this
> group was going to propose.
> We had been pushing back on requests to add named graphs to JSON-LD for
> quite some time and finally had to give in at the end because we had to
> understand how named graphs might affect the syntax in the future. We
> didn't want to paint ourselves into a corner. In the end, it was a
> fairly benign thing to add (from a syntax perspective), so we just went
> ahead and did it.
> Keep in mind that we go out of our way to not mention how advanced
> concepts like sharing bnode identifiers between named graphs works (or
> doesn't work). In other words, we specified the syntax for naming
> graphs, but have not really addressed any of the range issues since
> we're waiting on the RDF WG to propose something.
> Section 4.9 introduces the concept of a Named Graph in JSON-LD:
> http://json-ld.org/spec/latest/json-ld-syntax/

I'm not quite sure I understand the syntax, but if my guesses are right,
it seems like a reasonable design.   Excellent.   Glad to hear JSON-LD
is ready for broader attention.

Back on the subject of layers, I note that your use of the term "graph"
in this spec is, I think, evidence of the problem that's been causing us
such problems, and which I think the term "layers" solves:

        This example says that there is a linked data graph identified
        by http://example.org/linked-data-graph which is composed of the
        statements about Manu and Gregg and a reference to another IRI,
        which could make statements about Markus.
This text uses the word "graph" to mean g-box (now "layer", for me), not
to mean RDF Graph.   At least, I'm 99% sure it does.  It makes almost no
sense to talk about an RDF Graph that way, giving it a human-readable

    -- Sandro
Received on Monday, 30 April 2012 22:46:24 UTC

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