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Re: Turtle support for Multiple Graphs, suggestion

From: Richard Cyganiak <richard@cyganiak.de>
Date: Fri, 1 Apr 2011 23:45:09 +0530
Cc: nathan@webr3.org, Lee Feigenbaum <lee@thefigtrees.net>, RDF WG <public-rdf-wg@w3.org>
Message-Id: <060F9B2E-0C34-404C-A498-ACEFE3336903@cyganiak.de>
To: David Wood <david.wood@talis.com>
On 1 Apr 2011, at 23:07, David Wood wrote:
> The WG has expressed an interest in changing Turtle very, very little.

Right.

> That alone makes this proposal interesting enough to discuss.

I conclude the opposite!

Turning Turtle from a single-graph triple format to a multi-graph quad format is a *much* bigger change than any syntactic tweaks or extensions.

A fundamental change to the underlying data model of the existing media types (Turtle, RDF/XML) means that the changes won't be limited to the parser, but entire APIs and storage engines have to be rebuilt, not to mention the hairy webarch implications around authoritativeness.

I strongly believe that all quad/multigraph formats should get new, fresh media types.

(Maybe I'm just mishearing what you said Dave. My point is that once we add "@graph" or "<...> { ... }" or any other form of multi-graph support, we should no longer talk of making changes to Turtle, but we are making a new format. If there's any doubt about that, then it's important to raise a new ISSUE for this.)

Best,
Richard


> 
> Regards,
> Dave
> 
> 
> 
> 
> On Apr 1, 2011, at 13:19, Nathan wrote:
> 
>> Hi Lee,
>> 
>> Nothing I guess, other than lending to a single, simple, coherent specification and single format which supports virtually all use-cases needed.
>> 
>> That said, I also see many benefits in keeping two distinct formats (such as TriG and Turtle), since I /really really really/ don't want to be following my nose around the web to documents containing quads or multiple graphs, and perhaps selfishly, don't really want the pain that will induce in API land.
>> 
>> So, although I suggested it and would maintain that it may well be easier for newcomers to understand than TriG or N-Quads, I really don't like the idea of having a single format myself :D and see anything Quad or Multiple Graph as being related to data store synchronization and data dumps, rather than to RDF.
>> 
>> Best,
>> 
>> Nathan
>> 
>> Lee Feigenbaum wrote:
>>> Hi Nathan,
>>> What would be the benefit of inventing something like this compared to using TriG which is similar in spirit and already in (some) use?
>>> Lee
>>> On 4/1/2011 12:10 PM, Nathan wrote:
>>>> Hi All,
>>>> 
>>>> Just a quick, mini proposal wrt supporting multiple "named graphs" in
>>>> turtle.
>>>> 
>>>> We could add a new keyword and directive, @graph (or @namespace), who's
>>>> value was an IRI. This would be a minimal change to the grammar, for
>>>> example:
>>>> 
>>>> @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
>>>> @prefix dc: <http://purl.org/dc/elements/1.1/> .
>>>> @prefix foaf: <http://xmlns.com/foaf/0.1/> .
>>>> 
>>>> # default graph
>>>> <http://example.org/bob> dc:publisher "Bob" .
>>>> <http://example.org/alice> dc:publisher "Alice" .
>>>> 
>>>> @graph <http://example.org/bob> .
>>>> _:a foaf:name "Bob" .
>>>> _:a foaf:mbox <mailto:bob@oldcorp.example.org> .
>>>> 
>>>> @graph <http://example.org/alice> .
>>>> _:a foaf:name "Alice" .
>>>> _:a foaf:mbox <mailto:alice@work.example.org> .
>>>> 
>>>> I believe it's pretty self explanatory, so will spare getting in to any
>>>> heavy details, other than a couple of basic questions:
>>>> 
>>>> - What would the scope of @prefix and @base declarations be?
>>>> (either no change / file wide, or with a scope of the nearest "@graph")
>>>> 
>>>> - Would the value be an IRI, or an absolute-IRI?
>>>> (my own preference would be the latter).
>>>> 
>>>> Best,
>>>> 
>>>> Nathan
>>>> 
>>>> 
>> 
>> 
> 
> 
Received on Friday, 1 April 2011 18:15:55 GMT

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