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Re: Turtle support for Multiple Graphs, suggestion

From: Steve Harris <steve.harris@garlik.com>
Date: Sat, 2 Apr 2011 01:27:34 +0100
Cc: David Wood <david.wood@talis.com>, nathan@webr3.org, Lee Feigenbaum <lee@thefigtrees.net>, RDF WG <public-rdf-wg@w3.org>
Message-Id: <E475D28F-9F19-4F87-AC72-28A22CF4EE5E@garlik.com>
To: Richard Cyganiak <richard@cyganiak.de>
On 2011-04-01, at 19:15, Richard Cyganiak wrote:

> 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.

Absolutely.

> (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.)

+1

- Steve

>> 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
>>>>> 
>>>>> 
>>> 
>>> 
>> 
>> 
> 
> 

-- 
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Received on Saturday, 2 April 2011 00:28:16 GMT

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