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Dataset Syntax - checking for consensus

From: Sandro Hawke <sandro@w3.org>
Date: Tue, 25 Sep 2012 19:14:25 -0400
Message-ID: <50623AD1.4040706@w3.org>
To: W3C RDF WG <public-rdf-wg@w3.org>
I'm not sure how much progress we'll be able to make on dataset 
semantics tomorrow, so I thought I'd draft some proposals on dataset 
syntax.   The chairs can put this on the agenda is they like (but it's 
too short notice for these decisions to be binding yet).  I'm thinking 
it would be useful to see how close we are to agreement on these issues.

If you followup with votes, please use -1 for Formal Objection, 0 for 
abstain, +1 for approve.   Numbers in between are fine, too.

PROPOSED: We will produce a W3C Recommendation for a dataset syntax, 
similar to TriG and to SPARQL's named graph syntax.

PROPOSED: We'll request a media-type for this syntax which is different 
from the media-type for Turtle.  (That is, we will not consider this 
language to supplant Turtle and take over the name, becoming the new 
"Turtle", as was once proposed.)

PROPOSED: Our dataset syntax will allow for the expression of empty 
named graphs, whatever their semantics might be (to be decided). The 
syntax is an empty curly-braces expression, as in "<g> { }".

PROPOSED: Our dataset syntax will have some standard mechanism (to be 
determined within the next few weeks) through which a Dataset 
serialization can include some RDF data about the Dataset (that is, some 
metadata in the form of an RDF graph).


Below, there are groups of proposals which are alternative solutions to 
a design issue.   If you approve of more than one of the alternatives, 
please vote "+2" for your favorite.

* Name of the dataset syntax

PROPOSED: We will call our recommended dataset syntax "trig", 
capitalized to Trig as needed.
PROPOSED: We will call our recommended dataset syntax "TriG", but 
informally and in the media type, "trig".
PROPOSED: We will call our recommended dataset syntax "TriG", and use 
that capitalization everywhere.

* Use of equals sign, like <g> = { <s> <p> <o> } .  This is not in 
SPARQL but is in traditional TriG, for compatibility with N3.

PROPOSED: In our dataset syntax, a "=" MAY appear between the name and 
the graph.
PROPOSED: In our dataset syntax, a "=" MUST appear between the name and 
the graph.
PROPOSED: In our dataset syntax, a "=" MUST NOT appear between the name 
and the graph.

* Use of the "graph" keyword, which MUST be used in SPARQL and MUST NOT 
be used in traditional TriG.

PROPOSED: In our dataset syntax, the case-insensitive keyword "graph" 
MAY appear before the name, in a name-graph pair.
PROPOSED: In our dataset syntax, the case-insensitive keyword "graph" 
MUST appear before the name, in a name-graph pair.
PROPOSED: In our dataset syntax, the case-insensitive keyword "graph" 
MUST NOT appear before the name, in a name-graph pair.

* Use of curly braces { <a> <b> <c> } around the default graphs.   They 
MUST be used in traditional TriG, and MUST NOT be used in SPARQL.

PROPOSED: In our dataset syntax, triples of the dataset's default graph 
MAY be surrounded by curly braces.
PROPOSED: In our dataset syntax, triples of the dataset's default graph 
MUST be surrounded by curly braces.
PROPOSED: In our dataset syntax, triples of the dataset's default graph 
MUST NOT be surrounded by curly braces.

* Some designs for carrying for metadata

PROPOSED: In our dataset syntax, we'll say that metadata goes in the 
default graph
PROPOSED: In our dataset syntax, we'll say that the default graph goes 
inside curly braces and the metadata goes outside curly braces
PROPOSED: In our dataset syntax, we'll say that metadata goes inside a 
set curly braces after a keyword "meta".
PROPOSED: In out dataset syntax, we'll have a keyword "meta" followed by 
"default" or the name of a named graph, to indicate to readers where the 
metadata is.
Received on Tuesday, 25 September 2012 23:14:26 GMT

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