W3C home > Mailing lists > Public > public-rdf-wg@w3.org > May 2012

Re: n-quads & Turtle Levels

From: Sandro Hawke <sandro@w3.org>
Date: Wed, 30 May 2012 10:39:44 -0400
To: Richard Cyganiak <richard@cyganiak.de>
Cc: Andy Seaborne <andy.seaborne@epimorphics.com>, public-rdf-wg@w3.org
Message-ID: <1338388784.2332.284.camel@waldron>
On Wed, 2012-05-30 at 13:15 +0100, Richard Cyganiak wrote:
> Hi Sandro,
> 
> On 30 May 2012, at 12:17, Sandro Hawke wrote:
> > It's with these glasses that I think a turtle document can/should just
> > be an instance of our multiple-graph syntax which doesn't happen to have
> > any named graphs.
> 
> I've heard you say two mutually incompatible things:
> 
> 1. A Turtle file published at <i> containing graph G is an RDF dataset with only named graph <i,G>
> 
> 2. A Turtle file published at <i> containing graph G is an RDF dataset with only a default graph
> 
> Which one is it? It can't be both.

If I said (1), it was a mistake.

I would rephrase (1) as a conditional:

   A.  If it is true that a turtle file serializing G is what is
published at <i>,
   B.  Then the dataset consisting of the named graph <i,G> is true.

So, the presence and behavior of <i> implies the given dataset, but it's
not true that it *is* that dataset.

Statement (2) is close to correct, but I'd change it slightly; it's not
that it "is" a dataset, but that it can reasonably be read as a dataset.
It's a type-conversion thing.  A triple can be seen as a (trivial)
graph; a character can be seen as a (trivial) string; a graph can be
seen as a (trivial) dataset.    One can also be strict and note they are
not the same, but I think in practice it will be very useful to allow
this kind of conversion. 

In practice, I see this manifesting in the kinds of APIs one uses for
loading and manipulating dataset.  Can give the API a graph when it is
expecting a dataset and have it silently promote the graph to being a
dataset with that graph as its default graph?  I think that will be very
practical and useful.     And then this extends to linked data...

Alternative, we could define a class of things that is the union of the
class of graphs and the class of datasets -- that would be more crisp
and might be as convenient.    But I expect people will be find just
using datasets as those things.

To be clear: this is speculative.   My point is not to say we should
standardize this, but I don't think we should rule it out.

   -- Sandro

> Best,
> Richard
Received on Wednesday, 30 May 2012 14:40:07 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:49 GMT