Re: [Turtle] starting with http://www.w3.org/2010/01/Turtle/

From: Eric Prud'hommeaux <eric@w3.org>
Subject: Re: [Turtle] starting with http://www.w3.org/2010/01/Turtle/
Date: Thu, 10 Mar 2011 13:16:53 -0600

> * Peter Frederick Patel-Schneider <pfps@research.bell-labs.com> [2011-03-10 13:47-0500]
>> From: Sandro Hawke <sandro@w3.org>
>> Subject: Re: [Turtle] starting with http://www.w3.org/2010/01/Turtle/
>> Date: Mon, 28 Feb 2011 11:48:37 -0600
>> 
>> > On Wed, 2011-02-23 at 11:49 -0500, Peter Frederick Patel-Schneider
>> > wrote:
>> >> Unfortunately, this document is not self-contained.  In particular, it
>> >> points to the SPARQL document.  This makes it hard to be a starting
>> >> point for anything.
>> > 
>> > What do you mean?  I haven't studied the document in detail, but
>> > looking through it, especially for references to SPARQL nothing jumps
>> > out as a problem.  I see lots of references to SPARQL, but they seem
>> > like good and appropriate ones, given then design goal which many
>> > people support of Turtle being a sub-language of SPARQL.
>> > 
>> > Procedurally, it's fine for our Turtle spec to lean on the SPARQL 1.0
>> > Recommendation as much as we want, I believe.
>> > 
>> >     -- Sandro
>> 
>> Well, I was trying to follow various stuff and ended up in the SPARQL
>> document when I wasn't expecting to.  I was trying to determine the
>> intent of the section after 4.5 (the one labelled 3.5 RDF Triples) and
>> found GraphNode, which pointed off to the SPARQL spec, and didn't appear
>> anywhere else in the Turtle spec itself.  As this was the basis of the
>> triple generation stuff, I was unable to continue in determining how to
>> generate triples from a Turtle document.
> 
> Tx for the eyes, Peter. I assume you were in the section on lexing RDF
> terms <http://www.w3.org/2010/01/Turtle/#sec-terms>. I apologize, I had
> changed strategy at some point and failed to sweep the doc.
> 
> I've cleaned up a bunch and instantiated all of the tests referenced
> from the parsing section.

[...]

I'm afraid that this cleanup doesn't address a fundamental problem in
the document: Section 4.7 says "each GraphNode [...] in the document
produces an RDF triple" but "GraphNode" does not appear elsewhere in the
document, and following the link here leads to the SPARQL document.

As well, there are no rules for generating blank nodes, except that in
two places there is the mention of "novel blank node".  Even so, novelty
of generated blank nodes is inadequate for parsing Turtle.

The organization of 4.5 through 4.8 is unsettled, e.g., there is an
example in the middle of parsing rules.


peter

Received on Wednesday, 16 March 2011 14:45:49 UTC