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

From: Peter Frederick Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 17 Mar 2011 11:06:47 -0400
Message-ID: <20110317.110647.644290699705167358.pfps@research.bell-labs.com>
To: <eric@w3.org>
CC: <sandro@w3.org>, <public-rdf-wg@w3.org>
From: Eric Prud'hommeaux <eric@w3.org>
Subject: Re: [Turtle] starting with http://www.w3.org/2010/01/Turtle/
Date: Thu, 17 Mar 2011 09:43:03 -0500

[...]

>> 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.

> Indeed, was meant to be "object". I claim to again, but with more
> confidence, to have cleaned up.

However the statement
	Each object N in the document produces an RDF triple: curSubject
	curPredicate N . 
is not true, as objects can occur in collections.

>> 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.

> I added Map[string -> blank node] bnodeLabels to the state, and this
> to the Term Constructors:
> [[
> BLANK_NODE_LABEL | blank node | The string matching the second
> argument, PN_LOCAL, is a key in bnodeLabels. If there is no
> corresponding blank node in the map, one is allocated.
> ]]
> 
> Perhaps you have a proposed wording which better captures either the
> notion of every BLANK_NODE_LABEL maps to some blank node, or the more
> procedural view of allocationg a blank node every time a novel
> BLANK_NODE_LABEL is parsed.

I still think that the processing of blank nodes needs to be specified
much more fully.  I think that the wording in my initial proposal
(http://lists.w3.org/Archives/Public/semantic-web/2008Jan/0128) is
adequate.

>> The organization of 4.5 through 4.8 is unsettled, e.g., there is an
>> example in the middle of parsing rules.  peter
> 
> Re-worked to gather all of the parsing rules, and to place the parsing
> example in a separate informative section at the end.
>   http://www.w3.org/2010/01/Turtle/was
> has the old structure, in case folks want to argue that it's better.

I still think that the organization in Sections 5.1 to 5.4 should be
much better.

Another problem that remains is that the productions for anonymous blank
nodes are not really short forms or syntactic sugar, as they generate
blank nodes that cannot be referenced elsewhere.

> -- 
> -ericP

peter
Received on Thursday, 17 March 2011 15:07:54 UTC

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