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Re: N-triples white space question

From: Eric Prud'hommeaux <eric@w3.org>
Date: Fri, 18 May 2012 06:34:51 -0400
To: Richard Cyganiak <richard@cyganiak.de>
Cc: Andy Seaborne <andy.seaborne@epimorphics.com>, RDF-WG <public-rdf-wg@w3.org>
Message-ID: <20120518103450.GA5291@w3.org>
* Richard Cyganiak <richard@cyganiak.de> [2012-05-18 11:06+0100]
> RDF 2004 N-Triples [1] requires at least one character of horizontal white space between s, p and o.
> 
> This helps tremendously with quick-and-dirty parsing using regexes.
> 
> I think the WS rules for N-Triples should stay as they were in RDF 2004.
> 
> I would even go one step further and add some SHOULD-level guidance on where to put what whitespace. Perhaps something like: exactly one space between s and p; exactly one space between p and o; no WS before or after the period; no WS at the start of a line; CR+LF as EOL.

Does the existing body of N-Triples permit a grammar with no default whitespace rules?

  triples: triple (LF triple)* LF?
  triple: subject HWS predicate HWS object '.'

I.e, do all the N-Triples out there look like "<s> <p> <o>."?
I note that Oracle has been vigilent about preserving backwards-compatibility. Souri, do you have a sense of what Oracle has been using?

> I also note that RDF 2004 N-Triples allows comments (only at the start of a line). This makes sense for the use as a test case format, but not much sense for the use as a dump format.
> 
> Best,
> Richard
> 
> 
> [1] http://www.w3.org/TR/rdf-testcases/#ntriples
> 
> 
> 
> On 18 May 2012, at 10:04, Andy Seaborne wrote:
> 
> > Gavin, Eric,
> > 
> > rdf-turtle says:
> > 
> > [1] ntriplesDoc	::= (triple)? (EOL triple)* (EOL)?
> > [2] triple	::= subject predicate object '.'
> > [8] EOL		::= ([#xD#xA])+
> > 
> > What are the white space rules?
> > 
> > Does it inherit white space processing from the rest of Turtle? Comments seem to come from Turtle.
> > 
> > If it does not inherit white space rules,
> >    what about horizontal white space inside triples?
> > 
> > If it does inherit white space rules,
> >   that includes newlines within triples between S/P or P/O.
> > 
> > The simplest solution is to add text in section 12.3 to say that horizontal white space outside tokens is discarded (which is different to Turtle).
> > 
> > 	Andy
> > 
> 
> 

-- 
-ericP
Received on Friday, 18 May 2012 10:35:27 GMT

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