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Re: IRI references rewording

From: Dan Connolly <connolly@w3.org>
Date: Wed, 14 Sep 2005 08:41:20 -0500
To: andy.seaborne@hp.com
Cc: RDF Data Access Working Group <public-rdf-dawg@w3.org>
Message-Id: <1126705281.4430.729.camel@dirk>

On Wed, 2005-09-14 at 14:19 +0100, Seaborne, Andy wrote:
> 
> Dan Connolly wrote:
> > On Wed, 2005-09-14 at 11:08 +0100, Seaborne, Andy wrote:
> > 
> >>I have changed the text in the gramamr section for IRI references to 
> >>explicitly say which rules are required to generated valid IRIs
> >>
> >>"""
> >>IRI References
> >>
> >>SPARQL is defined in terms of absolute IRIs (this includes the fragment 
> >>identifier). IRI references formed by rule Q_IRI_REF and by rule QName (after 
> >>prefix expansion) must be valid according to RFC 3987 [RFC3987] and RFC 3986 
> >>[RFC3986].
> > 
> > 
> > That has the same problem; it's vacuuous. Anything that's an IRI
> > reference is already valid.
> > 
> > 
> >> They are converted to absolute IRIs according to RFC 3987 and RFC 
> >>3986, using the base IRI defined by the BASE clause if present in the query.
> >>"""
> > 
> > 
> > That's redundant w.r.t. some text under Query Term Syntax
> > ("SPARQL provides an abbreviation mechanism for IRIs ...") Please
> > either delete it or add forward and backward references.
> 
> 
> We put that text in as part of addressing the case of base IRI (this isn't 
> prefix expansion - it's IRI resolution) in response to a comment.

I wonder which comment. I have been working with EricP on
the under Query Term Syntax is in response to

SPARQL: BASE IRI resolution
http://www.w3.org/mid/431e392a.225659671@smtp.bjoern.hoehrmann.de

It seems that EricP got an action to respond to that comment,
but earlier you had an overlapping action...
  ACTION AndyS: draft language re <foo###bar> errors

Oops. Crossed wires, it seems.

> > I suggest:
> > 
> > IRI References
> > 
> > References formed by rule  Q_IRI_REF must be conform to the
> > generic syntax of IRI references in
> > section 2.2.  ABNF for IRI References and IRIs[RFC3987].
> > For example, the
> > Q_IRI_REF <abc#def> may occur in a SPARQL query string, but
> > the Q_IRI_REF <abc##def> must not.
> > 
> > References formed by rule QName (after prefix expansion) must conform
> > to the generic syntax of (absolute) IRIs. 
> 
> There is a "must" there but I am having rouble seeing how not to say something 
> along that line.
> 
> It does not exclude generation of non-IRI references as well as IRI 
> references.

I don't understand what you mean by that.

>   I was left wondering what a "Reference" was.

There's a lot that's left implicit in going from the concrete
syntax; e.g. removing the <>s from IRI references. I thought
that this wording was at the same level of rigor as the rest.

> Maybe:
> 
> """
> SPARQL is defined in terms of absolute IRIs (this includes the fragment 
> identifier).

I don't find that sentence helpful. I don't think the term "SPARQL"
is defined anywhere in the document. Er... actually, I see...

 SPARQL is a query language for getting information from
 such RDF graphs.

which seems odd, since SPARQL has both a protocol and a query language.
It seems like the 1st occurrence of the acronym should be expanded.

The discussion under Query Term Syntax discusses the relationship
between IRI references and absolute IRIs. It doesn't seem useful
to have part of it repeated here. If you want to move it, very
well. Or if you want to have forward and backward references
that make the repetition explicit, that's OK too.

> Grammar production <a>Q_IRI_REF</a> forms IRI references

er... but it forms things that are not IRI references as well.

>  and these must 
> conform to the generic syntax of IRI references described in section 2.2. of 
> [RFC3987].

again, it's vacuuous to say that IRI references must be IRI references.

> Grammar production <a>QName</a> forms IRI references after <a href="rq23 
> section 2.2">prefix expansion</a> and these must conform to the generic syntax 
> of IRI references.

actually, QNames have to expand to (absolute) IRIs. This isn't a SPARQL
query string, is it?

	PREFIX abc: <abc>.

	SELECT ?x WHERE { ?x abc:def ?y }


> For example, the
> Q_IRI_REF <abc#def> may occur in a SPARQL query string, but
> the Q_IRI_REF <abc##def> must not.
> 
> IRI references are converted to absolute IRIs according to RFC 3987 and RFC 
> 3986, using the base IRI defined by the BASE clause if present in the query.
> """
> 
> 	Andy
-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
Received on Wednesday, 14 September 2005 13:41:32 GMT

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