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Relative URIs

From: Graham Klyne <Graham.Klyne@Baltimore.com>
Date: Sat, 16 Jun 2001 20:41:56 +0100
Message-Id: <5.0.2.1.2.20010616204028.03099ec0@joy.songbird.com>
To: Sergey Melnik <melnik@db.stanford.edu>
Cc: rdf core <w3c-rdfcore-wg@w3.org>
Sergey,

I think you're suggesting that relative URIs be regarded as syntactic sugar 
in a surface syntax.

If so, I agree.

#g
--

At 03:58 PM 6/15/01 -0700, Sergey Melnik wrote:
>Currently, the concept of relative URIs is present in the M&S 1.0
>serialization syntax only, and is not reflected in the model in any way.
>That is, relative URIs is a just another "abbreviation feature" of the
>M&S syntax, and I'd like to emphasize that in the revised spec to avoid
>misconceptions. As abbreviation features, relative URIs have nothing to
>do with the fragment IDs described in
>http://www.w3.org/DesignIssues/Model.html#Fragement (for example, a
>fragment ID in an RDF document does *not* refer to a portion of this
>document). Therefore, IMO the axioms and benefits summarized by TimBL
>for HTML at above link do not seem to hold in the RDF world.
>
>I feel strongly about not using relative URIs, especially given the
>parsing/editing complication (see prev. postings in this thread), and
>the problems associated with moving RDF documents from one location to
>another. However, I think keeping cleaned-up rdf:ID, rdf:about and
>relative URIs in the revised M&S syntax is essential for backward
>compatibility and is the least bloody compromise (sigh...) I'd just
>suggest to word it so the developers understand the pros and cons.
>
>Sergey
>
>Dan Connolly wrote:
> >
> > "R.V.Guha" wrote:
> > >
> > > Ok, Aaron, you hit the nail on the head.
> > >
> > > RDF absolutely has to make sense even outside the context of
> > > an enclosing document which can be given a uri. so ...
> >
> > So... what? That doesn't make any sense to me.
> >
> > An RDF document is an XML document. Each XML document
> > has a base URI (cf the infoset spec).
> > If you copy the contents from one
> > place in the web to another, you get a different XML
> > document, and hence a difference RDF document; if
> > it uses relative URI references, the resulting triples
> > may be different.
> >
> > This is by design.
> >
> > This design does allow users to goof,
> > but it also allows folks to manage collections of
> > documents and by and large, it has succeeded over the course
> > of the last 10 years.
> >
> > Noone is forced to use relative URI references; anyone
> > who uses them does so by choice. Surely the consequences
> > of that choice for RDF documents should be the same
> > as the consequences for HTML, XML, PDF,
> > and other document formats in the Web, no?
> >
> > Or rather: surely the the consequences *are* the same for
> > RDF as for XML in general; we're not designing RDF 1.0 today;
> > we're just clarifying the spec; and the spec is already
> > pretty clear on this:
> >
> >   [[[ The value of the about attribute is interpreted as
> >   a URI-reference per Section 4 of [URI]. The corresponding
> >   resource identifier is obtained by resolving the
> >   URI-reference to absolute form as specified by [URI].
> >   ]]]
> >
> >   --        Resource Description Framework (RDF) Model and Syntax
> > Specification
> >   http://www.w3.org/TR/REC-rdf-syntax/
> >   Wed, 24 Feb 1999 14:45:07 GMT
> >
> > The only question is about this sort of fuzzy text:
> >
> >   [[[ The ID attribute signals the creation of a new resource ... ]]]
> >
> > But this text in particular suggests pretty strongly
> > that rdf:ID="foo" means the same thing as rdf:about="#foo" :
> >
> >   [[[ The ID attribute, if specified, provides the URI
> >   fragment identifier for c.
> >   ]]]
> >
> >   -- section 6. Formal Grammar for RDF
> >
> > --
> > Dan Connolly, W3C http://www.w3.org/People/Connolly/

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Graham Klyne                    Baltimore Technologies
Strategic Research              Content Security Group
<Graham.Klyne@Baltimore.com>    <http://www.mimesweeper.com>
                                 <http://www.baltimore.com>
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Received on Saturday, 16 June 2001 16:20:10 EDT

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