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RE: IRIs as node labels (proposals and counterproposals)

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Fri, 22 Mar 2002 11:25:28 -0000
To: "Dan Brickley" <danbri@w3.org>
Cc: <bwm@hplb.hpl.hp.com>, <w3c-rdfcore-wg@w3.org>
Message-ID: <JAEBJCLMIFLKLOJGMELDIEHLCDAA.jjc@hplb.hpl.hp.com>


It does seem reasonable to suggest that anyURI in XML Schema datatypes is
the current "standard web identifier".

This points to

http://www.w3.org/TR/xlink/#link-locators

which basically is the position I would like us to endorse (+ binary
compare).

[[[
The value [..snip..] must be a URI reference as defined in [IETF RFC 2396],
or must result in a URI reference after the escaping procedure described
below is applied. The procedure is applied when passing the URI reference to
a URI resolver.

Some characters are disallowed in URI references, even if they are allowed
in XML; the disallowed characters include all non-ASCII characters, plus the
excluded characters listed in Section 2.4 of [IETF RFC 2396], except for the
number sign (#) and percent sign (%) and the square bracket characters
re-allowed in [IETF RFC 2732]. Disallowed characters must be escaped as
follows:

+ Each disallowed character is converted to UTF-8 [IETF RFC 2279] as one or
more bytes.

+ Any bytes corresponding to a disallowed character are escaped with the URI
escaping mechanism (that is, converted to %HH, where HH is the hexadecimal
notation of the byte value).

+ The original character is replaced by the resulting character sequence.

Because it is impractical for any application to check that a value is a URI
reference, this specification follows the lead of [IETF RFC 2396] in this
matter and imposes no such conformance testing requirement on XLink
applications.

If the URI reference is relative, its absolute version must be computed by
the method of [XML Base] before use.
]]]


Sorry Dan I am not going to reply to your counter-counter proposal - it
seems surprisingly out of scope!

Jeremy

> -----Original Message-----
> From: Dan Brickley [mailto:danbri@w3.org]
> Sent: 22 March 2002 11:03
> To: Jeremy Carroll
> Cc: bwm@hplb.hpl.hp.com; w3c-rdfcore-wg@w3.org
> Subject: IRIs as node labels (proposals and counterproposals)
>
>
>
> (changed subject line)
>
> On Fri, 22 Mar 2002, Jeremy Carroll wrote:
>
> > > 14: IRI's
> > > Wheras nodes in an RDF graph are labelled with URI's and the
> > > standards for internationalization of URI's are not yet stable
> > >
> > > Propose the WG:
> > >
> > >   1) resolves that nodes in RDF graphs are labelled with standard
> > > web identifiers
> > >
> > >   2) resolves that the current standard web identifier is a URI
> > > as defined by RFC 2396
> > >
> > >   3) resolves that resolution 2 above may be updated by an errata
> > > to the specifications as new standards evolve.
> > >
> >
> > This is unclear. First my counterproposal, second a critique of
> the chair's
> > proposal.
> >
> > Counterproposal.
> >
> >  Propose the WG:
> >
> >    1) resolves that nodes in RDF graphs are labelled with standard
> >       web identifiers
> >
> >    2) resolves that the current standard web identifier is a URI
> >       as defined by RFC 2396, in its original character sequence
> >       (in UTF-8)
> >
> >    3) notes that the use of identifiers of resolution 2 that are
> >       not in normal form C presents internationalisation
> >       difficulties and security risks
> >
> >    4) resolves that resolution 2 above may be updated by an errata
> >       to the specifications as new standards evolve.
> >
> >    5) that equality between the identifiers of resolution 2 is
> >       binary identity.
>
> I have a counter-counter proposal:
>
>
> (this goes beyond the IRI issue, and is motivated in part by my
> exploration of the SOAP 1.2 Encoding Data Model, which uses XSD datatypes
> but doesn't label nodes with URIs)
>
> Propose the WG:
>
> 1) resolves that Web identifiers, like other characteristics of a
>    resource, can be considered properties of the the resource
> that they name
>
> 2) notes that RDF now provides datatyping facilities which can use
>    XML Schema datatypes (such as xsd:anyURI)
>
> 3) notes that RDF currently provides a privileged role for URI referring
>    expressions. Nodes in an RDF graph may be labeled using RFC2396 URI
>    references to indicate the resource that they represent.
>
> 4) further notes that this same information can be represented in a number
>    of ways using RDF properties, and that at this time RDF Core provide
>    no specific guidance on the representation of URI node labels as RDF
>    properties, or on equivalencies between these two strategies for
>    representing web identifiers in RDF.
>
> 5)
>    resolves that future revisions to RDF could accomodate IRI referring
>    expressions using a named property or datatyping convention.
>
> 6)
>    notes that labeling RDF graph nodes with new kinds of referring
>    expression (for eg. RDF definite descriptions) might be proposed as a
>    design feature for any hypothetical RDF 2.0 effort. The simpler case
>    of URI resource identifiers can be addressed using RDF's existing
>    property and datatyping machinery.
>
>
>
>
> Hmm, if this is true I ought to my money^H^H^H^H^Htestcases where my
> mouth is.
>
> I also have another argument (related to reification) in favour of our
> doing URIs as properties, but it'd be a distraction to include here
> (and probably a distraction from shipping Core in a timely fashion).
>
> Dan
>
>
>
> --
> mailto:danbri@w3.org
> http://www.w3.org/People/DanBri/
>
>
Received on Friday, 22 March 2002 06:26:20 EST

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