- From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Date: Tue, 17 Feb 2004 15:30:36 +0100
- To: "Graham Klyne" <gk@ninebynine.org>, "rdf core" <w3c-rdfcore-wg@w3.org>
This does not look disastrous to me. In RDF URIrefs ending in # (i.e. with explicitly empty fragment) only regularly occur as namespace names. All possible uses of such URIrefs involve qnames which give them a non-emtpy fragment part. The text in question "URI producers and normalizers should omit a delimiter if the component it delimits is empty" uses a "should" not a "MUST", and is hence sufficiently weak. We perhaps could suggest modifying the text: [[ , with one exception: a double-slash delimiter indicating an authority component should not be removed, even when the authority is empty, since doing so can lead to misinterpreting the path. ]] http://gbiv.com/protocols/uri/rev-2002/rfc2396bis.html#normalize-empty to [[ . A first exception is: a double-slash delimiter indicating an authority component should not be removed, even when the authority is empty, since doing so can lead to misinterpreting the path. A second exception is: a common idiom in RDF/XML uses URI references with empty fragments as XML namespace names. ]] The overall normalization rules in section 6 http://gbiv.com/protocols/uri/rev-2002/rfc2396bis.html#comparison inevitable create a many positive matches that are not honoured in RDF concepts. Like XML namespaces we chose the simplest possible definition of equality: string equality. The overall tone of section 6 ought to respect such a choice. Jeremy > -----Original Message----- > From: w3c-rdfcore-wg-request@w3.org > [mailto:w3c-rdfcore-wg-request@w3.org]On Behalf Of Graham Klyne > Sent: 17 February 2004 13:17 > To: rdf core > Subject: Heads up: RFC2996bis, possible problem for RDF > > > > I've just reviewed: > > http://gbiv.com/protocols/uri/rev-2002/rfc2396bis.html > Modified: 16 February 2004 11:36:15 > Size: 167.42 KB (171437 bytes) > > Which has recently been "last called" in the IETF URI informal group in > preparation for an IESG last-call request, per: > http://lists.w3.org/Archives/Public/uri/2004Feb/0082.html > > I am concerned that the empty component normalization rules may be > troublesome for RDF. My review comments are at: > http://lists.w3.org/Archives/Public/uri/2004Feb/0094.html > > The specific example raised is: > > [[[[ > Section 6.2.2.3: > I'm concerned about empty component normalization: > In RDF usage, the URIs: > http://example.org/ > and > http://example.org# > would result in quite distinct resource identifiers, e.g. in: > > [[ > Triples of the Data Model in N-Triples Format (Sub, Pred, Obj) > > <http://www.w3.org/RDF/Validator/run/foo> > <http://example.org/prop> "value" . > > The original RDF/XML document > > 1: <?xml version="1.0"?> > 2: <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > 3: xmlns="http://example.org/"> > 4: <rdf:Description rdf:about="foo"> > 5: <prop>value</prop> > 6: </rdf:Description> > 7: </rdf:RDF> > ]] > > and > > [[ > Triples of the Data Model in N-Triples Format (Sub, Pred, Obj) > > <http://www.w3.org/RDF/Validator/run/foo> > <http://example.org#prop> "value" . > > The original RDF/XML document > > 1: <?xml version="1.0"?> > 2: <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" > 3: xmlns="http://example.org#"> > 4: <rdf:Description rdf:about="foo"> > 5: <prop>value</prop> > 6: </rdf:Description> > 7: </rdf:RDF> > ]] > > (RDF triples generated by http://www.w3.org/RDF/Validator/) > > Are distinct RDF graphs, even though the URIs are equivalent under the > normalization rules given. > ]]]] > > #g > > > ------------ > Graham Klyne > For email: > http://www.ninebynine.org/#Contact > >
Received on Tuesday, 17 February 2004 09:30:55 UTC