- From: Dave Beckett <dave.beckett@bristol.ac.uk>
- Date: Thu, 7 Aug 2003 17:34:07 +0100
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: www-rdf-comments@w3.org, duerst@w3.org
On Thu, 07 Aug 2003 11:28:37 -0400 (EDT) "Peter F. Patel-Schneider" <pfps@research.bell-labs.com> wrote: > From: Dave Beckett <dave.beckett@bristol.ac.uk> > Subject: Re: support XML Literals in RDF > Date: Thu, 7 Aug 2003 12:59:40 +0100 > Not even all XML Literals that result from RDF/XML parsing will be valid > (exc-C14N checked). For example (modulo issues with using rdf: in places > where it really can't be used) > > <rdf:RDF> > <rdf:Description> > <http://ex.a/a#a rdf:datatype="rdf:XMLLiteral"><b/></http://ex.a/a#a> > </rdf:Description> > </rdf:RDF> That's nowhere near legal XML or RDF/XML and I can't see what you are getting at. Please try the RDF validator to correct it and make your point. > will result in the triple > > _:a <http://ex.a/a#a> "<b/>"^^rdf:XMLLiteral . > > which has an XML Literal in non-canonical form. <snip/> > > So in this hypothetical situation where you want to use XML literals in > > the RDF graph but don't want to use XML tools, you don't want to > > do any checks when you make the triples? Sorry, you will just have to > > use the exc-C14N, or not use the XML literals at all and make your own > > unchecked "XML" datatype, losing out on interop. > > Right, so if anyone wants to write a tool that determines RDFS entailment > between RDF graphs, they will have to incorporate a tool for exclusive > canonical XML. Possibly. In other conversations the working group are discussing this. This process is not complete and I am not providing you with an answer at this time. > > Your oracle is an exc-C14N implementation which I've already mentioned > > is fairly widely available - we've had no problems finding them free and > > working. > > Is there an oracle for exclusive canonical XML? I realize that there are > tools that will transform into exclusive canonical XML, but do they have a > simple oracle? I've explain these require low effort. You can do the trivial research to find them. > > You will also have to NFC-check your plain literals as we > > discussed in the other thread. Otherwise you've got garbage. > > Garbage? I disagree entirely. What you have is XML or strings that may > not be in some canonical form. This is not garbage. Not good data since it can possibly be pseudo-XML if you aren't going to attempt to use an XML processor on it. This is called XML tag soup and pretty worthless. Non-recommended forms of Unicode character normalization that are poor for I18N and prevent simple equality tests for plain literals. This is disappointing. <snip/> > > I said datatype-entailment and hence a pile of code for checking such > > XML functionality in the graph. That means whatever XSD does. I've not > > read the detail. There is normalization involved somewhere, I recall. > > Where? I can't find any XSD datatype that needs XML canonicalization. That's nice. But I said normalization. What detail that some datatypes require to be implemented isn't the point. I was giving an example of extra code that is required when you do extra things above basic RDF graph support - such as an XSD library if you do datatype entailment, or an XML tag soup one if you want to do funny things with pseudo-XML, or an inferencer if you want to do OWL using RDF. Dave
Received on Thursday, 7 August 2003 12:36:57 UTC