- From: pat hayes <phayes@ai.uwf.edu>
- Date: Sat, 1 Mar 2003 12:35:34 -0700
- To: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Cc: w3c-rdfcore-wg@w3.org
>>I took this comment as a rhetorical question meaning, "why bother >>even getting into canonicalization if you have implementation >>variance?" and hence suggesting a fourth option, which you did not >>consider: >> >>D. Ignore XML canonicalization and treat XML literals as strings, >>ie the L2V mapping is the identity. >> >>Then the entire rdf:XMLliteral datatype machinery is just an >>elaborate way of encoding the old 'XML bit', which I thought was >>the original intent in any case. Introducing XML canonicalization >>seems to have been one those neat ideas that got slipped in without >>too much discussion and has turned out to be a tar-pit. I am >>particularly concerned that this ugly mess is now centrally >>included in the very core of RDF. I would hope that many 'cheap and >>cheerful' RDF engines wouldn't even want to know about XML, still >>less about XML canonicalization. > >This really does not meet the requirements ... > >XML parsers really really have variability, when building RDF/XML >parsers we have to work out how to deal with that. I do not see why this is a central issue for us. We have said that the definitive RDF syntax is the graph. There is no variability in a graph, and that handles Webonts concerns. The issue you raise is an issue with XML, and I do not feel that XML's mess should be dirtying RDF's kitchen. >So the simple webont examples where they want a single well-defined >denotation of some literal constructed with an >rdf:parseType="Literal" cannot be addressed simply by saying "use >the original string". We can tell Webont that a given RDF graph has a single well-defined denotation. The issue arising from XML's variability, if real, should be addressed by the definition of RDF/XML >In some real contexts there isn't a string to use (e.g. parsing a DOM tree). I do not understand this. The RDF graph syntax is required to have a string in every literal. There is always a string to use. > >We could have put all the work in the parser, and then the semantics >could just use the string - that may be your preference, but it's >too late now. I don't think it is too late. >In practice I would expect a webont impl to work that way. However, >I also believe in practice that there will be cheaper parsers for >low footprint environments which don't do this. If I understand you, any parser which does not do this will produce ambiguous RDF/XML. Again, I disagree that it is too late to do this. We are not under any obligation to repair deficiencies in XML. I propose that we simply assert that we are not responsible for variability in XML parsers, and that the RDF graph is the definitive RDF syntax. Pat >Jeremy -- --------------------------------------------------------------------- IHMC (850)434 8903 or (650)494 3973 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Saturday, 1 March 2003 14:35:50 UTC