- From: Bill de hOra <bdehora@interx.com>
- Date: Fri, 19 Oct 2001 11:31:47 +0100
- To: <w3c-rdfcore-wg@w3.org>
Tim Berners-Lee: >> The idea of any "SHOULD" in the definition of equality for literals for any language give me the creeps. >> Which is to say 'should not' is inviting non-interop. Spot on. I reduced this constraint to 'should not' for a number of reasons, notably backward compatibility with text in the M&S, which fudges how lang tags affect comparison, and of which 'should not' is a reasonable interpretation, and the fact that a lang tag is optional. But really it all boils down to this sentence in the M&S: [[[ the language of a literal is considered by RDF to be a part of the literal. ]]] The problem with that sentence is the word 'part'. Without falling down a mereological rathole, using 'part' there without some kind of explanation of what that means isn't helpful. Especially when the lang tag is mandated to add no information to the consequent graph, and, the processor is expected to indicate how it deals with lang tags. None of this helps interoperability. If we want to harden this to must we have to admit that a literal cannot exist without a lang tag and that a literal+xml is some kind of natural type, or at least hold a notion that each 'part' of a literal affects decisions regarding its equality. I like to fight the good fight against that: a lang tag is clearly not necessary for all literals. A lang tag is not part of a literal anymore than an RDF statement about Tim Berners Lee is part of him. It's an interpretation of a literal that it's in English or French; interpretation implies semantics and that implies it belongs in the graph. That's to say, lang tags imply semantic equivalences over literals and not just the syntactic ones made by most string ops as you rightly point out. The layering is all out of kilter. The issue is symptomatic of a general problem, Each xml attribute used to qualify a literal is a hack to hang a property of a literal. Tim Berners-Lee: >> I am nervous about the effects of langauge tags, I must say. >> I'm more nervous about the way xml:lang has crept up from a syntactic artefact of XML-RDF, to be a candidate for an abstract description of a literal. And it makes abstract notions of RDF dependent on at least one other spec, that isn't in my mind central to web architecture. Tim Berners-Lee: >> Presumably the alternative choices would have been to deprecate the language tags on RDF literals, in favour of either using XML with parsetype literal, <d:name rdf:parseType="literal"><span xml:lang="fr">chat</></> or RDF itself >> Or just allow statements about literals. regards, Bill .. InterX bdehora at interx.com +44(0)20-8817-4039 www.interx.com
Received on Friday, 19 October 2001 06:34:36 UTC