- From: Turner, David <davidt@hp.com>
- Date: Thu, 19 Apr 2007 10:44:02 +0100
- To: <public-owl-dev@w3.org>
> > One goal behind the design of a new textual syntax was to > provide a parsable syntax. This is why we call the new syntax > "functional-style syntax", and not "abstract syntax": the new > syntax is quite concrete. > > For this, namespaces seem to be really important; without > them, any file would be just horribly difficult to read or > edit. Oh, I'm not saying that you shouldn't *use* namespaces when you serialise an ontology, just that they should be an implementation detail, not part of the ontology itself. Implementations are currently given a lot of freedom to manipulate namespace declarations, which allows us to work around corner cases (like 'amp' - see below), but making them an explicit part of the OWL syntax will make this job harder. > Therefore, we simply imported the XML style of defining > and expanding namespaces. We did not believe that this would > be difficult to implement: if you see an URI of the form > "a:b", just replace "a" with the declared namespace. Yes, that's right, and that happens at a much lower level than OWL. In particular, in an RDF/XML document the namespace declarations are not part of its semantics, and they usually get expanded at parse-time. Implementations are currently free to throw them away and use full URIs if it doesn't like them for some reason, or to introduce new ones if appropriate. > I did > not quite understand your point with "amp"; could you please > elaborate? If I use a namespace 'ns', in some places in the XML the entity '&ns;' has to be used; if the namespace is called 'amp' then you cannot use '&' because that entity is already defined. I'm led to believe that corner-cases to do with namespaces are a recurring support issue in Jena, which suggests that getting them correctly specified would be a nightmare, and that it's safer to leave it up to implementors to worry about them. Cheers, Dave -- Dave Turner Cube T400, HP Labs Bristol, Filton Road, Bristol BS34 8QZ davidt@hp.com +44 117 3129104 (Work) +44 7962 811627 (Mobile) Hewlett-Packard Limited. Registered No: 690597 England Registered Office: Cain Road, Bracknell, Berks RG12 1HN
Received on Thursday, 19 April 2007 09:44:33 UTC