- From: Mark Birbeck <mark.birbeck@x-port.net>
- Date: Mon, 29 Oct 2007 12:44:45 +0100
- To: "Ivan Herman" <ivan@w3.org>
- Cc: "Hausenblas, Michael" <michael.hausenblas@joanneum.at>, "W3C RDFa task force" <public-rdf-in-xhtml-tf@w3.org>
Hi Ivan, I hope you had a good trip. > I attach yet another test that I believe addresses an issue not covered > by the others. We had a discussion at some point on the list, and got to > an agreement, that an 'instanceof' placed on the <html> element would > automatically generate a type for the whole document by virtue of the > fact that there is an implicit @about="" on the <html>. We actually agreed that @about="" should apply to <head>. Just to re-emphasise the rationale, it's because we need to be careful that certain constructs don't change the meaning of typical HTML mark-up. For example: <html> <head instanceof="foaf:PersonalProfileDocument"> <link rel="foaf:maker" ... /> . . . If the 'default @about' was placed on <html> then <head> would acquire a bnode due to the presence of @instanceof, and the @rel would apply to the bnode and not to the current document. However, since in HTML this applies to the current document: <html> <head> <link rel="foaf:maker" ... /> . . . then I believe that the addition of @instanceof is merely adding a statement, and not changing the subject of other statements. The only way to achieve this is to put @about as 'close' as possible to those statements, i.e., on <head>. Of course this then means that we need a default for <body>, since there would no longer be one on <html>, and there are a number of ways to address that: * put @about on <html> as well; * put @about on <body>; * indicate that the contents of <head> are processed *before* the contents of <body> and that <head> essentially sets the context for processing <body>. My preferred approach is *both* the third one and second. :) I believe that there are other reasons for defining the processing rules quite precisely so that <head> is processed before <body>, which I won't go into here since they are more for 'future work'. But also I think we need to have @about on <body> for exactly the reasons we need it on <head>, which is to stop the presence of @instanceof from unexpectedly changing the subject for all child statements. Regards, Mark -- Mark Birbeck, formsPlayer mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232 http://www.formsPlayer.com | http://internet-apps.blogspot.com standards. innovation.
Received on Monday, 29 October 2007 11:44:54 UTC