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Re: ISSUE-117 (about-on-HTML): Consider disallowing @about on <html> [RDFa 1.1 in HTML5]

From: Ivan Herman <ivan@w3.org>
Date: Wed, 16 Nov 2011 13:39:24 +0100
Cc: RDF Web Applications Working Group WG <public-rdfa-wg@w3.org>, sysbot+tracker@w3.org
Message-Id: <4330D017-F510-49F1-B8FC-1372F1AADFF1@w3.org>
To: Toby Inkster <tai@g5n.co.uk>

On Nov 16, 2011, at 13:31 , Toby Inkster wrote:

> On Wed, 16 Nov 2011 09:07:59 +0100
> Ivan Herman <ivan@w3.org> wrote:
> 
>> Toby wrote:
>>> 1. Ditch the magic behaviour of the <head> and <body> elements in
>>> HTML+RDFa. Preferably in XHTML+RDFa too.
>> 
>> What this means is that the processing would begin by not having a
>> subject at all.
> 
> No, it wouldn't. From RDFa 1.1 Core:
> 
> | At the beginning of processing, an initial evaluation context is
> | created, as follows: 
> | * the base is set to the URI of the document (or another value
> |   specified in a language specific manner such as the HTML base
> |   element);
> | * the parent subject is set to the base value;

Oops, you are right. But, I must admit, I do not understand this any more. Why do we have this magic <head>/<body> behaviour in the first place? I mean, it was such a long time ago when we introduced it that I simply do not remember the rationale.

What this rule says, in terms of elements, is that <html> (or any top element) _has_ this magic behaviour, ie, an @about="" is introduced on that level, conceptually (unless there is an explicit @about, that is). So what does <head> and <body> magic brings us?

I am officially lost.:-)


> 
>> IN any case, lots of backward compatibility issues: although I dislike
>> them, but all those stylesheet triples would disappear, because they
>> are almost always generated through the <head> and its magic
>> property.
> 
> Nope, they wouldn't disappear. The initial evalutaion context would set
> the subject to be the document's base URI, so stylesheet triples would
> pick up that as their subject by default.
> 
>> Toby wrote:
>>> 2. Say that the magic behaviour of <head> and <body> only kicks in
>>> when the <head> or <body> element carries the @typeof attribute.
>>> Preferably in XHTML+RDFa too.
>> 
>> I do not think that works. I may have very legitimate reasons to use
>> <body typeof="T">
>> ie, to create a blank node of type 'T'.
> 
> Well, you're out of luck, because that will already fail in XHTML+RDFa
> 1.0 and 1.1 - it will set the rdf:type of the document's base URI, not
> a blank node.
> 

Oops again:-)

Ivan

> -- 
> Toby A Inkster
> <mailto:mail@tobyinkster.co.uk>
> <http://tobyinkster.co.uk>


----
Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
FOAF: http://www.ivan-herman.net/foaf.rdf
Received on Wednesday, 16 November 2011 12:36:51 GMT

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