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Re: link/@rel=profile, was: HTML5+RDFa first Editors Draft published

From: Leif Halvard Silli <lhs@malform.no>
Date: Fri, 17 Jul 2009 03:47:26 +0200
Message-ID: <4A5FD82E.4080205@malform.no>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
CC: Steven Pemberton <Steven.Pemberton@cwi.nl>, Julian Reschke <julian.reschke@gmx.de>, Manu Sporny <msporny@digitalbazaar.com>, RDFa Developers <public-rdf-in-xhtml-tf@w3.org>, HTMLWG WG <public-html@w3.org>
Mark Birbeck On 09-07-16 18.34:

> In other words, it's quite fundamental that any information required
> for processing a graph -- prefix mappings, default language, base
> URLs, character encodings, or anything else you can think of -- must
> be obtained prior to processing that graph.


> On Thu, Jul 16, 2009 at 5:02 PM, Steven Pemberton:
>> [...] I have to say I disagree.


>> By the time you have the graph, you have done the RDFa processing. The
>> statement "This document uses a profile of http://example.com/profile" is
>> true, whether or not the profile has been used in the generation of the
>> graph. There is no contradiction, Gödelian or other.


>> On Tue, 14 Jul 2009 11:06:59 +0200, Mark Birbeck
>>> Hi Julian,


>>> So the key point is not 'don't use RDFa to describe how to interpret
>>> RDFa' -- the key message here is that 'instructions on how to process
>>> a graph cannot go into the graph itself'.


I appear to conclude like Steven: If you write <html 
about="[_:Göteborg]" > then you have used a character which may 
depend on a child element of <head> for its correct interpretation 
w.r.t. the character encoding. (Ditto for e.g. @title, which HTML5 
permits inside <html>. Whereas HTML 4 only permitted ASCII content 
inside its attributes - @lang and @dir.)

In HTML 4, metadata is more or less limited to the <head> element 
[1]. Thus it was logical with <head profile=...">. But with RDFa, 
any element (even <html> and <head> itself, I gather) may have 
RDFa attributes. So, to be completely generic, shouldn't one 
switch from <head profile=...> to <html profile=... >?

Hence, if <head profile="..."> actually is good enough, then it 
ought to be good enough with <link rel="profile" ...> as well, no?

If RDFa is "a CSS for meaning"[2], then - just as the <html> 
element may be styled via a child element of <head> (which in turn 
may point to a style found in an external CSS document), then 
likewise should it not matter if the profile URI is found in a 
child of <head> instead of inside the <head> attribute. No?

[1] http://www.w3.org/MarkUp/2009/rdfa-for-html-authors#Generalise
[2] http://www.w3.org/MarkUp/2009/rdfa-for-html-authors#Introducti
-- 
leif halvard silli
Received on Friday, 17 July 2009 01:49:18 GMT

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