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Re: issue-base-param

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Fri, 30 Mar 2007 11:48:27 +0100
Message-ID: <460CEAFB.9050809@hpl.hp.com>
To: GRDDL Working Group <public-grddl-wg@w3.org>

Message summary:
Suggested small change for XML Base in XML docs

Much harder to make suggestion for XML Base in HTML docs.
Fairly long, informative, text, basically saying if you use xml:base in 
HTML docs, then, for GRDDL to be well-defined, you also have to use 
<base>, and do so consistently.

My suggestions are in html markup, intended to be copy/pasted into 
editor's draft, if he sees fit.

Jeremy



xml:base.
========
Suggested change to normative text, simply add reference to XML Base:

OLD
[[
by the
absolute form (see section 5.2 Relative Resolution in <a class="norm"
href="#rfc3986">[RFC3986]</a>) of <var>REF</var> with respect to the
base IRI of <var>E</var> is a <dfn>GRDDL transformation</dfn> of
<var>N</var>.
]]
NEW
[[
by the
absolute form (see section 5.2 Relative Resolution in <a class="norm"
href="#rfc3986">[RFC3986]</a>) of <var>REF</var> with respect to the
base IRI
(see <a class="norm"
href="#xmlbase">[XMLBASE]</a>)
of <var>E</var> is a <dfn>GRDDL transformation</dfn> of
<var>N</var>.
]]

Here is the new normative ref:
[[
<dt>
<a name="xmlbase" id="xmlbase">XMLBASE</a>
</dt>
<dd>
<cite>
<a href="http://www.w3.org/TR/2001/REC-xmlbase-20010627/">XML Base</a>

</cite>, J. Marsh,  Editor, W3C Recommendation, 27 June 2001, 
http://www.w3.org/TR/2001/REC-xmlbase-20010627/ . <a 
href="http://www.w3.org/TR/xmlbase/">Latest version</a> available at 
http://www.w3.org/TR/xmlbase/ .</dd>
]]

html:base
=========

At the end of section 4, in the subsection "Rules for GRDDL with valid 
XHTML" immediately after the first rule, add the following informative text:
[[
<p>
<strong>Note:</strong> the base IRI for an XHTML family document
is discussed in
<a 
href="http://www.w3.org/TR/1999/REC-html401-19991224/struct/links.html#edef-BASE">
section 12.4</a> of
[<a href="#HTML4">HTML4</a>].
This is set using the <code>html</code> <code>base</code> element, which
must come before any element that refers to an external source, in 
particular, any <code>link</code> elements as in the rule above.
</p>
]]

After the next rule, concerning meta data profiles,

[[
<p>
<strong>Note:</strong> A <code>html</code> <code>base</code> element,
if any,
comes after any <code>profile</code> attribute.
To avoid ambiguity as to whether any
<code>base</code> element has scope containing a
  relative reference by the <code>profile</code> attribute, document
authors are advised against using the combination of these two features.
A document using the <code>base</code> element is clearer if
it uses absolute URIs for metadata profile names.
</p>
]]

Finally, combining the xml:base and html:base approaches,
and combining with suggested text from
http://lists.w3.org/Archives/Public/public-grddl-wg/2007Mar/0194

Add, at very end of section 4, immediately before section 5.

[[
<p>
While these mechanisms are intended primarily
for valid XHTML family documents, they also
can be used with well-formed but not valid XHTML documents.
A validation error does not negate the applicability
of these mechanisms.
Thus, these features can be used with XML features that are
not permitted within valid XHTML, for example, namespace qualified
attributes.
This may lead to ambiguity concerning the base URI
for relative reference resolution, if
an <code>xml:base</code> attribute is used.
To avoid such ambiguity,
if an <code>xml:base</code>
is used with such an invalid XHTML document, then:
</p>
<ul>
<li>
It should only appear on the root <code>html</code> element.
</li>
<li>
There should be a <code>base</code> element, as a child of the
<code>head</code> element, before any <code>link</code> elements.
</li>
<li>
The base IRI indicated by the <code>base</code> element
and the <code>xml:base</code> attribute should be character by character 
identical.
</li>
<li>
The <code>profile</code> attribute on the <code>head</code> element
should use absolute IRIs, and not relative references.
</li>
</ul>
<p>
Unless all of these suggestions are followed, then the
above rules for the use of GRDDL with an XHTML family
document, may not be well-defined for an <code>html</code>
document containing an
<code>xml:base</code> attribute.
</p>
]]




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Received on Friday, 30 March 2007 10:48:57 UTC

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