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Re: Canonical XML and xmlns:xml

From: Joseph Reagle <reagle@w3.org>
Date: Tue, 27 Nov 2001 14:32:30 -0500
To: Christian Geuer-Pollmann <geuer-pollmann@nue.et-inf.uni-siegen.de>, XML Signature WG <w3c-ietf-xmldsig@w3.org>
Cc: John Boyer <jboyer@PureEdge.com>, Eric van der Vlist <vdv@dyomedea.com>, "Joseph Kesselman" <Joseph_Kesselman@lotus.com>, "Philippe Le Hégaret" <plh@w3.org>, "Rich Salz" <rsalz@zolera.com>
Message-Id: <20011127193231.5EAB7109F@policy.w3.org>
On Monday 26 November 2001 13:16, Christian Geuer-Pollmann wrote:
> This means that xmlns:xml="http://www.w3.org/XML/1998/namespace" does not
> have to be declared to be used. But this causes a problem for some XSLT
> folks so the Xalan developers decided to add the above xmlns:xml decl to
> the DOM tree and XPath results.

Hrmm... tricky. In the Python implementation [1] we don't even bother with 
*real* namespace nodes since they aren't in DOM Levels 1/2. They are only 
available as attributes and we then separate them for processing based on 
what they look like; implicit xmlns:xml declarations are not returned in 
the attribute list regardless.

In Xalan, do they have an implementation of a DOM  *and* XPath nodeset? Or, 
like in PyXML, is XPath filtered through a DOM nodeset? (I'm not sure if 
there is a python parser that provides a genuine XPath nodelist.) If so, 
when the xmlns:xml is added, is it added to an attribute list? (I would 
think this might "break" DOM in order to comply with XPath...).

[1] http://dev.w3.org/cvsweb/2001/xmlsec-python/

> At the moment, I don't know whether this makes sense or causes problems.
> Do you have some thoughts about that?

Regardless of what is happening in XPath/DOM, I believe Canonicalization 
allows us to ignore it [2] regardless, right?

[2] http://www.w3.org/TR/2001/REC-xml-c14n-20010315#ProcessingModel
  Element Nodes- ... Namespace Axis-...To finish processing L, simply
  process every namespace node in L, except omit namespace node with local
  name xml, which defines the xml prefix, if its string value is


Joseph Reagle Jr.                 http://www.w3.org/People/Reagle/
W3C Policy Analyst                mailto:reagle@w3.org
IETF/W3C XML-Signature Co-Chair   http://www.w3.org/Signature/
W3C XML Encryption Chair          http://www.w3.org/Encryption/2001/
Received on Tuesday, 27 November 2001 14:38:20 UTC

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