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Re: Test Case with xml-dsig

From: Norman Walsh <Norman.Walsh@Sun.COM>
Date: Mon, 07 Feb 2005 14:54:09 -0500
To: John Boyer <JBoyer@PureEdge.com>
Cc: Joseph Reagle <reagle@mit.edu>, Gabe Wachob <gwachob@wachob.com>, public-xml-id@w3.org, w3c-ietf-xmldsig@w3.org
Message-id: <87fz08tace.fsf@nwalsh.com>
/ John Boyer <JBoyer@PureEdge.com> was heard to say:
| C14N isn't "just plain broken" with respect to xml:id.
|
| C14N was produced years before xml:id and therefore 
| "does not support" xml:id.

No offense was intended, please accept my apologies for not expressing
that more carefully.

C14N was written with the assumption that all attributes in the xml:
namespace were inherited by their descendants. When C14N was written,
the only examples of attributes in the xml: namespace were xml:lang,
xml:space, and xml:base, all of which behave in this way.

It's risky for specifications to make assumptions about how other
specifications will evolve. It's an unfortunate fact that xml:id does
not share the "inheritable" behavior of the previous attributes in the
xml: namespace.

| Moreover, it cannot be modified to do so without also
| upgrading XPath, which also "does not support" xml:id.

As you note below, if a DTD or schema defines the xml:id attribute as
being an ID, then it's supported direclty in XPath.

| The only way to get these applications to support xml:id
| is to declare this attribute as being of type ID in the DTD.

That's not strictly true. It's possible to introduce xml:id
processing into the XML stack at or just after the parsing process,
producing an XPath 1.0 data model in which all attributes named xml:id
are of type ID irrespective of whether or not a DTD or schema is used.
In that case also, XPath supports xml:id.

| I would very much love to see a new C14N algorithm
| (which would naturally have a new algorithm URI),

Indeed.

                                        Be seeing you,
                                          norm

-- 
Norman.Walsh@Sun.COM / XML Standards Architect / Sun Microsystems, Inc.
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Received on Monday, 7 February 2005 19:55:03 GMT

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