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RE: Determining attribute uniqueness seems to require namespace prefix in Infoset

From: Tim Bray <tbray@textuality.com>
Date: Wed, 16 Aug 2000 11:32:02 -0700
Message-Id: <4.3.2.7.2.20000816112603.00e69f00@pop.intergate.ca>
To: "John Boyer" <jboyer@PureEdge.com>, "Donald E. Eastlake 3rd" <dee3@torque.pothole.com>
Cc: <xml-names-editor@w3.org>, <www-xml-infoset-comments@w3.org>, "XML DSig" <w3c-ietf-xmldsig@w3.org>
At 11:19 AM 16/08/00 -0700, John Boyer wrote:
>...
><dsig:Reference xmlns:dsig="&dsig;" URI="#X" dsig:URI="#Y>
>...

Now that's seriously ugly.

>As for the issue of why unqualified attributes do not simply default to the
>namespace of their parent element, I have been trying to find out from "the
>XML authorities" why they did not do it this way because the way they did it
>is so specific that it belies intent.  If we toss a coin and pick a
>processing model, it may be in violation of their intent. We don't know
>unless one of them gives the reason.

The policy decision went like this.  Given the following two things

  <html:a      href="foo"> 
  <html:a html:href="foo">

The namespace spec could have said

(a) these are always to be treated as identical
(b) these are always to be treated as distinct
(c) applications can make this decision

It went with (c).  Since the REC's publication, the majority of 
practitioners has grumbled experience teaches that we should have done 
(a).  Maybe this is correct; we didn't have that experience.  Frankly,
I can't remember anyone, during this debate, introducing the example

<html:a href="foo" html:href="bar">

and if they had, this might have driven the WG shrieking into the
arms of option (a).  

On the other hand, it should be noted that individual vocabularies
such as XHTML can specifically forbid practices such as that
given above.  And (I assume/hope) the schema machinery is also
powerful enough to make this distinction. -Tim
Received on Wednesday, 16 August 2000 14:32:12 GMT

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