W3C home > Mailing lists > Public > public-xml-id@w3.org > January 2005

Re: DTD and Schema Validation Technologies

From: Norman Walsh <Norman.Walsh@Sun.COM>
Date: Wed, 05 Jan 2005 12:11:11 -0500
To: "Klotz, Leigh" <Leigh.Klotz@pahv.xerox.com>
Cc: "'public-xml-id@w3.org'" <public-xml-id@w3.org>
Message-id: <87sm5fu7gw.fsf@nwalsh.com>
/ "Klotz, Leigh" <Leigh.Klotz@pahv.xerox.com> was heard to say:
| Dear Editors,
| In xml:id Version 1.0 W3C Working Draft 09 November 2004 in the section
| "With DTD Validation" [1], the last call working draft says
|   DTD authors must not declare xml:id as something other than ID. DTD
| authors who declare attributes other than xml:id as type ID will not receive
| the full benefits of xml:id processing. Such attributes may or may not be
| recognized processors, including xml:id processors.
| Similar language is used again in "With Schema Validation" [2].
| I note that these sections both occur in an appendix titled "Validation
| Technologies (Non-Normative)" [3], and I think that "must not" is odd to use
| inside a Non-Normative appendix.  Furthermore, placing it as a "must not"
| constraint on authors rather than a "should not" constrain on authors or a
| "must not" constraint on Schemas and DTDs begs semantic questions, because
| it is not possible to express conformance requirements on authors.  I found
| the switch in topic between the first and second sentences confusing, and
| recommend that they be split into two paragraphs.  Finally, I note a missing
| word in two sentences in these sections.
| Details:
| ----------------------------------------------------------------------------
| -------
| For violateion of the prohibition "DTD authors must not declare xml:id as
| something other than ID." in [1] and the similar sentence in [2], no
| consequences are given.  
| - Are all XML-aware processors expected to note type clashes?
| = All DTD or Schema aware processors?  
| - Only xml:id processors?  
| - Does it result in a non-terminating xml:id error as described in [4]? 

The Core WG discussed this issue and notes that the consequences are already
clearly defined by the second bullet point in Section 4:

  The declared type of the attribute, if it has one, is "ID". All
  declarations for xml:id attributes must specify "ID" as the type of
  the attribute.

We agree that the use of normative "must not" language in the
non-normative appendix is an error and will change the text. Our
anticipated change is simply to make a note for authors that use of
non-ID types in their schemas will result in xml:id errors and so they
should be avoided.

| It appears that the xml:id Working Draft is asking authors to refrain from
| using xsd:ID or ID DTD declarations and to convert documents to using xml:id
| exclusively from this day forward.
| If so, such a recommendation should be included prominently in the
| Introduction to the document.
| - Clarify whether this Working Draft proposes to deprecate XML Schema and
| DTD ID declarations not named "xml:id". 

I don't believe that any such deprecation is intended, though I note
that maximum interoperability will be achieved if xml:id is used.

Please let me know if you are satisfied with this resolution to your
comments. (I will address your editorial comments as well.)

                                        Be seeing you,

Norman.Walsh@Sun.COM / XML Standards Architect / Sun Microsystems, Inc.
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Received on Wednesday, 5 January 2005 17:11:34 UTC

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