W3C home > Mailing lists > Public > w3c-ietf-xmldsig@w3.org > October to December 1999

Re: Latest draft and Schema / DTD

From: Joseph M. Reagle Jr. <reagle@w3.org>
Date: Fri, 12 Nov 1999 12:01:07 -0500
Message-Id: <>
To: "Winchel 'Todd' Vincent, III" <Winchel@mindspring.com>
Cc: "Donald E. Eastlake 3rd" <dee3@torque.pothole.com>, "IETF/W3C XML-DSig WG" <w3c-ietf-xmldsig@w3.org>, "leg-xml-l" <leg-xml-l@gsulaw.gsu.edu>, <timbl@w3.org>
At 11:29 99/11/12 -0500, Winchel 'Todd' Vincent, III wrote:
 >Who is "we" -- (www.xml.com)? [your cite] or the W3C? -- and what is it
 >"we" would like to do, exactly?

That xml.com reference cites things that DTDs don't allow you to do, that I
(at least) would like to do. That includes validating XML namespaces and
using  mixed/open content models. We (xmldsig) will certainly be mixing
schemas (embedded signatures and the like).

 >Now, if I understand correctly, you are saying that using XML DTDs to
 >validate XML documents is the wrong way to go (contrary to the message of
 >the last two years) and now I (and everyone else) have to switch to XML
 >schemas and use the phantom tools that exists to make it happen.

Over time people will begin to use schemas. I'm not telling you have to do
anything. I am saying TimBL is encouraging WGs to use schemas and to press
on each other specifications.

 >> and our XML
 >> will be used in many circumstances that will not XML validate anyway.
 >Who is "our"?


 >I assume you will produce examples, so let me add, what about those people
 >who like the idea of SGML and valid documents?  Does this mean the W3C is
 >abandoning valid XML?

Of course not, people are advancing schemas such that you can have valid XML
applications that use XML facilities (like namespaces.)

 >Please recall, SGML and valid SGML documents based on
 >DTDs have been around for 20 years.  As I understood it, the idea of XML
 >was to simplify SGML to bring the SGML philosophy to the massses.  No one
 >ever said the idea of XML 1.0 was to throw away 20 years of SGML
 >experience, and software and replace it with XML schemas.
Todd, frankly I think you've gone off the handle. DTDs were advanced by the
typesetting community (not theoretical SGML wonks) to ensure people did not
submit documents that were broken and result in dumped jobs. XML simplifies
a lot of the SGML (80% functionality/ 20% complexity) and adds a few new
features like namespaces. It turns out that in order to support some of
those XML features your DTDs become extremely complex and still not very
expressive. That is why folks are working on XML Schemas.

 >> I'd ask that we keep the schema declarations I've used in the draft we
 >> working on until we post it early next week and the WG can discuss it.
 >Is the use of schemas mandated in the XML-Signatures "Requirements"
 >and/or is the "Requirements" document going to be amended?  Is this up for
 >vote or is it simply going to be done?  Does the W3C consensus policy

Of course, all I've asked is that people have a look at what we've done, and
we can discuss it.

 >During the second to last telephone conference, you (Joseph) *suggested*
 >that we try to put the XML-Signature syntax into an XML schema to see what
 >it would look like and asked for volunteers.  But, no one said or ever
 >suggested we were replacing DTDs with schemas.   

If you use schemas the idea is -- of course -- to get away from DTDs. I'd
like to post a draft of what the spec likes when using schemas, if the WG
doesn't like it, we can use DTD declarations.

Joseph Reagle Jr.   
Policy Analyst           mailto:reagle@w3.org
XML-Signature Co-Chair   http://www.w3.org/People/Reagle/
Received on Friday, 12 November 1999 12:02:58 UTC

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