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LC-104 and LC-105 XML Signature WG's review of XML Schema

From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
Date: Thu, 05 Oct 2000 21:48:20 -0600
Message-Id: <>
To: "Joseph M. Reagle Jr." <reagle@w3.org>
Cc: W3C XML Schema Comments list <www-xml-schema-comments@w3.org>, "IETF/W3C XML-DSig WG" <w3c-ietf-xmldsig@w3.org>
Dear Joseph:

The W3C XML Schema Working Group has spent the last several months
working through the comments received from the public on the last-call
draft of the XML Schema specification.  We thank you for the comments
you made on our specification during our last-call comment period, and
want to make sure you know that all comments received during the
last-call comment period have been recorded in our last-call issues
list (http://www.w3.org/2000/05/12-xmlschema-lcissues).

Among other issues, you raised the points registered as issue LC-104
and LC-105, which note the utility of various features in the spec and
urge the WG (a) to give priority to stabilizing the syntax of the
language and (b) to getting the spec to Recommendation soon.

We thank you for the comments.  We have attempted to resist urges to
improve the transfer syntax, and in many cases we have been
successful.  I must inform you, however, that in some cases we have
been forced, despite your encouragement to stabilize the syntax, to
make incompatible changes to the language.  These changes have been
necessary to gain functionality and to improve the degree to which the
grammar given in the schema for schemas actually captures the rules
governing the construction of schemas.

Two members of our WG (Henry Thompson and Martin Gudgin) have
made available a Web service for translating schema documents from
the old syntax into the new syntax; it is at


And we have formulated a policy which should reduce (we hope) the pain
caused by incompatible syntax changes: in addition to the generic (and
mutable) resources at URIs like http://www.w3.org/XML/1998/namespace,
which will at any time have the *current* schema syntax, it is our
recommendation that there also be immutable resources at known URIs,
so that it is possible to future-proof schemas which refer to W3C
resources and ensure that they remain valid even in the face of
non-compatible changes to the generic resources.

We are grateful to you and your WG for your early work with XML
Schema, and for giving us an occasion to think concretely about
how to reduce the troubles associated with evolution in the XML
Schema language.

It would be helpful to us to know whether you are satisfied with the
decision taken by the WG on this issue, or wish your dissent from the
WG's decision to be recorded for consideration by the Director of
the W3C.

with best regards,

-C. M. Sperberg-McQueen
  World Wide Web Consortium
  Co-chair, W3C XML Schema WG
Received on Thursday, 5 October 2000 18:29:02 UTC

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