XML Schemas now Proposed Recommendation at W3C

[Rick Jelliffe <ricko@allette.com.au>]

W3C has now released the Proposed Recommendation versions of XML Schemas
1.0,  at http://www.w3.org/

A Proposed Recommendation is the step before a final Recommendation. My
expectation is that there will be no changes to the technology before moving
to Recommendation.

On this list I have frequently posted that people should be cautious about
implementing XML Schemas for production systems, because it and its
implementations have been in flux. So it is appropriate to withdraw that
warning for the PR version: of course, with the caveats that I am not
speaking on behalf of anyone but myself, that there is always a slight
chance that there will be some changes for 1.0, and that implementations
will naturally lag behind.

The new specifications have been thoroughly revised, restructured and
reformatted for clarity.  Henry Thompson, the editor of the Structures spec,
gets a lot of flack for his highly-structured, checklist style. But I
believe it is very valuable that the Structures specification has been
edited by an actual developer of a Schema validator (XSV) who is conciously
organizing the decisions of the Schemas working group in the light of that
experience for other developers.

For clarity, there are now more examples, better overview and navigation
material, fluff has been cut, the Primer provides a very nice introduction
for the laity, there is a formalization in the works (MSL) which will help
type-theorists, and there is even a couple of pictures now.

I believe XML Schemas will be particularly useful for electronic commerce
and business; especially for connecting to databases, automatically
generating interfaces between processes, for
optimized queries, and for XHTML.

It is quite likely that there will be an XML Schemas 1.1.  (Procedurally, it
would not be decided to work on this until after the REC comes out and the
Schema WG gets re-chartered, so no-one can actually promise it.) Topics that
one might expect to be examined for XML Schemas 1.1 include modularization,
subsets, internationalization, date/time, keys, and cross-pollenation from
the 2000/2001 crop of schema languages (RELAX, TREX, Schematron, etc.).   I
am hopeful.

I hope, in future discussions of XML Schemas, we can separate issues related
to its features from how those features are used.  I think it is quite
consistent to hold that

  - XML Schemas is a good thing for many people because it meets a big
community's legitimate need and has been exhaustively and well-prepared

  - lots of things would be different if I were King of the world

  - there is nothing stopping anyone or any group making their own schema
languages, and that innovation and competition (and marketplace "confusion")
are not the enemies of XML Schemas (alternative schema languages provide new
ideas for XML Schema's evolution; alternative schema languages allow people
for whom XML Schemas is not appropriate to get their jobs done and therefore
would decrease discontent; alternative schema languages, if orthogonal, are
layers that can be used with XML Schemas, reducing the need for it to grow
to cover more and more cases.)  Open systems thrive by allowing oraganic
plurality.

  - the issue of the impact of XML Schemas (how it will be used in other new
specifications, in particular dependencies on PSVI information that cannot
be trivially serialized as attributes to augment the original XML document )
is important.

In other words, if I say "PSVI-reliance in new specs stinks" that is not the
same as saying "XML Schemas sucks".

That's my spin on it, as it looks now, anyway.

Cheers
Rick Jelliffe

P.S. I am leaving Taiwan, Geotempo and Academia Sinica, to return to Sydney
to finish a new book "XML Schemas Interlinear" and a great project with
Allette Systems, my old employers in the mid-90s.  All my current email
accounts should continue to operate.  I am very interested in feedback to
know what the most common stumbling blocks people have when trying to figure
out XML Schemas and the various W3C specifications: please email
ricko@allette.com.au if you have any dirt.