Solving current schema problems with DSDs

[Hugh Field-Richards <h.field-richards@eris.dera.gov.uk>]

Hi

I was wondering whether anyone out there has been looking at
(or even using) the Document Structure Description (DSD) schema
from http://www.brics.dk/DSD/. I have been using it with some
success within several bits of work here. It clearly solves some
of the more interesting problems that other schemas have trouble
with. Two of the most noteworthy are

1. Checking content (strings particularly) against different types
   of element attribute. For example how would the following be
   done in current schemas so that invalid cases were trapped?

        <AttribContext>
          <!-- Valid -->
          <Var Type="fixed">1234</Var>
          <Var Type="float">3.14159</Var>
          <Var Type="hex">345ABCH</Var>
          <Var Type="hex">03fe5a6H</Var>
          <!-- Invalid -->
          <Var Type="hex">34V56H</Var>
          <Var Type="hex">abcdh</Var>
          <Var Type="hex">2adef</Var>
          <Var Type="fixed">2a1217</Var>
          <Var Type="fixed">2+1217</Var>
          <Var Type="float">32.8.7</Var>
          <Var Type="fixed">2.1217</Var>
        </AttribContext>

2. The other and, I believe more critical, problem was the challenge
   I gave to Nis Klarlundis and described on the DSD site at
   http://www.research.att.com/projects/DSD/generic-lists/. I still
   do not believe that this challenge has been successfully answered
   in any other schema (except possibly the Schematron which I consider
   to be a validation rather than a definition language).

I am sure that I have given people enough ammunition above to be shot
down in flames, but I would be most interested in people's comments
on the above. Especially if I am wrong in my current view of the schema
situation.

If anyone else is using DSD I would also be most interested to know.
It deserves more exposure to the XML community than it currently enjoys.


Hugh F-R

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Dr Hugh S Field-Richards
QinetiQ, St Andrew's Road, Malvern, Worcs, WR14 3PS, UK
  tel: (44) 1684 895075
  fax: (44) 1684 896113
email: h.field-richards@qinetiq.com

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The views expressed above area entirely those of the writer and do
not represent the views, policy or understanding of any other person
or official body.
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