DOCBOOK: Basing a module in DocBook XML DTD

["E.L. Willighagen" <egonw at sci dot kun dot nl>]

Hi all,

I am trying to make a module based on DocBook XML 4.1.2 and have a working 
now, but it is not quite to my liking...

Consider this document:

<?xml version="1.0"?>
<!DOCTYPE article PUBLIC "-//JReferences//DTD DocBook JReferences Module //EN"
                         "../dtd/jreferences.dtd" []>
<article>

  <jref:mode>Number</jref:mode>

  <articleinfo>
    <title>Test Article</title>
    <author><firstname>Egon</firstname><surname>Willighagen</surname></author>
    <date> 3 May 2000</date>
  </articleinfo>

  <section>
    <title>Some section</title>
    <para>This is a text with a reference 
    <jref:cite id="Steinbeck99"/>.</para>
    <para>And now for some more serious tests, we add a second reference
      <jref:cite id="Bachrach99"/>. And again the first reference
      <jref:cite id="Steinbeck99"/>.
    </para> 
  </section>

  <jref:reflist/>

</article>

To be able to validate this document I made this customized DTD:

<!-- ...................................................................... 
-->
<!-- DocBook JReferences Module ........................................... 
-->

<!-- Copyright (C) 2002 E.L. Willighagen

     $Id: jreferences.dtd,v 1.2 2002/08/05 16:06:16 egonw Exp $

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

-->

<!-- ...................................................................... 
-->

<!-- This is the driver file for the DocBook JReferences Module.
     Please use the following formal public identifier to identify it:

     "-//JReferences//DTD DocBook JReferences Module //EN"

     If your document's top-level element is jref-article, and
     you are using DocBook directly, use this DOCTYPE
     declaration:

     <!DOCTYPE jref-article PUBLIC
                       "-//JReferences//DTD DocBook JReferences Module //EN"
                       "http://jreferences.sf.org/jreferences.dtd";
                       [...]>

     Or, if you have a higher-level driver file that customizes DocBook,
     use the FPI in the parameter entity declaration:

     <!ENTITY % JReferencesDTD PUBLIC
                               "-//OASIS//DTD DocBook MathML Module V1.0//EN"
                               "http://jreferences.sf.org/jreferences.dtd";>
     %JReferencesDTD;

-->

<!ENTITY % jref-colon               ':'>
<!ENTITY % jref-prefix              'jref'>

<!ENTITY % NamespaceDecl.attrib "
                xmlns%jref-colon;%jref-prefix;
                CDATA   #FIXED 'http://jreferences.sf.net/'
">

<!ELEMENT jref:cite (#PCDATA)>
<!ATTLIST jref:cite id     CDATA     #REQUIRED>

<!ELEMENT jref:mode (#PCDATA)>

<!ELEMENT jref:reflist (#PCDATA)>

<!ENTITY % jref-cite                '%jref-prefix;%jref-colon;cite' >
<!ENTITY % jref-mode                '%jref-prefix;%jref-colon;mode' >
<!ENTITY % jref-reflist             '%jref-prefix;%jref-colon;reflist' >

<!ENTITY % local.para.mix "| %jref-cite; ">

<!ENTITY % docbook PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
                   "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd";>
%docbook;

<!ELEMENT jref:article ((%jref-mode;)?,
                        (%div.title.content;)?, articleinfo?, tocchap?, lot*,
                        (%bookcomponent.content; | %jref-reflist;)*,
                        ((%nav.class;) | (%appendix.class;) | ackno)*)>
<!ATTLIST jref:article
                    %NamespaceDecl.attrib;>

<!-- End of jreferences.dtd ............................................... 
-->
<!-- ...................................................................... 
-->

(I took the MathML V1.0 module as a starting point)

If you carefully look at this DTD you'll see the jref:article document
that overwrites DocBook's article element. This is the part with which
I am not happy... the above document should thus be using
jref:article element instead of article and then it correctly validates...

Redefinition of the article element is a error (according to xmllint) and is 
thus not an option. And I could not find a way similar to the customization
of the para element with the local.para.mix entity which is empty in DocBook
XML 4.1.2 DTD...

My problem is thus:
How can I add the jref:mode element as a possible child element to DocBook's
article element?

More information about JReferences can be found at SourceForge:
jreferences.sf.net.

kind regards,

Egon Willighagen