DOCBOOK-APPS: Differences between SGML and XML

[Bartolich Alexander VAI/GAI 1 <Alexander.Bartolich@vai.at>]

I have some documents written in SGML for DocBook 3.1.
There is no problem processing them with OpenJade version 1.3
(shipped with RedHat 7.1).

But I want to have one version of my documents that can be
processed as both SGML and XML (after changing only the
doctype declaration). So I downloaded the XML-DTD (version 4.1.2)
and let Xerces 1.4.1 lose on them.

Eventually I could resolve all problems but one:
Entities declared as EMPTY.

The SGML-parses insists on this:
<colspec colnum="1" colname="c1">

The XML-parses accepts either:
<colspec colnum="1" colname="c1"/>
or:
<colspec colnum="1" colname="c1"></colspec>

The SGML error message for "/>" is:
E: character data is not allowed here

The SGML error message for "</colspec>" is:
E: end tag for element "COLSPEC" which is not open

IMHO this is major brain-damage.
And colspec is not the only tag having this problem:

$ /usr/share/sgml/docbook/sgml-dtd-3.1# grep EMPTY *
cals-tbl.dtd:<!ELEMENT colspec - O EMPTY >
cals-tbl.dtd:<!ELEMENT spanspec - O EMPTY >
dbpool.mod:<!ELEMENT Area - O EMPTY>
dbpool.mod:Graphic will be declared EMPTY.  This change will require that
end-tags
dbpool.mod:InlineGraphic will be declared EMPTY.  This change will require
that
dbpool.mod:<!ELEMENT VideoData - O EMPTY>
dbpool.mod:<!ELEMENT AudioData - O EMPTY>
dbpool.mod:<!ELEMENT ImageData - O EMPTY>
dbpool.mod:<!ELEMENT SBR - O EMPTY>
dbpool.mod:<!ELEMENT Void - O EMPTY>
dbpool.mod:<!ELEMENT VarArgs - O EMPTY>
dbpool.mod:<!ELEMENT CO - O EMPTY>
dbpool.mod:<!ELEMENT FootnoteRef - O EMPTY>
dbpool.mod:<!ELEMENT XRef - O EMPTY>
dbpool.mod:<!ELEMENT Anchor - O EMPTY>
dbpool.mod:<!ELEMENT BeginPage - O EMPTY>