XML Catalog files for XHTML

Murray Altheim murray11 at altheim.com
Tue Feb 8 12:25:47 UTC 2011

Reference:  package: w3c-dtd-xhtml; version: 1.1-5ubuntu


Anyone know who is maintaining the XML Catalog files for XHTML?

The current w3c-dtd-xhtml distribution is both incorrect and incomplete,
and it's not clear why the catalog and catalog.xml files supplied with
the package don't refer to the entities supplied with the package. This
may be simply an oversight, but it's not too difficult to fix this, and
anyone actually using XML Catalogs would be better served with a
functional set of catalogs for the entities supplied.

The incorrect files include:


These use incorrect public identifiers and could also point into
the other XHTML catalogs found in the subdirectories, but don't.

The catalogs in the 1.0 directory:


don't include the DTDs themselves.

The following are essentially correct but include an unnecessary module
reference (since the module is not used by the flattened DTD):


For the catalogs used for XHTML Basic 1.0:


these, like XHTML 1.1, should refer to the flattened DTD unless the
modular one is intended. If that latter is the case the rest of the
modules would need to be included. As with XHTML 1.1 it's easier to
simply refer to the flattened DTD:


The xhtml11-model-1.mod and xhtml-basic10-model-1.mod framework
modules are only used if the modular DTD drivers (xhtml11.dtd and
xhtml-basic10.dtd, resp.) are used; if this were the case the rest
of the XHTML modules would be needed. These modules are not included
in the Ubuntu distribution for XHTML 1.1.

On the other hand, I note that the XHTML Basic 1.0 distribution
includes most of the XHTML DTD modules. These aren't needed really if
the flattened XHTML Basic 1.0 DTD is used (and it is available in the
distribution -- there's no reason to the modular version unless one
plans to modify the DTD).

If the XHTML modules are to be included in the distribution it might
be better to move them out of the 'basic' directory since they're not
properly part of Basic but part of XHTML itself. This would also
permit XHTML 1.1 to be built from the modules if someone wanted to
create subsets or extensions (which is probably beyond the scope of
discussions here).

Finally, I probably should mention what xml1n.dcl is used for, as it's
inconsistently used in the /usr/share/xml tree:  whereas xml1.dcl is
the correct SGML Declaration to be used with XML, xml1n.dcl is necessary
when parsing with James Clark's SP toolkit (e.g., nsgmls). This is not
documented anywhere in the package and is certainly one of the more
arcane aspects of the XHTML distribution from W3C from whence this comes.
I.e., you wouldn't want to use xml1n.dcl with most other software, though
only no XML software would ever need to read an SGML declaration. By
definition all XML software implicitly uses the xml1.dcl declaration. No
variance is permitted and therefore its features are hardcoded into XML
itself. I know of no XML software that actually reads an SGML declaration,
but it is included for completeness, for XML as an SGML profile.

My apologies if any of this has been discussed recently -- I looked
through about six months of archives but didn't see any mention of the

I'm happy to supply corrected XML Catalog files if desired.



See: http://en.wikipedia.org/wiki/XML_Catalog
Murray Altheim <murray11 at altheim dot com>                       = =  ===
http://www.altheim.com/murray/                                     ===  ===
SGML Grease Monkey, Banjo Player, Wantanabe Zen Monk               = =  ===

       Boundless wind and moon - the eye within eyes,
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