DOCBOOK-APPS: A "search path" for XSL files (Was: XML catalogdocumentation)

[Steinar Bang <sb at dod dot no>]

>>>>> Bob Stayton <bobs@caldera.com>:

> I've rewritten my chapter on using XML catalogs with DocBook XSL so
> that it is more complete and accurate.  It is available at

> http://www.sagehill.net/xml/docbookxsl/Catalogs.html

> Comments welcome.

Is there a way of achiveing a "search path" for XSL files using XML
Catalogs. 

Eg. if some machines have DocBook XSL 1.48 installed in
	/var/www/html/xml/styles/xsl/docbook-xsl-1.48/
and some machines have DocBook XSL 1.60.1 installed in
	/var/www/html/xml/styles/xsl/docbook-xsl-1.60.1/
is there a way to create a single XML Catalog file that can be used on
both directory structures in such a way that
	http://docbook.sourceforge.net/release/xsl/current/
will find the 1.60.1 on those machines that have it, and 1.48 on those
machines that have it?

It doesn't look like this is possible.

The way I would have tried doing it would be to do this, in the hope
that the resolver would do a rewrite according to the first
<rewriteURI>, test if a match could be found, and if not, move on to
the next <rewriteURI>:

  <rewriteURI
    uriStartString="http://docbook.sourceforge.net/release/xsl/current";
    rewritePrefix="/var/www/html/xml/styles/xsl/docbook-xsl-1.60.1"/>

  <rewriteURI
    uriStartString="http://docbook.sourceforge.net/release/xsl/current";
    rewritePrefix="/var/www/html/xml/styles/xsl/docbook-xsl-1.48"/>

However, if I read
 http://www.oasis-open.org/committees/entity/spec-2001-08-06.html#s.uri.resx
correctly, a resolver will just do the rewrite in the first rule (or possibly
the order is undefined?), and then return with the rewritten URI.