Re: DOCBOOK-APPS: libxslt/xsltproc and XML catalogs

[Daniel Veillard <veillard at redhat dot com>]

Hum, it's getting off-topic for DOCBOOK-APPS, no ? I'm Cc'ing the
XML Catalog comment list.

On Sat, Nov 24, 2001 at 08:00:41PM -0800, Alex Lancaster wrote:
> DV> <!-- Disgression on XML Catalog I disagree on the split between
> DV> the System/Uri handling in the XML Catalog spec and in this case
> DV> this is typically an URI-Reference and not an entity lookup and
> DV> what would be needed per the spec is actually a rewriteUri
> DV> instruction and not a rewriteSystem, unfortunately so far the XML
> DV> Catalog comitee refuses to admit that an URI reference is an URI
> DV> reference and that the resolution mechanism should be unified.  As
> DV> a result I suggested the Tim Waugh (Red Hat DocBook packager) and
> DV> I'm afraid it will have to become a rule that all rewriteSystem
> DV> should be duplicated as rewriteUri to avoid troubles by pedantic
> DV> XML Catalog implementations (and similar for others System related
> DV> instructions).  End of the disgression -->
> 
> I'm a bit confused, does this mean that I will need to put both

  Me too about the where the distinction between URI and System really is,
so far I didn't got a good answer :-)

  http://www.oasis-open.org/committees/entity/issues-15.html
  Issue 30
  "because they are different" ... ah !
   
> rewriteSystem and rewriteURI into the catalog, something like:
> 
> <rewriteSystem
>  systemIdStartString="http://docbook.sourceforge.net/release/xsl/snapshot/";
>  rewritePrefix="file:///home/alex/packages/share/sgml/docbook-xsl-1.46-experimental/"/>
> 
> <rewriteURI
>  URIStartString="http://docbook.sourceforge.net/release/xsl/snapshot/";
>  rewritePrefix="file:///home/alex/packages/share/sgml/docbook-xsl-1.46-experimental/"/>
> 
> or will I merely need to change all <rewriteSystem>s to <rewriteURI>s
> to  get the effect I want?

  Possibly, in theory. I assume that if you use the URI on the command
line or in the stylesheet PI of an XML document, only the URI based 
XML Catalog lookup should be done.

> Can you outline the mechanism/spec proposed by the XML catalog
> committee and how this differs from your current implementation, and
> what you think needs to be done?

  I can't really speak for the XML catalog committee, Norm can probably try
to clarify things. In practice since I hinted that people would have troubles
understanding this distinction too, I simply modified my XML Catalog resolution
mechanism to always do a System lookup, and then fallback to an URI lookup
if the first failed. IMHO all this is completely redundant since the algorithm
and data for URI and System resolution when there is no public ID are strictly
of similar nature.
  My issue was rejected, I still don't understand, it's likely to bite
other people, so I decided to be pessimistic, expect errors and correct
them in my implementation.

    Sorry for the off-topic-ness of this thread, I'm ready to shut-up on
this issue if anybody requests it :-)

Daniel

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