Re: DOCBOOK-APPS: libxslt/xsltproc and XML catalogs (was Re: websitedtd newbie)

[Daniel Veillard <veillard@redhat.com>]

On Sat, Nov 24, 2001 at 06:04:42AM -0800, Alex Lancaster wrote:
> (By the way, if Daniel is listening in on this mailing list, a

  yup :-)

> suggestion might be to change the `--catalogs' option for xsltproc to
> `--sgml-catalogs' to avoid user confusion, because it seems to imply
> enabling of *all* catalog processing not just SGML.  It also seems to
> imply that XML catalogs set in the environment variable
> XML_CATALOG_FILES are *not* read if `--catalogs' is not supplied,
> which is *not* the case, they *are* always read, AFAICT).

  Well... There is some legacy, I added this options while XML Catalog
were not yet implemented in libxml, and at the time the name was not
confusing.
  And yes if XML Catalogs are installed, libxml will make use of them
by default (starting from $XML_CATALOG_FILES or /etc/xml/catalog if 
present). I think there is less legacy with them that enabling them
by default is safe (and enabling them by default won't add much burden
if the application use no or little part of them, which is not the
case for SGML Catalogs).
  Changing the option name is doable, but could annoy some existing
users, maybe I should improve the description of the option instead.

> <rewriteSystem
> systemIdStartString="http://docbook.sourceforge.net/release/xsl/snapshot/" rewritePrefix="file:///home/alex/packages/share/sgml/docbook-xsl-1.46-experimental/"/>
> 
> and it works!  (it resolves the first part of the URI and then uses
> the remaining [unmatched] suffix from the original URI, so no need to
> write multiple URIs for files in the same hierarchy).

  Well yes XML Catalog works really well, but this example might be wrong
with respect to the spec :-)

<!-- Disgression on XML Catalog
I disagree on the split between the System/Uri handling in the XML Catalog
spec and in this case this is typically an URI-Reference and not an
entity lookup and what would be needed per the spec is actually a rewriteUri 
instruction and not a rewriteSystem, unfortunately so far the XML Catalog
comitee refuses to admit that an URI reference is an URI reference
and that the resolution mechanism should be unified.
As a result I suggested the Tim Waugh (Red Hat DocBook packager) and 
I'm afraid it will have to become a rule that all rewriteSystem should
be duplicated as rewriteUri to avoid troubles by pedantic XML Catalog
implementations (and similar for others System related instructions).
     End of the disgression -->

  Except for this annoying but not critical point, XML Catalog indeed rocks !

Daniel

-- 
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