XML::Catalog - Resolve public identifiers and remap system identifiers

       Current Author:

               Jeff Fearn E<lt>jfearn@cpan.orgE<gt>.

       Former Authors:

               Eric Bohlman E<lt>ebohlman@netcom.comE<gt>.

       Searching  of  chained  catalogs  is  not  purely  depth-first (EXTEND items in a chained catalog will be
       searched before EXTEND items in the original catalog.

       Error checking leaves much to be desired.

       new(URL [,URL]*)
           Read the catalog identified by URL and return a catalog object implementing it.  If more than one URL
           is  given,  chain  the additional catalogs as extensions to the catalog (they will be searched before
           catalogs specified by EXTEND entries).

           All URLs must be absolute.  A URL with no protocol is treated as a filename.

       Copyright (c) 1999-2000 Eric Bohlman.  All rights reserved.  Copyright (c) 2013 Jeff  Fearn.  All  rights
       reserved.

       This program is free software; you can use/modify/redistribute it under the same terms as Perl itself.

perl v5.34.0                                       2022-06-28                                  XML::Catalog(3pm)

       This module implements draft 0.4 of John Cowan's XML Catalog (formerly known as XCatalog) proposal
       (<http://www.ccil.org/~cowan/XML/XCatalog.html>).  Catalogs may be written in either SOCAT or XML syntax
       (see the proposal for syntax details); XML::Catalog will assume SOCAT syntax if the catalog is not in
       well-formed XML syntax.

       This module, as of 1.0.0, also supports Oasis XML catalogs.

       add(URL [,URL]*)
           Chain the catalogs identified by the URL(s) to the current catalog.

       resolve_public(PUBID)
           Translate the public identifier PUBID to a system identifier.  Returns undef if the identifier  could
           not be translated.

       remap_system(SYSID)
           Remap  the  system  identifier  SYSID  as  specified  by  the catalog.  Returns SYSID unchanged if no
           remapping was found.

       get_handler(PARSER)
           Returns a coderef to a resolver suitable for use as the ExternEnt handler for an XML::Parser  object.
           The resolver will first attempt to resolve a public identifier if supplied, and then attempt to remap
           the  resulting  system  identifier  (or  the  original  system identifier if no public identifier was
           supplied).  It will then call the original ExternEnt  handler  associated  with  the  parser  object.
           PARSER is the parser object; it is needed as an argument in order to obtain the original handler.

       add_delegate($pubid,  $href)
           TBD

       add_extend($href)
           TBD

       add_extend_object($cat, $group )
           TBD

       add_map($pubid,  $href)
           TBD

       add_remap($sysid,  $href)
           TBD

       build($url)
           create new catalog object

       fix_base($url)
           TBD

       parse
           TBD

       parse_SOCAT($ct)
           TBD

       parse_XML($ct)
           TBD

       set_base($href)
           TBD

       XML::Catalog - Resolve public identifiers and remap system identifiers

         use XML::Catalog;
         my $catalog=XML::Catalog->new('/xml/catalog.cat');
         $catalog->add('http://www.w3.org/xcatalog/mastercat.xml');
         my $sysid=$catalog->resolve_public('-//John Cowan//LOC Diacritics');
         my $newsysid=$catalog->remap_system('http://www.w3.org');
         $parser->setHandlers(ExternEnt=>$catalog->get_handler($parser));

   OasisExample
         $ perl -e 'use XML::Catalog; \
         $pubid = q|-//OASIS//DTD DocBook XML V4.5//EN|; \
         my $catalog=XML::Catalog->new("/etc/xml/catalog"); \
         print $catalog->resolve_public($pubid), "\n";'

         file:///usr/share/sgml/docbook/xml-dtd-4.5-1.0-51.el6/docbookx.dtd