XML::SAX::Machines - manage collections of SAX processors

    use XML::SAX::Machines qw( :all );

    my $m = Pipeline(
        "My::Filter1",   ## My::Filter1 autoloaded in Pipeline()
        "My::Filter2",   ## My::Filter2     "       "      "
        \*STDOUT,        ## XML::SAX::Writer also loaded
    );

    $m->parse_uri( $uri ); ## A parser is autoloaded via
                           ## XML::SAX::ParserFactory if
                           ## My::Filter1 isn't a parser.

    ## To import only individual machines:
    use XML::SAX::Machines qw( Manifold );

    ## Here's a multi-pass machine that reads one document, runs
    ## it through 5 filtering channels (one channel at a time) and
    ## reassembles it in to a single document.
    my $m = Manifold(
        "My::TableOfContentsExtractor",
        "My::AbstractExtractor",
        "My::BodyFitler",
        "My::EndNotesFilter",
        "My::IndexFilter",
    );

    $m->parse_string( $doc );

SAX machines are a way to gather and manage SAX processors without going nuts. Or at least without going completely nuts. Individual machines can also be like SAX processors; they don't need to parse or write anything:

   my $w = XML::SAX::Writer->new( Output => \*STDOUT );
   my $m = Pipeline( "My::Filter1", "My::Filter2", { Handler => $w } );
   my $p = XML::SAX::ParserFactory->new( handler => $p );

More documentation to come; see XML::SAX::Pipeline, XML::SAX::Manifold, and XML::SAX::Machine for now.

Here are the machines this module knows about:

    ByRecord  Record oriented processing of documents.
              L<XML::SAX::ByRecord>

    Machine   Generic "directed graph of SAX processors" machines.
              L<XML::SAX::Machine>

    Manifold  Multipass document processing
              L<XML::SAX::Manifold>

    Pipeline  A linear sequence of SAX processors
              L<XML::SAX::Pipeline>

    Tap       An insertable pass through that examines the
              events without altering them using SAX processors.
              L<XML::SAX::Tap>

As mentioned in LIMITATIONS, you might occasionally need to edit the config file to tell XML::SAX::Machine how to handle a particular SAX processor (SAX processors use a wide variety of API conventions).

The config file is a the Perl module XML::SAX::Machines::SiteConfig, which contains a Perl data structure like:

    package XML::SAX::Machines::SiteConfig;

    $ProcessorClassOptions = {
        "XML::Filter::Tee" => {
            ConstructWithHashedOptions => 1,
        },
    };

So far CW$Processors is the only available configuration structure. It contains a list of SAX processors with known special needs.

Also, so far the only special need is the ConstructWithHashes option which tells XML::SAX::Machine to construct such classes like:

    XML::Filter::Tee->new(
        { Handler => $h }
    );

instead of

    XML::Filter::Tee->new( Handler => $h );

WARNING If you modify anything, modify only XML::SAX::Machines::SiteConfig.pm. Don't alter XML::SAX::Machines::ConfigDefaults.pm or you will lose your changes when you upgrade.

TODO: Allow per-app and per-machine overrides of options. When needed.