# $Id: ZOOM.pod,v 1.3 2005-11-15 17:33:04 mike Exp $

use strict;
use warnings;

=head1 NAME

ZOOM - Perl extension implementing the ZOOM API for Information Retrieval

=head1 SYNOPSIS

 use ZOOM;
 eval {
     $conn = new ZOOM::Connection($host, $port)
     $conn->option(preferredRecordSyntax => "usmarc");
     $rs = $conn->search_pqf('@attr 1=4 dinosaur');
     $n = $rs->size();
     print $rs->record(0)->render();
 };
 if ($@) {
     print "Error ", $@->code(), ": ", $@->message(), "\n";
 }

=head1 DESCRIPTION

This module provides a nice, Perlish implementation of the ZOOM
Abstract API described at http://zoom.z3950.org/api/

the ZOOM module is implemented as a set of thin classes on top of the
non-OO functions provided by this distribution's C<Net::Z3950::ZOOM>
module, which in 
turn is a thin layer on top of the ZOOM-C code supplied as part of
Index Data's YAZ Toolkit.  Because ZOOM-C is also the underlying code
that implements ZOOM bindings in C++, Visual Basic, Scheme, Ruby, .NET
(including C#) and other languages, this Perl module works compatibly
with those other implementations.  (Of course, the point of a public
API such as ZOOM is that all implementations should be compatible
anyway; but knowing that the same code is running is reassuring.)

The ZOOM module provides two enumerations (C<ZOOM::Error> and
C<ZOOM::Event>), a single utility function C<diag_str()> in the C<ZOOM>
package itself, and eight classes:
C<ZOOM::Exception>,
C<ZOOM::Options>,
C<ZOOM::Connection>,
C<ZOOM::Query>,
C<ZOOM::ResultSet>,
C<ZOOM::Record>,
C<ZOOM::ScanSet>
and
C<ZOOM::Package>.
Of these, the Query class is abstract, and has two concrete
subclasses:
C<ZOOM::Query::CQL>
and
C<ZOOM::Query::PQF>.
Many useful ZOOM applications can be built using only the Connection,
ResultSet and Record classes, as in the example code-snippet above.

A typical application will begin by creating an Connection object,
then using that to execute searches that yield ResultSet objects, then
fetching records from the result-sets to yield Record objects.  If an
error occurs, an Exception object is thrown and can be dealt with.
More sophisticated applications might browse the server's indexes to
create a ScanSet, from which indexed terms may be retrieved; others
might send ``Extended Services'' Packages to the server, to achieve
non-standard tasks such as database creation and record update.
Searching using a query syntax other than PQF can be done using an
query object of one of the Query subclasses.  Finally, sets of options
may be manipulated independently of the objects they are associated
with using an Options object.


=head1 SEE ALSO

The C<Net::Z3950::ZOOM> module, included in the same distribution as this one.

The C<Net::Z3950> module, which this one supersedes.

=head1 AUTHOR

Mike Taylor, E<lt>mike@indexdata.comE<gt>

=head1 COPYRIGHT AND LICENCE

Copyright (C) 2005 by Index Data.

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself, either Perl version 5.8.4 or,
at your option, any later version of Perl 5 you may have available.

=cut

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