#!/usr/bin/perl

=head1 NAME

xml2marc - convert LC SlimSchema XML to MARC21 

=head1 SYNOPSIS

    # convert a file 
    % xml2marc marc.xml > marc.dat.

    # or use in a pipeline
    % cat marc.xml | xml2marc > marc.dat 

=head1 DESCRIPTION

xml2marc is a command line utility for converting XML that uses the Library of
Congress Slim Schema to MARC21 bibliographic data. Conversion is handled using
the MARC::Record and MARC::File::XML packages.

=cut

use strict;
use warnings;
use MARC::Batch;
use MARC::File::XML;

my $file = shift;
my $fh;

## read from a file?
if ( $file ) { 
    fatal( "no such file: $file" ) if ! -r $file;
    $fh = IO::File->new( $file );
} 

## or from STDIN?
else {
    $fh = \*STDIN;
}

## set up intput/output for utf8 encoding
binmode( STDOUT, ':bytes' );
binmode( $fh, ':utf8' );

my $batch = MARC::Batch->new( 'XML', $fh );
while ( my $record = $batch->next() ) { 
    print $record->as_usmarc();
}

sub fatal {
    print STDERR shift, "\n";
    exit( 1 );
}