Salve a tutti, c'è qualche volenteroso che è in grado di spiegarmi che cosa fa esattamente questo script?

codice:
use lib '../lib/';
use NoCat qw( ANONYMOUS );
use strict;

my $authserv	= NoCat->auth_service( ConfigFile => $ENV{NOCAT} );
my $cgi		= $authserv->cgi;
my $params	= $cgi->Vars;

# Debug configuration setup.
$authserv->check_config(qw( 
    LoginForm FatalForm RenewForm LoginOKForm ExpiredForm
    LoginGreeting LoginMissing LoginBadUser LoginBadPass
));

$authserv->log( 7, sprintf( "User %s from %s requests %s", 
    $params->{user} || "UNKNOWN", $cgi->remote_host, 
    lc( $params->{mode} ) || "form" ) 
);

# Figure out which image button was clicked (since they don't have value="" attributes).
if (my ($button) = grep { defined $params->{"mode_$_.x"} } qw( login skip logout )) {
    delete $params->{$_} for ( "mode_$button.x", "mode_$button.y" );
    $params->{mode} = $button;
}

# Have we filled in the form yet?  No?  If not, present one.
$authserv->display( LoginForm => "LoginGreeting" ) unless $params->{mode};