#!/usr/bin/perl -w

use strict;

use Getopt::Long;
use Data::Dumper;

$| = 1;

my (@foo);
my ($bar);
my $baz = 0;
my $bop = 0;
my $quux;

if ( scalar( grep( /^-/, @ARGV ) ) ) {
    GetOptions(
        'foo:s'   => \@foo,
        'bar:s'   => \$bar,
        'baz+'    => \$baz,
        'gazonk+' => sub { $bop = !$bop; $bop += 0; },
        'quux' => sub { $quux = scalar localtime; },
        'help' => \&help,
    );
    @foo = split( /,/, join( ',', @foo ) );

    print Data::Dumper->Dump(
        [ \@foo, \$bar, \$baz, \$bop, \$quux ],
        [qw(*foo *bar *baz *bop *quux)]
        ),
        qq{\n};

    if ( !$baz ) {
        if ( !scalar(@foo) ) {
            &help;
        }
        if ( ( !defined($bar) ) or ( !length($bar) ) ) {
            &help;
        }
    }
}
else {
    &help;
}

sub help {
    printf <<HELPTEXT, $0, ( 'alice[,bob,eve]', 'xyzzy' ) x 2;

%s [-foo %s] [-bar %s] [-baz] [-gazonk] [-quux] [-help]

    -foo %s - one or more options, either comma-separated
                or the option listed more than once
    -bar %s - another option
    -baz    - a flag
    -gazonk - another flag, trying to flip on/off
    -quux   - option which results in a subroutine being called
    -help   - display this help text

HELPTEXT
    exit;
}