my $extract;
my $file;
{
    local @ARGV;

    foreach my $key ( param ) {
        if ( param($key) ) {
            foreach my $value ( param($key) ) {
                push @ARGV, $key, $value;
            }
        } else {
              # arg-less booleans
            push @ARGV, $key;
        }
    }

    GetOptions(
        'file=s'   => \$file,
        'extract!' => \$extract,
    );
}