my $str = "foo:bar:";

my( $a, @options ) = split /:/, $str;
my( $b, $c, $d )   = split /:/, $str;

use Data::Dumper;
print Dumper( [ $a, \@options ] );
print Dumper( [ $b, $c, $d ] );

##</code><code>##

$VAR1 = [
          'foo',
          [
            'bar'
          ]
        ];
$VAR1 = [
          'foo',
          'bar',
          ''
        ];

##</code><code>##

my( $a, @options ) = ( "foo", "bar", "" );
my( $b, $c, $d )   = ( "foo", "bar", "" );

use Data::Dumper;
print Dumper( [ $a, \@options ] );
print Dumper( [ $b, $c, $d ] );

##</code><code>##

$VAR1 = [
          'foo',
          [
            'bar',
            ''
          ]
        ];
$VAR1 = [
          'foo',
          'bar',
          ''
        ];