use strict;
use warnings;
use feature 'say';


my $i = Iterator->new([1,0,2,undef,3]);

while ( <$i> ) {
    say "<$_>";
}


package Iterator;

use overload
  '<>' => sub {
      shift @{$_[0]}
  };

sub new {
    my ($class,$obj) =@_;
    bless $obj, $class;
}

##</code><code>##

<1>
<0>
<2>