just a thought: it's not really the index you're interested in. you just want to loop over more than one array in parallel and perl provides no operator for this. other than writing a sub which messes with lots of array and code refs do any of the perl gurus know of some idiom for this? here's the sub i'd use (untested):

sub arrloop {
  my ($arrays, $code) = @_;
  # keep calling code until we've been through all of the 
  # arrays.
  for (my $i = 0; 
       grep { $i <= scalar(@$_) } @$arrays; 
       $i++) {
    $code->(map { $_->[$i] } @$array);
  }
}
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which i could use like this:

arrloop [\@first, \@middle, \@last], sub {
  my ($first, $middle, $last) = @_;
  print "Hello $first $middle $last\n";
}
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this is just as contrived an examples as Limbic~Region's example, but my question is about iterating over arrays, not proper choice of data structures. if i'm not mistaken perl6's for will solve this.

Edit: s/PRE/CODE/ tags. larsen