#! perl -slw
use strict;
sub getIter{
  my ($start, $end, $aryRef) = @_;
  $end = $#$aryRef if $end == -1;
  return sub {
    return $aryRef->[$start++] if $start < $end;
    ();
  }
}
my @a = 1 .. 1000000;

my $iter = getIter 500000, 500005, \@a;
print while $_ = $iter->();
__END__
500001
500002
500003
500004
500005