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;
while ( $iter->() ) {
    print $_, $/;
}