row filling code

Hi All,

Can you please help me to explain on this?

<?if:not(count($invLines) mod $lpp=0) and ($start+$lpp>count($invLines))?>

<?for-each:$invLines?>

<?if:position()<$lpp - (count($invLines) mod $lpp)?>

<?end if?>

<?end for-each?>

<?end if?>

$invLines  -->12 lines

$invLines -->30 per page defined.

so what is not(count($invLines)?  what is $start used for? what is position()?

could you please help me how the above code is working , step by step please. i just want to know on this.

Thanks much!