simple tree menu

<?
if(!defined("B_PROLOG_INCLUDED") || B_PROLOG_INCLUDED!==true)die();

$menuList = array();
$lev = 0;
$lastInd = 0;
$parents = array();
foreach ($arResult as $arItem) {
   $lev = $arItem['DEPTH_LEVEL'];
   
   if ($arItem['IS_PARENT']) {
      $arItem['CHILDREN'] = array();
   }
   
   if ($lev == 1) {
      $menuList[] = $arItem;
      $lastInd = count($menuList)-1;
      $parents[$lev] = &$menuList[$lastInd];
   } else {
      $parents[$lev-1]['CHILDREN'][] = $arItem;
      $lastInd = count($parents[$lev-1]['CHILDREN'])-1;
      $parents[$lev] = &$parents[$lev-1]['CHILDREN'][$lastInd];
   }
}
$arResult = $menuList;