CRestUtil::processBatchElement

static function processBatchElement($query, $arResult, $keysCache = '')
{
	$regexp = "/\$(".$keysCache.")([^s]*)/i";

	if(preg_match_all($regexp, $query, $arMatches, PREG_SET_ORDER))
	{
		foreach($arMatches as $arMatch)
		{
			$path = $arMatch[2];
			if(preg_match_all("/\[([^\]]+)\]/", $path, $arPath))
			{
				$r = $arResult[$arMatch[1]];

				while(count($arPath[1]) > 0)
				{
					$key = array_shift($arPath[1]);
					if(isset($r[$key]))
					{
						$r = $r[$key];
					}
					else
					{
						break;
					}
				}
				if($arMatch[0] === $query)
				{
					$query = $r;
				}
				else
				{
					if (is_numeric($r))
					{
						$r = (string)$r;
					}

					if (!is_string($r))
					{
						continue;
					}
					$query = str_replace($arMatch[0], $r, $query);
				}
			}
		}
	}

	return $query;
}