is::makeTypeGroupFile

private function makeTypeGroupFile($file = '')
{
	$fd = $this->fileOpen(strlen($file) ? $file : self::GROUP_FILE);

	fputs($fd, implode(';', $this->headers['GROUP_FILE']).PHP_EOL);
	foreach($this->typeGroups as $code => $group)
	{
		$line = array();
		foreach($this->headers['GROUP_FILE'] as $colCode)
			$line[] = is_array($group[$colCode]) ? implode(':', $group[$colCode]) : $group[$colCode];

		fputs($fd, implode(';', $line).PHP_EOL);
	}

	fclose($fd);
}