protected function _changeDelimiter($tag_name, $leading, $trailing) {
		list($otag, $ctag) = explode(' ', $tag_name);
		$this->_otag = $otag;
		$this->_ctag = $ctag;

		$this->_tagRegEx = $this->_prepareTagRegEx($this->_otag, $this->_ctag);

		if ($leading !== null && $trailing !== null) {
			if (strpos($leading, "\n") === false) {
				return '';
			}
			return $this->_stringHasR($leading, $trailing) ? "\r\n" : "\n";
		}
		return $leading . $trailing;
	}