@Override
	protected String readLineInternal() throws IOException {
		String s = super.readLineInternal();
		if (s == null) {
			return null;
		}
		Matcher m = endifPattern.matcher(s);
		if (m.find()) {
			return null;
		}
		m = elsePattern.matcher(s);
		if (m.find()) {
			do {
				s = readLine();
				if (s == null) {
					return null;
				}
				m = endifPattern.matcher(s);
				if (m.find()) {
					return null;
				}
			} while (true);
		}
		return s;
	}