private static Boolean parseBoolean(ListIterator<Character> chars) {
		String t = "true", f = "fals";
		StringBuilder b = new StringBuilder();
		while (chars.hasNext() && b.length() < 4) {
			b.append(Character.toLowerCase(chars.next()));
		}
		if (b.toString().equals(t))
			return true;
		else if (b.toString().equals(f)) {
			if (chars.hasNext()) {
				chars.next();
				return false;
			} else {
				return null;
			}
		} else {
			return null;
		}
	}