public String toString() {
		if (value instanceof String) {
			return "\"" + value.toString() + "\"";
		}
		else if (value instanceof ListInstance) {
			return "[" + value.toString() + "]";
		}
		else if (value instanceof Instance) {
			return "{" + value.toString() + "}";
		}
		if (value == null) {
			return "null";
		}
		return value.toString();
	}