private Object maybeReadSymbol(int cfaslOpcode) throws IOException {
    switch (cfaslOpcode) {
      case CFASL_KEYWORD:
        // Keywords can be distinguished from Symbols by internal evidence
        return readKeyword();
      case CFASL_SYMBOL:
        return readSymbol();
      case CFASL_NIL:
        return CycObjectFactory.nil;
      default:
        return null;
    }
  }