String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */
  LOWER_UNDERSCORE(CharMatcher.is('_'), "_") {
    @Override

    String convert(CaseFormat format, String s) {
      if (format == LOWER_UNDERSCORE) {
        return s.replace('-', '_');
      }
      if (format == UPPER_UNDERSCORE) {
        return Ascii.toUpperCase(s.replace('-', '_'));
      }
      return super.convert(format, s);
    }
  },

  /** C++ variable naming convention, e.g., "lower_underscore". */
  LOWER_UNDERSCORE(CharMatcher.is('_'), "_") {
    @Override

    protected Map<String, Object> toLowerHyphen(final Map<String, Object> source) {
        return source.entrySet()
                .stream()
                .collect(Collectors.toMap(e -> CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_UNDERSCORE, e.getKey()), e -> {
                    final Object value = e.getValue();
                    if (value instanceof Map) {
                        @SuppressWarnings("unchecked")