Method Add

cpp/src/arrow/type.cc:2189–2202

      size_t size() const { return referents.size(); }

      void Add(const FieldPath& prefix, const FieldPath& suffix,
               const FieldVector& fields) {
        auto maybe_field = suffix.Get(fields);
        DCHECK_OK(maybe_field);
        referents.push_back(std::move(maybe_field).ValueOrDie());

        std::vector<int> concatenated_indices(prefix.indices().size() +
                                              suffix.indices().size());
        auto it = concatenated_indices.begin();
        for (auto path : {&prefix, &suffix}) {
          it = std::copy(path->indices().begin(), path->indices().end(), it);
        }
        prefixes.emplace_back(std::move(concatenated_indices));
      }
    };

    std::vector<FieldPath> operator()(const std::vector<FieldRef>& refs) {