Class exception

examples/server/json.hpp:4300–4394

@brief general exception of the @ref basic_json class @sa https://json.nlohmann.me/api/basic_json/exception/

/// @brief general exception of the @ref basic_json class
/// @sa https://json.nlohmann.me/api/basic_json/exception/
class exception : public std::exception
{
  public:
    /// returns the explanatory string
    const char* what() const noexcept override
    {
        return m.what();
    }

    /// the id of the exception
    const int id; // NOLINT(cppcoreguidelines-non-private-member-variables-in-classes)

  protected:
    JSON_HEDLEY_NON_NULL(3)
    exception(int id_, const char* what_arg) : id(id_), m(what_arg) {} // NOLINT(bugprone-throw-keyword-missing)

    static std::string name(const std::string& ename, int id_)
    {
        return concat("[json.exception.", ename, '.', std::to_string(id_), "] ");
    }

    static std::string diagnostics(std::nullptr_t /*leaf_element*/)
    {
        return "";
    }

    template<typename BasicJsonType>
    static std::string diagnostics(const BasicJsonType* leaf_element)
    {
#if JSON_DIAGNOSTICS
        std::vector<std::string> tokens;
        for (const auto* current = leaf_element; current != nullptr && current->m_parent != nullptr; current = current->m_parent)
        {
            switch (current->m_parent->type())
            {
                case value_t::array:
                {
                    for (std::size_t i = 0; i < current->m_parent->m_value.array->size(); ++i)
                    {
                        if (&current->m_parent->m_value.array->operator[](i) == current)
                        {
                            tokens.emplace_back(std::to_string(i));
                            break;
                        }
                    }
                    break;
                }

                case value_t::object:
                {
                    for (const auto& element : *current->m_parent->m_value.object)
                    {
                        if (&element.second == current)
                        {
                            tokens.emplace_back(element.first.c_str());
                            break;
                        }
                    }