Function unflatten

include/behaviortree_cpp/contrib/json.hpp:14611–14637

    */
    template<typename BasicJsonType>
    static BasicJsonType
    unflatten(const BasicJsonType& value)
    {
        if (JSON_HEDLEY_UNLIKELY(!value.is_object()))
        {
            JSON_THROW(detail::type_error::create(314, "only objects can be unflattened", &value));
        }

        BasicJsonType result;

        // iterate the JSON object values
        for (const auto& element : *value.m_data.m_value.object)
        {
            if (JSON_HEDLEY_UNLIKELY(!element.second.is_primitive()))
            {
                JSON_THROW(detail::type_error::create(315, "values in object must be primitive", &element.second));
            }

            // assign value to reference pointed to by JSON pointer; Note that if
            // the JSON pointer is "" (i.e., points to the whole value), function
            // get_and_create returns a reference to result itself. An assignment
            // will then create a primitive value.
            json_pointer(element.first).get_and_create(result) = element.second;
        }

        return result;
    }

    // can't use conversion operator because of ambiguity
    json_pointer<string_t> convert() const&