Iterative destruction of JSON containers (objects and arrays) - #1431

               case value_t::object:
               {
                    if (!this->object->empty())
                    {
                         destroy_subelements_depth_first(this);
                    }

                    AllocatorType<object_t> alloc;
                    std::allocator_traits<decltype(alloc)>::destroy(alloc, object);
                    std::allocator_traits<decltype(alloc)>::deallocate(alloc, object, 1);
                    break;
                }
                //// Ditto for array ....

void destroy_subelements_depth_first(json_value *value)
{
    std::vector<std::pair<json_value*, value_t>> stack;
    stack.emplace_back(this, t);
    while (!stack.empty())
    {
        json_value* value;
        value_t type;
        std::tie(value, type) = stack.back();
        bool all_done;
        if (type == value_t::object)
        {
             all_done = destroy_object_subelements(stack, value);
        }
        else
        {
             all_done = destroy_array_subelements(stack, value);
        }
        if (all_done)
        {
             stack.pop_back();
        }
    }
}