traversal_3_fold_summarizing.cpp

auto to_nice_result = [](auto min, auto avg, auto big) {
   return batch_result{ min, avg.m_value, big.m_count };
};

auto typed = apply(to_nice_result, fold_result);
std::cout
  << "Result summary:\n"
  << " - Minimum: " << typed.m_minimum << "\n"
  << " - Average: " << typed.m_average << "\n"
  << " - Variations: " << typed.m_variation_count << "\n";