Proper digit separators in C++

Have you ever hoped that C++ would have digit separators? That you wouldn’t have to strain your eyes when reading 2147483647 (is it std::numeric_limits<int32_t>::max(), or is it just similar)? That you wouldn’t have to count the zeros 5 times when typing 1000000000?

Well, the C++ Standards Committee doesn’t have your back. Oh, sure, they have introduced a digit separator, – , but it’s completely unusable in production code! Here’s why.