[roenxi]

> It might be a bit extreme but the more I'm exposed to operator overloading the more I think that it's a bad idea 99% of the time.

Quite a moderate position in practice. There are a substantial number of programmers who enjoy being able to tell what basic syntax does from memory without having to cross-reference documentation and source files.

And as you allude to, the example in question isn't a sum; it is an append. It would be far more appropriate to have an a = append(a, {1,2,3,4,5}) style construct. Or something with pointers if efficiency is important. Or construct the vector inline in older versions of C++. The += should be reserved for actual vector summing.

This whole article stands as a reminder that C++ is a remarkable language, and is starting to make up a lot of ground on achieving feature parity with Common Lisp.