I'm working on a game. I have a templated 2D vector implementation. Tile positions use Vector2<int>, entity positions and such use Vector2<float>.

I wanted a map from tile position to something else. I found that I had to implement operator<, because std::map uses operator<. That's an issue, because:

1. I didn't want to implement every single possible comparison operator just to put vectors in an array, but also didn't want to arbitrarily make `foo < bar` legal but `foo > bar` illegal.

2. What does it even mean for one vector to be "bigger than" another vector? For vector math purposes, I'd maybe expect operator< to compare magnitudes, but that would be absolutely terrible for std::map. Not everything has an unambiguous concept of "smaller than".

In the end I just made a std::map<std::pair<int, int>> and added an implicit conversion from Vector2<T> to std::pair<T, T>.