[cballard]

Objective-C bridges to and from Swift easily, so it would be easily to incrementally replace Objective-C code with Swift code. Since C++ doesn't interact with Swift at all, it would either have to be wrapped in C/Objective-C, or the entire compiler would need to be rewritten at once.

That being said, C++ is probably a better choice, because dynamic dispatch sucks and there's better platform support.