But that _is_ true: the Foundation library — which because Swift has a super small core library is really kind of critical to basically any kind of program — be

But that _is_ true: the Foundation library — which because Swift has a super small core library is really kind of critical to basically any kind of program — behaves differently on Linux. I write Swift code that runs on Linux and also on macOS or iOS, and we frequently have to have sections of "if Linux, run this code, else run this other code". And while that's trivial to write, it's not trivial to find all the places where you have to do that. (Nevertheless, I like Swift a lot and am using it on Linux.)