I really wish Swift could find a way to be useful on platforms other than Apple. I'd be willing to commit more to it if I could write truly portable code in it. It's got a good start on Linux, but Windows and Android would be cool too. Though Kotlin won out over Swift for Android (very similar languages but I like Swift a bit better there).

It's probably going to end up similar to the equally hyped objectiveC where the core language was made portable but few of the tooling/API's used for real world OSX applications ended up supporting anything but OSX in any production ready capacity despite GNUSTEP actually shipping a ObjetiveC/OpenSTEP clone for Linux.

For the time being swift on Linux is a case of a few PaaS vendors trying to product differentiate by also offering swift frameworks because they can(due to modern container wrangling) more then due to any real market demand.

amorde

One of the biggest causes of this for Objective-C was the lack of the Foundation framework (a higher-level interface to Core Foundation) - but this is being reimplemented in Swift. See https://github.com/apple/swift-corelibs-foundation

Of course UIKit will still be missing, but thats sort of expected.