[sime2009]

But why?

Sure, there are people who want to tinker with it for fun, but outside of that what is the point in having Swift on Linux and Windows?

You can't use it to build mac or iOS apps on Linux because the important libraries aren't there. There is no cross platform UI and Apple isn't likely to port and support theirs from macOS. If you are into servers then you have plenty of better languages options with established ecosystems. Maybe there are some command line apps on macOS which can now be ported to Linux/Window, but beyond that, what is the point? Where is Apple trying to go with this?

[ElFitz]

It's a fully fledged programming language. An open-source programming language, at that, with a lot of community input and involvement.

Not a macOS or iOS app creation DSL.

It's also quite pleasant to use, and has already seen a few uses beyond macOS and iOS apps, including some backend development (Vapor, Kitura, SwiftNIO, probably others).

So you could use it to write command line tools. To write Linux or Windows apps. Or to write servers. Just like any other programming language.

[jbverschoor]

I'd say swift is currently probably the best languages out there. Language features, standard library, performance, memory management.

[blauditore]

I'm curious, how do people judge this?

Personally I have some significant experience with maybe 5 different languages, which is already more diverse than the average software dev as far as I know. But I still wouldn't be comfortable to judge something like this.

For instance, I haven't worked with Swift, but I find it hard to believe it's much better than, say, C#, Scala, or Typescript, regarding those metrics. Do you have experience in those languages?

[dimatura]

It's subjective, naturally. I don't know if I'd be that enthusiastic, but I definitely like it a lot.

My main languages are Python and C++. I've also used Java, C#, Javascript but not Typescript, among others.

In my opinion Swift does a pretty good job at striking a balance between expressiveness/usability, safety and performance. If it gets more traction under Linux (including a larger ecosystem and better tooling around it) I'd definitely consider it for projects where Python could become a bottleneck but C++-level performance is not absolutely required.

On the other hand, other languages in a similar niche - Rust, Go, even D or Nim? are already more established outside of iOS/MacOS, so I don't know. My experience with Swift has definitely made me more interested in learning Rust, which seems quite similar in some respects.

[DagAgren]

Agreed. I have not seen any other language that is as pleasant to use. It is not perfect, but everything else is even further from perfect.

[skohan]

I use it for all kinds of things, like computer graphics and various tools in my CLI-driven workflows.

I find it nice to work with, because it has a lot of the nice features Rust does, like affine types, 1st class optional handling, decent single-threaded safety guarantees, and it has a very nice, ergonomic interface. Generally the performance characteristics are not what you would get with Rust, but I am generally more productive in Swift because I don't have to worry about the low level details.

There's definitely some downsides - cross platform support being one of them - but if I'm just working on a tool for me myself to use, I will generally reach for Swift because it's pleasant to work with. I would be happy if I could use it for projects which need to be deployed across different platforms.

[HacklesRaised]

I was not aware that swift had affine types. Never been a big fan of Swift, I loved objective-c, so there is some built in bias there.

[jmull]

> But why?

This is basic foundation building. It's true there aren't too many good use-cases for Swift on Windows or Linux now. But that can't really start to change until Swift has decent support for Windows and Linux.

Of course, it will take a lot more than this for Swift to catch on outside of its home territory. This is just one necessary step.

More broadly, I think we're still in the middle of the language wars, where the limitations of the historically dominant languages (like C, C++, Java, Javascript) have created openings for one or more newer languages. I think Apple and other Swift proponents would like Swift to become one of those newer established languages and take steps like these to at least keep it in the running.

[MattDamonSpace]

They’re looking to build demand over time by making Swift available in as many places as possible.

And this is the Swift Open Source team, not Apple specifically. It’s not an Apple business decision (aside from lowering the learning hurdle for new iOS projects)

Not to mention there’s Swift for TensorFlow, would be nice if you could handle your code locally on a Windows machine: https://github.com/tensorflow/swift/blob/master/docs/WhySwif...

[m463]

Exactly. Why would you buy into a language that is controlled by apple?

Apple's behavior with open source is kind of "throw it over the wall" which isn't really good leadership.

The good stuff at apple is frameworks and apps, none of it released.

For examples of this, look at Darwin on https://opensource.apple.com

They provide some sources, but they are not complete and are more to look at than to use.

I figure this got through the approval process because it could plausibly get developers to pay attention to apple without letting others exit the apple ecosystem.

[mfDjB]

I've begun using Swift for Linux to build sites on Publish (https://github.com/JohnSundell/Publish) on my CI.

[manmal]

Apple has to ensure that Swift is adopted as widely as possible to ensure that enough people in the world are theoretically able to submit apps to their store.

[saagarjha]

Nobody is submitting Windows apps written in Swift to the Mac App Store.

[manmal]

That’s not what I implied. Without a vibrant app ecosystem, way less iDevices would be sold. Without developers, the ecosystem suffers.

[pjmlp]

And without Mac hardware their sales suffer.