CODEWITHSUNDEEP
iosswiftswift2
jonpeter
jonpeter

Reputation: 599

Swift 3.0 will not be 2.2 source compatible... will I have to rebuild my apps?

http://thenextweb.com/apple/2016/05/09/swift-3-0-developer-previews-wwdc/#gref

Does this mean anything? Will I have to completely rebuild my apps or merely convert 2.2 syntax to 3.0?

Upvotes: 0

Views: 441

Answers (4)

SevenBits
SevenBits

Reputation: 2874

@CodeDifferent provided a great answer, but I'd like to extend on it.

AFAIK, if your Swift 2 app is compiled with its own runtime linked in (i.e., not relying on the system runtime), then your app will run fine & there's no need to rebuild on a Swift 3 machine to run on a Swift 3 machine. But if there's no runtime compiled into the app, then your app won't run on a machine with a Swift 3 ABI.

Of course, if you are going to compile with application with Swift 3, then you will have to re-build.

Upvotes: -1

matt
matt

Reputation: 535138

I'm currently adapting all my code to the present state of Swift 3. The existing code is certainly not compatible; most methods have been renamed, case names have been lowercased, and so on. To what extent Apple will assist by providing a migration tool is unknown, as that's in the future.

Upvotes: 1

Code Different
Code Different

Reputation: 93161

I'd say no. Every Swift app comes with its own runtime and standard libraries of whatever Xcode version you used to build it. Some of my Swift 1.0 app still runs on the latest version of El Capitan.

Source incompatibility means you can't take valid code written in Swift 2, feed it to the Swift 3 compiler and expect everything to go smoothly. There will be errors and deprecation warnings, much of which you already see today with Swift 2.3.

You also can't take a compiled application written in Swift 2 and make it run without modification on a Swift 3 runtime either. Swift is lacking a stable Application Binary Interface (ABI) at the moment. That's why every Swift app must carry its own runtime. OS X and iOS don't provide those at the system level. Hence Swift app tends be larger in size, more of a problem on iOS than OS X.

With Swift 3, Apple is trying to establish a stable ABI so your compiled Swift 3 can run without modification on the Swift 4 runtime, whenever that comes.

What about source code compatibility? No one knows what Chris Lattner has in mind or what he considers archaic. Removing the ++ and -- operator in Swift 3 seem superfluous to me. And why kill C-style for loop too?

Upvotes: 2

sonique
sonique

Reputation: 4762

Swift 3.0 will not be compatible with 2.2. Here is the list of the current proposals, it also details what has been implemented already, and what will be :

https://github.com/apple/swift-evolution

You will not have to entirely rebuild your App, but you will have to adapt your code.

Upvotes: 3

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