Swift language opinions

[John H]

Hello everyone,

I've been interested in iOS programming for some time but Objective-C was never an appealing language to me. For this reason, I was happy to see Apple announce Swift. I would like to know what the group thinks of Swift. Any serious limitations compared to OC? Advantages? 

Thanks

John

[Randy Hsiao]

I've only played with Swift a bit, but so far I like it more than Obj-C.

1. Simpler syntax. In general function/variable/constant/class names not as verbose. Easier to read.

2. Safer. Type can be inferred, but not implicitly converted. People say it's annoying peppering code with "let" and "var". I think it'll actually prevent a lot of unintentional value assignments and make developer really think if something only needs to be assigned once or should be variable.

3. Switch, struct, and enum are very powerful with a lot of dynamic features. Might lead to misuse or abuse, but you know what comes with great power.

4. Has modern language features like closure, generic, extension. Closure and extension were somewhat available in Obj-C (as block and category), but Swift's versions are more powerful and resembling similar features in other languages.

5. Function and class got some nice new built-in features like returning multiple values and property observer. Finally there's no difference between ivar and property, yay!

Also, not specifically Swift but more Xcode, but Playground is fantastic. Great way to prototype or test. REPL is another very useful tool. I haven't verified Apple's speed improvement claim, but I can't imagine Swift slower than Obj-C. Also, I haven't mixed Swift and Obj-C. Would like to see how well that works performance-wise.

Swift is really an evolution of Obj-C. I've always liked Apple's approach with Obj-C: statically typed, but has dynamic features; ARC provides the convenience of managed memory system as well as the performance of MRR environment. Apple always seems to strive for the best of both worlds, and Swift looks to be a great result of that approach.

[Ray Fix]

That’s a good list.  

One of my favorite things about Swift is that it allows for very clean, lightweight, and affordable abstractions.  Things that you just can’t do in Obj-C.  Before, a way to get around it was to write C++ code, but I was never a big fan of ObjC++ as the tools support for it were always slightly lagging.

An amazing thing about Swift is how a large portion of the language is defined in terms of itself.  For example, open a playground, type in “Int" and then command-click on it.  This will take you to the definition of a Swift Int which you can see conforms to the SignedIntegerType protocol, etc.

Now suppose you want to represent complex numbers in your program.  It is possible for you to create a clean Complex abstraction that run just as efficiently as Swift’s Ints.  Pretty awesome.

While the language still has some rough edges, as I follow the discussions in the developer forums, it seems that the Swift team is moving in the correct direction, striking a balance between performance, safety, teachability, and pragmatism.

Ray

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[Randy Hsiao]

Haha, ya, that's why the first time I saw this (from the Swift book), my mind was blown:

extension Int {

     func repetitions(task: () -> ()) {

          for i in 0..<self {

               task()

          }

     }

}

500.repetitions {

     println("Hello!")

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[John H]

Ray, Randy,

Thanks for your list of Swift features. My other question would have been about a Linq equivalent, so I searched and found this:

https://github.com/mythz/swift-linq-examples

Linq is incredibly useful in the .Net language suite. Hopefully the github project will be useful to others in the group.

John

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