Swift 2.1

http://www.russbishop.net/swift-2-1

by ingve • 11 years ago

81 46 11 years ago

melling• 11 years ago

Apple is evolving Swift quite fast. It's a great language. I like that they adopted Go's _ to ignore unused variables. Xcode 7 also recommends where to change var's to let's where you don't mutate the value after initial assignment.

Anyway, let's hope the developer community jumps onboard for the ride. For anyone interested in learning Swift, I've accumulated just under 1800 Swift urls in the past 15 months:

http://www.h4labs.com/dev/ios/swift.html

seivan3• 11 years ago

Actually, some of those features are still buggy when operating to Obj-C land :)

      //Warning if you don't use let :-) 
      let array = NSMutableArray(capacity: 50)
      array.addObject(notification)

I am aware that the let essentially means I can't reassign the variable, and does not have anything to do with the mutability of the class. Since it's a class and not a struct.

However, what I am saying is that Apple needs to somehow add the keywords to the container classes imported from Cocoa, this is manually I guess.

I wonder if adding a mutating keyword on the declaration would help

    public mutable func addObject(anObject: AnyObject) mutable

That way that should throw a warning on a let usage. But that keyword only exists on Swift. They would have to go through all of them like they did with nullable keyword.

If you're wondering why I am using CFArray -> performance. Structs are pretty slow since you'd have to copy it from the dictionary to mutate and then insert into the dictionary again.

Though, those numbers were with Swift 1. Will try with Swift 2 again, but given the nature of immutability, I suspect it will still be slower.

Now that I think about it. I might make my own generic structs that uses NSArray/NSDictionary internally. Though I wonder if you can pass structs by reference instead of copy, that would be more useful.

solomone• 11 years ago

I wouldn't call that a bug. That's like saying you can't do

  let a = Foo()
  a.addItem(i)

mattdw• 11 years ago

Swift seems to distinguish 'mutating' from 'changing'. The name 'array' in your example remains pointing to the same object, it's just that that object is being internally mutated. Not sure that there'd be a foolproof way to catch all possible mutations, so that may be the best they can do.

supster• 11 years ago

For objects passed by reference, a Swift "let" signifies immutability of reference (not value); thus you can append to the NSMutableArray but not reassign to a different NSMutableArray. On the other hand a native Swift Array assigned via "let" would be immutable from both a value and assignment perspective.

ecopoesis• 11 years ago

That's not a bug. Your array reference isn't changing, just the data in the object. Scala (which uses var and val for mutable and immutable) would do exactly the same thing.

Heck, even Java (using final to mark immutable) would work like this. This is basically how every OO language works.

xenadu022• 11 years ago

Remember that Swift collection types have the semantics of copy-on-write. Under the hood they actually only copy if the collection is non-uniquely referenced.

An Array<T> is a struct but uses a storage reference type under the covers. In theory the standard library is actually free to make common slices of arrays share storage so pure additions don't even require copying but I have no idea if it is actually implemented that way (neither String nor Array guarantee contiguous storage)

btmiller2• 11 years ago

Not to be antagonistically pedantic or anything, but just FYI, Go was definitely not the first to use an underscore to ignore variables.

sekasi• 11 years ago

If you don't mind me asking, what was? I thought it was too.

lololololwut• 11 years ago

_ for unused variables isn't a Go innovation. Haskell's been around for over 20 years and it has it. I don't think Haskell was first to do it, either.

s_kilk• 11 years ago

Looks like a good set of changes.

A question for the more switched-on among us: has there been any word on when Swift 2 will be open-sourced?

xenadu022• 11 years ago

Author here; my understanding is the compiler team is hard at work doing some necessary house cleaning and reworking. It is something they've wanted to do for some time.

No official word from Apple though.

madeofpalk• 11 years ago

Chris Lattner said on reddit that they're on track to deliver when they originally promised, by the end of the year.

namelezz• 11 years ago

Anyone knows of a safe way to use Selector in Swift. I am not a fan of using string though.

tl• 11 years ago

I've been experimenting with python scripts in my build process to create structs of static strings for Apple APIs that require strings (ex: Storyboard filenames/identifiers, Core Data entity/properties, Image filenames) for compile time safety.

I haven't done selectors yet partially because I use relatively few of them and partially because parsing code is slightly harder than file system walks and xml parsing.

blazespin5• 11 years ago

Wake me up when they open source it like they said they were going to. Proprietary languages are evil acts of lock-in committed against unwary junior developers. Swift is a great language, but I'd really like my skills to be somewhat transportable.

webwielder2• 11 years ago

Swift is a great language, but I'd really like my skills to be somewhat transportable.

Huh?

jaywunder• 11 years ago

I think OP is talking about multi platform code. Swift isn't "write once compile anywhere" like C or C++. This is also the reason I haven't used it yet, although I read the swift book and I'm looking forward to multiplatform capabilities (if that were to happen)

bla2• 11 years ago

I'm guessing they'll announce open source Swift at the next llvm conference this fall.

rektide• 11 years ago

Perhaps the Swift conference end of October?

Coupled with the amazing NeXTBSD work that's spun up, I've found myself surprisingly excited about what Swift might become.

supercoder• 11 years ago

"Swift is a great language, but I'd really like my skills to be somewhat transportable."

If your skills are locked in to a certain language then you're doing it wrong.

blazespin5• 11 years ago

9/10, given two coders of the same talent, I'll always hire the one with the experience in the language/framework. But I hire for velocity - ie, people who can develop productized solutions (bug free) in a short period of time. People who know the theory but not the in the trenches reality, well, you don't need that many folks.

incepted3• 11 years ago

Apple open sourcing Swift is not magically goingto make your skills transportable.

The only person who can make your skills transportable is yourself.

blazespin5• 11 years ago

Yep! And the way to do that is stay away from proprietary technologies wherever possible.

pjmlp• 11 years ago

Which makes me think you aren't doing any iOS or Mac OS X development anyway. So the state of Swift openness doesn't matter.

So go pick OCaml, Haskell, Rust, Idris,.... instead.

jhallenworld• 11 years ago

String interpolation now allows string literals.

But do editors highlight this properly? (JOE 4.1 does).

sobinator• 11 years ago

Swift is a language designed from its core to build apps that work well for Apple hardware. I understand why developers gag at its quirky paradigms, but at the end of the day, if you play by the rules, you end up with an extremely valuable product. The positives outweigh the negatives, open source or not.

cageface• 11 years ago

The problem is that it's actually very unlikely you'll wind up with a valuable product. The odds of getting on a user's home screen get longer every day and if you're not on the home screen you might as well not be on the phone at all.

I would like to see Swift eventually become a general purpose programming language useful outside of Apple's niche but it's got enough baggage from its ties to UIKit & ObjC I'm not sure how likely this is to happen.

Swift 2.1

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