Swift, the new way to build iOS Apps. Here's how
iosblog.co.uk
iosblog.co.uk
Mostly for selfish reasons to share it easily with friends.
“If a stored value in your code is not going to change, always declare it as a constant with the let keyword. Use variables only for storing values that need to be able to change.”
Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks. https://itun.es/us/jEUH0.l
1. It gives you additional safety against accidental reassignment.
2. It gives the compiler a major optimization hint since the value is not a variable.
Does Swift really replace Objective-C?
Lets say around XCode version 10 gets released.
Swift is targeted at the largest user base of the Obj-C language, the iOS developers. Obj-C will be around for a long time both for legacy purposes and because Swift doesn't interop with K&R C (unless that code has an Obj-C wrapper, like CoreFoundation), and C++ code. Since both Swift and Obj-C support using Cocoa libraries, any API added to Cocoa will be usable by both, but Cocoa is only one of many libraries in the Macintosh ecosystem.
Swift will become a replacement for the development the vast majority of people do, but that doesn't mean that Obj-C is going away. Apple has done nothing to indicate so; they've really been stressing the point that Swift is intended as a new tool to work along side your old one (Obj-C).
From my point of view, many will jump to Swift if given the chance.
https://developer.apple.com/library/prerelease/ios/documenta...
Additionally, this is just version 1.0. So nothing rules out that if Apple sees the language being widely adopted, other improvements in the FFI area aren't made.
The only Java apps of the era that I remember used non-native UIs, and were painful.
Whereas I'd be shocked if Swift wasn't adopted wholesale by iOS developers.
Rather back when Mac OS X 10.0 was being released and Apple was unsure if developers would be willing to write Objective-C code.
They created their own JVM, with Objective-C runtime support (JavaBridge) and let the developers choose.
At the same time, Apple representatives did sessions at UNIX heavy user groups, like CERN, where they sold Mac OS X as a better BSD, and Java as first class language was part of the feature list.
As they saw developers were comfortable adopting Objective-C in their toolchains, the JavaBridge was dropped.
BSD is implemented in C, so it's not left around, it's the foundation of the system. The syscalls at the base level (read(), write(), socket(), fork(), etc,) are implemented in C and so are the tools that are used by virtually every programming language at some level. C is the standard upon which several abstractions are made, not just another programming language.
UNIX and C are symbiotic, so any UNIX system requires C, there is no way around it.
However everything else outside what POSIX requires can be done, and should be, in a more secure and productive language.
Seems much better then ObjectiveC
But the basic idea around optionals is a much better and cleaner way of dealing with possible null (nil) values. Lots of other languages have and are getting optionals.
Being a mediocre Objective C programmer myself, I really like the look of Swift. The difficulty of programming for iOS (or any platform) is partly the language syntax and partly the library/frameworks. I think Swift will help greatly with the language, but there is still a lot to learn as far as the UI kit and such. Swift doesn't really change the fundamental way the libraries work - the syntax is just cleaner (as a matter of opinion, I suppose).
In addition to looking a lot more familiar and certain functions being much more readable, apparently using Swift will be safer in regards to memory issues too, which is comforting for people like me who are not guru-level with managing memory. I'm personally looking forward to using it starting this week.
Things that are complex in objective-c will also be simpler and more robust in swift.
There is a kind of complex coding using generics and the type system that would be harder for an inexperienced developer to understand, but that seems to me to be strictly additive to Objective-C.
Example 1 - implementing a protocol (AVAudioPlayerDelagate)
You get errors unless you also implement NSObjectProtocol. The easiest way to do that is to also inherit from NSObject.
Example 2 - typed arrays/dictionaries
You can shove any NSObject in an NSArray or NSDictionary but the Swift arrays are typed (a good thing) but one that may make some things more difficult for beginners.
I suspect it is the tip of the iceberg of type related complication. This is a worthwhile tradeoff for greater safety and despite this Swift will still be easier to use overall that ObjC in my view.
It may also take a while for the documentation particularly across the internet to catch up with the quantity of examples for Obj C but this is only an interim issue.
For #2 you are flat out incorrect. Swift arrays can be containers of AnyType, in which case they interoperate perfectly with NSArray, and this is the default behavior when working with Cocoa.
Your fear about type related complexity being a real issue seems not to be justified by your examples.
Compared to dealing with the C based fragility of Objective-C, Swift is simply better for anything that it can do.
I remember initially struggling with the stuff in ML in the first year at university, I got it but I and many others had an initial struggle. I think that at least for beginners and maybe those coming from runtime duck typed languages Python, PHP, Ruby etc. it will be more of a barrier than you think.
For #1 in Objective C you inherit from NSObject (or a subclass thereof) for every class anyway so it is in all the examples and it isn't something that you need to do especially for a protocol.
For #2 yes of course you can have an array of a generic type but firstly you need to understand enough about the type system to create your array in that form and secondly what you get out will <AnyType> objects rather than <id>'s which get automatically cast to whatever you assign them to. But I do like the idiom for downcasting using as?:
if let movie = item as? Movie {
println("Movie: '\(movie.name)', dir. \(movie.director)")
} else if let song = item as? Song {
println("Song: '\(song.name)', by \(song.artist)")
}
https://developer.apple.com/library/prerelease/ios/documenta...
This is based on a SA thread posted by a Swift team member that I linked in another HN thread, the post is available here: http://forums.somethingawful.com/showthread.php?threadid=363...
and the relevant quote is from the second post:
Is this under NDA?
No.
Is this open source?
Not yet. It probably will be, but I can't make promises. Right now, our repository still has a lot of history that we don't want to make public, and we have a lot of work to do before we release.
Objective-C is a difficult language to work with and has decades of cruft. Swift is a start-over, but with Objective-C interop so you still have full access to the full existing APIs for OSX and iOS. Thus, the same boiler plate.
“You indicate type methods for classes by writing the keyword class before the method’s func keyword, and type methods for structures and enumerations by writing the keyword static before the method’s func keyword.”
Excerpt From: Apple Inc. “The Swift Programming Language.” iBooks. https://itun.es/us/jEUH0.l
I do think the new language is neat and will be fun to work in, but it doesn't solve the parts that tripped up many people when working in Objc.
[1]
@lazy var asHTML: () -> String = {
[unowned self] in
if let text = self.text {
return "<\(self.name)>\(text)</\(self.name)>"
} else {
return "<\(self.name) />"
}
}
It seems important for traction to make the beginning learning curve non-steep. See PHP, Python, etc.
For me, Lua+LuaJIT+C/C++ as a cross-platform solution to everything is a start-over, and it gives me all kinds of things I don't get from Swift, one of them is the ability to make decisions for myself about how the basic structures of the application are going to be managed and under what conditions, either in the VM as needed or out of it, and with whatever current frameworks you want to interface with (e.g. everything). Plus, LuaJIT for the win. Plus put it, simply everywhere. (On:iOS,Linux,OSX,Win,Web,&etc.)
Swift is interesting, but I will not again be swayed to the darkside of using platform-provider-provided-platforms to achieve platform nirvana, for that harness contains nails upon which to be pinned.
Planks can be assembled of many kinds, but mine is shiny enough without another dastardly developer-mindset-grab by a very, very serious cult.
(<<--MacbookPro'er)
1) Function Types ( = higher order functions)
This allows functions to be passed around as function parameters or return values.
2) Immutable variables via let
let a = 1 // a is always bound to the constant 1
a = 2 // error
You could argue that the frameworks should ship with such a wrapper, but I'd personally rather that they spent their time making difficult things easier than making easy things easier.