First and the biggest change to say so is ++ and -- deprecation
It feels strange to say what's new in SWIFT 2.2 and jump right into deprecation:)If you ask why? There has been a fair bit of confusion with the new generation on prefix and postfix behavior. In the past, with people from C++ experience, they know how to overload those operators and how postfix and prefix works. With the proliferation of other languages, people's experience on these intrinsic factors have gone down to say the least. There is a easy replacement with the same number of charecters += 1 or -= 1
Traditional C-style loops are gone
for(i=0;i<20 i="" p=""> //do what ever you want
}<20 i="" p="">
There are lesser & lesser situations we use something like above. SWIFT took note of it and replaced it with ranges. We can achieve the same with the code below
for i in 1...20 {
// do something
}
What if I want to jump by an interval of 2, here's how we can do that
<20 i="" p="">for i in 1.stride(through:20, by:2) {
// do something
}
If you need to do the reverse loop, any attempt to do the following will fail
WRONG approach
for i in 20...1 {
// do something
}
RIGHT approach for the same is
for i in 1...20.reverse() {
// do something
}
We more often work on arrays or collections for for loop and that remains the same
var array = Array(1...10)
for num in array {
// do something
}
var parameters have been deprecated
This is a big change from development perspectivefunc printPersonInformation(var name:String, var age:Int) {
// do something
}
We no longer need "var" against those argument variables. Now the problem with getting rid of "var" is how are we going to differentiate between const and non-const parameters. Well the argument SWIFT came up with was with "var" people got it confused with "inout". So there are give and takes with both approches. Any attempt to change name or age parameter in function body will result in a compilation error. Only way out will be to do a variable copy and proceed.
var personName = "Mr. " + name.lowerStringThis may need some amount of work, given that people have been following this syntax for bit.
String selectors are deprecated
This is another big one in the block. We have all used strings as selectors in SWIFT (as opposed to @selector in objc). No escape on that now, SWIFT came around and said, no more passing string. SWIFT made it more statically linked and that's a welcome news (not the syntax though). I reckon, in the future versions there will be more changes to the syntaxSWIFT 2.0
navigationItem.rightBarButtonItem = UIBarButtonItem(title: "More", style: .Plain, target: self, action: "moreButtonTapped:"
navigationItem.rightBarButtonItem = UIBarButtonItem(title: "More", style: .Plain, target: self, action: #selector(moreButtonTapped:)
Arrays introduces removeFirst
We have always used removeLast() method to remove the last item/object from Array. Now step into removeFirst. This method allows to remove the top most or the first item from array. But remember, this will not work on optional objects, unlike removeLast(). If the collection on which removeFirst is invoked happens to be NIL, then application crash is imminentTuples splat syntax is deprecated
If we have a method like the followingfunc personInformation(name:String, age:Int) {
// do something
}
let person = ("Leland Stottlemeyer", 35)
personInformation(person)
This way of passing tuples as argument has been deprectaed. This invocation way will be removed in subsequent releases. Talking about tuples, In SWIFT 2.2 we can now compare tuples directly
Like the following
let person1 = ("Arron Flinch", 23)
let person2 = ("Steven Smith", 24)
if person1 == person2 {
print("Matching person")
} else {
print("Non-mathing people, try someother person(s)")
}
Now, although this is sweet, I see what your next question is. you ask, will it work for all sizes? Answer is no, but then, SWIFT supports sufficiently good enough size, until arity 6.
Why only until 6 and not bigger than that. Well the answer is simple. If arity is more than 6, then I'd say you should re-think on the implementation and perhaps switch to "structure". What happens, when you compare tuples with different data structure, like (String, String) with (Int, String). As in the case of segment fault(s), be prepared to see some long error messages, which may or may not make much sense to you
As you have noticed above, "repeat" is an argument label as much as it is a SWIFT keyword. What it means is, you can use SWIFT keywords as argument labels too. That will bring a smile on everybody's face. Now, there's no reason to NOT make your swift functions more readable or read-friendly.
In addition, if you want to compare SWIFT versions, here's how you can do...
Here's how we can use it
As you can see, recommended lets you say "prefer this other method instead", whereas recommendedover lets you say "prefer me over this other method."
Changes to Argument labels
You can now use a variety of language keywords, here's an example of itfunc printGreeting(name: String, repeat repeatCount: Int) {
// do something
}
As you have noticed above, "repeat" is an argument label as much as it is a SWIFT keyword. What it means is, you can use SWIFT keywords as argument labels too. That will bring a smile on everybody's face. Now, there's no reason to NOT make your swift functions more readable or read-friendly.
Renamed DEBUG identifiers
It's not just selectors have been renamed, debug identifiers have also been__FILE__ renamed to #file
__LINE__ renamed to #line
__COLUMN__ renamed to #column
__FUNCTION__ renamed to #function
In addition, if you want to compare SWIFT versions, here's how you can do...
#if swift(>=2.2)
print("Running Swift 2.2 or later")
#else
print("Running Swift 2.1 or earlier")
#endif
Changes to documentation keywords
We know we can add comments as metadata to our code, in addition to what we had in the past, we now have 3 new additional one's "recommended, recommendedover and keyword"Here's how we can use it
/**
Convert Kgs to lbs
- parameters:
- kgs: weight in kgs
- returns: weight in lbs
- recommended: convertWeight
- authors:
Kat Dennings
Beth Behrs
- bug: Max, I can’t believe it. I screwed me and the horse I rode in on
*/
func convertWeight(weight: Float, kgsTolbs:Bool) -> Float {
var lbs: Float = 0.0
//do something
return lbs
}
var pounds = convertWeight(40.03)
/**
Convert Kgs to lbs
- parameters:
- kgs: weight in kgs
- returns: weight in lbs
- authors:
Tony Shalhoub
- recommendedover: convertWeight
- bug: It's a Jungle Out There
*/
func convertKgsToLbs(weight: Float) -> Float {
var lbs: Float = 0.0
//do something
return lbs
}
As you can see, recommended lets you say "prefer this other method instead", whereas recommendedover lets you say "prefer me over this other method."
Other minor stuff
Xcode 7.3 does feature all-new code completion: you can now type something like "strapp" to have "stringByAppendingString" highlighted in the code completion, or "uitavc" to have "UITableViewCell" highlighted. It will take a little thinking to rewire your brain to use these text shortcuts, but it does promise a significant speed up for your coding. In addition you can see code completion in console window too. That's a big win from a developer stand-point.On the downside XCode still crashes when you print certain variables in console window or attempt to debug through breakpoints on some occassions. Hope they get addressed soon enough.
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