Welcome to Swift (CocoaCoder 6/12/14)
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The document provides an overview of the key features of the Swift programming language, including its support for standard types like Int and String, optional types, generics, closures, functions, classes and objects, and interoperability with Objective-C. It notes that Swift is a new language from Apple that compiles like a scripting language but is intended to eventually replace Objective-C, and it showcases various language constructs through code examples.
![Looks a lot like a scripting language*
let individualScores = [75, 43, 103, 87, 12]
var teamScore = 0
for score in individualScores {
if score > 50 {
teamScore += 3
} else {
teamScore += 1
}
}
println ("the score is (teamScore)")
*but it’s compiled](https://image.slidesharecdn.com/welcometoswift-cocoacoder-140612-140613195501-phpapp02/85/Welcome-to-Swift-CocoaCoder-6-12-14-5-320.jpg)
![Standard-ish Types
var int1: Int = 30
var float1: Float = 30.5
var bool1: Bool = false
var str1: String = "Hello, playground"
var array1: Array = ["Hi", 40]
var dict1: Dictionary <String,String> = [ "key" : "value"]](https://image.slidesharecdn.com/welcometoswift-cocoacoder-140612-140613195501-phpapp02/85/Welcome-to-Swift-CocoaCoder-6-12-14-7-320.jpg)
![Loops
var firstForLoop = 0
for i in 0..3 {
firstForLoop += i
}
var n = 2
while n < 100 {
n = n * 2
}
var m = 2
do {
m = m * 2
} while m < 100
let individualScores = [75, 43, 12]
for score in individualScores {
teamScore += 3
}](https://image.slidesharecdn.com/welcometoswift-cocoacoder-140612-140613195501-phpapp02/85/Welcome-to-Swift-CocoaCoder-6-12-14-10-320.jpg)
![“Closures”
var strings = ["a","b","c","d"]
let uppercaseStrings = strings.map {
(s1: String) -> String in
return s1.uppercaseString
}
//["A", "B", "C", "D"]](https://image.slidesharecdn.com/welcometoswift-cocoacoder-140612-140613195501-phpapp02/85/Welcome-to-Swift-CocoaCoder-6-12-14-18-320.jpg)
Welcome to Swift (CocoaCoder 6/12/14)
- 1. Welcome to Swift Carl Brown (@CarlBrwn) CocoaCoder.org, 12 June 2014 (WWDC Keynote + 10 days)
- 2. Disclaimer • We’ve known of this language’s existence for less than two weeks • I’ve yet to ship a project with it • We’ve been told the language will be changing over time *image: http://vectorgoods.com/wp-content/uploads/2012/01/nuclear-danger-vector.jpg
- 3. Event Interactivity Please(!) stop me if you have questions http://farm3.static.flickr.com/2197/2200500024_e93db99b61.jpg
- 4. What is Swift? New Programming Language from Apple Announced at WWDC 2014 After being worked on in secret for 4 years Interoperates with (and may eventually replace) Objective-C Currently still a work in progress
- 5. Looks a lot like a scripting language* let individualScores = [75, 43, 103, 87, 12] var teamScore = 0 for score in individualScores { if score > 50 { teamScore += 3 } else { teamScore += 1 } } println ("the score is (teamScore)") *but it’s compiled
- 6. Swift != Obj-C Goodbye Square Brackets* ! …and semicolons *Except Array definitions and subscripts
- 7. Standard-ish Types var int1: Int = 30 var float1: Float = 30.5 var bool1: Bool = false var str1: String = "Hello, playground" var array1: Array = ["Hi", 40] var dict1: Dictionary <String,String> = [ "key" : "value"]
- 8. Type-safe (and types can be implied)
- 9. Swift Still has Immutability let individualScore = 75 ! ! var teamScore = 0 Read-Only Read-Write *Array immutability seems complicated for performance reasons
- 10. Loops var firstForLoop = 0 for i in 0..3 { firstForLoop += i } var n = 2 while n < 100 { n = n * 2 } var m = 2 do { m = m * 2 } while m < 100 let individualScores = [75, 43, 12] for score in individualScores { teamScore += 3 }
- 11. Switch directly on Objects let vegetable = "red pepper" switch vegetable { case "celery": let vegetableComment = "Add some raisins." case "cucumber", "watercress": let vegetableComment = "Make a good tea sandwich." case let x where x.hasSuffix("pepper"): let vegetableComment = "Is it a spicy (x)?" default: let vegetableComment = "Everything okay in soup." } *All possibilities MUST be covered or compiler error
- 12. “Tuples” let (statusCode, statusMessage) = http404Error let http404Error = (404, "Not Found") println("The status code is (statusCode)") // prints "The status code is 404" println("The status message is (statusMessage)") // prints "The status message is Not Found” *This Excerpt (and many others) From: Apple Inc. “The Swift Programming Language.” iBooks.
- 14. “Optionals” Primitive Types can’t be nil Types have “Optional” versions (nil or value) You have to “Unwrap” Optionals before you can use them in non-optional context
- 15. Convention: Use “if let” to “Unwrap” var optionalString: String? ! if let definiteString = optionalString { println(definiteString) } *You can also use (!) and risk a run-time crash
- 18. “Closures” var strings = ["a","b","c","d"] let uppercaseStrings = strings.map { (s1: String) -> String in return s1.uppercaseString } //["A", "B", "C", "D"]
- 19. Functions func getGasPrices() -> (Double, Double, Double) { return (3.59, 3.69, 3.79) } getGasPrices() *This Excerpt (and many others) From: Apple Inc. “The Swift Programming Language.” iBooks.
- 20. Classes/Objects class NamedShape { var numberOfSides: Int = 0 var name: String init(name: String) { self.name = name } func simpleDescription() -> String { return "A shape with (numberOfSides) sides." } } var shape = NamedShape(name: "square") shape.numberOfSides = 4
- 21. Interoperability let path="/tmp/stringFile.txt" ! let content : AnyObject? = NSString.stringWithContentsOfFile(path) ! if let contentString = content as? String { contentString }