Swift 2.0 language changes

Swift2Point0.swift

/*
    Power of Protocol Extensions
    Some global functions became methods
*/

var languages = ["Spanish", "English", "Chinese", "Japanese"]

languages.contains("Italian")
print("We have \(languages.count) languages.")

for (index, value) in languages.enumerate() {
    print("\(index). \(value)")
}

// Global function equal is replaced by simple equality operator
let easternLanguages = ["Chinese", "Japanese", "Korean", "Thai"]
if languages == easternLanguages {
    print("Same set of languages")
} else {
    print("Different sets")
}

languages.extend(["Dutch"])

for lang in languages.filter({ $0 != "Chinese"}) {
    print(lang)
}

// Instead of global function find, we have method indexOf
languages.indexOf("Chinese")

for item in languages.map({ "- " + $0 }) {
    print(item)
}

let languageString = languages.reduce("") { $0 + $1 }
languageString

languages.sort() // equivalent to the old global function sorted
languages.sortInPlace() // equivalent to the old global function sort

languages.startsWith(["Japanese"])
easternLanguages.startsWith(["Chinese"])



/*
    String Character Count
*/

let greeting = "Hello my dear friend!"
// Swift 1.0
//countElement(greeting)
// Swift 1.2
//count(greeting)
// Swift 2.0
greeting.characters.count



/*
    Do-While Gone, Welcome Repeat-While
*/

var counter = 3
repeat {
    print("Go Chargers!")
    counter--
} while counter > 0



/*
    New Error Handling
*/

enum InvalidLanguageSetError: ErrorType {
    case EnglishNotIncludedError
}

func verifyLanguageSet(languages: [String]) throws {
    if !languages.contains("English") {
        throw InvalidLanguageSetError.EnglishNotIncludedError
    }
}

do {
    try verifyLanguageSet(easternLanguages)
    print("Verified!")
} catch {
    print("No English in the set!")
}



/*
    New Keyword guard
    Note: Wondering why would you use guard? Read this, http://ericcerney.com/swift-guard-statement/
*/

func greetUser(user: String?) {
    guard let username = user where username.characters.count > 0 else { return }
    
    print("Hello \(username)!")
}

var user: String?
greetUser(user)
user = ""
greetUser(user)
user = "George"
greetUser(user)



/*
    Other notable changes:
    - Availability #available
    - No more println, just print
    - No more toString, use String initializer which takes pretty much any type
    - New keyword defer

    Online resource about Swift 2.0:
    - https://developer.apple.com/swift/blog/?id=29
    - http://www.raywenderlich.com/108522/whats-new-in-swift-2
    - https://www.youtube.com/watch?v=pHsvYPMqsOc
    - http://airspeedvelocity.net/2015/06/09/changes-to-the-swift-standard-library-in-2-0-beta-1/
*/