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KOTLIN
FOR SWIFT DEVELOPERS
(SWIFT εЀυϘί΄͵Η΄KOTLIN)
TRY! SWIFT | TOKYO, JAPAN | MARCH 2018
@DESIGNATEDNERD | BAKKENBAECK.COM | JUSTHUM.COM
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HEY, @d_date
THANK YOU FOR THE TRANSLATION!
(෭承΅扖ͭΔͱ
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!"
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✨ " ☕ $ ✨
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WHAT IS KOTLIN ?
( KOTLIN 承ͼ֜ Ҙ)
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WHY SHOULD I CARE?
( Ͳᐺ΅䶲ͯΡ΄͡?)
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A CONSTANT STRING
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SWIFT
let greeting = "Hello World"
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SWIFT
let greeting = "Hello World"
KOTLIN
val greeting = "Hello World"
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AN OPTIONAL INTEGER VARIABLE
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SWIFT
var something: Int?
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SWIFT
var something: Int?
KOTLIN
var something: Int?
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☠ NullPointerException ☠
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!"
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GENERICS
AND
FUNCTIONS AS PARAMETERS
( Ϟ϶ϮЄό;ͭͼֵ͞Ρ樛හ)
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SWIFT
func useFunction(on item: T, function: (T) -> U) -> U {
return function(item)
}
func insertExclamationPoint(in string: String) -> String {
return string
.components(separatedBy: " ")
.joined(separator: "! ")
}
let result = useFunction(on: "try Swift",
function: insertExclamationPoint(in:))
// result: "try! Swift"
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KOTLIN
fun T.useFunction(action: (T) -> U): U {
return action(this)
}
fun insertExclamationPoint(in: String) : String {
return in.split(" ").joinToString("! ")
}
val result = "try Kotlin".useFunction { insertExclamationPoint(it) }
// result: "try! Kotlin"
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map
filter
reduce
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map
filter
reduce*
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(0, +)
// reduced: 6
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(0, +) // !
// reduced: 6
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(0) { $0 + $1 }
// reduced: 6
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26
KOTLIN
val numbers = arrayOf(1, 2, 3)
val reduced = numbers.reduce
{ total, current -> total + current }
// reduced: 6
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26 ⬆
KOTLIN
val numbers = arrayOf(1, 2, 3)
val reduced = numbers.reduce
{ total, current -> total + current }
// reduced: 6
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26
KOTLIN
val numbers = arrayOf(1, 2, 3)
val folded = numbers.fold(20) ⬅
{ total, current -> total + current }
// folded: 26
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SWIFT
let doubled = [ 1, 2, 3 ].map { $0 * 2 }
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SWIFT
let doubled = [ 1, 2, 3 ].map { $0 * 2 }
KOTLIN
arrayOf(1, 2, 3).map { it * 2 }
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SWIFT
let doubled = [ 1, 2, 3 ].map { $0 * 2 }
KOTLIN
arrayOf(1, 2, 3).map { it * 2 }
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26
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$0 $1 $2...$∞
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SWIFT
let numbers = [ 1, 2, 3 ]
let reduced = numbers.reduce(20) { $0 + $1 }
// reduced: 26
KOTLIN
val numbers = arrayOf(1, 2, 3)
val folded = numbers.fold(20)
{ total, current -> total + current }
// folded: 26 ⬆
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!"#
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guard
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NOW (匍ࣁ) (KOTLIN)
optionalThing?.let {
it.doSomething()
}
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NOW (匍ࣁ) (WORSE KOTLIN)
if (optionalThing != nil) {
optionalThing!!.doSomething()
}
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PROPOSED (ໜ) (KOTLIN)
guard val thing = optionalThing else {
return
}
thing.doSomething()
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apply
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NOW (匍ࣁ) (SWIFT)
UserDefaults.standard.set(true, forKey: "DefaultOne")
UserDefaults.standard.set(false, forKey: "DefaultTwo)
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NOW (匍ࣁ) (BETTER SWIFT)
let defaults = UserDefaults.standard
defaults.set(true, forKey: "DefaultOne")
defaults.set(false, forKey: "DefaultTwo)
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PROPOSED (ໜ) (SWIFT)
UserDefaults.standard.apply {
"DefaultOne" = true,
"DefaultTwo" = false,
}
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KOTLIN / NATIVE
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LLVM
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LLVM
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LLVM
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SUPPORTED PLATFORMS
▸ x86-64 (macOS, Linux, Windows)
▸ arm64 (iOS, Android)
▸ arm32 (Android)
▸ arm32 hardfp (Raspberry Pi)
▸ WebAssembly (Web)
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DOCUMENTATION
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DOCUMENTATION?
¯\_(ϑ)_/¯
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KOTLIN:
☕ OR " = #
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try? kotlin
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https://try.kotlinlang.org
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EDU TOOLS
PLUGIN FOR INTELLIJ OR ANDROID STUDIO
(INTELLIJ Δ͵΅ ANDROID STUDIO አ΄Ϥ϶ναЀ)
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OBLIGATORY SUMMARY SLIDE
(嬝㵗ጱᥝ夹)
▸
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OBLIGATORY SUMMARY SLIDE
(嬝㵗ጱᥝ夹)
▸ Make Friends With Android
▸ (Android ;լᜉͥΣ͜)
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OBLIGATORY SUMMARY SLIDE
(嬝㵗ጱᥝ夹)
▸ Make Friends With Android
▸ (Android ;լᜉͥΣ͜)
▸ Kotlin Native Is Cool But Not Ready For Production
▸ (Kotlin Native΅̵͚͚ͩ͢͡ϤϺύ
μτϴЀ΅ΔͶֵ͚͞)
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try! Kotlin
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ONE MORE THING
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✨ "#$ ✨
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͘Π͢;͚ͪͬ͜Δͭ͵!
(THANK YOU VERY MUCH!)
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LINKS!
▸ Kotlin Home & Documentation
https://kotlinlang.org
▸ KotlinConf iOS App in Kotlin/Native:
https://github.com/JetBrains/
kotlinconf-app/tree/master/ios
▸ The Edu Tools Plugin for IntelliJ or Android Studio
https://kotlinlang.org/docs/
tutorials/edu-tools-learner.html
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MORE LINKS!
▸ Creating an iOS Framework With Kotlin
http://viteinfinite.com/2018/02/creating-an-ios-
framework-with-kotlin
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ILLUSTRATION CREDITS
▸ Monica Komperda, Native Code Forever
(Hire her! She's awesome!)
http://mokomperda.com/design