Kotlin > 🏝 (Kotlin: more than an island)

2017-07-15: MobileOptimized 2017
2017-05-31: https://www.meetup.com/GDG-Berlin-Android/events/238173227

The last Google I/O was probably the most exciting ever, especially for one reason: Kotlin received official recognition as a first-class citizen on Android.
The quantity of developers cheering for this shouldn't come as a surprise, as some of them have already been using the language for years, and for good reasons.
Join us to understand what Kotlin really is, and witness how its principles and advanced features make it so unique today, plus what will make it transcend into something even more powerful in the future.

Animated slides (Keynote): https://goo.gl/QfQLdp

Transcript

1. !
2. ! “…Kotlin is a new JVM language…”
3. ! “…Kotlin is a new JVM language…”
4. ! “…Kotlin is a new JVM language…”
7. made by JetBrains open source, non-profit foundation pragmatic safe(r than Java) “good” magic ✨ FUN
8. packages optional no need to match folder files multiple classes top level functions
9. // src/main/kotlin/covfefe/Whatever.kt fun main(args: Array<String>) { } println("Hello World!")
10. fun main(args: Array<String>) { val immutable = 0 immutable += 1 }
11. fun main(args: Array<String>) { var mutable = 0 mutable += 1 }
12. fun main(args: Array<String>) { val nullable: String? = null val alternative = nullable ?: "¯\_(ϑ)_/¯" val lengthOrNull = nullable?.length if (nullable != null) { println(nullable.length) } } }
13. fun Int.twice() = this * 2 fun test() = 1.twice() // 2
14. inline fun <K, V> Map<K, V>.getOrElse( key: K, defaultValue: () -> V ) = get(key) ?: defaultValue()
15. abstract class NetworkResult { object Cancelled : NetworkResult() data class Success(val json: String) : NetworkResult() data class Error(val error: Throwable) : NetworkResult() } fun test(result : NetworkResult) = when (result) { NetworkResult.Cancelled -> null is NetworkResult.Success -> result.json is NetworkResult.Error -> throw result.error else -> error("WTF") }
16. sealed object Cancelled : NetworkResult() data class Success(val json: String) : NetworkResult() data class Error(val error: Throwable) : NetworkResult() } fun test(result : NetworkResult) = when (result) { NetworkResult.Cancelled -> null is NetworkResult.Success -> result.json is NetworkResult.Error -> throw result.error class NetworkResult { }
17. why?
18. everything you can do in Kotlin can be done in Java
19. everything you can do in Java can be done in bytecode
20. high level abstractions, enforced by the compiler extend the language through DSL built in symbiosis with tools moving fast, but carefully change of mindset
21. myths
22. slow compilation runtime overhead learning curve not knowing what’s really going on confusing without IDE
23. cons
24. occasional rough edges around tooling not being able to go back to Java, ever
25. future
26. immutable collections universal serialization type classes multiplatform metaprogramming
27. Official website goo.gl/xL99fk Kotlin and Android (blog) goo.gl/FQYAcW Introduction to Kotlin (video) goo.gl/3n6wic Life is Great and Everything Will Be Ok, Kotlin is Here (video) goo.gl/NTaYqi Using Project Kotlin for Android (doc) goo.gl/T0SDTJ The Future of Kotlin (video) goo.gl/INLPDl Kotlin 1.1 (video) goo.gl/iKojmn
28. BIT .LY /KO TLIN -M O RE -TH A N -A N -ISLA N D Eugenio Marletti @workingkills