Scala vs. Kotlin; Friend or Foe?

Talk in scalapeno 2018

5. Conflicts
6. Threats • Identify • Compete • Conquer https://www.americanlearninglibrary.com/search/C/caesar/caesar.html
7. https://ja.wikipedia.org/wiki/%E3%82%B9%E3%83%86%E3%82%A3%E3%83%B3%E3%82%AC%E3%83%BC%E3%83%9F%E3%82%B5%E3%82%A4%E3%83%AB
8. What is Kotlin • Statically typed • Multi-Platform (JVM first, JS and Native) • Open Source by JetBrains https://medium.com/@octskyward/why-kotlin-is-my-next-programming-language-c25c001e26e3
9. Kotlin Features • Concise
10. Kotlin Features • Concise • Safe
11. Kotlin Features • Concise • Safe • Interoperable
12. Kotlin Features • Concise • Safe • Interoperable • Tool-friendly
13. Kotlin Features • Concise • Safe • Interoperable • Tool-friendly • Fun
14. Side by side comparison Scala val hello: String = “hi" var hello: String = "hi" Kotlin val hello: String = “hi" var hello: String = "hi"
15. Side by side comparison Scala val hello = “hi" var hello = "hi" Kotlin val hello = “hi" var hello = "hi"
16. Case / data class Scala case class Service( name: String ) Kotlin data class Service( val name: String )
17. Null safety Scala var hello: Option[String] = None hello.foreach { s => println(s.toUpperCase()) } println(hello.map( _.toUpperCase()) .orNull()) Kotlin var hello: String? = null println(world.toUpperCase()) if (world != null) { println(world.toUpperCase()) } println(world?.toUpperCase())
18. Singleton Scala object Single { } Kotlin object Single { }
19. Enum Scala Coming soon… Kotlin enum class Fruits { Apple, Banana }
20. Implicit class / Extension method Scala 5.hours() Kotlin 5.hours()
21. Implicit class / Extension method Scala object Helpers { implicit class IntMillis(x: Int) { def hours() = TimeUnit.HOURS.toMillis(x) } } … 5.hours() Kotlin fun Int.hours() = TimeUnit.HOURS.toMillis( this.toLong()) … 5.hours()
22. Operator overloading Scala It’s actually methods with fancy names Kotlin Limited to arithmetic operators + - \ * 
 etc’
23. Pattern matching Scala Cool and Useful! Kotlin Very limited
24. Implicit conversion Scala Yes we can! Kotlin no no no!
25. Where Scala shines • Popularity • Evangelism https://www.cvm.org.uk/blog/demolition-squad/eight-evangelism-strategies/
26. Where Scala shines https://redmonk.com/sogrady/2018/03/07/language-rankings-1-18/
27. Where Kotlin shines • Java++ - hit the sweet spot • Great Java inter-op • Lean • Tooling • Pragmatic - not reinventing the wheel
28. • Compete http://www.zimbio.com/photos/Mesut+Oezil/Germany+v+Argentina/xxHxKC8AyXD
29. Suggestions for Scala designers • Let’s be practical:
30. Suggestions for Scala designers • Let’s be practical: • Binary compatibility https://stackoverflow.com/questions/32255023/how-would-i-go-about-parsing-the-java-class-file-constant-pool
31. Suggestions for Scala designers • Let’s be practical: • Binary compatibility • Faster compilation http://www.doodleosophies.com/doodle/30
32. Suggestions for Scala designers • Let’s be practical: • Binary compatibility • Faster compilation • Improve Java inter-op
33. Suggestions for Scala users • Stick to features exists in Kotlin
34. Suggestions for Scala users • Stick to features exists in Kotlin • Make your code readable by all team members
35. Suggestions for Scala users Move to Kotlin…
36. Question?
37. Thank You! @OhadShai