Kotlinってこんな言語 #jkug

Kotlin言語について、その特徴とサードパーティ製ライブラリの簡単な紹介。

1. Kotlinͬͯ͜Μͳݴޠ 2013.7.26 ୈ1ճ͔Θ͍͍Kotlinษڧձ @ngsw_taro
2. ࿩͢͜ͱ •Kotlin is Կ •؆ܿ •҆શ •3rd Party Library/FW
3. Kotlin is Կ
4. Better Java
5. JetBrains͕։ൃ͍ͯ͠Δ ੩తܕ෇͚ݴޠ for JVM, Android, JavaScript
6. ΫϥεΦϒδΣΫτ εϚʔτΩϟετ ϥϜμࣜ ߴ֊ؔ਺ null҆શ τϨΠτ ֦ுؔ਺ ܕਪ࿦
7. Scala࢖͑͹ʁ
8. ·͔͊֬ʹɻɻ
9. Kotlinͷઃܭ໨ඪ̍ JavaฒͷίϯύΠϧ଎౓
10. Kotlinͷઃܭ໨ඪ̎ දݱྗΛҡ࣋ͭͭ͠ ScalaΑΓ΋γϯϓϧʹ
11. ؆ܿ
12. val hoge: Int = 5.inc() ͢΂ͯΦϒδΣΫτ ϓϦϛςΟϒܕ͸ͳ͍
13. ҉໧ͷܕม׵͸ͳ͍ val a: Float = 2 val b: Float = 2.toFloat() ←NG
14. ߴ֊ؔ਺/ϥϜμࣜ (1..999).filter { it % 3 == 0 || it % 5 == 0 }.reduce { sum, e -> sum + e }
15. Ϋϥε class Person( val name: String, val age: Int = 20 )
16. Ϋϥε class Person( val name: String, val age: Int = 20 ) ίϯετϥΫλ ϓϩύςΟ σϑΥϧτ஋
17. Πϯελϯεੜ੒ Person(“Taro”, 25) Person(“Taro”) Person(name=“Taro”)
18. Πϯελϯεੜ੒ Person(“Taro”, 25) Person(“Taro”) Person(name=“Taro”) ύϥϝʔλলུ ໊લ෇Ҿ਺ new͸ෆཁ
19. ֦ுؔ਺ τϨΠτ ςϯϓϨʔτࣜ ͦͷଞʹ ͳͲͳͲ
20. ҆શ
21. null҆શ Φʔόϔουͷͳ͍ OptionܕͷΑ͏ͳ΋ͷ
22. val name: String = name() assert(name != null) ஋͸ඞͣ͋Δ
23. val name: String? = name() ஋͕ͳ͍͔΋
24. val name: String? = name() val len = name.length ҆શͰͳ͍ͷ͸ېࢭ ←NG
25. val name: String? = name() if(name != null) val len = name.length ҆શͳͷ͸OK
26. val name: String? = name() val len = name?.length ʮ҆શݺͼग़͠ʯ
27. Ωϟετ δΣωϦΫε ͦͷଞʹ
28. 3rd Party Library/FW
29. Kara Web Framework Kotlinݴޠ಺DSLͰϧʔςΟϯά͔ΒϏϡʔ·Ͱ࡞ΕΔ
30. class IndexView(val task: Task = Task()): HtmlView() { override fun render(context: ActionContext) { h2("λεΫͷొ࿥") formFor(task, "/task".link(), FormMethod.post) { p { labelFor("title", "໊݅") textFieldFor("title") } p { labelFor("content", "಺༰") textAreaFor("content") } p { input(inputType = InputType.submit, value = "ొ࿥") } } } }
31. Spek ಡΈ΍͍͢࢓༷Λهड़͢ΔͨΊͷDSL
32. public class calculatorSpecs : JUnitSpec() {{ given("a calculator") { val calculator = Calculator() on("calling sum with two numbers") { val sum = calculator.sum(2, 4) it("should return the result of adding the first number to the second number") { shouldEqual(6, sum) } } } }} https://github.com/hhariri/spekΑΓҾ༻
33. Node.kt funKTionale ͦͷଞʹ
34. ͋Γ͕ͱ͏͍͟͝·ͨ͠