Swift と Kotlin

iosdc2017

Transcript

1. Swift & Kotlin
   2017/9/16
   ezura
   

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2. ezura (@eduraaa)
   • iOS engineer @ LINE

   • like: programming
   • mock mock radio
   • ΪϦγϟ఩ֶ / Swift
   • Blending Kotlin's culture into Swift
   • ఈ͔ΒֶͿ Swift
   • …
   

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3. official on Android
   

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4. Kotlin
   

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5. Kotlin
   OOP
   extension
   interface

   default
   implementati
   on
   generics
   delegation
   null
   safety
   tailrec
   static

   type
   Java
   GC
   sealed
   class
   variance

   declaration
   object
   JS
   companion 

   object
   if, when
   expression
   Type
   inference
   (Corout
   ines)
   inline
   annotation
   FP
   

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6. • Started in 2010
   • Object-oriented programming
   • Support functional programming
   • Static typing
   • Type inference
   • Null safety
   • Generic programming
   

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7. Kotlin’s background
   

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8. started in 2010
   first official 1.0 release in 2016
   Let's make a new language

   based on the knowledge 

   that has developed IDEs
   

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9. class Class: Super() {
   var property = ""
   fun method() {
   var nullable: String? = null
   if (nullable != null) {
   nullable.length
   }
   val list = listOf(1, 2, 3)
   list.forEach { print(it) }
   }
   }
   

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10. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    }
    Object-oriented programming
    

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11. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    } Support functional programming
    

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12. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    }
    Static typing
    

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13. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    }
    Type inference
    

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14. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    }
    Generic programming
    

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15. class Class: Super() {
    var property = ""
    fun method() {
    var nullable: String? = null
    if (nullable != null) {
    nullable.length
    }
    val list = listOf(1, 2, 3)
    list.forEach { print(it) }
    }
    }
    Null safety
    

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16. • Started in 2010
    • Object-oriented programming
    • Support functional programming
    • Static typing
    • Type inference
    • Null safety
    • Generic programming
    

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17. • Started in 2010
    • Object-oriented programming
    • Support functional programming
    • Static typing
    • Type inference
    • Null safety
    • Generic programming
    

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18. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    

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19. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    

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20. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    ❌ runtime environment
    ❌ memory management
    ❌ background
    ❌ calling Java/Objective-C
    ❌ Culture
    ❌ features
    

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21. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    Is the learning cost low?
    

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22. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    ෦෼΋͋Δ
    Is the learning cost low?
    

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23. Swift ͱ Kotlin ͸ࣅ͍ͯΔʁʁ
    ෦෼΋͋Δ
    Is the learning cost low?
    

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24. Kotlin ֶश

    Swift ஌ࣝͰϒʔετՄೳ
    

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25. Index
    • What is Kotlin
    • Is Kotlin like Swift?
    • some keyword
    • some features
    • Traps
    

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26. Index
    • What is Kotlin
    • Is Kotlin like Swift?
    • some keyword
    • some features
    • Traps
    

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27. Syntax
    Swift Kotlin
    var, let
    func f(arg: Any) -> Any
    class AnyType { … }
    var obj = Obj()
    obj.method(arg: v)
    var, val
    fun f(arg: Any): Any
    class AnyType { … }
    var obj = Obj()
    obj.method(v)
    see also: http://nilhcem.com/swift-is-like-kotlin/
    

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28. Support functional programming
    Swift Kotlin
    val f = { x: Int ->
    /* … */
    }
    obj.map { /* … */ }
    let f = { Int -> String in
    /* … */
    }
    obj.map { /* … */ }
    

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29. Support functional programming
    Swift Kotlin
    val f = { x: Int ->
    /* … */
    }
    obj.map { /* … */ }
    let f = { Int -> String in
    /* … */
    }
    obj.map { /* … */ }
    constant constant
    

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30. Support functional programming
    Swift Kotlin
    val f = { x: Int ->
    /* … */
    }
    obj.map { /* … */ }
    let f = { Int -> String in
    /* … */
    }
    obj.map { /* … */ }
    first class function first class function
    

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31. Support functional programming
    Swift Kotlin
    val f = { x: Int ->
    /* … */
    }
    obj.map { /* … */ }
    let f = { Int -> String in
    /* … */
    }
    obj.map { /* … */ }
    higher-order function higher-order function
    

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32. Null safety
    Swift Kotlin
    let i: Int?
    i?.description
    if let i = i {
    i.description
    }
    val i: Int?
    i?.toString()
    if (i != null) {
    i.toString()
    }
    

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33. Null safety
    Swift Kotlin
    let i: Int?
    i?.description
    if let i = i {
    i.description
    }
    val i: Int?
    i?.toString()
    if (i != null) {
    i.toString()
    }
    

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34. extension
    Swift Kotlin
    extension String {
    func f() {}
    var v: String { return "" }
    }
    let string = ""
    string.f()
    string.v
    fun String.f() = {}
    val String.v: String get() = ""

    val string = ""
    string.f()
    string.v
    

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35. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f() {
    /* do something */
    }
    }
    

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36. • Started in 2010
    • Object-oriented programming
    • Support functional programming
    • Static typing
    • Type inference
    • Null safety
    • Generic programming
    • Some syntax
    • Extension
    • Default implementation
    

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37. Kotlin
    OOP
    extension
    interface

    default
    implementati
    on
    generics
    delegation
    null
    safety
    tailrec
    static

    type
    Java
    GC
    sealed
    class
    variance

    declaration
    object
    JS
    companion 

    object
    if, when
    expression
    Type
    inference
    (Corout
    ines)
    inline
    annotation
    FP
    

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38. Kotlin
    OOP
    extension
    interface

    default
    implementati
    on
    generics
    delegation
    null
    safety
    tailrec
    static

    type
    Java
    GC
    sealed
    class
    variance

    declaration
    object
    JS
    companion 

    object
    if, when
    expression
    Type
    inference
    (Corout
    ines)
    inline
    annotation
    FP
    

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39. Trap
    

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40. extension
    Swift Kotlin
    extension String {
    func f() {}
    var v: String { return "" }
    }
    

    fun String.f() = {}
    val String.v: String get() = “"
    

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41. extension
    Type Type
    function
    property
    function
    property
    Swift Kotlin
    

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42. extension
    Type Type
    function
    property
    function
    property
    Swift Kotlin
    

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43. extension
    function
    Util class
    instance
    static Result method(Some target)
    Some

    Type
    Java
    

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44. extension
    Util.method(instance)
    Java
    function
    Util class
    instance
    Some

    Type
    static Result method(Some target)
    

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45. extension
    Collections.max(list)
    Java
    function
    Util class
    instance
    Some

    Type
    static Result method(Some target)
    

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46. extension
    max(list)
    Java
    function
    Util class
    instance
    Some

    Type
    static Result method(Some target)
    

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47. extension
    max(list)
    Java
    function
    Util class
    instance
    Some

    Type
    list.max()
    want to …
    static Result method(Some target)
    

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48. extension
    Some

    Type
    function
    property
    Kotlin
    Util.extensionMethod(instance)
    

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49. extension
    Some

    Type
    function
    property
    Kotlin
    obj.extensionMethod()
    

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50. extension
    Type Type
    function
    property
    function
    property
    Swift Kotlin
    extend type by

    functions/properties
    add

    functions/properties
    

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51. extension
    Type Type
    function
    property
    function
    property
    Swift Kotlin
    protocol interface
    extension String: MyProtocol {
    /* ... */
    }
    -
    

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52. extension
    Type Type
    function
    property
    function
    property
    Swift Kotlin
    extend type by

    functions/properties
    add

    functions/properties
    

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53. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f() {
    /* do something */
    }
    }
    

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54. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f() {
    /* do something */
    }
    }
    P f()
    extension P
    f()
    

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55. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f()
    }
    fun I.f() {
    /* do something */
    }
    P f()
    extension extension
    P f()
    

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56. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f()
    }
    fun I.f() {
    /* do something */
    }
    class A: I {} // error
    P f()
    extension extension
    P f()
    

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57. default implementation 

    for protocol/interface
    Swift Kotlin
    protocol P {
    func f()
    }
    extension P where … {
    func f() {
    /* do something */
    }
    }
    interface I {
    fun f() {
    /* do something */
    }
    }
    P f()
    extension

    where …
    P
    f()
    

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58. default implementation 

    for protocol/interface
    Protocol
    Interface
    Implementation
    Implementation
    extension
    Swift Kotlin
    

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59. Null safety
    Swift Kotlin
    let i: Int?
    i?.description
    if let i = i {
    i.description
    }
    val i: Int?
    i?.toString()
    if (i != null) {
    i.toString()
    }
    

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60. Null safety
    Swift Kotlin
    let i: Int?
    i?.description
    if let i = i {
    i.description
    }
    val i: Int?
    i?.toString()
    if (i != null) {
    i.toString()
    }
    Optional Nullable
    

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61. Null safety
    Swift Kotlin
    enum Optional {
    case none
    case some(Wrapped)
    }
    nullable
    Optional Nullable
    

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62. Null safety
    Swift Kotlin
    enum Optional {
    case none
    case some(Wrapped)
    }
    nullable
    exist some value 

    or not null or not null
    Optional Nullable
    

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63. Null safety
    Swift Kotlin
    ɹ
    exist some value 

    or not not null or null
    Value none
    or Value or null
    Optional Nullable
    

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64. Null safety
    Swift Kotlin
    ɹ
    exist some value 

    or not not null or null
    Value none
    or Value or null
    Optional Nullable
    Value = Int?
    

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65. Null safety
    Swift Kotlin
    ɹ
    exist some value 

    or not not null or null
    Int? none
    or Int? or null
    Optional Nullable
    Value = Int?
    

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66. Null safety
    Swift Kotlin
    ɹ
    exist some value 

    or not not null or null
    1 

    or

    nil
    none
    or 1 

    or

    null
    or null
    Optional Nullable
    Value = Int?
    

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67. Null safety
    Swift Kotlin
    ɹ
    exist some value 

    or not not null or null
    .some

    (nil) none
    or or null
    null
    ??
    Optional Nullable
    Value = Int?
    

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68. Some familiar functions
    Swift Kotlin
    [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    

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69. Some familiar functions
    Swift Kotlin
    [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    

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70. [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    Some familiar functions
    Swift Kotlin
    1
    3
    1
    

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71. [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    Some familiar functions
    Swift Kotlin
    1
    3
    1
    

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72. Some familiar functions
    Swift Kotlin
    @_inlineable
    public func forEach(
    _ body: (Element) throws -> Void
    ) rethrows {
    for element in self {
    try body(element)
    }
    }
    public inline fun
    Iterable.forEach(action: (T) -> Unit): Unit {
    for (element in this) action(element)
    }
    

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73. Some familiar functions
    Swift Kotlin
    @_inlineable
    public func forEach(
    _ body: (Element) throws -> Void
    ) rethrows {
    for element in self {
    try body(element)
    }
    }
    public inline fun
    Iterable.forEach(action: (T) -> Unit): Unit {
    for (element in this) action(element)
    }
    

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74. Some familiar functions
    Swift Kotlin
    @_inlineable
    public func forEach(
    _ body: (Element) throws -> Void
    ) rethrows {
    for element in self {
    try body(element)
    }
    }
    public inline fun
    Iterable.forEach(action: (T) -> Unit): Unit {
    for (element in this) action(element)
    }
    inline: ݺͼग़͠ݩʹத਎Λల։
    inline: ݺͼग़͠ݩʹத਎Λల։
    

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75. Some familiar functions
    Swift Kotlin
    @_inlineable
    public func forEach(
    _ body: (Element) throws -> Void
    ) rethrows {
    for element in self {
    try body(element)
    }
    }
    public inline fun
    Iterable.forEach(action: (T) -> Unit): Unit {
    for (element in this) action(element)
    }
    inline: ϩδοΫʹӨڹ͠ͳ͍
    inline: ϩδοΫʹӨڹ͢Δ
    

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76. Some familiar functions
    Swift Kotlin
    @_inlineable
    public func forEach(
    _ body: (Element) throws -> Void
    ) rethrows {
    for element in self {
    try body(element)
    }
    }
    public inline fun
    Iterable.forEach(action: (T) -> Unit): Unit {
    for (element in this) action(element)
    }
    {
    if (it == 2) { return }
    println(it)
    }
    inline: ݺͼग़͠ݩʹத਎Λల։
    

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77. Some familiar functions
    Kotlin
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    Iterable $receiver$iv =
    (Iterable)CollectionsKt.listOf(new Integer[]
    {Integer.valueOf(1), Integer.valueOf(2),
    Integer.valueOf(3)});
    Iterator var2 = $receiver$iv.iterator();
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    int it = ((Number)element$iv).intValue();
    if(it == 2) {
    return;
    }
    System.out.println(it);
    }
    

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78. Some familiar functions
    Kotlin
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    /* ... */
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    int it = ((Number)element$iv).intValue();
    if(it == 2) {
    return;
    }
    System.out.println(it);
    }
    

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79. listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    /* ... */
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    int it = ((Number)element$iv).intValue();
    if(it == 2) {
    return;
    }
    System.out.println(it);
    }
    Some familiar functions
    Kotlin
    

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80. listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    /* ... */
    while(var2.hasNext()) {
    Object element$iv = var2.next();
    int it = ((Number)element$iv).intValue();
    if(it == 2) {
    return;
    }
    System.out.println(it);
    }
    Some familiar functions
    Kotlin
    non-local return
    

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81. [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    Some familiar functions
    Swift Kotlin
    1
    3
    1
    

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82. Kotlin
    OOP
    extension
    interface

    default
    implementati
    on
    generics
    delegation
    null
    safety
    tailrec
    static

    type
    Java
    GC
    sealed
    class
    variance

    declaration
    object
    JS
    companion 

    object
    if, when
    expression
    Type
    inference
    (Corout
    ines)
    inline
    annotation
    FP
    

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83. Conclusion
    

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84. • Started in 2010
    • Object-oriented programming
    • Support functional programming
    • Static typing
    • Type inference
    • Null safety
    • Generic programming
    • Some syntax
    • Extension
    • Default implementation
    

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85. &
    

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86. Same word, different concept
    

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87. Swift ͱ Kotlin
    ͲͪΒ΋ɺଞͷݴޠ͔Βػೳ΍ࢥ૝ΛऔΓೖΕ͍ͯΔ
    ͦΕΛͦΕͧΕʹݟ߹ͬͨܗͰ༥߹ͤͭͭ͞΋ɺ

    ֤ࣗͷจԽΛங͍͍ͯΔ
    ڞ௨͢Δ෦෼͸ੜ͡Δ
    

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88. enjoy Swift, enjoy Kotlin :)
    

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89. References
    Kotlin (official reference)

    https://kotlinlang.org/docs/reference/
    The Swift Programming Language (Swift 4)

    https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/AboutTheLanguageReference.html
    Programming Kotlin

    by Stefan Bocutiu, Stephen Samuel
    Swift is like Kotlin: Hacker News (discussion)

    https://news.ycombinator.com/item?id=14364612
    Swift is like Kotlin

    http://nilhcem.com/swift-is-like-kotlin/
    SwiftKotlin

    https://github.com/angelolloqui/SwiftKotlin
    Swift vs Kotlin for real iOS/Android apps (ͱͯ΋ྑ͍هࣄͰͨ͠ʂ)

    http://angelolloqui.com/blog/38-Swift-vs-Kotlin-for-real-iOS-Android-apps
    Swift is NOT like Kotlin..?

    http://blog.applibot.co.jp/blog/2017/04/03/swift-is-not-like-kotlin/
    iOSΞϓϦ։ൃऀ͔ΒݟͨKotlin (࣌ؒͷ౎߹Ͱল͍ͨ෦෼΋͋Γ·͕͢ɺߏจͷൺֱ͕៉ྷʹ·ͱ·͍ͬͯ·͢)

    https://speakerdeck.com/koishi/iosapurikai-fa-zhe-karajian-takotlin
    null҆શͰͳ͍ݴޠ͸ɺ΋͸΍ϨΨγʔݴޠͩ (nullable ͷछྨͱಛ௃)

    http://qiita.com/koher/items/e4835bd429b88809ab33#nullable-%E3%81%AE%E7%A8%AE%E9%A1%9E%E3%81%A8%E7%89%B9%E5%BE%B4
    Android։ൃΛड஫͔ͨ͠ΒKotlinΛΨοπϦ࢖ͬͯΈͨΒ࠷ߴͩͬͨ

    http://qiita.com/omochimetaru/items/98e015b0b694dd97f323
    ๩͍͠SwiftΤϯδχΞͷͨΊͷKotlinೖ໳

    https://speakerdeck.com/inamiy/mang-siiswiftenziniafalsetamefalsekotlinru-men
    Kotlin and Swift. Is it a whole new era in Mobile Development?

    https://medium.com/@andycherkashyn/kotlin-and-swift-is-it-a-new-mobile-development-era-b4c5e81feb08
    Swift/Kotlin߹ಉษڧձ

    https://oi-study.connpass.com/event/62521/
    

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90. Q & A
    

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91. [1, 2, 3].forEach {
    if $0 == 2 { return }
    print($0)
    }
    listOf(1, 2, 3).forEach {
    if (it == 2) { return }
    println(it)
    }
    Some familiar functions
    Swift Kotlin
    1
    3
    1
    ࣭໰
    Swift Έ͍ͨͳڍಈʹͰ͖Δʁ
    

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92. A: ಗ໊ؔ਺Λ࢖͍·͢
    listOf(1, 2, 3).forEach(fun(element: Int) {
    if (element == 2) { return }
    print(element)
    return
    }) ͜ͷ return ͸ಗ໊ؔ਺ͷ return
    ͘͢͝ৄ͍͠આ໌

    JavaϓϩάϥϚ͕KotlinͰͭ·͖͕ͮͪͳͱ͜Ζ

    http://qiita.com/koher/items/
    d9411a00986f14683a3f#inline%2d%e3%81%a8%2dnon%2dlocal%2dreturn
    

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93. ձ৔Ͱ౴͑ͯͩͬͨ͘͞ @omochimetaru ͞Μɺ

    هࣄΛࣥචɺπΠʔτ͍͖ͨͩ·ͨ͠ @koher ͞Μ

    ͋Γ͕ͱ͏͍͟͝·͢ʂ
    

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94. Some familiar functions
    Swift
    @_inlineable
    public func first(
    where predicate: (Element) throws -> Bool
    ) rethrows -> Element? {
    var foundElement: Element?
    do {
    try self.forEach {
    if try predicate($0) {
    foundElement = $0
    throw _StopIteration.stop
    }
    }
    } catch is _StopIteration { }
    return foundElement
    }
    ྫ֎౤͛ͯ୤ग़
    ༨ஊ

    Swift Ͱ forEachൈ͚͍ͨͱ͖

    ྫ: first(where: )
    

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95. ࣭໰

    inline ࢦఆΛ͢Δ͜ͱʹΑΔϩδο
    ΫޡΓͷճආΛͲ͏͢Δ͔
    ճ౴͸དྷिதʹΞοϓσʔτ͠·͢ʂ
    ><
    

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