Annotation Processing in a Kotlin World Zac Sweers @pandanomic - - PowerPoint PPT Presentation

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annotation processing in a kotlin world
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Annotation Processing in a Kotlin World Zac Sweers @pandanomic - - PowerPoint PPT Presentation

May 23, 2023 211 likes •1.85k views

Annotation Processing in a Kotlin World Zac Sweers @pandanomic Annotation Processing in a Kotlin World https://goo.gl/rSHTn4 Annotation Processing in a Kotlin World Annotation Processing in a Kotlin World Annotation Processing in a

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Annotation Processing in a Kotlin World

Zac Sweers @pandanomic

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Annotation Processing in a Kotlin World

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https://goo.gl/rSHTn4

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Annotation Processing in a Kotlin World

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Annotation Processing in a Kotlin World

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Annotation Processing in a Kotlin World

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Dagger

@Inject @Qualifier

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@Provides fun provideList(): List<Taco> { return emptyList() }a

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@Provides fun provideList(): List<Taco> { return emptyList() }a @Inject lateinit var tacoList: List<Taco>

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@Provides fun provideList(): List<Taco> { return emptyList() }a @Inject lateinit var tacoList: List<@SuppressJvmWildcard Taco>

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@Provides fun provideList(): List<Taco> { return emptyList() }a @Inject lateinit var tacoList: List<@SuppressJvmWildcard Taco>

🤕

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@Provides fun provideTaco(): Taco { return BreakfastTaco() }a @Inject lateinit var taco: Taco

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@Breakfast @Provides fun provideTaco(): Taco { return BreakfastTaco() }a @Breakfast @Inject lateinit var taco: Taco

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@Breakfast @Provides fun provideTaco(): Taco { return BreakfastTaco() }a @field:Breakfast @Inject lateinit var taco: Taco

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@Breakfast @Provides fun provideTaco(): Taco { return BreakfastTaco() }a @field:Breakfast @Inject lateinit var taco: Taco 🤕

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@Module class NetworkModule { @Provides static HttpClient provideHttpClient() { return HttpClient.create(); }a }b

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@Module class NetworkModule { @Provides static HttpClient provideHttpClient() { return HttpClient.create(); }a companion object { }c }b

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@Module class NetworkModule { companion object { @Provides fun provideHttpClient(): HttpClient { return HttpClient.create() }a }c }b

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@Module class NetworkModule { companion object { @JvmStatic @Provides fun provideHttpClient(): HttpClient { return HttpClient.create() }a }c }b

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@Module class NetworkModule { @Module companion object { @JvmStatic @Provides fun provideHttpClient(): HttpClient { return HttpClient.create() }a }c }b

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@Module class NetworkModule { @Module companion object { @JvmStatic @Provides fun provideHttpClient(): HttpClient { return HttpClient.create() }a }c }b

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@Module class NetworkModule { @Module companion object { @JvmStatic @Provides fun provideHttpClient(): HttpClient { return HttpClient.create() }a }c }b

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Quick refresher

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Quick refresher

  • Compile time
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate

format

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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate

format

  • Elements, Types, Filer, etc APIs
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate

format

  • Elements, Types, Filer, etc APIs
  • Cannot modify code, only generate more
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate format
  • Elements, Types, Filer, etc APIs
  • Cannot modify code, only generate more
  • Multiple rounds
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate format
  • Elements, Types, Filer, etc APIs
  • Cannot modify code, only generate more
  • Multiple rounds
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Quick refresher

  • Compile time
  • Since Java 5ish (APIs in Java 6)
  • Reads Java (byte) code in intermediate format
  • Elements, Types, Filer, etc APIs
  • Cannot modify code, only generate more
  • Multiple rounds
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class Person(val name: String)

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SLIDE 34 @kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004\b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/String;)V", "getName", "()Ljava/lang/String;", "test- project"} ) public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }
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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }

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class Person(val name: String)

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a }b

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a }b

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a }b

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class Person(val name: String = "Joe")

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a }b

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a public Person() { super(); }d }b

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; }c public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); }a public Person() { super(); }d }b

🧑

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class Person(val names: List<String>)

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class Person(val names: List<String>) public Person(@NotNull List<String> names)

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class Person(val names: MutableList<String>)

public Person(@NotNull List<String> names)

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public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }

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SLIDE 48 @kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004\b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }
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SLIDE 49 @kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004\b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }
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annotation class Metadata( )a

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annotation class Metadata( val k: Int = 1 )a

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annotation class Metadata( val k: Int = 1, val mv: IntArray = [] )a

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annotation class Metadata( val k: Int = 1, val mv: IntArray = [], val bv: IntArray = [] )a

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annotation class Metadata( val k: Int = 1, val mv: IntArray = [], val bv: IntArray = [], val d1: Array<String> = [] )a

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annotation class Metadata( val k: Int = 1, val mv: IntArray = [], val bv: IntArray = [], val d1: Array<String> = [], val d2: Array<String> = [] )a

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internal annotation class Metadata( val k: Int = 1, val mv: IntArray = [], val bv: IntArray = [], val d1: Array<String> = [], val d2: Array<String> = [] )a

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SLIDE 57 @kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n\u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u00020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004\b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a public final class Person { @org.jetbrains.annotations.NotNull() private final java.lang.String name = null; @org.jetbrains.annotations.NotNull() public final java.lang.String getName() { return null; } public Person(@org.jetbrains.annotations.NotNull() java.lang.String name) { super(); } }
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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

🤕

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val metadata = typeElement.getAnnotation(Metadata::class.java)

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"Reading information from an annotation, you say?"

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Compiler Plugins

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Compiler Plugins

  • Faster/incremental
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Compiler Plugins

  • Faster/incremental
  • No stubs generation
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Compiler Plugins

  • Faster/incremental
  • No stubs generation
  • No kapt
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Compiler Plugins

  • Faster/incremental
  • No stubs generation
  • No kapt
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BUT!

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BUT!

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BUT!

  • Undocumented and not stable
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BUT!

  • Undocumented and not stable
  • Only applies to Kotlin sources
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BUT!

  • Undocumented and not stable
  • Only applies to Kotlin sources
  • Tooling can be painful
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BUT!

  • Undocumented and not stable
  • Only applies to Kotlin sources
  • Tooling can be painful
  • github.com/hzsweers/redacted-compiler-

plugin

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BUT!

  • Undocumented and not stable
  • Only applies to Kotlin sources
  • Tooling can be painful
  • github.com/hzsweers/redacted-compiler-

plugin

  • The talk title was Annotation Processing in

a Kotlin

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BUT!*

  • Undocumented and not stable
  • Only applies to Kotlin sources
  • Tooling can be painful
  • github.com/hzsweers/redacted-compiler-

plugin

  • The talk title was Annotation Processing in

a Kotlin

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"Reading information from an annotation, you say?"

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kotlin-metadata

https://github.com/takhion/kotlin-metadata

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val metadata = typeElement.getAnnotation(Metadata::class.java)

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val Element.kotlinMetadata: KotlinMetadata?

val metadata = typeElement.getAnnotation(Metadata::class.java)

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val Element.kotlinMetadata: KotlinMetadata?

val metadata = typeElement.kotlinMetadata

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when (typeElement.kotlinMetadata) { is KotlinPackageMetadata -> is KotlinClassMetadata -> is KotlinFileMetadata -> is KotlinMultiFileClassPartMetadata -> is KotlinMultiFileClassFacadeMetadata -> is KotlinSyntheticClassMetadata -> is KotlinUnknownMetadata -> }a

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when (typeElement.kotlinMetadata) { is KotlinClassMetadata -> }a

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when (metadata) { is KotlinClassMetadata -> { val classData: ClassData = metadata.data }a }b

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when (metadata) { is KotlinClassMetadata -> { val classData: ClassData = metadata.data val proto: ProtoBuf.Class = classData.classProto }a }b

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when (metadata) { is KotlinClassMetadata -> { val classData: ClassData = metadata.data val proto: ProtoBuf.Class = classData.classProto }a }b

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when (metadata) { is KotlinClassMetadata -> { val classData: ClassData = metadata.data val proto: ProtoBuf.Class = classData.classProto val nameResolver = classData.nameResolver }a }b

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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@kotlin.Metadata( mv = {1, 1, 11}, bv = {1, 0, 2}, k = 1, d1 = {"\u0000\u0012\n\u0002\u0018\u0002\n\u0002\u0010\u0000\n \u0000\n\u0002\u0010\u000e\n\u0002\b\u0004\b\u0007\u0018 \u00002\u00020\u0001B\r\u0012\u0006\u0010\u0002\u001a\u0 0020\u0003\u00a2\u0006\u0002\u0010\u0004R\u0011\u0010\u0 002\u001a\u00020\u0003\u00a2\u0006\b\n\u0000\u001a\u0004 \b\u0005\u0010\u0006\u00a8\u0006\u0007"}, d2 = {"Ltest/Person;", "", "name", "", "(Ljava/lang/ String;)V", "getName", "()Ljava/lang/String;", "test- project"} )a

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when (metadata) { is KotlinClassMetadata -> { val classData: ClassData = metadata.data val proto: ProtoBuf.Class = classData.classProto val nameResolver = classData.nameResolver }a }b

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val proto: ProtoBuf.Class = classData.classProto val constructors: List<Constructor> = proto.constructorList val properties: List<Property> = proto.propertyList val functions: List<Function> = proto.functionList

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class Person(val name: String = "Joe")

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class Person(val name: String = "Joe") val name = TODO()

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class Person(val name: String = "Joe") val name = TODO() val mutable = TODO()

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class Person(val name: String = "Joe") val name = TODO() val mutable = TODO() val nullable = TODO()

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class Person(val name: String = "Joe") val name = TODO() val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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class Person(val name: String = "Joe") val name = TODO() val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val name = TODO() val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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it.isPrimary

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val Constructor.isPrimary: Boolean get() { return !Flags.IS_SECONDARY[flags] }

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val name = TODO() val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = TODO() val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = nameResolver.getString(nameParam.name) val mutable = TODO() val nullable = TODO() val hasDefault = TODO()

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = nameResolver.getString(nameParam.name) val mutable = TODO() val nullable = TODO() val hasDefault = nameParam.declaresDefaultValue

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = nameResolver.getString(nameParam.name) val mutable = TODO() val nullable = nameParam.type.nullable val hasDefault = nameParam.declaresDefaultValue

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = nameResolver.getString(nameParam.name) val mutable = proto.propertyList[0].isVar val nullable = nameParam.type.nullable val hasDefault = nameParam.declaresDefaultValue

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class Person(val name: String = "Joe") val proto = classData.classProto val constr = proto.constructorList.find { it.isPrimary } val nameParam = constr.valueParameterList[0] val name = nameResolver.getString(nameParam.name) val mutable = proto.propertyList[0].isVar val nullable = nameParam.type.nullable val hasDefault = nameParam.declaresDefaultValue

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SLIDE 121

kotlin-metadata

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kotlinx-metadata

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kotlinx-metadata

https://github.com/JetBrains/kotlin/tree/master/libraries/kotlinx-metadata/jvm
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SLIDE 124

kotlinx-metadata?

https://github.com/JetBrains/kotlin/tree/master/libraries/kotlinx-metadata/jvm
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kotlinx-metadata?

https://github.com/JetBrains/kotlin/tree/master/libraries/kotlinx-metadata/jvm

https://github.com/square/moshi/pull/642

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SLIDE 126

Case Studies

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copydynamic

https://github.com/hzsweers/copydynamic

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–Chris Banes, somewhere online once upon a time

“I wish I could use copy but like, conditionally set properties”

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data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

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data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a val taco = Taco(setOf("el paso"), true)

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data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a val taco = Taco(setOf("el paso"), true) val newTaco = taco.copyDynamic({ if (isBreakfastTime) { isBreakfast = true } }

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class TacoDynamicBuilder constructor( private val source: Taco) { var seasoning: Set<String> = source.seasoning var isBreakfast: Boolean = source.isBreakfast fun build(): Taco = source.copy(seasoning, isBreakfast) }a fun Taco.copyDynamic( copyBlock: TacoDynamicBuilder.() -> Unit): Taco { return TacoDynamicBuilder(this) .also { copyBlock(it) } .build() }b

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class TacoDynamicBuilder constructor( private val source: Taco) { var seasoning: Set<String> = source.seasoning var isBreakfast: Boolean = source.isBreakfast fun build(): Taco = source.copy(seasoning, isBreakfast) }a fun Taco.copyDynamic( copyBlock: TacoDynamicBuilder.() -> Unit): Taco { return TacoDynamicBuilder(this) .also { copyBlock(it) } .build() }b

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class TacoDynamicBuilder constructor( private val source: Taco) { var seasoning: Set<String> = source.seasoning var isBreakfast: Boolean = source.isBreakfast fun build(): Taco = source.copy(seasoning, isBreakfast) }a fun Taco.copyDynamic( copyBlock: TacoDynamicBuilder.() -> Unit): Taco { return TacoDynamicBuilder(this) .also { copyBlock(it) } .build() }b

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data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )aa

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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )aa

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet
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@CopyDynamic data class Taco( val seasoning: Set<String>, val isBreakfast: Boolean )a

  • Read the proto off Taco
  • Ensure it's a data class
  • Find constructor
  • Get all params + matching properties
  • Generate with KotlinPoet

"kapt.kotlin.generated"

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Moshi

https://github.com/square/moshi

API overview blog post: https://goo.gl/dRjqFb

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Guidelines

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Metadata is added signal

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Abstract your renderer

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Be mindful of mixed source sets

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SLIDE 149

Lean on language features

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Be mindful of quirks and caveats

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Quirks & Caveats

  • Not public yet
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SLIDE 152

Quirks & Caveats

  • Not public yet
  • Not incremental
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SLIDE 153

Quirks & Caveats

  • Not public yet
  • Not incremental
  • No multiplatform
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SLIDE 154

Quirks & Caveats

  • Not public yet
  • Not incremental
  • No multiplatform
  • (Kapt) No multiple rounds*
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SLIDE 155

Quirks & Caveats

  • Not public yet
  • Not incremental
  • No multiplatform
  • (Kapt) No multiple rounds*
  • (Kapt) Varying build system support
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SLIDE 156

Quirks & Caveats

  • Not public yet
  • Not incremental
  • No multiplatform
  • (Kapt) No multiple rounds*
  • (Kapt) Varying build system support
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–you?

“I have a processor and want to support kotlin today! What should I use?”

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“I have a processor and want to support kotlin today! What should I use?” “kotlin-metadata, probably”

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“I have a processor and want to support kotlin today! What should I use?” “kotlin-metadata, probably” “and KotlinPoet”

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Thanks!

  • kotlin-metadata: github.com/takhion/kotlin-metadata
  • kotlinx-metadata: https://github.com/JetBrains/kotlin/tree/master/

libraries/kotlinx-metadata/jvm

  • Moshi: github.com/square/moshi
  • Km API prototype: github.com/square/moshi/pull/642
  • CopyDynamic: github.com/hzsweers/copydynamic
  • FR for value type API: youtrack.jetbrains.com/issue/KT-26602
  • Multiple rounds demo: github.com/Takhion/generate-kotlin-multiple-rounds
  • redacted compiler plugin: github.com/hzsweers/redacted-compiler-plugin
  • KotlinPoet: github.com/square/kotlinpoet
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Thanks!

Special thanks to Eugenio Marletti (@workingkills)

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Thanks!

Zac Sweers @pandanomic