Writing Kotlin Compiler Plugins with Arrow Meta

We’ll learn about how to write and test compiler plugins with Arrow Meta. This library provides an API for source transformations, automatic code refactoring, and much more. We’ll look at main use cases from type classes, comprehensions, and lenses that are made possible with Arrow Meta. We’ll also look at how to test each use case.

Transcript

1. Mohit Sarveiya Writing Compiler Plugins with Arrow Meta www.twitter.com/heyitsmohit www.codingwithmohit.com
2. Writing Compiler Plugins with Arrow Meta • Kotlin Compiler • Compiler Plugin with Meta • Testing Compiler Plugins • IDE Plugins
3. Motivations • How do we build tools with Kotlin? • How do we introduce Functional Programming?
4. Code Parsing Analysis Resolve Code-gen Done class UserRepo { fun getUsers(): List<User> fun addUser() fun deleteUser(id: Int) }
5. Code Parsing Analysis Resolve Code-gen Done Abstract Syntax Tree (AST)
6. Code Parsing Analysis Resolve Code-gen Done Semantics
7. Code Parsing Analysis Resolve Code-gen Done Type Information
8. Code Parsing Analysis Resolve Code-gen Done Type Checking
9. Code Parsing Analysis Resolve Code-gen Done class UserRepo { fun getUsers(): List<User> fun addUser() fun deleteUser(id: Int) } Type Checking
10. Code Parsing Analysis Resolve Code-gen Done if ("hello" "== 1) { } Operator ‘"==’cannot be applied to ‘String’ and ‘Int’ Type Checking
11. Code Parsing Analysis Resolve Code-gen Done Intermediate Representation (IR) Js JVM Native
12. Code Parsing Analysis Resolve Code-gen Done Compiled!
13. ARROW META
14. arrow-kt/arrow-meta Code ! Issues Pull Requests rrow Meta Writing compiler plugins, source transformations, IDEA plugins, linters, type search engines, automatic code refactoring,""... Gradle Build passing latest snapshot v1.3.61
15. Code Parsing Analysis Resolve Code-gen Done
16. Code Parsing Analysis Resolve Code-gen Done class UserRepo { fun getUsers(): List<User> fun addUser() fun deleteUser(id: Int) }
17. Code Parsing Analysis Resolve Code-gen Done Abstract Syntax Tree (AST)
18. Code Parsing Analysis Resolve Code-gen Done Quote Templates Search and transform
19. Code Parsing Analysis Resolve Code-gen Done Type Checking
20. Code Parsing Analysis Resolve Code-gen Done Type Checker
21. Code Parsing Analysis Resolve Code-gen Done Type Checker Custom Type Checker
22. Code Parsing Analysis Resolve Code-gen Done Intermediate Representation (IR) Js JVM Native Hook into IR
23. Code Parsing Analysis Resolve Code-gen Done Compiled!
24. Compiler Plugins Write & Test
25. Writing Complier Plugins with Arrow Meta - Simple Hello World Plugin - Write & Test Plugin for logging - Combine Transformations - Custom Type Checker
26. Steps to Write Compiler Plugin 1. Create Compiler Plugin(s) 2. Register Plugin
27. fun main() { helloWorld() } fun helloWorld() { } HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
28. fun main() { helloWorld() } fun helloWorld() { println("Hello DroidCon EMEA!”) } Generate HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
29. val Meta.helloWorld: CliPlugin Entry Point for compiler
30. val Meta.helloWorld: CliPlugin Type alias
31. val Meta.helloWorld: CliPlugin typealias CliPlugin = Plugin<CompilerContext>
32. val Meta.helloWorld: CliPlugin data class Plugin<A>( val name: String, val meta: A.() "-> List<ExtensionPhase> ) Name of compiler plugin
33. val Meta.helloWorld: CliPlugin data class Plugin<A>( val name: String, val meta: A.() "-> List<ExtensionPhase> ) Phases of compilation
34. val Meta.helloWorld: CliPlugin get() = "Hello World" { } Creates a Plugin object
35. val Meta.helloWorld: CliPlugin get() = "Hello World" { } operator fun String.invoke( phases: CompilerContext.() "-> List<ExtensionPhase> ): CliPlugin = Plugin(this, phases)
36. val Meta.helloWorld: CliPlugin get() = "Hello World" { } How do we hook into the parsing phase?
37. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( ) } Intercept compilation phases
38. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( ) } fun meta( vararg phases: ExtensionPhase ): List<ExtensionPhase> Define list of phases
39. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> } ) } Finds a function named “helloWorld"
40. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> } ) } Quote Template DSL fun nodeName { } Function, Expression
41. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> } ) } Quote Template DSL fun nodeName { } Specify Transformation
42. val Meta.helloWorld: CliPlugin get() = "Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> } ) } Function
43. val Meta.helloWorld: CliPlugin get() = “Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> Transform.replace( ) } ) } Replace Transformation
44. val Meta.helloWorld: CliPlugin get() = “Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> Transform.replace( replacing = c newDeclaration = """|fun helloWorld(): Unit = | println("Hello DroidCon EMEA!") |""".function.syntheticScope ) } ) } Function to replace
45. val Meta.helloWorld: CliPlugin get() = “Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> Transform.replace( replacing = c, newDeclaration = """|fun helloWorld(): Unit = | println("Hello DroidCon EMEA!") |""".function.syntheticScope ) } ) } Replacement
46. val Meta.helloWorld: CliPlugin get() = “Hello World" { meta( namedFunction(this, { name "== "helloWorld" }) { c "-> Transform.replace( replacing = c, newDeclaration = """|fun helloWorld(): Unit = | println(“Hello DroidCon EMEA!") |""".function.syntheticScope ) } ) }
47. Writing Complier Plugins with Arrow Meta 1. Create Compiler Plugin(s) 2. Register Plugin
48. class MetaPlugin : Meta { override fun intercept(ctx: CompilerContext): List<CliPlugin> = listOf( helloWorld ) } Create Meta Class
49. class MetaPlugin : Meta { override fun intercept(ctx: CompilerContext): List<CliPlugin> = listOf( helloWorld ) } Register All Plugins with Kotlin Compiler
50. class MetaPlugin : Meta { override fun intercept(ctx: CompilerContext): List<CliPlugin> = listOf( helloWorld ) } Register Hello World Plugin
51. Plugin Build
52. compileKotlin { kotlinOptions { jvmTarget = "$JVM_TARGET_VERSION" freeCompilerArgs = [“-Xplugin=${project.rootDir}/libs/my-plugin-all.jar"] } } Add Plugin jar
53. fun main() { helloWorld() } fun helloWorld() { } HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
54. fun main() { helloWorld() } fun helloWorld() { println("Hello DroidCon EMEA!”) } HelloWorld.kt Hello DroidCon EMEA! HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
55. fun main() { helloWorld() } fun helloWorld() { } HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
56. fun main() { helloWorld() } fun helloWorld() { } HelloWorldKt src main kotlin com learn arrow-meta HelloWorldKt
57. Writing Complier Plugins with Arrow Meta - Simple Hello World Plugin - Write & Test Plugin for logging - Combine Transformations - Custom Type Checker
58. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last()
59. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() Annotation to log execution time
60. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last()
61. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result }
62. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Original Operation
63. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Log method name & argument
64. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Get current time
65. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Original Operation
66. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Calculate execution time
67. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } Log execution time
68. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long { println(""-> calculate(n=${'$'}n)") val startTime = System.currentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(""<- calculate[ran in ${'$'}timeToRun ms]") return result } How do we generate this code?
69. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last()
70. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() Filter
71. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() Modify
72. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Specify plugin name
73. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Specify Extension Phases
74. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Find Function
75. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Function
76. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Filter Function with DebugLog Annotation
77. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Create extension to find method
78. fun KtNamedFunction.validateFunction(): Boolean = Extension for getting a function with annotation
79. fun KtNamedFunction.validateFunction(): Boolean = hasOneIntParam() "&& hasLongReturnType() "&& hasAnnotation(DEBUG_LOG) Find method with a signature
80. fun KtNamedFunction.validateFunction(): Boolean = hasOneIntParam() "&& hasLongReturnType() "&& hasAnnotation(DEBUG_LOG) Check method has debug annotation
81. fun KtAnnotated.hasAnnotation( vararg annotationNames: String ): Boolean { val names = annotationNames.toHashSet() val predicate: (KtAnnotationEntry) "-> Boolean = { it.typeReference "?.typeElement "?.safeAs<KtUserType>() "?.referencedName in names } return annotationEntries.any(predicate) } Annotations to match
82. fun KtAnnotated.hasAnnotation( vararg annotationNames: String ): Boolean { val names = annotationNames.toHashSet() val predicate: (KtAnnotationEntry) "-> Boolean = { it.typeReference "?.typeElement "?.safeAs<KtUserType>() "?.referencedName in names } return annotationEntries.any(predicate) } Convert to set
83. fun KtAnnotated.hasAnnotation( vararg annotationNames: String ): Boolean { val names = annotationNames.toHashSet() val predicate: (KtAnnotationEntry) "-> Boolean = { it.typeReference "?.typeElement "?.safeAs<KtUserType>() "?.referencedName in names } return annotationEntries.any(predicate) } Match annotation’s name
84. fun KtAnnotated.hasAnnotation( vararg annotationNames: String ): Boolean { val names = annotationNames.toHashSet() val predicate: (KtAnnotationEntry) "-> Boolean = { it.typeReference "?.typeElement "?.safeAs<KtUserType>() "?.referencedName in names } return annotationEntries.any(predicate) } Check function’s annotations
85. fun KtAnnotated.hasAnnotation( vararg annotationNames: String ): Boolean { val names = annotationNames.toHashSet() val predicate: (KtAnnotationEntry) "-> Boolean = { it.typeReference "?.typeElement "?.safeAs<KtUserType>() "?.referencedName in names } return annotationEntries.any(predicate) }
86. fun KtNamedFunction.validateFunction(): Boolean = hasOneIntParam() "&& hasLongReturnType() "&& hasAnnotation(DEBUG_LOG)
87. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Filter function
88. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Transform function
89. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Add debug log to function
90. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Modify Function
91. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
92. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" } Get info on function
93. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" } Create new function
94. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
95. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
96. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
97. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
98. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
99. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
100. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
101. fun replace(function: KtNamedFunction): String { val functionName = function.name val paramName = function.valueParameters.first().name val functionBody = function.body()"?.bodySourceAsExpression() return """ |fun ${functionName}(${paramName}: Int): Long { | println(""-> $functionName(${paramName}=$${paramName})") | val startTime = System.currentTimeMillis() | val result = $functionBody | val timeToRun = System.currentTimeMillis() - startTime | println(""<- ${functionName}[ran in ${'$'}timeToRun ms]") | return result | }""" }
102. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } Convert to function
103. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } val String.function get() = NamedFunction( delegate.createFunction(trimMargin().trim()) )
104. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) }
105. class DebugLogMetaPlugin : Meta { override fun intercept(ctx: CompilerContext): List<CliPlugin> = listOf( debugLog ) } Register Debug Log Plugin
106. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin fun main() { calculate(10) } @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last()
107. DebugLogPlugin src main kotlin com learn arrow-meta DebugLogPlugin fun main() { calculate(10) } @DebugLog fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() DebugLogPlugin.kt "-> calculate(n=10) "<- calculate[ran in 36 ms]
108. val Meta.debugLog: CliPlugin get() = "DebugLog" { meta( namedFunction(this, { validateFunction() }) { c "-> Transform.replace( replacing = c, newDeclaration = replace(c).function ) } ) } How do we test this?
109. arrow-kt/arrow-meta Code ! Issues Pull Requests compiler-plugin 447 commits 2060af5 2 days ago ide-plugin gradle-plugin prelude docs meta-testing
110. arrow-kt/arrow-meta Code ! Issues Pull Requests compiler-plugin 447 commits 2060af5 2 days ago ide-plugin gradle-plugin prelude docs meta-testing Testing utilities
111. val source = """ |annotation class DebugLog | |@DebugLog |fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source
112. val source = """ |annotation class DebugLog | |@DebugLog |fun prime(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source val String.source = Code.Source(text = this)
113. val expectedOutput = """ |annotation class DebugLog | |fun calculate(n: Int): Long { | println(""-> calculate(n=${'$'}n)") | val startTime = System.currentTimeMillis() | val result = listOf(1L,2L,3L).take(n).last() | val timeToRun = System.currentTimeMillis() - startTime | println(""<- calculate[ran in ${'$'}timeToRun ms]") | return result | }""".trimMargin().trim().source Plugin should generate this
114. @Test fun `should log function time execution`() { }
115. @Test fun `should log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source }, assert = { quoteOutputMatches(expectedOutput) } ) } Testing utility
116. @Test fun `should log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source }, assert = { quoteOutputMatches(expectedOutput) } ) } Plugin to test
117. @Test fun `should log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source }, assert = { quoteOutputMatches(expectedOutput) } ) } Source to test
118. @Test fun `should log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source }, assert = { quoteOutputMatches(expectedOutput) } ) } Expected generate code
119. @Test fun `should log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { debuglog }, assert = { quoteOutputMatches(expectedOutput) } ) } How do we run this test?
120. @Test fun `sshould log function time execution`() { CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { debuglog }, assert = { quoteOutputMatches(expectedOutput) } ) } fun assertThis(compilerTest: CompilerTest) = compilerTest.run(interpreter)
121. @Test fun `should log function time execution`() { val compilerTest = CompilerTest(…) assertThis(compilerTest) } Run test
122. @Test fun `should log function time execution`() { assertThis(CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source}, assert = { quoteOutputMatches(expectedOutput) } )) } How does this test run?
123. val source = """ |annotation class DebugLog | |@DebugLog |fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source Source of compiler plugin
124. val source = """ |annotation class DebugLog | |@DebugLog |fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source DebugLogPlugin.kt START quote.doAnalysis: [KtFile: Source.kt] Create a file with source
125. val source = """ |annotation class DebugLog | |@DebugLog |fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source DebugLogPlugin.kt START quote.doAnalysis: [KtFile: Source.kt] Transform file into AST Transformed file: KtFile: Source.kt.
126. val source = """ |annotation class DebugLog | |@DebugLog |fun calculate(n: Int): Long = listOf(1L,2L,3L).take(n).last() | """.trimMargin().trim().source DebugLogPlugin.kt Transformed file: KtFile: Source.kt. [(KtFile: Source.kt, File(decls=[Structured(mods=[Lit(keyword=ANNOTATION)], ""... Structure of file
127. @Test fun `should log function time execution`() { assertThis(CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source}, assert = { quoteOutputMatches(expectedOutput) } )) } DebugLogPlugin.kt Transformed file: KtFile: Source.kt. [(KtFile: Source.kt, File(decls=[Structured(mods=[Lit(keyword=ANNOTATION)], ""... Run test
128. @Test fun `should log function time execution`() { assertThis(CompilerTest( config = { listOf(addMetaPlugins(DebugLogMetaPlugin())) }, code = { source}, assert = { quoteOutputMatches(expectedOutput) } )) } DebugLogPlugin.kt ktFile: KtFile: Source.kt ——————————————— fun calculate(n: Int): Long { println(""-> calculate(n=$n)") val startTime = System.curentTimeMillis() val result = listOf(1L,2L,3L).take(n).last() val timeToRun = System.currentTimeMillis() - startTime println(“"<- calculate[ran in $timeToRun ms]") return result } Generate log
129. Writing Complier Plugins with Arrow Meta - Simple Hello World Plugin - Write & Test Plugin for logging - Combine Transformations - Custom Type Checker
130. Transformations - Replace - Remove - New Sources - Combine Transformations
131. Quotes - Expressions - Declarations - Class & Object - Properties - Type Reference
132. fun main() { helloWorld() } fun helloWorld() { println("Hello DroidCon EMEA!”) } Remove ReplacePluginKt src main kotlin com learn arrow-meta ReplacePluginKt
133. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } Define Plugin
134. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } Quote
135. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } Filter function
136. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } NamedFunction
137. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) }
138. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) }
139. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } Template
140. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) } Convert to expression
141. val Meta.removePlugin: CliPlugin get() = “Remove" { meta( namedFunction(this, { name "== “helloWorld" }) { c "-> Transform.remove( removeIn = c, declaration = """println("Hello Droidcon EMEA!")""".expressionIn(c) ) } ) }
142. fun main() { helloWorld() } fun helloWorld() { println("Hello DroidCon EMEA!”) } ReplacePluginKt ReplacePluginKt src main kotlin com learn arrow-meta ReplacePluginKt Greeting is not printed
143. Transformations - Replace - Remove - New Sources - Combine Transformations
144. NewSourcePluginKt src main kotlin com learn arrow-meta NewSourcePluginKt data class User(""...)
145. data class User(""...) NewSourcePluginKt src main kotlin com learn arrow-meta NewSourcePluginKt class UserAdapter_Generated { fun deserialize() = { } fun serialize() = { } } Generate adapter in new file
146. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Create Plugin
147. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Define Extension Phases
148. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Quote
149. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Find user class
150. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Transform class
151. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Create adapter in new file
152. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Adapter
153. val Meta.adapterGenerator: CliPlugin get() = "Adapter Plugin" { meta( classDeclaration(this, { name "== "User" }) { Transform.newSources( """ package adapters class ${name}Adapter_Generated { fun deserialize() = { } fun serialize() = { } } """.file("${name}Adapter_Generated") ) } ) } Create a new file
154. data class User(""...) NewSourcePluginKt src main kotlin com learn arrow-meta NewSourcePluginKt
155. NewSourcePluginKt src main kotlin com learn arrow-meta UserAdapter_Generated.kt class UserAdapter_Generated { fun deserialize() = { } fun serialize() = { } } Generated file
156. Transformations - Replace - Remove - New Sources - Combine Transformations
157. CombineTransformKt src main kotlin com learn arrow-meta CombineTransformKt public class SimpleClass { fun printGreeting() { println("Hello DroidCon EMEA!”) } }
158. CombineTransformKt src main kotlin com learn arrow-meta CombineTransformKt public class SimpleClass { fun printGreeting() { println("Hello DroidCon EMEA!”) } } Change class visibility to private
159. CombineTransformKt src main kotlin com learn arrow-meta CombineTransformKt public class SimpleClass { fun printGreeting() { println("Hello DroidCon EMEA!”) } } Remove Expression
160. CombineTransformKt src main kotlin com learn arrow-meta CombineTransformKt private class SimpleClass { ""... }
161. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "ManySimpleCase" }) { c "-> changeClassVisibility("ManySimpleCase", c, this) + removeGreeting(c, this) } ) }
162. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility("SimpleClass", c, this) + removeGreeting(c, this) } ) } Filter Class
163. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility(“SimpleClass", c, this) + removeGreeting(c, this) } ) } Change Class visible to private
164. fun CompilerContext.changeClassVisibility( className: String, context: KtClass, declaration: ClassDeclaration ): Transform<KtClass> = declaration.run { } SimpleClass
165. fun CompilerContext.changeClassVisibility( className: String, context: KtClass, declaration: ClassDeclaration ): Transform<KtClass> = declaration.run { } Class to transform
166. fun CompilerContext.changeClassVisibility( className: String, context: KtClass, declaration: ClassDeclaration ): Transform<KtClass> = declaration.run { } Class’s Declaration
167. fun CompilerContext.changeClassVisibility(""...): Transform<KtClass> = declaration.run { Transform.replace( replacing = context, newDeclaration = """ | private class $className { | $body | } """.`class`.syntheticScope ) }
168. fun CompilerContext.changeClassVisibility(""...): Transform<KtClass> = declaration.run { Transform.replace( replacing = context, newDeclaration = """ | private class $className { | $body | } """.`class`.syntheticScope ) } New Identifier
169. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility(“SimpleClass", c, this) + removeGreeting(c, this) } ) } Remove Greeting
170. fun CompilerContext.removeGreeting( context: KtClass, declaration: ClassDeclaration ): Transform<KtClass> = declaration.run { Transform.remove( removeIn = context, declaration = """ fun printFirst() = println("Hello DroidCon EMEA!") """.expressionIn(context) ) }
171. fun CompilerContext.removeGreeting( context: KtClass, declaration: ClassDeclaration ): Transform<KtClass> = declaration.run { Transform.remove( removeIn = context, declaration = """ fun printGreeting() = println("Hello DroidCon EMEA!") """.expressionIn(context) ) } Remove Method
172. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility(“SimpleClass", c, this) + removeGreeting(c, this) } ) } Combine?
173. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility(“SimpleClass", c, this) + removeGreeting(c, this) } ) } Use Plus Operator + +
174. operator fun Transform<K>.plus(transform: Transform<K>): Transform.Many(arrayListOf(this, transform)) Transform 1 Transform 2
175. operator fun Transform<K>.plus(transform: Transform<K>): Transform.Many(arrayListOf(this, transform)) New Combine Transform
176. val Meta.composeTransforms: CliPlugin get() = "Compose Transforms" { meta( classDeclaration(this, { name "== "SimpleClass" }) { c "-> changeClassVisibility(“SimpleClass", c, this) + removeGreeting(c, this) } ) } Remove Greeting
177. CombineTransformKt src main kotlin com learn arrow-meta CombineTransformKt private class SimpleClass { ""... }
178. Transformations - Replace - Remove - New Sources - Combine Transformations
179. Writing Complier Plugins with Arrow Meta - Simple Hello World Plugin - Write & Test Plugin for logging - Combine Transformations - Custom Type Checker
180. Type 1 Type 2
181. Type 1 Type 2 "== Define equality & Subtyping
182. val Meta.typeChecker: CliPlugin get() = “Custom Type Checker” { meta( typeChecker { ProofTypeChecker(ctx) } }
183. val Meta.typeChecker: CliPlugin get() = “Custom Type Checker” { meta( typeChecker { CustomTypeChecker(ctx) } }
184. class CustomTypeChecker() : NewKotlinTypeChecker { override fun isSubtypeOf( subtype: KotlinType, supertype: KotlinType ): Boolean { override fun equalTypes( subtype: KotlinType, supertype: KotlinType ): Boolean = } Type Checker Provided by Kotlin Compiler
185. class CustomTypeChecker() : NewKotlinTypeChecker { override fun isSubtypeOf( subtype: KotlinType, supertype: KotlinType ): Boolean override fun equalTypes( subtype: KotlinType, supertype: KotlinType ): Boolean } Define Sub-typing
186. class CustomTypeChecker() : NewKotlinTypeChecker { override fun isSubtypeOf( subtype: KotlinType, supertype: KotlinType ): Boolean override fun equalTypes( subtype: KotlinType, supertype: KotlinType ): Boolean } Define Equality
187. class CustomTypeChecker() : NewKotlinTypeChecker { override fun isSubtypeOf( subtype: KotlinType, supertype: KotlinType ): Boolean override fun equalTypes( subtype: KotlinType, supertype: KotlinType ): Boolean } Define Equality
188. Custom Type Checking Example - Type Proofs Plugin - Refinement Type Plugin
189. IDE Plugins
190. class TasksViewModel { fun refreshTasks() { setState { } } }
191. class TasksViewModel { fun refreshTasks() { setState { ""... } } } Show icon in IDE
192. val MetaIde.mviPlugin: IdePlugin Create extension property
193. val MetaIde.mviPlugin: IdePlugin Create an IDE Plugin
194. val MetaIde.mviPlugin: IdePlugin typealias IdePlugin = Plugin<IdeContext>
195. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin” { } Create Plugin object
196. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin” { } operator fun String.invoke( phases: IdeContext.() "-> List<ExtensionPhase> ): IdePlugin
197. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin" { meta( ) } Add extension phases
198. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) } Add marker for a node in AST
199. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) } Path to icon in resources
200. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) } AST Node
201. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) } Message to show on mouse over
202. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) } Filter function with property
203. val MetaIde.mviPlugin: IdePlugin get() = “MVI Plugin".invoke { meta( addLineMarkerProvider( icon = PluginIcons.UPDATE, composite = KtNamedFunction"::class.java, message = { f: KtNamedFunction "-> “State will be updated by action.” }, transform = { it.safeAs<KtNamedFunction>()"?.takeIf { f "-> f.name "== "setState" } } ) ) }
204. class IdeMetaPlugin : MetaPlugin(),{ override fun intercept(ctx: IdeContext): List<IdePlugin> = listOf( mviPlugin ) } Extend MetaPlugin
205. class IdeMetaPlugin : MetaPlugin() { override fun intercept(ctx: IdeContext): List<IdePlugin> = listOf( mviPlugin ) } Add all IDE plugins
206. class TasksViewModel { fun refreshTasks() { setState { ""... } } } Show icon in IDE
207. class TasksViewModel { fun refreshTasks() { setState { ""... } } } Show message for feature State will be updated by action.
208. Plugins in Arrow Meta • Monad Comprehensions • Lens • Type Proofs
209. https:"//codingwithmohit.com/arrow-meta/writing-compiler-plugin-with-arrow-meta/ Compiler Plugin
210. Thank you Arrow Team & All Contributors • Rachel M. Carmena • Raúl Raja • Imran Settuba • Simon Veragauwen • and all contributors!
211. Kotlin Slack Channels • #compiler • #arrow-meta
212. Resources • Writing Kotlin Compiler Plugins with Arrow Meta • Lambda World 2019 - Arrow Meta - Enabling Functional Programming in the Kotlin Compiler • Arrow Meta. Kotlin Metaprogramming for the masses • Type Proofs and FP for the Kotlin Type System
213. Thank You! www.twitter.com/heyitsmohit www.codingwithmohit.com