kotlinpoet

Create extension function (function with . in name)

I want to generate a very simply class that just contains extension functions, like e.g. following:

import com.my.app.SomeClass

fun SomeClass.function() {
}

What I try:

val packageName = ...
val annotatedClassName = annotatedElement.simpleName
val fileName = "${annotatedClassName}_KotArgsExtensions"

val extensionBuilder = FileSpec.builder(packageName, fileName)

val funSpecBuilder= FunSpec.builder("${SomeClass::class.java.simpleName}.function").build()
extensionBuilder.addImport(SomeClass::class.java.`package`.name, SomeClass::class.java.simpleName)

extensionBuilder.addFunction(funSpecBuilder)

What I get:

import com.my.app.SomeClass

fun `SomeClass.function`() {
}

Question

How I can I correctly create an extension function like fun SomeClass.function()?

Solution

  • Use FunSpec.Builder.receiver():

    val builder = FunSpec.builder("function")
    .receiver(SomeClass::class)
    .build()
println(builder.build().toString())

    Will give you:

    fun com.my.app.SomeClass.function() {
}