Kotlin Swift Export Sample

This project demonstrates how to export Kotlin code as native Swift modules using JetBrains' Kotlin Multiplatform. The sample consists of three modules: :shared, :module-a, and :module-b, showcasing how to configure the DSL to export these Kotlin modules into Swift with custom configurations.

⚠️ Experimental Feature Notice

Swift Export is an experimental feature and subject to change in any future releases. It may not function as expected, and you may encounter bugs. This project serves as an early technology demonstration and is not production-ready. Use it at your own risk.

Project Structure

• :shared - The main shared module that aggregates and exports the other modules (:module-a and :module-b) as native Swift modules.
• :module-a - A sample Kotlin module to be exported as ModuleA in Swift.
• :module-b - Another sample Kotlin module to be exported as ModuleB in Swift.

Swift Export Configuration

The export process is configured in the build.gradle.kts file within the kotlin {} block. Below is the configuration:

kotlin {
    iosX64()
    iosArm64()
    iosSimulatorArm64()

    @OptIn(ExperimentalSwiftExportDsl::class)
    swiftExport {
        // Root module name
        moduleName = "Shared"

        // Collapse rule
        flattenPackage = "com.github.jetbrains.swiftexport"

        // Export external modules
        export(project(":module-a")) {
            // Exported module name
            moduleName = "ModuleA"
            // Collapse exported dependency rule
            flattenPackage = "com.github.jetbrains.modulea"
        }

        export(project(":module-b")) {
            // Exported module name
            moduleName = "ModuleB"
            // Collapse exported dependency rule
            flattenPackage = "com.github.jetbrains.moduleb"
        }
    }

    sourceSets.commonMain.dependencies {
        api(project(":module-a"))
        api(project(":module-b"))
    }
}

Getting Started

Prerequisites

• Enable Swift Export by adding kotlin.experimental.swift-export.enabled=true to your local.properties or gradle.properties.

Running the Project

1. Clone this repository.
2. Open the project iosApp/iosApp.xcodeproj with Xcode (tested with version 16.0).
3. Ensure you have the following command in your Run Script build phase: ./gradlew :shared:embedSwiftExportForXcode.
4. Build the project. The Swift modules will be generated and can be found in the build output directory.

Key Features

• moduleName: Allows setting a custom module name for the exported Kotlin module. For instance, the :module-a module is exported as ModuleA in Swift.
• flattenPackage: A package collapsing rule that simplifies package usage in Swift. In Kotlin, modules are typically organized within packages (e.g., com.github.jetbrains.modulea). Using flattenPackage, you can omit the package name and directly use classes from the module in Swift.

Learn More

• For more information on Kotlin Multiplatform, check out the Kotlin Multiplatform Documentation.