Evaluating Swift-to-Kotlin and Kotlin-to-Swift Transpilers

Abstract

Unlike most popular mobile cross-platform development frameworks, transpilers promise maintainable code bases that are independent of the continued life of the development tools used. As more and more transpiler projects using the native programming languages Kotlin (Android) and Swift (iOS) were presented in recent years, this paper provides an overview of the language coverage of three representative transpilers, Gryphon (Swift-to-Kotlin), Kotlift (Kotlin-to-Swift), and SequalsK (both directions). For the test cases based on the overview chapters of the Swift and Kotlin documentation, good results were obtained in terms of functionality and readability of the output code for Gryphon and SequalsK. Although some shortcomings are visible in all transpilers, Kotlift is classified as a less mature project.