Kotlin code challenge @sellmair

gistfile1.kt

fun main() {
    val transformation = Transformation.TransformationComposite(listOf(Transformation.NoOpTransformation()))
    println("Res: ${transformation(Shape())}")
}

class Shape

sealed class Transformation {
    class NoOpTransformation : Transformation()
    class TransformationComposite(val transformations: List<Transformation>) : Transformation()
}

inline operator fun Transformation.invoke(shape: Shape): Shape =
    when (this) {
        is Transformation.NoOpTransformation -> shape
        is Transformation.TransformationComposite -> transformations.fold(shape) { acc, transformation ->
            transformation(acc) // This is calling the invoke method recursively
        }
    }