Is it possible to create extension constructors in Kotlin?

Question

In other languages like Swift, there is the possibility of creating a function extension that adds a new constructor.

Something like this:

// base c         


        

Answer 1

Another alternative is to just declare an extension function on the argument (or the first one if there are many):

// base class
class Whatever() {
    ...
}

// extension
fun String.toWhatever() = Whatever().apply { setPotato(this) }

fun main(args: Array) {
    println("holi".toWhatever())
}

The pros:

• You avoid the hassle of declaring an empty Companion object
• Still possible when the Whatever class doesn't have a Companion AND is not yours, so you couldn't add a Companion even if you wanted
• Compact and idiomatic approach