Kotlin Enum that is simultaneously a String

July 7, 2023

I’d like to define a set of constants strings as a convenient enumeration for peace of mind on compile time. It feels obvious (with my Python background at least) that simple enumerations could be used as string instances.

// Fine for overall use
enum class Things{ FIRST, SECOND, THIRD }
containsThings[Things.FIRST]

// If a String is expected, this works but has extra stuff
enum class Things(val v: String){
    FIRST("FIRST"), SECOND("SECOND"), THIRD("THIRD")
}
// I want to get rid of ".v"
containsThings[Things.FIRST.v]

// Naïve desired syntax
enum class Things: String { FIRST, SECOND, THIRD }
containsThings[Things.FIRST]

Am I missing something obvious?

>Solution :

For that to work, your enum class would have to be a subclass of String. That’s doubly impossible, first because you can’t specify a superclass for an enum class, and second because String is not open and cannot be subclassed.