If I have:

interface Foo {
   fun printlog(msg: String) = "... - $msg"
}

class Bar : Foo

How can I get the printlog in the interface to print out

Bar - some message

? If I use

${this::class.simpleName}

it just gives me the interface's name...

Using

${this::class.simpleName}

does work: https://pl.kotl.in/3LrWAHRvp

interface Foo {
   fun printlog(msg: String) = "${this::class.simpleName} - $msg"
}

class Bar : Foo

fun main() {
   val log = Bar().printlog("hello")
   println(log)
}

This correctly prints

Bar - hello

I have:

interface BaseResult {
    fun toLogFmt(): String =
        "type=${this::class.simpleName} literal=${toString()}"
}

I guess there must be something else going on, because even when I complicate things a bit more to do what you describe, I still get the correct output: https://pl.kotl.in/LYzJ3k3Vy

Something like this (not working, but I need to rush out now...): https://play.kotlinlang.org/#eyJ2ZXJzaW9uIjoiMS40LjAiLCJjb2RlIjoiaW50ZXJmYWNlIEJhc2VSZX[…]AgIH1cbiAgIFxufSIsInBsYXRmb3JtIjoiamF2YSIsImFyZ3MiOiIifQ==

I fixed the compile errors in your example (which is close to my last example), and it still does work fine: https://pl.kotl.in/3noHQTl-1

Oh... It was the logger library printing that 🙃, I guess I was expecting that it should give me the use case's name which is a different problem... I guess that's what happens when one is overworked... Thanks for pointing this out! Side point, do I need kotlin reflection library to use simpleName like that? Is it better to use class.java?

I'm glad you figured it out 🙂 I believe you don't need

kotlin-reflect

for

simpleName

.