strrr | Functional-ish string utilities

It runs just fine as posted: Kotlin Playground example

That error usually comes up where you've checked something isn't null, so you can treat it as a non-null type (Int in this case), but that doesn't work for vars because they can change, and could be null again - so you need to use something like hippo?.hunger?.let { bla bla } where the value gets assigned to a temporary val (it by default) which can't be changed.

I'm not sure why you're getting the error there, maybe it's trying to use the println(message: Int) call instead of the println(message: Any?) call for some reason? You can put the cursor on println and do ctrl+Q (or your equivalent) to find out which function it thinks it's calling.

But yeah, if the smart casting is messing you around, it's probably a bug. Casting to Int? like you're doing is one way of doing it, or doing the let/run thing might work too (hippo?.hunger.run(::println)).

Is your main block closed by the way? The curly brace is missing

As documentation states:

On the JVM, if all of the parameters of the primary constructor have default values, the compiler will generate an additional parameterless constructor which will use the default values.

By the way, this constructor will be visible from Java too.