private val items : MutableList<String> by lazy {
        // a lot of init code
    }

how do I exclude my initialisation code into a separate function? I can think of creating something like

private val items : MutableList<String> by lazy {
        init()
}
fun init() : MutableList<String> {...}

but maybe there is more elegant way

You can use a function reference:

by lazy(::myFunction)

nice, thanks

Then you need to actually call it

ah, ok

You could use one of the existing FP libraries and then use

curry

. But I think that is a bit overkill here.