geni VS kotlinx.collections.immutable

sparkling is fine. there is also geni

I haven't tried Spark from Kotlin, but it's a nice experience working with it in Clojure, and I have yet to see a language more expressive than Clojure. :)

I think for the large scale stuff, wrappers like geni are pretty nice and built on top of established tech. There were several distributed computing platforms like onyx and storm that popped up in clojure as well that may be interesting to look at. clojure toolbox has a good index of libraries to examine.

In Clojure, it is called an Atom. I created my own via AtomicReference and https://github.com/Kotlin/kotlinx.collections.immutable. It works really well in Kotlin. It works especially well if you use tons of coroutines.

So does Java! Also, kotlinx.collections is still not stable and I don't think they are intending to make it so any time soon.

If you want to have O(1) with prepend you use the LinkedList. You get a lot of functional benefits but also all of the downsides like no random access. You can use the https://github.com/Kotlin/kotlinx.collections.immutable library to get O(log_64(n)). I haven't spent a ton of time on Tries so I might be a little wrong on that bound. BTW, these are persistent immutable data structures. At work, we use them inside of AtomicReference to roll our own Clojure Atoms.

This is why Kotlin refers to List as read-only, and not immutable, and has created a library for truly immutable collections: https://github.com/Kotlin/kotlinx.collections.immutable

What I know is only based on this discussion. It seems that pcollections is really outdated and should not be considered.

If you want true immutable collections, kotlinx.collections.immutable provides them. They will likely be integrated into the language eventually with value classes and better immutability support.

I could see this argument made with Clojure, but I don't really see what makes Scala significantly better at FP than Kotlin. Kotlin has an official persistent data structures library nowadays, and it's got lambdas and higher order functions.

It's not immutable, it's read-only, https://kotlinlang.org/docs/reference/collections-overview.html . I think that's a false assumption. But I get the point - immutable collections are not part of the std - for very good reasons. But we know each other, I assume that you will disagree :) For people who know what they want and know all the implications, there is https://github.com/Kotlin/kotlinx.collections.immutable .