Is there an unfold equivalent in Kotlin? F# definition:

val unfold: 
   generator: 'State -> option<'T * 'State> ->
   state    : 'State 
           -> seq<'T>

I'm not very familiar with F#. but I guess you're looking for generateSequence

I want a state.

can you be more specific? l - like Tobias - can't read F#. It's too for me foreign to make sense of it.

val x = 1

is already a state, but your

unfold

seems way more elaborate.

@Jason5lee I'm also not sure what you mean with state? Is it about having the last value available in the lambda for creating the next value?

generateSequence

can do that, just look at the second example on the page I linked above. If you mean something else, please elaborate.

or maybe

sequence

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.sequences/sequence.html

so something like so?

fun countDown(n: Int) = generateSequence(n) { n ->
  if(n > 0) n-1 else null
}