It’s just an iterable of iterables of `T` which ge...

# announcements

[egorand]

It’s just an iterable of iterables of T which gets flattened into a list of T. Here’s an example:

[[1, 2, 3], [4], [5, 6]] -> flatten -> [1, 2, 3, 4, 5, 6]

[Ifvwm]

I thought it was like a recursive type, it seems I was wrong, so I wonder can we do that MapTree on kotlin?
data Tree a = Leaf a | Node (Tree a) (Tree a)
deriving (Show)

[Shawn]

It is indeed a recursive generic type but you’re not going to be able to do anything particularly Haskell-ey with them

[Ifvwm]

@Shawn aha, why?

[Dico]

You can do @Ifvwm

sealed class Tree<T> {
    class Leaf<T>(val value: T) : Tree<T>() 
    class Node<T>(val left: Tree<T>, val right: Tree<T>) : Tree<T>()
}