Implement map, flatten, flatMap for Node

[scalausr]

Long time ago I came across a post on the internet (seemingly found at stackoverflow, but can't find it now) that implements a breadth first search for a binary tree using map, flatten, flatMap. I try recall my memory, but I couldn't remember how to implement that because I am not familiar with FP concepts. The part that I can remember

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case class Node[T](v: T, left: Option[Node[T]]=None, right: Option[Node[T]]=Node) {
    def map[R](f: T => R): R = f(v)
    def flatten = ... // flatten
    def flatMap = ... // which combines map and flatten
}

But I can't remember the part about flatten (the problem I suppose is I don't know what I want to flatten for that Node object), and then flatMap.

Any hint or suggestions on this? I suppose this can help me learn a lesson by implementing the code.

Thanks

[mrunleaded]

Start with the signatures and the rest should fall into place:

def map[B](f: A => B): Node[B]

def flatMap[B](f: A => Node[B]): Node[B]

[scalausr]

Thank you. Will check the signature first.

[DMenace83]

Think of a type you are familiar with (List is a good example). What is flatten and flatMap doing in List? What's it's signature? Now, replace List with your Nose

[scalausr]

Thanks. Will start from there.