Hi, can one accomplish this ```flowNodes.forEach {...

# announcements

[Philipp Mayer]

Hi, can one accomplish this

flowNodes.forEach { initialNode ->
        initialNode.succeedingNodes.list().forEach { nextNode ->
            graph.addArc(initialNode to nextNode)
        }
    }

in a more fluent way? Seems like I'm missing something.

The use case would be the following:
I have an initial Node 1 with the succeeding nodes 2 and 3.
The target is to add 1 to 2 and 1 to 3 to the graph.
thanks a lot!

[Javier]

maps chain maybe?

[Javier]

and maybe a flatMap for list()

[Javier]

well the deep initialNode breaks the chain I want to do :/

[Philipp Mayer]

The latter is exactly the problem where I also had to stop. 😞
Anyway, thanks for the input!

[pablisco]

Maybe something like:

flowNodes.flatMap { initialNode ->
  initialNode.succeedingNodes.list()
    .map { initialNode to it } 
}.forEach(graph::addArc)

I’m assuming that glowNodes is a list.
It’s basically the same but allows to have two separate operations which means you can move things around more easily. If everything here under your control? Would be good to see more of the code

[pablisco]

If you want something even easier to read:

private fun Node.succeedinPairs() = 
  succeedingNodes.list().map { this to it } 

// then
flowNodes.flatMap(Node::succeedinPairs)
  .onEach(graph::addArc)

Always good to split things into smaller (and easier to understand) parts 🙂

[Philipp Mayer]

I actually played around with it and had a comparable solution to your second one, @pablisco!

[Philipp Mayer]

Main difference was that I was not using the method references. Looking at your solution, I should finally dig into it..

[pablisco]

Depending on your application you may want to use lambdas instead as method references can be (or used to) a bit heavier as they create an extra class