Personally I almost always prefer `followedBy` ove...

# arrow

[simon.vergauwen]

Personally I almost always prefer followedBy over flatMap { _ -> or bind.

[kitttn]

Why?
.bind() still gives you sequential execution in the .fx { .. } block, that’s the idea over it, right?

[simon.vergauwen]

Yes, but that's not used in the snippet.

[simon.vergauwen]

In most cases there will dependencies between the functions and you'll end up using fx but a program could look like this.

IO.fx {
   val a = !produceA()
   val b = !sleep(1.seconds).followedBy(consumeA(a))
   b
}

[kitttn]

hmmm
why can’t i just do

IO.fx {
  val a = !produceA()
  !sleep(1.seconds)
  val b = !consumeA(a)
  b
}

?

[simon.vergauwen]

Sorry I'm on my phone. followedBy serves for a different purpose and provides convenient syntax over plain bind or flatMap.

[simon.vergauwen]

That's purely asthetic

[kitttn]

But both snippets are valid and do the same thing from purity-point-of-view and intention?

[simon.vergauwen]

Absolutely

[kitttn]

Good, thanks for clarification!

[simon.vergauwen]

fun IO<A>.followedBy(fb: IO<A>): IO<B> = flatMap { fb }

[simon.vergauwen]

And bind is flatMap with suspension.