Hi again!. Does anyone know equivalent to: ```arrow.core.andThen``` in 1.0??

# arrow

[Alvaro Blazquez checa]

Hi again!. Does anyone know equivalent to:

arrow.core.andThen

in 1.0??

[simon.vergauwen]

https://arrow-kt.io/docs/apidocs/arrow-core/arrow.core/index.html#functions

[Alvaro Blazquez checa]

I did use andThen to add another step to a function type

[Alvaro Blazquez checa]

I think it is not the same

[simon.vergauwen]

The signature hasn’t changed, it moved to a different package

[simon.vergauwen]

can you share a snippet?

[Alvaro Blazquez checa]

sure

[Alvaro Blazquez checa]

https://arrow-kt.io/docs/0.11/apidocs/arrow-core-data/arrow.core/-and-then/

[Alvaro Blazquez checa]

I was looking for that andThen @simon.vergauwen. to do function composition

[Alvaro Blazquez checa]

Since higherkinds are deprecated in 1.0 i dont know if that is still available

[simon.vergauwen]

It’s still available here. https://github.com/arrow-kt/arrow/blob/main/arrow-libs/core/arrow-core/src/commonMain/kotlin/arrow/core/composition.kt#L8

[simon.vergauwen]

Oh, you’re looking for the higher kind?

[simon.vergauwen]

This is now being used underneath andThen and you no longer need to keep AndThen around

[simon.vergauwen]

You can safely use typealias AndThen<A> = () -> A to replace it

[Alvaro Blazquez checa]

i need to check that out. I dont get it right now. Thx

[Alvaro Blazquez checa]

migrating to 1.0 old andThen use gives me an error. It was used over an exetenssion function so:
MyClass.() -> Try<T> was the signature of the function I was using andThen over, like:
val a: MyClass.() -> Try<T> = createFunction().andThen()

[Alvaro Blazquez checa]

now migrating to 1.0 it does not compile

[Alvaro Blazquez checa]

i have checked old signature of andThen ans was:
infix fun <A, B, C> ((A) -> B).andThen(g: (B) -> C): (A) -> C

[Alvaro Blazquez checa]

now it is:
public expect infix fun <P1, IP, R> ((P1) -> IP).andThen(f: (IP) -> R): (P1) -> R

[Alvaro Blazquez checa]

So for example:

val a: () -> String = { " 2323" }.andThen { s -> s }
val b: Myclass.() -> String = { " 2323" }.andThen { s -> s }

[Alvaro Blazquez checa]

b does not comiple now in 1.0

[Alvaro Blazquez checa]

cant figure out why

[Alvaro Blazquez checa]

Ok. my fault. Extension function I was applying and Then to was refactored to suspend. That is why compiler was complaining because receiver of andThen was different. 😑.

[simon.vergauwen]

I think it’d be interesting to add suspend variants of those functions maybe? If you’re interested feel free to create a issue/PR 😉

[Alvaro Blazquez checa]

sure Simon

[Alvaro Blazquez checa]

I do not know if people would like it since if you are using suspend it implies it is an impure function.
And may be it is not the best way to use function composition with side effect functions

[Alvaro Blazquez checa]

for now I have just write my own

[Alvaro Blazquez checa]

Ill think abou that