rename traverseX and sequenceX for Iterable

[i-walker]

for parTraverse I'll add another PR since this needs a bit of investigating

[i-walker]

For parTraverse I will provide an example repo and leave a comment https://youtrack.jetbrains.com/issue/KT-49658 where it is failing

[nomisRev]

The issue you linked @i-walker isn't the ticket what is causing issue with parTraverse.

parTraverse for suspend (A) -> B conflicts with any other lambda having a data type in it's return type. Since here B can be Either<?, ?> or any other data type.

If we would rename parTraverse to parMap for suspend (A) -> B that solves the problem, but renaming the other parTraverse results in the following bug. https://youtrack.jetbrains.com/issue/KT-43907
So we can currently not rename parTraverseXXX to parTraverse yet, we can however already consider renaming parTraverse to parMap for suspend (A) -> B. But let's take that into another PR.

We should create a ticket for this deprecation, and work when the above issue in Kotlin is fixed.

[nomisRev]

Curious that this doesn't conflict with the other traverse functions 🤔
This seems like one of those signatures that breaks all other functions 😅

What happens in the case of:

fun either(i: Int): Either<String, Int>? = null

val x: ??? = listOf(1, 2, 3).traverse { either(i) }

I guess ??? here is List<Either<String, Int>>?, and to turn it into Either<String, List<Int>>? we'd need to chain it with ?.sequence(). That'd be pretty cool if that works like that out of the box.

[i-walker]

Yes this one would be List<Either<String, Int>>? I can set up a small example test

[pakoito]

These are some of the coolest functions in the lib, would it possible to save them in some form? 🥺

[nomisRev]

@pakoito not sure what you mean?
Not of this functionality is being removed, we're trying to simplify the naming from traverseXXX to traverse. All functionality is being preserved.

The only "big" change that is happening is that we're changing the signature from Sequence#traverse to return List instead of Sequence because it's actually a ListSequence under the hood. So we felt that returning Either<E, Sequence<A>> is a lie and it should be returning Either<E, List<A>> to be more correct.

[pakoito]

Gotcha!

[nomisRev]

Looks great to me @i-walker! Awesome clean-up. Now all methods are simply traverse and sequence and the compiler automatically picks the correct one 🥳

[nomisRev]

Thanks, @i-walker! This is pretty cool that it works out of the box!

[raulraja]

thanks @i-walker