Reading Arrow Lens' docs and I'm a bit confused. Docs mention that `set` has type `A -> S -> T...

# arrow

[dimsuz]

Reading Arrow Lens' docs and I'm a bit confused. Docs mention that set has type A -> S -> T, but actual set implementations seem to have it reversed: S -> A -> T.

Screenshots are from: api docs

Similarly main page of Arrow Optics mentions set: A -> S -> S, but then has an example of playerLens.set(player, health). Am I reading this wrong or is this a little bug?

[simon.vergauwen]

Hey @dimsuz,

That piece of the documentation can definitely be improved but Arrow Optics is the oldest stable library by far.. Sadly it didn't get very much attention/love, especially the docs.

The signatures there should probably be updated to the latest constructor that we have in Arrow Optics.


operator fun <S, T, A, B> invoke(get: (S) -> A, set: (S, B) -> T): PLens<S, T, A, B>

https://arrow-kt.io/docs/apidocs/arrow-optics/arrow.optics/-p-lens/-companion/invoke.html

[simon.vergauwen]

Please feel free to create a ticket for this, or a PR if you're up for it 🙏

[dimsuz]

got it! If I'll manage sometime will create a PR!