Any chance to have something similar to an eta red...

# functional

[gian]

Any chance to have something similar to an eta reduce in Kotlin?

[elizarov]

What is the problem you are trying to solve?

[gian]

It’s just styling, I would like to say that a function is equal to another function, without manually passing the parameter

[elizarov]

why would you need this?

[gian]

to delegate, for example

[gian]

Maybe I’ve been spoiled by haskell

[elizarov]

can you give a snippet of code?

[elizarov]

(can be in Haskell)

[gian]

funName i = otherFun i
vs
funName = otherFun

fun funName(i: A) = otherFun(i)

[gian]

in kotlin I can do that provided that it’s not a function, but a val

[gian]

e.g.

val a:(Int)->String = ::otherFun

[elizarov]

Yes. What’s the problem with that?

[elizarov]

And you can even omit type.

[gian]

that I need the original declaration to be a val and not a fun, right? 🤔

[elizarov]

But why it matter? Like there’s no difference between them in Haskell.

[gian]

I don’t always control the function

[gian]

maybe it comes from an interface

[gian]

and I want to “delegate” the implementation

[gian]

I guess in Kotlin would be something like:
fun funName by otherFun

[elizarov]

There are some plans for fun a(i: Int) by ::otherFun but not in the near future.

[gian]

Well, nice to hear that 😄

[elizarov]

For now, if you come from Haskell you can use val everywhere, even in your interfaces.

[gian]

Yes, I’m doing that when I control them
Thank you!