Hi. Is it possible to use suspend function for mod...

# arrow

[Alexander Levin]

Hi. Is it possible to use suspend function for modify inside Arrow optic? Like:

MyType.foo.bar.every.baz.modify(obj) { someSuspendFun(it) }

[than_]

currently, unfortunately no. The modify would have to be inline . But I have a feeling @simon.vergauwen could have some some near future good news regarding this topic 🙂

[simon.vergauwen]

Currently, this is indeed not possible since interface cannot contain any inline functions (this is because there no code to inline, since it's dispatched to a runtime implementation).

[simon.vergauwen]

It's possible however to add, extension functions to the interface that allow inlining.

i.e.

inline fun <S, A> Lens<S, A>.modifySuspend(source: S, f: (A) -> A): S {
  val focus = get(source)
  f(focus)
  return set(source, focus)
}

This could be solved by moving to class, and revering the current hierarchy to not use inheritance for auto-conversion between optics.

[simon.vergauwen]

If interested, we could move this to a ticket to discuss further there.

[Alexander Levin]

@simon.vergauwen as it was single use case only the problem was just solved without optics. However for the future it would be nice to have some solution that works with suspend (and I guess with other "code coloring" as well but idk)
So yeah, adding this discussion to some ticket would be great :)