Hello, are there any examples on `monad-comprehens...

# arrow

[Fabian]

Hello,
are there any examples on monad-comprehensins on StateMonad?
I'm having some code that when implemented with flatMap s compiles and run without issues BUT with monad-comprehensions throws
java.lang.NoSuchMethodError: arrow.typeclasses.Monad.getFx()Larrow/typeclasses/MonadFx
So I wanted to check for a reference example

[Bob Glamm]

Can you post the two different code samples?

[Fabian]

I'm on 0.10.4.

This impl works

evalOne("1").flatMap(Id.monad()) {
            evalOne("2").flatMap(Id.monad()) {
                evalOne("+")
            }
        }.runA(Id.monad(), ListK(emptyList())).value()

This impl does not (throws the exception shown in my previous post)

val result: State<List<Int>, Option<Int>> = State.fx(Id.monad()) {
            val (_) = evalOne("1")
            val (_) = evalOne("2")
            val (c) = evalOne("+")
            c
        }
        result.runA(Id.monad(), ListK(emptyList())).value()

And this is my function

fun evalOne(sym: String): State<List<Int>, Option<Int>> {...}

thanks a lot for any ideas on how to solve this

[pakoito]

can you please take a look at your ./gradlew dependencies and see if you're pulling a consistent version or if gradle resolves to a previous one due to a transitive dependency

[pakoito]

maybe from KotlinTest

[Fabian]

thanks, I'm gonna take a look

[pakoito]

otherwise, try using .bind() or ! instead of destructuring

[pakoito]

maybe it's a compiler issue