Was expecting:

sealed class Element<T>(val value: T)

object Test : Element(10) // expecting compiler somehow able to refer the implicit integer 10 value to resolve T

But actually need to explicitly declare the argument type to satisfy the compiler:

object Test : Element<Int>(10)

Any reason why? Thank you.

Say my app version is using Kotlin 1.6.21, and I include two other dependencies that are using Kotlin

1.7.0

and

1.4.32

. Is there any possibility that there could be some sort of conflict since the versions are different? What about a similar situation with something like Jetpack Compose or Koin?

Anyone ever needed to make a class with an

init

block entirely lazy? Example in the thread. (I suspect I'm going to get "smells of a poor design" and that may well be right but my imagination is failing me on how to fix it at the moment...)

sealed interface EmptyResult {
    object Success : EmptyResult
    class Failure(val error: Throwable) : EmptyResult
}

sealed class DeleteResult : EmptyResult
sealed class SetResult : EmptyResult

Why can’t I access SetResult.Success or DeleteResult.Success?

Hello. I am trying to make a simple game based on choices. Do I have to make a new empty activity every time I want a new screen to appear when you lcikc a choice or is there any simpler way? Thanks!

Looking for suggestions on Coroutines book for server side applications (Non-Android platform). Any book which you would recommend here. thanks..

What’s a good way to read YAML and/or CSV?

Is there some library I can use for storing data efficiently? I've tried out exposed and ktorm but they are sorta confusing to me. i just want something simple but fast

Modernstorage

As postfix has greater precedence than prefix, then why

var num = 0
println(--num + num++) // equals to -2 instead of 0

Any way to make an object such as a sound start on background without a button on Android studio? I can make it as a button to start but haven't found resources to make it start automatically as the activity starts . Would really appreciate the help. Using kotlin language that is

What’s the function that sorts a list of things into buckets, like partition(list: List<A>, key: (A -> B)): Map<B, List<A>> ?

Is it normal that one adds useless

else

branch even if not needed in Kotlin 1.7? See say https://github.com/streetcomplete/StreetComplete/commit/1972a7139bff92e894474d1d3d1969b83da2d375 For example

private fun wat(element: StackUnderflow) {
    when (element) {
        is Unicorn -> {}
        is Multicorn -> {}
        else -> {}
    }
}

requires useless

else

where

sealed class StackUnderflow
sealed class Unicorn(val surface: Surface) : StackUnderflow()
sealed class Multicorn : StackUnderflow()
sealed class Tricorn(val surface: Surface) : Multicorn()
sealed class Doublecorn(val surface: Surface) : Multicorn()

is imported from another file.

i just found out about lateinit, this is super cool so that we don’t have to construct something using null 🥰

Any idea how to retrieve the version defined in build.gradle.kts so that i can use it in my code ?

How to use

reified

in a function that, when using a generic function, shows a compiler error message? The compile error message:

Cannot use 'T' as reified type parameter. Use a class instead.

there is something i don’t understand. is everything non-nullable by default (unless i use “?”) or is there something specific to write to ensure that something can’t be nulled ?

I found this problem when I was using

if-else-if-else

I'm trying to replixate the kogito quarkus example where they use this injection method:

@Named("approvals")
    @Inject
    Process<? extends Model> approvalsProcess;

When i try the same thing in Kotlin, i'm only getting an

[error]: Build step io.quarkus.arc.deployment.ArcProcessor#validate threw an exception: javax.enterprise.inject.spi.DeploymentException: javax.enterprise.inject.AmbiguousResolutionException: Ambiguous dependencies for type org.kie.kogito.process.Process<? extends org.kie.kogito.Model> and qualifiers [@Default]

exception. The same constructor injection 'way' actually works:

@ApplicationScoped
class FooBar (
    @Named(value = "approvals")
    private val approvalsProcess: Process<out Model>
        ){

But now i need to do the injection in my Test class for a unit test and i can't use this as its not allowed. only propery assignment is allowed

Apparently doing this:

@field: Named(value = "approvals")

actually works. No clue what this should do

Hi experts I can read in this kt.academy article that

Fan-out
Multiple coroutines can receive from a single channel; however, to receive them properly we should use a for-loop (consumeEach is not safe to use from multiple coroutines)

I wonder if this statement regarding consumeEach is still accurate? In which sense it is not safe?

Hello, I have a questions regarding transformation of list:

val result = myList
            .filter { it.nullableProperty != null }
            .map { it.nullableProperty!!.fromAccount }

Why do I have to use the non-null asserted call in the map step?

is

try-catch

idiomatic in Kotlin?

I need some help with this class io.github.realyusufismail.ydwk.event.EventReceiver cannot be cast to class io.github.realyusufismail.ydwk.impl.event.handle.coroutine.CoroutineEvent I have this interface and trying to cast it to a class which implements it I dont get it why it does not work

Is there some library I can use to generate graphs as image files? I just need some way to convert a map of values into a pie chart then export as a png or something similar

Is there static analysis tool which work for both kotlin and java?

is there some way to do

filterNotNull().filter { //… }

with one function?

better yet, is there an equivalent of

filter_map()

from, say, Rust?

I have java code that uses the pattern of say Inquiry().status(sts).notes(blah). Which enables chaining. what can i do from a kotlin aspect to define a similar class as that? the fields are not required, so you may want to set only 2 of those 3

hey all, is there a preferred or "standard" way to do http calls in kotlin? like an external library or some built in http library