hey! so i have two enum classes that don't directly depend on each other right now (obviously), but my idea is to make a relationship between the two, because they are actually directly related. let's say one is spell categories, and the other one is spells. so for example, a spell category could be fire, and the spells would only be fire-based spells (following on thread)

Is there a plan for there to be reified generics for inline classes?

Is there a way to call super functions/properties with recievers?

open class A {
    open fun String.x() {
        // implementation
    }
}

open class B : A() {
    override fun String.x() {
        // implementation
        
        // 'super' is not an expression, it can not be used as a receiver for extension functions
        super.run { this@x.x() }
    }
}

Interestingly, when I click on the last

x

, IntelliJ highlights the

x

function name in

A

, and if I remove

super.

it'll highlight the

x

function name in

B

is this channel good for a question that has a slightly longer context (~50 lines of code), or is another channel preferable?

Alright, here my question pertains to this code:

class JsonValue {
    constructor()

    sealed class JsonData {
        class IntWrapper(val x: Int) : JsonData()
        class StringWrapper(val x: String) : JsonData()
        class ListWrapper(val x: MutableList<JsonValue>) : JsonData()
        class ObjectWrapper(val x: MutableMap<String, JsonValue>) : JsonData()
        class NullWrapper() : JsonData()
    }

    var jsonData: JsonData = JsonData.NullWrapper()
    
    companion object {
        fun make(x: Int): JsonValue {
            val j = JsonValue()
            j.jsonData = JsonData.IntWrapper(x)
            return j
        }
        fun make(x: String): JsonValue {
            val j = JsonValue()
            j.jsonData = JsonData.StringWrapper(x)
            return j
        }
        inline fun <reified T> make(x: List<T>): JsonValue {
            val j = JsonValue()
            j.jsonData = JsonData.ListWrapper(x.map { JsonValue.make(it) })
            return j
        }
    }
}

So, json is basically a recursive sum type. Sum types in kotlin are typically done via sealed classes, so I'm doing my best with those. I'm trying to have a generic factory function here that works recursively. The problem is, my generic

make

that takes a List complains, because the T is not constrained. However, I can only constrain types in Kotlin by interfaces/classes, and I can't add add any new bases/interfaces to types like Int and String, that I want this to work with conveniently. So, is there any nice way to work around this? Or should I basically declare defeat, change the signature to

fun make(x: List<JsonValue>)

and put the onus on the user to convert e.g. a

List<int>

into a

List<JsonValue>

?

is there some kind of trick to understand this low level kotlin syntax ? I dont understand what is Key, T and * in here

fun <Key:Comparable<Key>, T: IdTable<Key>> T.insertIgnoreAndGetId(body: T.(UpdateBuilder<*>)->Unit) = InsertStatement<EntityID<Key>>(this, isIgnore = true).run {
    body(this)
    execute(TransactionManager.current())
    getOrNull(id)
}

Is it possible to write a helper method in kotlin so that java code can create a

KType

?

Is there any way at all in Kotlin to be able to have a new constraint on generics, that is met by existing types? AFAICS, generics are only constrainable via inheritance, and you can't make a type you don't control inherit from one of your classes. Is that all there is to it? Is a solution for this being discussed anywhere?

Hi i am trying to get data from my database but i am getting error

Caused by: java.lang.IllegalStateException: Cannot invoke setValue on a background thread

this is my code written on Java (Im new on Android), someone knows why it’s the problem whit my line?

what is the

<http://gobyexample.com|gobyexample.com>

or

<http://elixirschool.com|elixirschool.com>

for kotlin? I usually refer to a short with concise example to get up and running with prog language

Trying to threshold compare floats; Is there a standard extension for this?

Just converting the Java code to Kotlin seems a bit lame to me. 🙂

KotNET "a .NET backend for Kotlin" hmm interesting https://blog.jetbrains.com/blog/2020/07/17/jetbrains-8th-annual-hackathon-home-edition

Is there a built-in way to do something like

groupBy { }

, but only group on elements where the key is contiguous? Say I have a

List<Sample>

where sample is

class Sample(duration: Int)

. I need something like a

List<List<Sample>>

, where samples are grouped by duration, but not reordered. If durations are 100, 100, 100, 200 and 100, that should be three groups, not two.

Hello everyone 👋, does anyone have sample project with RxJava, MVVM, Kotlin, (some DI)?

anyone having problems building today if you clean your gradle caches? This appears to have the wrong artifactId: https://bintray.com/kotlin/kotlinx.html/kotlinx.html/0.7.1 looks like "-assembly" has been appended to it compared to previous versions.

can takeif be used instead of a normal if else in the following code somehow?

I do this a lot :

(1..100).forEach{ }

but I never reference

it

and my linter get's upset w/ me. Is there a better way to do this?

Kotlin nullability/android question. If your backend dev is sending a payload with a String which is never expected to be null, should we be making that string nullable in our response object on the client-side, on the off-chance that the backend sends a null string? Should every response object and its fields be nullable to avoid NPEs?

Hello guys, Does any one have a sample MVI project with Coroutines/Flow or LiveData (Without RxJava) + DI

When i work with null-types and I tried to access their attributes, functions etc.. in the members with null-types I need add

!!

or

?.

in every call. It's annoying, could be added a feature: Operator that spreads through the members. Sample:

bob?.department?.head?.name
bob!!.department!!.head!!.name

Something like this: [Edit]

bob.department.head*?.name
bob.department.head*!!.name

@Alexey Belkov [JB] , You know if it is on the Road-MAP or if there is any request for this feature? Or would it not be viable? Edit: I'm new with Kotlin but I'm not understand Why this request is so unpopular. Someone to give Feedback

huh, tried every possible combination, both with interfaces and inheritance... I guess it's not working, you can't require a class to implement static members... (new to this OOP thing, maybe it's something obvious :D)

Would JB going to have a plan for XML parsing?

Can I make a java library that has functions that can be interpretted as operator overloading in Kotlin?

i am encountering a weird error when calling java code that tries to load a private inner class and java throws a

IllegalAccessError

the call is

.addFilter(Query.NumericFilter("price", 0.0, 1000.0))

which is this java code

public Query addFilter(Filter f)

and i think the issue is

Filter

which is a private inner class i don't know if there is something wrong with my code or the library.. is this supposed to work in java ? if so.. why does it break here ? or why did they write it like that.. if it does not work just asking if its worth raising a issue over or its a thing related to using kotlin or such

i'v heard that there is some kind of solution for this but I can't dig up the article where I read about this

Hi all, I'm trying to use Harmonica (migrations of Exposed). I created migration like this

import com.improve_future.harmonica.core.AbstractMigration
import org.jetbrains.exposed.sql.SchemaUtils.create
import org.jetbrains.exposed.sql.SchemaUtils.drop
import org.jetbrains.exposed.sql.Table

object Cities : Table("cities") {
  val id = integer("id")
  val name = varchar("name", 20)

  override val primaryKey = PrimaryKey(id)
}

/**
 * Migration
 */
object : AbstractMigration() {
    override fun up() {
        create(Cities)
    }

    override fun down() {
        drop(Cities)
    }
}

but when I try to run harmonicaUp it says

> Task :harmonicaUp FAILED
Task ':harmonicaUp' is not up-to-date because:
  Task has not declared any outputs despite executing actions.
:harmonicaUp (Thread[Execution worker for ':',5,main]) completed. Took 0.002 secs.

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':harmonicaUp'.
> org/jetbrains/kotlin/scripting/repl/GenericReplCompiler

Hi guys I have a such interface

interface RequestsExecutor : Closeable {
    suspend fun <T : Any> execute(request: Request<T>): T
}

Is possible to implement

ConstantRequestsExecutor

to satisfy the interface and use T parameter on the class level? Thanks

class ConstantRequestsExecutor<T : Any> (
        private val responseValue: T
) : RequestsExecutor {
    override fun close() {
    }

    override suspend fun execute(request: Request<T>): T {
        return responseValue
    }
}

Kotlin/Native Memory Management Roadmap TL;DR: The current automatic memory management implementation in Kotlin/Native has limitations when it comes to concurrency and we are working on a replacement. Existing code will continue to work and will be supported. Read on for the full story. A bit of history Kotlin/Native is designed to be the Kotlin solution for smooth integration with […]