why shouldn't i always go with the latest minor version of everything ? eg in build.gradle.kts instead of

kotlin("jvm") version "1.5.10"

i'd just do

kotlin("jvm") version "1.5.+"

afaik breaking changes only happen across major version updates so "auto bumping" the minor version should be fine ?

This message was deleted.

Why do I lose precision when using Duration from kotlin.time with some values?

// 18 minutes and 17.1 seconds => 1097.1 seconds => PT18M17.099999999S
val duration = 1097.1.toDuration(DurationUnit.SECONDS)
print(duration.toIsoString())

This loss of precision also exists if I use the

toComponents

extension or

inWholeX

accessors

why is

x.Y

not allowed ?

how would you write a

ReplaceWith

for this:

@Deprecated("Use BigDecimal for prices")
fun Double.formattedWithCurrency(locale: Locale = Constants.LOCALE): String {
    return toBigDecimal().formattedWithCurrency(locale)
}

or for this constructor?

@Deprecated("Use the constructor with BigDecimal(s)")
constructor(
    originalPrice: Double?,
    price: Double,
    locale: String,
    percentage: Double?
): this(
    originalPrice = originalPrice?.toBigDecimal(),
    price = price.toBigDecimal(),
    locale = locale,
    percentage = percentage?.toBigDecimal()
)

What is the most efficient way to modify the values of an immutable

Map<K,V>

using is Key?

x-post..

Hello, My company restricts access to certain URLs. And it seems that the URL for the Kotlin compiler is blocked. Can someone point me the URLs for Kotlin ecosystem that are needed? Including Kotlin JVM and Kotlin Native

How do I change this List<T>?

data class Foo (val id: String, val name: String)
val fooList = listof<Foo>(Foo("1","foo1"),Foo("2","foo22)

Imagine I get this 

fooList

 as a parameter and I want to update this list, do I need to do a 

clone

  of the list and then a 

copy

 of the 

data class

 and update there the values? If i want to find first in the list of fooList if the id is equals 1 then change the "foo1" to another string is there any way to avoid to add an else? Otherwise the ide is complaining because I'm not using the result of copy.

fun whateverFun(list: List<Foo>, predicate: Int){
  val foundValue = list.find{it.id == predicate}
  foundValue?.let{
    it.copy(title = "foo3"
  }
}

The only way to avoid this warning is to do an if else of a map and in the else remain the same value as it was I did it but I do not like tis..

list.map { example -> if(example.id == predicate){example.copy(title="foo3")}else{example.copy(it.title)}

Hi all, is there a discord group for kotlinlang or is this the definitive hang out place for kotlin folks?

any way i can work around this problem ? i want to be able to instantiate

Y

with either a

String

or an

X

Any idea about this error? Please Help me.

Github Apparently Changed Code Color of Kotlin from Orangish :large_orange_circle: -> Purple :large_purple_circle: I personally liked orangish color better... 🙃

Hello guys. In the following class:

sealed class GUIModel {
    
    abstract val id: Id
    
    interface Selectable {
        val isSelected : Boolean
    }
    
    data class Model1(override val id: Id, override val isSelected: Boolean) : GUIModel(), Selectable
    data class Model2(override val id: Id, override val isSelected: Boolean) : GUIModel(), Selectable
    data class Model3(override val id: Id) : GUIModel()
}

is there a way to create a copy of the instance with updated

isSelected

field? Without having to check the type:

fun GUIModel.createCopyWithUpdatedSelection(isSelected: Boolean) : GUIModel {
        return when(this) {
            is Model1 -> this.copy(isSelected = isSelected)
            is Model2 -> this.copy(isSelected = isSelected)
            is Model3 -> this
        }
    }

and without switching to

var

in

Selectable

interface. Thanks!

Hello all, I am using a Webview, and I was wondering how to use

evaluateJavascript(...)

to set a javascript variable to a javascript object.

val javascriptString = "javascript: someString = {\"key\":\"value\"}"
webView.evaluateJavascript(javascriptString, null)

This is not working. Can someone point me in the right direction?

Do you make sense to have a specialized function to add an item to an immutable List?, something like this: (in the collections package i mean)

fun <T> Collection<T>.plusHead(element: T): List<T> {
    val result = ArrayList<T>(size + 1)
    result.add(element)
    result.addAll(this)
    return result
}

When overriding your operator overloads, you can omit `operator`:

(https://github.com/JetBrains/kotlin-web-site/blob/f3096d05fdfbc29ec4a704f42112028cdc7f48b7/docs/topics/operator-overloading.md#L15-L21) Why? Isn't it a bit implicit to override an operator, but not mark it as being an operator? I mean: if you'd override an operator without the keyword, you'd have to check the super declaration whether or not it actually is an operator. In turn, that can be an override without the keyword, all the way to the topmost declaration. I guess this is a non-issue because you wouldn't do this often. Without the explicit keyword it might be difficult to discover that a function is actually an

operator

, so that you could use the operator syntax instead of a regular function invocation (e.g.

obj.invoke()

vs

obj()

).

what access modifier should unit tests have ?

how do i get rid of "unused symbol" warnings when developing an api wrapper library? do i just turn off the inspection for the project ?

Wanna get the first character of the first two words from the string, below is my code snippet can any one help to optimize it?

val lbl = {txt:String -> txt.toCharArray()[0].toString()}

val username = "Rajendra prasad guru" 
val initials = username.split(" ").let {
    val l = lbl(it[0])
    if(it.size>1) "$l${lbl(it[1])}" else l
}.toUpperCase()
println(initials)

Output is :RP

what exactly is the difference between

B

and

D

here (other than the name) ? I've noticed that in

B

i can use

super.x

which i can't do in

D

, but there doesn't seem to be any use in that since bot

x

and

super.x

point to the same variable note: i know that

A

technically doesn't need to be

abstract

in this example. just assume that there's other abstract properties that require

A

to be

abstract

Can anyone update kotlin plugin to 1.5.10 from within AS?

Hi guys! I'm having some troubles with Kotlin + Antlr. I have this class:

package br.com.colman.dicehelper


import br.com.colman.dicehelper.br.com.colman.dicehelper.Dice
import org.antlr.runtime.ANTLRStringStream

public fun String.dice(): List<Dice> {
    DiceNotationLexer(ANTLRStringStream(this))
    return emptyList()
}

But the compiler warns me (via gradlew compileKotlin)

Type mismatch: inferred type is ANTLRStringStream but CharStream! was expected

ANTLRStringStream is a Java class, and it's definition is

public class ANTLRStringStream implements CharStream {

I assume that the "Type Mismatch" is wrong, as ANTLRStringStream is a CharStream, but it seems that the Kotlin compiler isn't very happy. Does anybody know how what is going on here?

I've noticed that companion objects behave in a lazy-fashion of sorts. For example, having

open class B() {
    init {
        println("Instance of B created!")
    }
}

class A {
    companion object Companion: B()
}

B's

init

won't be called unless I access

A

in any way, or create an instance of it (

A.Companion

,

A()

). So this isn't just like Java's

static

(as the docs point out anyway: "Note that, even though the members of companion objects look like static members in other languages, *at runtime those are still instance members of real objects, and can, for example, implement interfaces*"). But this lazy-thing is something I wasn't expecting. Can I expect this behaviour no matter the platform?

I’ve issue in building KMM project

val ktorHttpClient = HttpClient(OkHttp) {

    engine {

    }

I need OkHttp in my HttpClient. This is in shared/commonMain. But commonMain not able to access OkHttp. If I add OkHttp in commonMain then getting build error.

implementation ("io.ktor:ktor-client-okhttp:$ktorVersion")

Failed building KotlinMPPGradleModel
org.gradle.internal.resolve.ArtifactNotFoundException: Could not find ktor-client-okhttp-1.6.0-samplessources.jar (io.ktor:ktor-client-okhttp:1.6.0).

This message was deleted.

Hi all! I’m getting a weird

AbstractMethodError

when I try to call a

fun interface

method with Kotlin 1.5:

// definition
fun interface OnItemClickListener {
  fun onChannelClicked(channelId: ChannelId)
}

internal var clickListener: OnItemClickListener? = null

// callsite
holder.itemView.setOnClickListener {
  clickListener?.onChannelClicked(channelId)
                 // ^^^ line 63, crash here
}
                
// Runtime crash
java.lang.AbstractMethodError: abstract method "void path.to.ChannelItemViewAdapter$OnItemClickListener.onChannelClicked-Grz9ttw(java.lang.String)"
  at path.to.ChannelItemViewAdapter.onBindViewHolder$lambda-3$lambda-2(ChannelItemViewAdapter.kt:63)
  at path.to.ChannelItemViewAdapter.lambda$CKDKaveMGRwL-cim-kOMtD1bOuU(Unknown Source:0)
  
// decompiled Kotlin
public interface OnItemClickListener {
  void onChannelClicked_Grz9ttw/* $FF was: onChannelClicked-Grz9ttw*/(@NotNull String var1);
}

public final void onClick(View it) {
  ChannelItemViewAdapter.OnItemClickListener var10000 = this.this$0.getClickListener$communication_debug();
  if (var10000 != null) {
    var10000.onChannelClicked-Grz9ttw(this.$this_with.getChannelId-WlYWy3A());
  }
}

Any idea what the culprit might be here?

Can anybody let me know IntelIJ-community package for lint tool source on github ?

Kotlin IDE Performance The performance of your tools, and especially your IDE, has a significant impact on your development experience. For a long time, performance was a pain point for Kotlin developers, especially those who worked with large codebases or with complex code structures. This is why for the past year we’ve been focusing on improving this experience […]