Question about coroutines @Lakedaemon wrote: I just stumbled on this link http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2018/p1364r0.pdf Which basically says that fibers where hot in 1996 and that all operating systems experienced with them for years and then finally recommanded not to use them because they sucked. I would...

People are confused by async {throw} @mtimmerm wrote: I’ve noticed lots of people (including myself) being surprised that async {throw Exception(...)} job fails and cancels the parent (non-supervisor) job, even though the Deferred result also transmits the exception to the consumer. It’s too late to change the default behaviour, but it would maybe be a good idea to add a common safe async function to the standard library....

Kotlin's idiomatic way to achieve request hedging? @smallufo wrote: Spring’s reactor has an interesting feature : Hedging . It means spawning many requests and get the first returned result , and automatically clean other contexts. Josh Long recently has been actively promoting this feature. Googling <a...

Implementation(kotlin("compiler")) Breaks Java Compiler @gchallen wrote: I maintain a fast online Java compilation and execution engine named Jeed that we use to support a playground for my course on introductory programming. Jeed is actually implemented in Kotlin and I’d like to start teaching in Kotlin at some...

Execute lambda remotely @dmytro.tolstyi wrote: Hi, I got a cluster and I would like to execute lambda function no matter if it’s a local instance or a remote one. Lambda seems a good candidate as far as it’s Searializable by default. So, my idea is to serialize lambda, pass it to instance and execute it. Is it possible somehow to pass lambda and params at the same time or pass lambda and force it to take params from the context...

Problem With ForEach @metinozturk wrote: While adding a TextView and two ImageView s to root ConstraintLayout and setting constraints programmatically, something weird happens while I am setting Tag s of the views. Here is how I create aforementioned views and add them to view: val confirmLocationText = TextView(context!!) confirmLocationText.text = "Confirm?" confirmLocationText.textSize = 20f confirmLocationText.typeface =...

Allow creating generic subtype functions on a parent class @Martmists wrote: Example usecase: fun T.someFunc(...): OtherClass { return OtherClass(...) } This way: class X(...) : SomeClass(...) myX = X() myX.someFunc(...) // return type: OtherClass Right now I have to define this function outside of the SomeClass class definition, but there should be a way for kotlin to support this. The alternative I’m using right now is class SomeClass { // ... fun...

Tips on changing the compiler to add more checks @elifarley wrote: For some context, see: NRE from an "uninitialized this" in constructor How should I go about changing the Kotlin compiler in order to provide more extensive checks against access to uninitialized properties in init blocks? What parts of it should I study first?...

How to send variable from php to Android Webview? @gesquivel.ob wrote: Hi! thanks in advance for taking the time to help me few dasy ago I’ve purchased a codecanyon webview framework, made with Kotlin, it is really a great framework since it helped me to turn my website into a real app (I only know how to develope on php & mysql, not java lol) And the framework has integrated the OneSignal & Firebase push notifications service… To this point all is...

CPointer and CFunction how to invoke the method @dickensas wrote: I have a basic question with cinterop var testFun:CPointer>? @CCall(“remoteapp_getter”) external get How should we invoke this method named testFun in kotlin Posts: 1 Participants: 1 Read full topic

You can, apparently, recreate if expressions in Kotlin @kyay10 wrote: As we all know, Kotlin allows extension infix functions. Kotlin also allows lambdas to look more syntax-like by being able to use them in a method call at the end of it. With both of those features, you can totally recreate the if-elseif…-else ladder expressions in Kotlin with the following methods: typealias IfResult = Pair inline fun If(boolean: Boolean, block: () -> Any) : IfResult{ return...

Delegated classes and JPA/Hibernate @cq2000 wrote: I’m trying to compose a JPA entity using class delegation (in a java+kotlin project) with no avail. I have something like this: interface TestTrait : Serializable { var traitValue: Int } @MappedSuperclass open class TestTraitImpl : TestTrait { override var traitValue: Int = 0 } @MappedSuperclass class TestMixin : TestTrait by TestTraitImpl() { var mixinValue: Int = 0 }...

Coroutine error stack traces give no clue about error location @rnikander wrote: I’m using coroutines in JS. When my code throws an exception, I can’t see the source location. I understand that much of the stack will be in the coroutine library, but I expected the top of the stack (ie, closest to the error) to still show my code. However, it doesn’t. Obviously this makes debugging much more difficult. Is there anything that can be done to alleviate this? Here’s a...

Kotlin JS doesn't add “new” keyword where needed @st063194 wrote: I am creating interactive infographics using Google Charts and Kotlin JS. This is snippet from Quick Start Page. var data = new google.visualization.DataTable(); var chart = new google.visualization.PieChart(document.getElementById('chart_div')); Here “new” keyword is used. I tried to...

Coroutines - read from input stream @fedorov1984 wrote: I am reading buffered input stream inside suspended function. suspend fun read(): Double? { val line = serialPortReader.readLine() ... Idea shows warning: Inappropriate blocking call. Why is it happening? Posts: 1 Participants: 1 Read full topic

Kotlinx.serialization - deserializer runs before init blocks? @rnikander wrote: The code below prints “Default”, not “abc” as I expected. Apparently the init block runs after deserialization, and wipes out whatever was set by the deserializer. I thought init blocks ran as part of the primary constructor, which would run before anything else could touch the object. Is that not so? @Serializable class Foo { var name: String init { name = "Default" } }...

Generic parameter is lost in `Supplier` lambda but not in `Callable` @expert wrote: Can anybody explain why generic parameter is lost in Supplier lambda but not in Callable? I created interface that captures generic type and helper function that instantiates it abstract class TypeRef protected constructor() { val type: Type = (javaClass.genericSuperclass as ParameterizedType).actualTypeArguments[0] override fun toString(): String { return type.toString() } }...

Using Android Studio versions 3.5.2 and 4.0 Canary 2 @daveTheCoder wrote: I’m currently using the latest stable version of Android Studio, 3.5.2. I’m using Jetbrains Toolbox for upgrades. I’d like to run it in parallel with 4.0 Canary 2. Two questions: Can I install 4.0 Canary 2 with Jetbrains Toolbox without affecting the existing installation of 3.5.2? Or do I need to download 4.0 Canary 2 directly from the web site? If I accidentally open an existing...

Shutdown hook with coroutine @dd4k wrote: How can we add a shutdown hook from main for coroutines? fun poll() = arrayOf(1,2,3,4,5,6,7,8,9) val job = scope.launch { while (isActive) { val records = poll() records.forEach { Thread.sleep(500) print("$it, ") } println("job completed") } } GlobalScope.launch { Runtime.getRuntime().addShutdownHook(object : Thread() {...

Upcast exposed internal properties to supertype @ftabashir wrote: I’m looking for a syntactic sugar or something else to facilitate exposing private/internal properties as an upcasted instance. Suppose there exist a mutable array in a class: class Person{ private val _addressList = MutableList() } If we need to expose _addressList then should write a function or another property which upcasts addressList as List fun getAddressList = _addressList as...

Android + iOS + React Native on Kotlin/Native? @summerywinter wrote: Hello, I am completely new to Kotlin (and native mobile development - I do react native apps), I want to build a Kotlin/Native library that can be used on both iOS and Android, and that I can create a wrapper for React Native, is that reasonable and achievable with Kotlin/Native, first part seems so, only React Native wrapper worries me a little bit ? If you have any good resources to...

Kotlin not work with Java 13 @LaoTsing wrote: [ERROR] Failed to execute goal org.jetbrains.kotlinkotlin maven plugin1.3.50:kapt (kapt) on project: Compilation failure [ERROR] Unknown JVM target version: 13 [ERROR] Supported versions: 1.6, 1.8, 9, 10, 11, 12 Please remove hard coding supported version numbers, because new Java not working Posts: 1 Participants: 1 <a...

Kotlin.js function Kotlin.Long.prototype.getNumBitsAbs has bug @cheblin wrote: Posts: 1 Participants: 1 Read full topic

Edit textview from different class @anej.mrvic wrote: 0 I am working on a bluetooth android application that will need to display some data to the screen… I have a layot kotlin file and I have a seperate BluetoothService.kt file for bluetooth connection. I have established the connection now i have problems displaying data to the layout. How do I access the TextView from the bluetooth class? I have tried creating a function test that would...

IntelliJ has odd autocomplete behaviour, insisting on prefixing specific class name from Java import @CodingBeagle wrote: Hey everyone, hope this is the right place to ask. I’m using IntelliJ with Kotlin, and use the Lightweight Java Game Library (LWJGL) framework. LWJGL has a set of OpenGL classes existing in packages within org.lwjgl.opengl.* (examples: org.lwjgl.opengl.GL20, org.lwjgl.opengl.GL43, etc. a class for each OpenGL version). Anyways, say that I want to use method glDeleteShader, which exists...

Const val multiplication @pasn1ak wrote: In many places I want to express constants in seconds (and compile them as ms). Is there something like C++ units (aka User literals) in Kotlin? const val MS_IN_SECOND = 1000 const val MS_IN_SECOND_L = MS_IN_SECOND.toLong() fun Int.longSeconds() = MS_IN_SECOND_L * this const val TIME_BETWEEN_EXECUTIONS...

Intellij and extension that implies not null @cpuydebois wrote: I face a problem with Intellij and extension function that implies not null on the receiver. With this code snippet : fun myFunction(myValue: String?) { when { myValue.isNullOrBlank() -> println("myValue is blank") else -> println(myValue.length) } } Intellij complains on the line ‘println(myValue.length)’ (Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable...

Iterating over kotlin.js data class @Latesoft wrote: Hi, The solution for iterating over data class in Kotlin.jvm side is via reflection, but that is unavailable in javascript. What is the non-explict alternative in javascript? Posts: 1 Participants: 1 Read full topic

Remove `String.plus(Any?)` @Revin wrote: I’d like to discuss the possibility to remove String.plus(Any?) It is useful in Java for sure, which doesn’t have string interpolation. But in Kotlin, things are different All that can be accomplished by a+b can be accomplished(more elegantly?) by using "$a$b", especially when a is String? instead of String It’s more elegant because of the symmetry: val a=1 val b="" "$a$b" // consistent a+b //...

Running App issue @omar_kys88 wrote: Hello Am trying to run a kotlin source code and each time i face the same issues ! if i can have any help with this i would be thankful <a class="lightbox" href="" data-download-href="/uploads/short-url/a7hM5C4U1JOxdRpizYhLX8yKNOq.jpeg?dl=1"...