I'm completely at a loss here as to how to use

Continuation

in my Java code when trying to run async coroutines. Anyone have any resources?

'^((?![Ww][Ee])[ -~])*$'.)]). What does that expression with tilda sign and - mean in regex?

I want to remove all characters in a given string, which do not match the regex above. How can I accomplish this?

What is a Kotlin way of

Collections.sort(contributors, (c1, c2) -> c2.contributions - c1.contributions);

fun x(a: String) {
    print(::a.name) // References to variables aren't supported yet.
}
val someVar = 1;
x(someVar) // ::a.name should be someVar

Is there a way to know the name of a property or a variable passed to the function by reflection?

Now the challenge is that if I call in my test

makeCashPeriod()

I get a nice randomized model, but I need to change some of the parameters depending by the test. Can I achieve that with the language from intelliJ usign something ,do not know, maybe generics, default constructor values, other?

So the reason Spring Data cannot use

inline

classes https://jira.spring.io/browse/DATACMNS-1517 - what’s the appropriate place to provide this feedback to the kotlin team on the “experimental” inline classes?

Is there any way to combine two functions to make a third function such as this?

val function1: (Int, String, Byte) -> String = { i: Int, s: String, byte: Byte -> "example" }

val function2: (String) -> Int = { -1 }

//to get something like 
val function3: (Int, String, Byte) -> Int = function1.then(function2)

obviously the “then” function is fictional otherwise i wouldn’t ask. I’d love to be able to do this without actually having to know function1's arguments explicitly… just that it returns a type that matches the arguments of function2

I've got a logging helper function like this:

inline fun <reified T : Any> T.createChildLogger(
    parentLogger: Logger,
    childContext: Map<String, String> = emptyMap()
): Logger =
    parentLogger.createChildLogger(getClassForLogging(T::class.java).name, childContext)

Which is used to abstract out the logic for obtaining the 'name' of the logger using the caller's class, but I'm finding I can't invoke it in-place when calling a parent constructor, like so:

class Foo(parentLogger: Logger) : Parent(createChildLogger(parentLogger))

I assume this is because the receiver function can't be applied here? Is there a workaround for something like this? (either in the definition of

createChildLogger

, or how it would be invoked by the child class?

This is very weird. I have an array converted to a

List

using

Arrays.asList(...)

coming from Java and when I compare it with a list created with

listOf()

in Kotlin: https://pl.kotl.in/cQxTchtL0 Why aren’t following the

equals

contract? Anyone experienced this before? 🤔

I've found that I can only call a receiver function while invoking a parent class' constructor if a companion object is defined. Is this some subtle type system thing? Or a bug?

fun <T : Any> T.double(num: Int): Int = num * 2

abstract class Parent(val num: Int)

// Works
class Child(
    num: Int
) : Parent(double(num)) {
    private companion object
}

// Error: unresolved reference 'double'
class Child2(num: Int) : Parent(double(num))

for example I have a field like

{
        "name": "parameters",
        "type": [
          "null",
          {
            "type": "array",
            "items": "Parameter"
          }
        ],
        "default": null

so it can have a null value but the avro generator generates a java getter like this

public java.util.List<Parameter> getParameters() {
    return parameters;
}

my problem is that when calling getParameters that returns null I get

java.lang.IllegalStateException: order.getParameters() must not be null

I asked the below question a couple of days ago but got no answer. I tried to convince my callers that adding

.INSTANCE

is really not a big deal but so far they are not buying it... Anyone has a better idea? I have a mixed Kotlin and Java codebase and a singleton in Kotlin with its methods called from Java. The singleton

Manager

delegates all calls to an implementation of an interface

Service

(there are multiple possible implementations of

Service

,

Manager

picks one at startup). Right now, the code does

object Manager { val delegate = pickImpl(); @JvmStatic fun foo() = delegate.foo(); @JvmStatic fun bar(a: Int) = delegate.bar(a); ... }

and the Java code calls

Manager.foo()

. This could be simplified to

object Manager : Service by pickImpl()

but then the Java code has to be changed to call

Manager.INSTANCE.foo()

. Is there a way to use delegation but retain the

@JVMStatic

for the Java code?

i recall someone publishing a kotlin formatter project recently that was more in the style of google-java-format, i.e. the “there’s exactly one correct representation of this code” approach

fun <K, V> MutableMap<Set<K>, V>.put2(vararg keys: K, value: V) = put(keys.toSet(), value)

fun main() {
    val map = mutableMapOf<Set<Int>, String>()
    map.put2(1, 2, 3, value = "x") // no errors
    map.put2(1, 2, 3, "x") // compiler error: No value passed for parameter 'value'
}

wouldn't it make sense for the compiler to figure the last argument on its own in this scenario?

@channel Is there any one who is working with lambda functions at a higher level!

so for a multiplaftform desktop/mobile app frontend, do you recommend kotlin-jvm with tornadofx/javafx, or kotlin-js with angular or something?

Anyone familiar with Gradle Kotlin DSLs and Multiplatform? I'm attempting to create a shared module between all my platforms but am only stuck when I attempt to do jvm("android") and jvm() as two separate targets (client/server).

val foo : String? = null

bar(foo)

fun bar(value: Any?){
    when(value){
        is Int? -> println("Int?") // always prints Int? when value == null
        is String? -> println("String?")
    }
}

Is there any way to get the actual type of

value

?

Hi all, do coroutines support the concept of scheduling a task to be run periodically?

How do I fix this code?

private val SUB_REGEXES: Map<String, Pair<Regex, String>> =
  SUBSTITUTIONS.keys.associate {
    it to Pair(Regex("\\b$it\\b", RegexOption.IGNORE_CASE), SUBSTITUTIONS[it])
}

It doesn’t compile because

SUBSTITUTIONS[it]

is of type

String?

instead of the needed `String`; however, I know it is always a

String

because its key is in the map

SUBSTITUTIONS

. Here’s a rewrite with

associateWith

:

private val SUB_REGEXES: Map<String, Pair<Regex, String>> =
  SUBSTITUTIONS.keys.associateWith { 
    Pair(Regex("\\b$it\\b", RegexOption.IGNORE_CASE), SUBSTITUTIONS[it]) 
}

I am learning TornadoFX (Kotlin desktop GUI). Is there anyone know any sample code accessing SQLite from Kotlin desktop app?

Does anyone know a good alternative to org.json (https://github.com/stleary/JSON-java) more 'Kotlinsh' to read and write json?

@Barddo what are you trying to do?

Does anyone know if there is a way to import all the members of an enum which is in the same file as where you want to use them? I want to do this:

// myfile.kt
enum MyEnum {
  HELLO, GOODBYE, HEY, GREETINGS
}

fun myFunction() {
  doSomethingWith(HELLO) // instead of MyEnum.HELLO
  doSomethingElse(GOODBYE) // instead of MyEnum.GOODBYE
}

I'd normally use

MyEnum.HELLO

and

MyEnum.GOODBYE

but I have a use case where that causes more harm than anything else. The current workaround I use is to simply declare

MyEnum

in a separate file, but that is quite annoying. (please redirect me to the right channel where I can ask this if there's a better place for this question!)

It's possible to do this?

fun<T: Any> testing( id: UUID, name: String) : T {

return T

}

If no, how do I return a T ?

Weird appears to only be broken on EAP

We’re developing applications using kotlin and spring boot which runs in kubernetes. Are there any issues running kotlin in a java 11 docker image? For example

adoptopenjdk:11-jre-hotspot

? Are there any others more appropriate? And if a kotlin app is developed and run in java 11, are there any reasons for seting jvmTarget = 1.8 i gradle? When i generate a new kotlin java 11 project using spring boot initialiser it sets the

jvmTarget = "1.8"

even though i choose java 11 in the project creator.

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