Hey guys which channel is best for kotlin-native questions?

Not sure if I am chasing ghosts but on my local machine as well as on our CI

1L.rem(200) == 0

compiles without errors while it should fail because rem returns Long. Using Kotlin playground the code does not compile as expected. Any idea whats going on?

org.jetbrains.kotlin:kotlin-stdlib-jdk8:jar:1.4.30:compile

Is the jetbrains kotlin build pipeline team hanging around here somewhere?

I have a mutablelist of items. One of the items properties is a date value. They are currently sorted by said date value. I want to insert separator items in-between the items that have different days. What's an idiomatic way to iterate through the mutablelist list and compare the current item and the next item to see if I should insert a separator?

Is it intentional that the compiler infers the choice between two

<in T>

as

<out Any?>

?

what kind of optimizations could i do to this function?

const val LOWER_CASE_LETTERS = "abcdefghijklmnopqrstuvwxyz"
const val UPPER_CASE_LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"

fun rotateLetter(input: Char, rotations: Int): Char {
    val isUpperCase = input in UPPER_CASE_LETTERS
    val isLowerCase = input in LOWER_CASE_LETTERS
    var variableRotations = rotations
    var variableInput = input

    while (variableRotations != 0) {
        when {
            isUpperCase -> {
                if (variableInput.toInt() == 90) variableInput = 'A'
                else variableInput += 1
            }
            isLowerCase -> {
                if (variableInput.toInt() == 122) variableInput = 'a'
                else variableInput += 1
            }
            else -> return input
        }
        variableRotations--
    }
    return variableInput
}

Possibly a dumb question, but does anyone here have experience with mockk.io, and happen to know if there’s a way to mock constructors that doesn’t result in the underlying class’s real constructor actually being called? From what I can tell (somewhat astonishingly), the default behavior of mockkConstructor() is to actually call a real constructor, then discard its output and substitute a mockk singleton. This is somewhat disappointing, since it suggests that you can’t actually mock constructors with mockkConstructor().

Hello everyone, Thank you very much for allowing me to be part of this wonderful team.

I apologize in advance for my English, I am in the process of learning.

Good morning! Some of the kotlinx libraries are hosted on jcenter only. Since it is shutting down, what are the plans for moving those to Maven Central? See https://github.com/Kotlin/kotlinx.collections.immutable/issues/96 for instance? I wanted to remove jcenter, but I got a library with a transitive dependency to kotlinx-collections-immutable.

Jcenter shutting down? :O

val loginPage = loginPageResponseBody.loginPage
if (loginPage != null) {
    loginPageData.postValue(loginPage)
}

If I am doing the null check then why does

postValue

method complains about requiring

Expected non-nullable value

. I don't get this error with

loginPage.let { loginPageData.postValue(it) }

.

My naive implementation

operator fun <T> T.plus(list: List<T>): List<T> {
  val result = list.toMutableList()
  result.add(0, this)
  return result
}

I was reading about coroutines recently and I noticed that quite a lot of blog posts have links to JetBrains documentation which no loger works. For example lots of posts link to https://kotlinlang.org/docs/reference/coroutines/basics.html#structured-concurrency which doesn't work anymore. It would be cool to fix that or add a redirect to the new docs.

Why are non-local returns not allowed in lambdas? I can't find an explanation about the "why" anywhere

Hello there, Hope you are all having a blast. I am trying to understand multifield value classes so I have dumbed it down and I need some correction If I am wrong 1. Multifield value classes are like Cpp Structs, and normal classes (including data classes) are like Cpp Classes, Correct? 2. Does that translate to stack and heap allocations for Kotlin/Native?

I wanna my

data class

to have non optional field, but to be able to initialize it with a nil, which will be replaced by a default value. Something like this:

data class Text(val text: String) {
    constructor(textNullable: String?) : this(textNullable ?: "", nullable)
}

It works well on native, but on JVM I got following error:

Platform declaration clash: The following declarations have the same JVM signature (<init>(Ljava/lang/String;)V):
    constructor Text(text: String) defined in ...
    constructor Text(textNullable: String?) defined in ...

Any way I can bypass it? I think I could replace

data class

with

class

to remove the default constructor, but in this case I’ll lose other data class advantages, like

copy(...)

Hi Everyone, I started an initiative to help Junior and Intermediate developers to improve their skills on Scala/Kotlin and in FP/OO programming but at this moment it's only to people that speak Portuguese, sorry about that. I will accept 3 to 5 Jr/Pl developers and we will have two meetings every week for 5 months, we will study, principles (FP and OO), microservices(ktor, finch), persistence (quill, object prevalence, spring jpa), clean architecture, etc. price: free :-), again only for Jr and Pl devs (Portuguese language) Tks everyone. If you want to join, please send me a message on linkedin: https://www.linkedin.com/in/agnaldo4j/

Hey all. I’ve been pondering idly how much I miss Spock’s syntax in Kotlin, and found myself wondering whether it’s even possible to implement the same thing? Spock uses some groovy feature that allows rewriting the AST, I think.

Okay so I rewrote the code, is this more optimized? how can i make stuff better

fun rotateLetter(input: Char, rotations: Int): Char {
    var variableInput = input.toInt()
    val isUpperCase = variableInput in 65..90
    val isLowerCase = variableInput in 97..112

    when {
        isUpperCase -> {
            if (variableInput + rotations <= 90) variableInput += rotations
            else variableInput = 64 + (variableInput + rotations - 90)
        }
        isLowerCase -> {
            if (variableInput + rotations <= 122) variableInput += rotations
            else variableInput = 96 + (variableInput + rotations - 122)
        }
        else -> return input
    }

    return variableInput.toChar()
}

Why does

javax.xml.xpath.XPathFactory.newInstance().newXPath().compile("/").evaluateExpression(null)

give

error: unresolved reference: evaluateExpression
javax.xml.xpath.XPathFactory.newInstance().newXPath().compile("/").evaluateExpression(null)
                                                                   ^

when compiling the Kotlin code using Java 11? The IDE has no problem, but if you compile it in a file or execute it in a REPL it says unresolved reference. The method was added in Java 9

Is there any way to distinguish these two?

fun test(a: () -> Unit) { println("A") }

fun test(a: suspend () -> Unit) { println("B") }

suspend fun main() {
    test {}
}

According to the language i.e. if kotlin - allow suspend lambda whereas call from non-kotlin like java/js - allow normal lambda 👀

spring_boot which should I choose?

Thread()

vs Kotlin coroutines?

Does Kotlin/Native support processing of annotations? Is it possible to provide processing in commonMain for KMM project?

org.jetbrains.kotlinx:kotlinx-collections-immutable

is still only available on jcenter / bintray. What's the right place to file a bug to move it over to Maven Central or Jetbrains' own space?

update: solved adding this code to `build.gradle`:

configure<SourceSetContainer> {
    named("main") {
        java.srcDir("src/main/kotlin")
    }
}

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- spring_boot

@PostMapping("/my-endpoint")
fun createProject(@RequestParam request: Map<String, String>): ResponseEntity<Map<String, String>> {
    val filePath = request["filepath"]

    try {
        val thread = thread {

            try {
                MyCustomClass(filePath)
            } catch (e: Exception) {
                when (e) {
                    is IOException, is SAXException, is ParserConfigurationException, is SQLException -> {
                        println(e)
                    }
                    else -> throw e
                }
            } // end of thread's try

        }

        thread.start()

        return ResponseEntity.ok().body(
            mapOf(
                "message" to "success"
            )
        )
    } catch (e: java.lang.Exception) {
        return ResponseEntity.badRequest().body(
            mapOf(
                "message" to "error"
            )
        )
    }
}

why does spring boot give me noclassdeffound on

MyCustomClass

?

Hi guys!!! Can anyone recommend for me a kotlin roadmap

Hi 👋 (@here) What is the ideal way to get hooks for method execution such as before & after to use with delegate for decorator pattern to perform some action before & after of method execution without using reflection to work with graalvm