Hi ! Is there any reliable way to create a zip from a folder ? I've seen 5 pages from StackOverflow and tried all the examples listed and I still come up with a zip that doesn't work with Minecraft because Minecraft is extremely strict with Zip files :/

list[2:5] = mlist

This python code assigns mlist into list at indices 2 to 5. I am not able to do the same in kotlin using inbuilt methods. Can anyone help me.

Hey I was wondering if it was possible to use settings in the root gradle.properties in my sub-projects? I tried accessing like this

val test: String by rootProject

but that just produces null. Thank you in advance.

Any good gradle course? Updated if it’s possible to use with Kotlin. I plan to use Gradle to manage monorepos

Hi! I’m new to Kotlin and compiled languages and my question is: are there some practice to develop server application? I want to add an ability to our team unwrap project with some microservices in a couple of clicks for development. So things I’m trying to do is setup docker compose with these service, DB, etc. mount code via volume to app container and run by command. It is good way to develop JVM application or not? I asked because a lot of examples made by just compiling jar, copy to container and run from it and examples like that. These examples seem not as good decisions, because we need to recompile it every time and build again and again and also because we can use auto-rebuild on code changes that we don’t use. So could anyone explain? Thanks!

Which channel would be great to discuss the kotlin language itself? I am not getting any channel name general ?

Hi! I’ve been following a tutorial on how to create a mini compiler, but the tutorial is in JavaScript. I’m trying to convert it to Kotlin, and I’ve ran into the following problem (detailed in the thread) and I’m not sure how to solve it.

Hi all. I'm creating a class to encrypt and decrypt strings using bouncy castle. everything works perfect that way:

What are the technical reasons for

1.7.22

?

Hello everybody, I'm new in this slack, I'm from México and I feel so exited to learn and discovery new things all the days.

Hi, I'm new to serialization(in JS it is just about JSON.stringify and JSON.parse from my perspective) , could someone tell me why the code below doesn't print

name:"foo"

? though I didn't initialize the field in the constructor, but they got a default value.

Hi everyone! I’m new to the Kotlin slack and would like to create an OpenRewrite AST for Kotlin. I want to use the Kotlin compiler to collect the type attribution of Kotlin and Java sources. The goal is primarily to have a Kotlin AST that will allow us to migrate APIs. I’m having trouble creating a

FirSessionFactory.INSTANCE

using

createLibrarySession

and am getting an error (will be linked in thread). Could someone point me to an example of how to instantiate the Kotlin compiler?

👋 Hello, team!

Is there an easy/already existing way to replace all integer additions, subtractions and multiplications to strict math variants in kotlin code?

Hi there. I have a general question about generics. Suppose I have input data in form of lines, each matching some regex that could be then mapped to a data class or whatever. But on each day it will be different format, different regex and data. YES it’s #advent-of-code time again 🙂 I created an extension function to help me deal with it:

fun <R> String.parseRecords(regex: Regex, op: (MatchResult) -> R): Sequence<R> =
    lineSequence().filterNot(String::isBlank)
        .map { regex.matchEntire(it) ?: error("WTF `$it`") }
        .map(op)

That works just fine. How would it look like if I want to make parameters optional (with some default mapping)? I can use

regex: Regex = "(.*)"

but the

op: (MatchResult) -> R = { it.destructured.component1().toInt()}

is a big no-no, because of Type mismatch: inferred type is Int but R was expected. Is it even possible to add default parameter values for generic functions?

Non programmer I want to learn Kotlin to create Android apps and design them in a way that I can port them to iOS as well. Please share the best way to start learning. Any course would do.

Hey everyone, I'm looking for a solution to keep track of coroutines launched from a hot flow so I can cancel them if the same event arrives again. I've created this distilled example of combining a state flow but I'm not sure if this is safe/intended usage. Is updating state inside of the flow an anti-pattern?

@Test
    fun start() {
        val sourceFlow = (0..20).asFlow()
        val stateFlow = MutableStateFlow(mutableMapOf<String, Int>())

        runBlocking {
            stateFlow.asStateFlow().combine(sourceFlow) { state, number ->
                println("got number $number")
                state[(number % 2).toString()] = number
                state
            }
                .take(20)
                .collect { result -> println("got result $result") }
        }
    }

Hi, is there optional parameters in Kotlin ? the doc have no hints about that. I've marked the param

info

as

nullable

, why still got error?

Hi there, please someone can give me a few explanation about the use of text@ and @text after run function, please check the following code:

private fun getClickTagName(textOptions: List<String>, tag: StringBuilder): String {
        var textToSearch = ""
        run clickTags@{
            textOptions.forEach { clickTag ->
                if (tag.contains(clickTag, true)) {
                    textToSearch = clickTag
                    return@clickTags
                }
            }
        }

        return textToSearch
    }

Is it kind of notation? does someone know it?

Does anyone know of an alternative for

?.let { } ?: emptyList()

that lets you place the default value at the beginning of the

.let

statement? One of my few complaints with Kotlin is that it becomes hard to read in cases like this:

val foo = maybe?.null?.let {
  // really long series of statements
} ?: someDefault()

I'd love something like:

val foo = maybe?.null?.letWith(someDefault) {}

(I know I could define an extension function but it seems so common I thought maybe there's a native/built-in for this)

Essentially

.ifEmpty { }

but for nullable values

New here, just saying hi. I occasionally write server side Kotlin (JVM) @ work.

when debugging and looking at the values at a breakpoint, I often get

Unable to evaluate the expression Cannot find source class for java.util.Map

(or

java.util.List

, etc.) for everything that is a `Map`/`List`/etc. only reindexing the project solves it, which is time consuming what is the cause of this issue? can I prevent it?

Hi guys, which channel is best for asking for guidance of multiple api call in single screen ?

Hey everyone, new to programming and Kotlin. Trying to learn about classes and objects, and having a hard time understanding OOP concepts like polymorphism, inheritance, constructors etc. I'd like to remake what Google has done with the FIFA World Cup summaries of match results,fixtures,list of teams with ranking, list of players with number of goals etc. I was wondering if there was a complete project that you could point me to to help me understand how everything connects together? Appreciate any advice at all

In Kotlin/JVM, is there a fast way to check if a byte array contains a given subarray? This is for a high-throughput filtering requirement. The subarray is known at design time. The byte array is UTF-8 encoded. I can convert the byte array to String and just

String.contains

(or

a in b

), but if I can do a byte-array search instead it would be preferable as it would save the overhead of converting to String. I don't want to write a Boyer-Moore (or similar fast algorithm) implementation for this myself, as (1) I might get it wrong and (2) there may already be one and I don't want to reinvent the wheel. I'm hoping there's something already there in the stdlib.

This message was deleted.