Does anybody at JetBrains have any pull at all with somebody at leetcode? Their Kotlin interpreter is version 1.3 and I can’t find anything about any plans to upgrade it to something more recent. Also, continually using

val

as the name of a property is annoying and not idiomatic, but I can live with that if they truly can’t fix that. (Note: I fully realize that JB has absolutely nothing to do with leetcode, just asking if there’s been any discussions re: versioning)

Reddit question, but curious if anyone knows - why does function declaration use ":" to designate the return type, but lambda syntax uses "->"? Was there some language design reason this was required?

Hey anyone know to default selection in RecyclerView Android kotlin

I am trying to login into the Space plugin for my IDE. I am blocked by a sign in dialog in my web browser. I have tried my Space login credentials and my PC login credentials. Neither has worked. What do I need here?

IMG-20220221-WA0013.jpg

Is it just me? the highlighting for Kotlin in Slack is broken right now, it always highlighted as C++

Kotlin slack is surviving a lot better than other Slack workspaces this morning 😂 🎉

anyone a fleet expert yet? I have questions. (I am not a VSCode user and primarily use jetbrains products)

I made a thing that, quite honestly, will make Roman Elizarov smite me...

fun main() {
    println((2 + 2 == 4) `?` {42} `:` {5})
}

@JvmName("questionMark")
infix fun <T> Boolean.`?`(block: () -> T): IfResult<T> = IfResult<T>(if(this) block() else ElseIndicator)

@Suppress("INVALID_CHARACTERS")
@JvmName("colon")
infix fun <T> IfResult<T>.`:`(block: () -> T): T = if(isElse) block() else result as T

object ElseIndicator
@JvmInline value class IfResult<T> internal constructor(internal val result: Any?) {
    val isElse get() = result == ElseIndicator
}

(psssst, it works for bitwise operators too...)

🇺🇦 ❤️😢

Today I realised that because

return

is an expression (of type

Nothing

), you can

return return

.

fun madness() {
    return return return return return return return return return return
}

Dear Friends, my country Army need ur help! https://uahelp.monobank.ua

Anybody with logitech mx master 3 mouse and a mac?

Hey there! Is there any way to get the file name in a Kotlin file? This functionality could be helpful with e.g. logging, where the other approaches have drawbacks: • need to manually define tag (manual, can be messed up when filename changes) • or: throw a full

Throwable()

, to only get the file / class name (performance issues) • or: using

reified

to get the class name (will print weird log tags when scope changes (e.g. it will print

CoroutineScope

in some instances))

Is the map returned by mutableMapOf(...) multihread-capable? E.g. is it a ConcurrentHashMap or something similiar? If not, what map should I use in multithreading environment. e.g ConcurrentHashMap?

Hey guys! Is there any channel for Kover? I searched it but only found an archived one. Where does discussion about Kover occur?

Not sure where to ask this 😅 Regarding Contracts, I was wondering if it’s possible (or will ever be) to signal something about a parameter if a lambda is called. Like this:

I really want a

<http://DeprecationLevel.INFO|DeprecationLevel.INFO>

. It would be super useful within a large codebase, where I need to signal intent to other developers without littering the place with compiler warnings. Is it something that's ever been discussed? I'll raise a ticket if not.

please how is this affecting kotlin's team and kotlin's future? https://blog.jetbrains.com/blog/2022/03/11/jetbrains-statement-on-ukraine/

Hi, If you haven't already seen in the past, I've posted an issue about how It's time all JetBrains based IDEs give the user the option to change their default search engine from 'Search with Google' to 'Search with DuckDuckGo/Bing' to promote freedom-of-choice. And remember, this isn't about 'cancelling' Google or anything. Google will still remain as the default search engine, all this feature is about is just giving the user the simple freedom-of-choice to change their search engine for this otherwise useful feature. Reasons people might want to change their default search engine from Google to an alternative: • For privacy reasons (some people like to use DDG/Qwant/Brave Search) • For easily being able to search queries directly on sites such as StackOverFlow or Github • And in some countries (as someone mentioned below) Google is blocked This issue has been gaining some traction, and I'd encourage everyone who is interested in getting this feature into the next update to please look, I've written in detail about my proposal below and why I believe it's important JetBrains add this feature: https://youtrack.jetbrains.com/issue/IDEA-289262 If you think it's good please like 👍 the issue so we can get this in the next update ASAP, and JetBrains listens to us. Also before commenting anything, please read the whole issue. If you have any other questions, check if they are answered there: for example, I speak about the Smart Search plugin and why I believe direct-IDE support is better than plugin support, I also go in detail about how this feature will work, etc. If you have any feedback let me know.

Suppose you're writing a REST API service. You want to query a data from DB, and if no record found, you response a 404 not found. I have two possible implementations. 1.

class SomethingNotFoundException : Exception()

// DB query side
if (result.isEmpty()) {
    throw SomethingNotFoundException()
}

// API implement
try {
    ....
} catch (e: SomethingNotFoundException) {
    return HttpResponse(404, "SOMETHING_NOT_FOUND")
}

2.

// DB query side
if (result.isEmpty()) {
    throw HttpException(404, "SOME_THING_NOT_FOUND")
}

where

HttpException

is handled by the framework or a single

catch

that extracts the response parameter from the exception fields. The second approach is simpler, but it couples with the protocol as you involves the HTTP exception and related concept like status code. Which one would you choose?

My previous problem, but since many people suggest NOT using exception, I asked the non-exception version. Which of the following is your preferred way to define error? 1.

sealed class QueryResult {
    data class Success(...) : QueryResult()
    object NotFound : QueryResult()
    object SomeOtherError : QueryResult()
}

// API Code
when(result) {
    is QueryResult.Success -> HttpResponse(200, "...")
    QueryResult.NotFound -> HttpResponse(404, ...)
    ...
}

2.

sealed class QueryResult {
    data class Success(...) : QueryResult()
    data class Error(val status: HttpStatus, ...) : QueryResult()
}

// API Code
when (result) {
    is QueryResult.Success -> HttpResponse(200, ...)
    is QueryResult.Error -> HttpResponse(result.status, ...)
}

The second way is more convenient but the

Error

type is coupled with the HTTP protocol.

Why kotlin allows such code? 😉

throw throw RuntimeException("i am double throw")

Here's a quick sneak-peek on a hobby project I've been working on just for the fun of it. This is 4 different ways to do multiplication using add and shift, all in a DSL I'm working on that generates ARM code out of Dsl calls:

fun ArmBuilder.multiply2(
    first: ArmTransferableValueOperand, second: ArmTransferableValueOperand
): ArmCalculationOperand = buildSubroutine("multiply2", first, second) {
    var operand1 by register(first)
    var operand2 by register(second)
    operand1.compare(operand2, "optimizeSmallerValue") {
        greaterThan("swapValues") {
            swap(operand1 as ArmStorageOperand, operand2 as ArmStorageOperand)
        }
    }
    result = constant(0)
    val mainLoop by labeled
    val mainLoopEnd by labeled
    label(mainLoop)
    operand1.compare(constant(0), "rangeCheck") {
        lessThan = mainLoopEnd
        equal = lessThan
    }
    If(operand1 and constant(1), "oddCheck") {
        result += operand2
    }
    operand2 = operand2 shl constant(1)
    operand1 = operand1 shr constant(1)
    branch(mainLoop)
    label(mainLoopEnd)
}

fun ArmBuilder.multiply3(
    first: ArmTransferableValueOperand, second: ArmTransferableValueOperand
): ArmCalculationOperand = buildSubroutine("multiply3", first, second) {
    var operand1 by register(first)
    var operand2 by register(second)
    If(operand1 greaterThan operand2, "swapValues") {
        swap(operand1 as ArmStorageOperand, operand2 as ArmStorageOperand)
    }
    result = constant(0)
    val mainLoop by labeled
    val mainLoopEnd by labeled
    label(mainLoop)
    If(operand1 lessThanOrEqual constant(0), "rangeCheck") {
        branch(mainLoopEnd)
    } Else If(operand1 and constant(1), "oddCheck") {
        result += operand2
    }
    operand2 = operand2 shl constant(1)
    operand1 = operand1 shr constant(1)
    branch(mainLoop)
    label(mainLoopEnd)
}

fun ArmBuilder.multiply4(
    first: ArmTransferableValueOperand, second: ArmTransferableValueOperand
): ArmCalculationOperand = buildSubroutine("multiply4", first, second) {
    var operand1 by register(first)
    var operand2 by register(second)
    If(operand1 `>` operand2, "swapValues") {
        operand1.out `<->` operand2.out
    }
    result = 0.c
    While(operand1 `>` 0.c, "mainLoop") {
        If(operand1 `&` 1.c, "oddCheck") {
            result += operand2
        }
        operand2 = operand2 `<<` 1.c
        operand1 = operand1 `>>` 1.c
    }
}

fun ArmBuilder.multiply5(
    first: ArmTransferableValueOperand, second: ArmTransferableValueOperand
): ArmCalculationOperand = buildSubroutine("multiply4", first, second) {
    val operand2 = register(second)
    result = 0.c
    For(first, { it `>` 0.c }, { it `>>=` 1.c; operand2 `<<=` 1.c }, "mainLoop") { operand1 ->
        If(operand1 `&` 1.c, "oddCheck") {
            result += operand2
        }
    }
}

(Yes some of these look horrendous, but it's all meant just to show off the current features with a trivial example)

Folks, a curious question: I really enjoying reading Design Proposal from the Kotlin Team (ie, Context Receivers) and I find its quality outstanding - so I was wondering… is there any comprehensive material on how the Kotlin Team approach these Design Proposals? Any reference would be really appreciated. 🙂

IDEA takes a stance on the pronunciation of SQL 😄 (the screenshot says "an SQL" which is only valid if you pronounce it as S Q L, while a SQL is valid if it's SeQueL) Also how dare they use lowercase letters for SQL keywords

Anyone know of a slack /discord / irc where people discuss the JVM? I really want to ask for some advice on

ModuleLayer

and how to use it.

Is there any particular reason that JB compose not supporting iOS, while supporting most other major platforms and web?

Hey, I’m trying to get a working knowledge of ios/swift (to get kmp going) Does someone here know what’s the state of the art for ios in terms of libraries? 1. What’s the go to persistance library? (is sqlite popular as well?) 2. What’s the go to networking library? 3. What’s the go to DI library? 4. What’s the go to reactive framework? (I read there is frst party Combine?) 5. What’s the status of async-await? Does it play nice with Combine as suspend functions do with kotlin Flow? 6. Should I still bother to learn UIKit when swift ui exists? Is it not prod ready?