kotlinlang #announcements

val items = Arrays.asList("a", "b", "c")
// doesn't compile because it is Stream<String?>!
val stream: Stream<String> = items
    .stream()
    .map { item ->
       // call that returns nullable, i.e. String?
    }
    .filter(Objects::nonNull)

utikeev

02/11/2019, 1:20 PM

Hello. I have this class where I’ve got some properties which should act both lazy and observable (so none of delegates suits me). What is the Kotlin-way I can get rid of the boilerplate on

name

and

age

variables?

-.kt

thana

02/11/2019, 4:04 PM

something is constantly removing the

Target Platform

from the Kotlin facet in my intellij instance which results in annoying reports from kotlin that somthing isn't availble on platform 1.6

tekjar

02/11/2019, 5:50 PM

Can someone please point me to an example of decompressing a zlib file idiomatically

dumptruckman

02/11/2019, 8:08 PM

Anyone know a way to make this more clear and concise?

var talentName: String = NameDisplayFormatterFactory.getNameFormatterInstance(SPACE_DELIMITED_FORMATTER, locale)
                      .formatName(talent.firstName, talent.middleName, talent.lastName, talent.nameTitle, talent.nameSuffix)
            talentName = if (order.w2Order.orElse(false)) order.icName.orElse(talentName) else talentName

xenoterracide

02/11/2019, 8:55 PM

@Value("${spring.artemis.host}:${spring.artemis.port}"

kotlin says string must be a compile time constant, this should be valid in java, how do I write it in kotlin?

Viet Hoang

02/12/2019, 1:46 AM

Hello, does anyone know the difference between

::class

and

.javaClass.kotlin

? And why is that in below example, the later declaration works but the prior doesn’t ?

class Test {
    fun testMethod() {
        this::class.memberProperties.forEach { println(it.get(this)) } // compile error 
        this.javaClass.kotlin.memberProperties.forEach { println(it.get(this)) }
    }

Kulwinder Singh

02/12/2019, 7:09 AM

Hello all, i have very general question that is it safe to use

inline

classes in production android app ?,because its in experimental

landoulsi

02/12/2019, 7:59 AM

Hey guys, I have a problem: after I migrated to the new multiplatform plugin, I am not able to use

Mockk

library on the common module test:

MyTest.kt: (74, 9): Unresolved reference: every

, does any one can help with this ?

karelpeeters

02/12/2019, 9:56 AM

Default arguments are faked via an extra function or constructor with an extra

Int

as the first argument that's basically a bitset of parameters that were actually passed.

arve

02/12/2019, 10:04 AM

I often come across a situation where i fetch some data class, process a field, then return the result. A contrived example:

fun getFilm(title: String): Film {
    val data = db.getFilm(title)
    return data.copy(actors = data.actors.filterNot { it.isDead) })
}

Is there a way to avoid the temp variable without hitting the db twice? Or put differently, is there a way of referencing the source object in a copy operation somehow? Ideally I'm looking for something like

fun getFilm(t: String) = db.getFilm(t).copy(actors = actors.filterNot { it.isDead })

I'm aware of

with

, but in cases like this,

with

feels even more convoluted.

gildor

02/12/2019, 10:09 AM

run is fine name, it converts one value to another. And this is not about naming, you can add any alias to run, but it still will be better imo to use local variable

elect

02/12/2019, 10:09 AM

another thing: I find myself often in the situation where I do need a

lateinit

on inline classes (which is forbidden) which workarounds exist other than nullability?

Davide Giuseppe Farella

02/12/2019, 10:20 AM

Basically I got an Android lib where users can create a Drawer menu, 99% of the user will download the lib for the Drawer, but they also can add other `Panel`s, I dont wanna 1 force the user to use

drawer = Panel()

2 I don’t wanna leave

Panel

open only for

class Drawer(): Panel()

thana

02/12/2019, 10:39 AM

a method expects as argument something like

(String) -> Any

. Shouldnt it be possible then, to pass

this::someMethod

if it takes a string and returns something?

02/12/2019, 4:18 PM

val sPayload = payload?.let(::String)

👍 2

Andrew Gazelka

02/12/2019, 5:48 PM

iyo does it make sense to have classes which should probably be immutable mutable to make database management easier? for example... let's say I am using MongoDB with POJO mapping... if I have a complex immutable class it will be a pain to make a copy of it...

GarouDan

02/12/2019, 6:43 PM

Hi guys, I would like to build a kotlin mpp project with circleci. Someone knows which configuration can I put on my

.circleci/config.yml

file to put it to work?

version: 2
jobs:
  build:
    docker:
      - image: circleci/<language>:<version TAG>
    steps:
      - checkout
      - run: ./gradlew clean build

Specially I don’t know what I could use in the place of:

docker:
      - image: circleci/<language>:<version TAG>

Does anyone have a suggestion of a pre-build docker image or some other configuration?

SOFe

02/13/2019, 6:47 AM

Is CLion still needed for Kotlin/Native to WebAssembly development? I saw a lot of articles that say so, including some from JetBrains websites, but I no longer see Kotlin/Native plugin in CLion 2019 EAP, and there is a Kotlin/Native template in IntelliJ IDEA. So are those articles outdated?

Hexa

02/13/2019, 5:23 PM

i fixed the above by changing data class to

data class Message(val message: String? = null)

M Jones

02/13/2019, 9:51 PM

@channel Hi folks, I just used the Spring BeanDefinitionDSL for kotlin. I was just wondering, how do I include an existing XML spring configuration in this?

😱 1

🙉 1

📢 4

02/13/2019, 9:55 PM

You just tried to notify 20,000 people. That's basically a sports arena full of people.

💤 1

😂 11

M Jones

02/13/2019, 9:57 PM

Wow, sorry @jw, I'll be more careful next time

pavel

02/13/2019, 11:58 PM

which, of course, works

Joe

02/14/2019, 1:15 AM

what's an idiomatic way to get a list that has a single element prepended to an existing list. I've been doing:

listOf(listOf(newElement), existingList).flatten()

but that's a bit cumbersome. realized I can do

listOf(newElement).union(existingList)

, but that gives a

Set

instead of a

List

, which isn't always desired.

PHondogo

02/14/2019, 5:13 AM

Hi, guys! I have, for example, 'expect fun test() : Unit' and i want specify default actual for it, so in case there is no actual for any platform this implementation should be substituted. Does Kotlin have such possibility?

sitepodmatt

02/14/2019, 5:18 AM

Is there any movement on plans for GADTs. Or is there a better way of representing lets say an unknown json payload Map<String, Any?> where Any? can recursively be Map<>, String, Integer, Float, Boolean etc..

safa

02/14/2019, 12:09 PM

Hello, a Kotlin/Native question: is it possible to have a shared .so KN runtime? Under the hood, I see program.bc runtime.bc and hello.bc being combined and linked. Our project needs to generate a lot of shared libs for interop and runtime loading, and it quickly grows in size considering the same stuff being put into all of them. Ideally I'd look into generating a shared runtime and lightweight libraries that are dynamically linked to that. moved to #kotlin-native

carlos cdmp

02/14/2019, 12:39 PM

I have a question, when you define a inner private object like

class A{
    private object O{
        const val someConstant = 1
    }
}

The object has some kind of lifecycle attached to the A class or is it created at the beggining no matter if A will be created or not?

Title

carlos cdmp

02/14/2019, 12:39 PM

I have a question, when you define a inner private object like

class A{
    private object O{
        const val someConstant = 1
    }
}

The object has some kind of lifecycle attached to the A class or is it created at the beggining no matter if A will be created or not?

gildor

02/14/2019, 1:24 PM

There is no lifecyle, O is a singleton and has static field under the hood with instance of this companion object

carlos cdmp

02/14/2019, 2:43 PM

ok thanks, I supposed that but wanted to make sure 🙂

karelpeeters

02/14/2019, 3:20 PM

But in practice if you put some side effect code in

init

of course it runs at some point and so there's a lifecycle.

I don't know whether Kotlin or even the JVM guarantees anything about it though.

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