kotlinlang #announcements

Did anybody manage to get codecov.io working with Kotlin + JaCoCo when source path and package name do not match? The generated coverage report XML only contains source file names, not paths, which prevents codecov from reporting any coverage 😞

Hullaballoonatic

11/29/2018, 9:59 PM

is there a unifying comparable class to which all primitive numbers belong, or better yet, one on which you can use mathematical operators?

Hullaballoonatic

11/29/2018, 11:11 PM

+ concatenates strings, but not numbers

Shawn

11/29/2018, 11:14 PM

in any event, implement it yourself

infix fun <http://Int.cat|Int.cat>(other: Int): Int = (toString() + other.toString()).toInt()

🐱 1

diesieben07

11/29/2018, 11:14 PM

a * pow(10, log10(b)) + b

Shawn

11/29/2018, 11:15 PM

Are you sure you wouldn’t rather just write R? Maybe Matlab? lol

🤣 1

😛 1

Hullaballoonatic

11/29/2018, 11:36 PM

to me, is a worthwhile trade-off, but why not both?

agrosner

11/30/2018, 2:30 AM

Per earlier question about data class extending sealed class and duplicating properties in the constructor, is there plans to add inheriting constructors? Something like what swift supports where if a subclass doesn't define a constructor, it inherits the constructor of the super class.

kschlesselmann

11/30/2018, 7:42 AM

enum class

looks like

enum class Condition {

    EXACT {
        override fun evaluate(actual: Set<String>, expected: Set<String>) = actual == expected
    },

//....

    abstract fun evaluate(actual: Set<String>, expected: Set<String>): Boolean
}

coder82

11/30/2018, 8:47 AM

then I guess rather pass "this" ?

thijs

11/30/2018, 10:50 AM

So right now I have something like this:

private val journeyId by DetailFragmentArgs.journeyId

And I would like to make this lazy

bartvh

11/30/2018, 1:01 PM

Generics are great, but when building code that uses runtime type information the compiler sometimes needs to be told to shut up 😄 In this case involving enums, however, I can't get it to do so without using reflection:

when (v) {
            is Enum<*> -> {
                val ev: Enum<*> = v
                val kc: KClass<Enum<*>> = ev.javaClass.kotlin
                val ser: EnumSerializer<*> =
//                        EnumSerializer(kc)
                        EnumSerializer::class.primaryConstructor!!.call(kc)

Does anybody know a combination of casts/suppressions/*/magical incantations that could allow the commented out line to work?

Yogesh Gosavi

11/30/2018, 4:27 PM

What's difference between reduce and fold ?

Alowaniak

11/30/2018, 9:32 PM

So I was messing around with something and tried to do a delegate (Comparable) by a primitive, but then there's some internal error in the compiler instead of syntax error or w/e?

Andrew Gazelka

12/01/2018, 4:28 AM

how should I make a delegate with a default value from a config if the current val DNE or is the wrong type? From what I see, I would need to have both

DelegateClass<A>

and

inline operator fun <reified T> getValue

which would look really messy since we are assuming

and

are the same. I would need to do this, because I need to input the default value into the class, but classes can't be reified.

Yutsa

12/01/2018, 6:12 PM

Hello, I have an issue with Spring Boot and Junit4 testing

@SpringBootTest
class ParsingIntegrationTest(@Autowired val cardPriceService: CardPriceService) {

It gives me this error :

java.lang.Exception: Test class should have exactly one public zero-argument constructor

hudsonb

12/01/2018, 6:30 PM

But there isn't a kotlin stdlib solution that I'm aware

Marcin Wisniowski

12/01/2018, 11:43 PM

I'm trying to write a Kotlin contract so I can get smart casts in code calling my function, but this syntax doesn't work, what's the correct way to achieve this?

karelpeeters

12/02/2018, 11:23 AM

Found the link to the last time I found this 😒imple_smile:

👌 1

➿ 1

rrader

12/02/2018, 1:14 PM

object Users  {
    val id: Long = 10
    val name : String ="name"
    val cityId : Long = 42
}


fun main(args: Array<String>) {
    slice(Users::name)
}

fun slice(vararg properties: KProperty<Users>) {
    properties.forEach { println(it.name) }
}

what should be

properties

type that will accept only Users properties?

bod

12/02/2018, 4:40 PM

Hello, Word! I was wondering if there's any way to craft a Java method in such a way that it can be called in Kotlin like a "function literals with receiver". So I could call

myObj.foo { bar() }

where

bar

is a method on some class passed as the receiver of the lambda - but

foo

is declared/implemented in Java. Ideas? 🙂

keturn

12/02/2018, 8:00 PM

why doesn't my environment seem to be able to find this function? https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.streams/kotlin.sequences.-sequence/as-stream.html does my JRE_1.8.0 not have Streams or something?

silas.schwarz

12/03/2018, 10:25 AM

Hey 👋, i'm totally aware of the fact that this is some what unconventional but why not give it a try. my current employer sadly decided to turn kotlin the cold shoulder. I've used it for the past ~1.5 years, mostly creating SpringBoot Backend Apps aka microservices and APIs, AWS Lambdas, http4k app, reactor rabbit apps. I really enjoy kotlin and would ❤️ to continue working with it. so... if you have a opening in your company, preferably in 🇩🇪 (not a must) and in the Frankfurt area (not a must) , please DM me here or on twitter @silasschwarz thx 🙇

miguelsesma

12/03/2018, 12:47 PM

I know, but why it behaves differently in 1.2.71 and 1.3.0?

Paul Woitaschek

12/03/2018, 2:05 PM

Is there any kind of discussion on union types?

Paul Woitaschek

12/03/2018, 2:08 PM

I have a class that takes a list of

Any

but the subtypes are not directly related so they can't be sealed classes.

Joe

12/03/2018, 3:26 PM

This works, but isn't really what I want:

class PhaseDefinition<C: GameContextBase, T: GamePhaseBase<C>>(val init: PhaseDefinition<C, T>.() -> Unit) {...}

APXEOLOG

12/03/2018, 4:26 PM

Guys, i want to execute some code only once, i wonder if there is any way to implement function like

...
once { some code ... }
...

APXEOLOG

12/03/2018, 4:54 PM

Yes, but i wondered is there is a way to create generic function for this instead of adding flags for every place like this

APXEOLOG

12/03/2018, 5:09 PM

Yeah, i actually did same thing with stacktraces

private val checkPoints: MutableSet<String> = HashSet()

fun once(action: () -> Unit) {
    val stackTrace = Throwable().stackTrace[1]
    val key = "${stackTrace.fileName}_${stackTrace.methodName}_${stackTrace.lineNumber}"
    if (!checkPoints.contains(key)) {
        checkPoints.add(key)
        action()
    }
}

fun main() {
    repeat(100) {
        once { print("Say hi!") }
    }
}

😱 3

Title

APXEOLOG

12/03/2018, 5:09 PM

Yeah, i actually did same thing with stacktraces

private val checkPoints: MutableSet<String> = HashSet()

fun once(action: () -> Unit) {
    val stackTrace = Throwable().stackTrace[1]
    val key = "${stackTrace.fileName}_${stackTrace.methodName}_${stackTrace.lineNumber}"
    if (!checkPoints.contains(key)) {
        checkPoints.add(key)
        action()
    }
}

fun main() {
    repeat(100) {
        once { print("Say hi!") }
    }
}

😱 3

karelpeeters

12/03/2018, 7:12 PM

Tiny suggestion:

!checkPoints.contains(key)

key !in  checkPoints

Alan Evans

12/03/2018, 9:40 PM

Never check before adding a value, that's doing double work,

add

returns a boolean https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-mutable-set/add.html.

if (checkPoints.add(key)) {
    action()
}

rnpy

12/03/2018, 10:19 PM

not that I'd recommend using it anywhere except for debug stuff, but

Thread.currentThread().stackTrace

can give you current stacktrace without creation a Throwable

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