@hhariri might be interesting to add a channel for adjudicating violations, a couple times when @orangy has run in to suppress something, I have thought an actual discussion would be fruitful.. 🙂

I'm having some difficulty figuring out the correct syntax for calling a Vararg with lambdas. The Kotlin converter in IDEA gave me what is shown below. But it results in a compile error. What's the syntax I need?

public static void assertAll(String heading, Executable... executables)

// "Executable" is an interface with a single "execute()" method

// JAVA
assertAll("test the 'add' method",
          () -> assertEquals(4, calculator.add(2, 2)),
          () -> assertEquals(5, calculator.add(2, 3))
);

// KOTLIN
# the 'assertEquals' is underscored with error "None of the following functions can be called with the arguments supplied."
assertAll("test the 'add' method", 
          { assertEquals(4, calculator.add(2, 2)) },
          { assertEquals(5, calculator.add(2, 3)) }
         )

I tried asking in the reflect channel and couldn’t get a response. It might be a dumb question but I figured I would ask here. Which of these approaches would be the most performant way of finding a constructor of a generic that takes an argument that is a subclass of type ‘Item’

T::class.constructors.find {
       it.parameters.size == 1 &&
       it.parameters[0].type.isSubtypeOf(Item::class.createType())
}
    
T::class.constructors.find {
        it.parameters.size == 1 &&
        it.parameters[0].type.jvmErasure.isSubclassOf(Item::class)
}

you can do something similar to that with a reified generic but kotin doesn’t have a Self type

Thank you @nfrankel . I thinking about maybe a static code analyzer like PMD or FindBug for Kotlin

Hello, I got one question about Kotlin-Java, when we use Kotlin we don’t write builders since we have named arguments + default values, that’s ok, but what in case we write library in Kotlin and this library will also be used in Java project? It would be messy, we end up with constructor with

n

arguments. Is there a way to generate proper builder for Java? Some sort of annotation like

@JvmOverloads

my boss is ordering an android wearable watch for testing purposes. Any1 can give suggestions?

Is there some 'delegate' way to do the following?

val container: Container
var property: Int
  set(value) {
    container.property = value
  }
  get() {
    container.property
  }

I was thinking about something like this, but that doesn't work obviously

val container: Container
var property: Int by container.property

https://twitter.com/kotlin/status/870387404154261508 "Vaadin ♡ Kotlin" https://twitter.com/joonaslehtinen/status/870363854966054912 Twitter #Kotlin is a great fit to writing user interfaces. Just look at how powerful this DSL for @vaadin is.… https://twitter.com/i/web/status/870363854966054912 Twitter

Hey Guys, new to Kotlin so wanted to know what's the difference between "let" and "apply" block?

search for class fields that begin with m and remove it

Either one works. I prefer the second though, but it could also be context dependent

It is inline, and Java does not inline at compile time no?

Yes. Reification is a Kotlin only feature. So it's not available to Java. If you try to call it via reflection for example, you'll get an

UnsuportedOperationException

Hey, can anyone explain to me what the difference is between a getter/setter and a delegate?

Hey! In exposed (https://github.com/JetBrains/Exposed), is it possible to have an entity without an ID?

just put it in the body of your class

val arrayCopy = ...

?

Is there an ETA on when reflection for Kotlin JS will come out? I've asked around for a

JSON -> Kotlin JS Object

de-serialization framework and since nobody seems to know of one, I plan to write one myself. Unfortunately, my job is severely hampered by the lack of reflection in Kotlin JS. I just want to know whether or not I should wait for reflection before I start or if I should just start but put in some hacky workarounds instead of using reflection.

Thanks for such a great language! I have a question, since Kotlin is interoperable with Javascript, what prevents the use of Kotlin for React Native apps?

Kotlinx.HTML is escaping

"

to

&quot

, is there a fix for that?

@ramsrib Without looking at it, a likely candidate would be kotlin classes being final by default preventing the creation of a proxy

why it's not possible to write

.map(parser.parse)

instead of

.map { parser.parse(it) }

?

I was wondering if any maven gurus or kotlin experts can point me towards a good way for me to make sure that I'm using Kotlin and Kotlin libraries that work nicely together in terms of version numbers.

@brumla you don't understand the question. Let me give sample source:

class Test(val thing:String, val other:Int)

public class Authority implements GrantedAuthority {

    private User user;


    private String role;

    public Authority(User user, String role) {
        this.user = user;
        this.role = role;

    }

}

test code:

public class Foo {

    public static void main(String[] args) {
        Arrays.stream(Test.class.getDeclaredConstructors()).map(Constructor::getParameters)
                .flatMap(Arrays::stream).map(Parameter::getName).forEach(System.out::println);

        Arrays.stream(Authority.class.getDeclaredConstructors()).map(Constructor::getParameters)
                .flatMap(Arrays::stream).map(Parameter::getName).forEach(System.out::println);
    }
}

output: arg0 arg1 user role if you compile the java code with

-parameters

you get the bottom 2 lines with java. Without it, you get the same as the 2 kotlin lines

How come this compiles successfully. Referencing the class fails at runtime with

VerifyError

open class Base(val me: String) {

  companion object : Base(string()) {
  
    private fun string() = "companion object"
    
  }
}

Is there any way around this?

An annotation parameter must be a class literal (T::class)

I want to do something like

myclass<myType>::class.java

It's looking like I'm going to have to define a class for each of my types 😞

like

operator fun shl(other: Foo): Foo { }

could work on

val foo = Foo(); foo << Foo()

Hello, when I declare a typealias, am I supposed to be able to discriminate between the alias and the aliased type in a when expression?

just a question is it possible to convert all java to Kotlin in IDEA intellij (i mean does this always work ?)

btw, what library is it?