Interesting Bug I just discovered. If you have

-Xjsr305=strict

enabled and you have a java class annotated with:

@ParametersAreNonnullByDefault

. If that class overrides

equals(Object other)

without having

@Nullable

on the

other

param, kotlin can't use the

==

operator. Eg. The following won't compile:

JavaSomething("one") == JavaSomething( "one")

Java side:

@ParametersAreNonnullByDefault
public class JavaSomething {

    private final String something;

    JavaSomething(String something) {
        this.something = something;
    }

    @Override
    public boolean equals(final Object other) {
        if (this == other) return true;
        if (other == null) return false;
        if (this.getClass() != other.getClass()) return false;
        final JavaSomething javaOther = (JavaSomething) other;
        return something.equals(javaOther.something);
    }
}

Any of you have any experience with ktor.io and Spark Java? Does ktor have filters, I can't find any in the documentation.

What would be the channel to talk about

build.gradle.kts

?

so local functions cannot be recursive?

ok, another question: how do you guys implement FSMs?

@robin it compiles, but is it tail call optimized?

is it possible to match like this?

when (x) { is Foo && x.aFooField > 10 -> ... }

no

catch (e: MyException if e.foo = 25) { .. }

??

anyone aware the font that was used to create the “kotlin” logo (not the colorful K, the whole word, like here :

Sure, it may work fine in some cases. And then in others it doesn't, eg.

data class Foo(var x: Int)

fun main(args: Array<String>) {
    val f = Foo(3)
    val s = mutableSetOf(f)
    f.x = 7
    println(s == setOf(Foo(7)))
}

on try.kotlinlang.org.

I'm seeing something really weird. If I declare a var and set it to a declared constant value to initialize it, when I change it (in a overriden method called by the superclass's constructor) I see the value change, yet when I access the value later it seems to have been reset back to the constant. companion object { private const val DEFAULT_MAX_COLLAPSED_LINES = 3 } private var collapsedMaxLines: Int = DEFAULT_MAX_COLLAPSED_LINES ... In method called in constructor: collapsedMaxLines = 5 ... when I later access collapsedMaxLines it's 3 again. If I initialize to a number like 0, it gets the change, but when I used the declared constant in the companion (edit: or any non-zero value it appears), it seems to always revert back to the constant - is this a bug?

I would guess that you are making wrong assumptions of the evaluation order

New plugin update? Is Kotlin 1.3.0-rc-116 an RC2? Updated to rc-116, everything works great 👍

Why vararg Nothing is forbidden?

why use Nothing though.. whats the usecase ?

@jw Any idea when okhttp will move to okio >= 2.0? I want to get rid of the java source asap

What would be the best way to pragmatically get the latest stable version number for Kotlin?

Is it possible to take in a lambda that is based around generics? For example, can we simplify the following:

enum class Order {
   ASCENDING {
       override fun <T : Comparable<T>> sort(iterable: Iterable<T>): List<T> =
               iterable.sorted()
   }, DESCENDING {
       override fun <T : Comparable<T>> sort(iterable: Iterable<T>): List<T> =
               iterable.sortedDescending()
   };

   abstract fun <T : Comparable<T>> sort(iterable: Iterable<T>): List<T>
}

Such that it is something in the form of

enum class Order(...) {
  ASCENDING(::sorted), DESCENDING(::sortedDescending)
}

Well this is nostalgic. I've got a defined grammar and was wondering if there's a recommended Kotlin library that will build the AST from the definition and an input string.

yes in fact my class does make network calls/read disk

@karelpeeters thanks my main problem is that

fun processIncomingMessages(incomingMessage: List<IncomingMessage>)

is actually a function that thats a list of

SomeOtherType

but not

IncomingMessage

.

SomeOtherType

is just a json message, so I need to process each json message and wrap them in a IncomingMessage class. So it's actually look more like this this ( I try to use jacksonmapper library)

// example incoming messages:
    //  {"message":"message1", phoneType":"iPhoneX", "test1"},
    //  {"message":"message1", phoneType":"Samsung1", "test2"}

    fun processIncomingMessages(incomingMessage: List<SomeType>): Map<MessageIndex, List<Message>>{


      //how do  I need to process each incoming json messsage and wrap them in IncomingMessage class?
        return incomingMessage.forEach {

                          val eventObj = jacksonObjectMapper().readValue(String(it.data.array()), IncomingMessage::class.java)

        }

not a question, rather a highlighting of the fun of kotlin:

Hi community I am new here , any advice before begining kotlin journey

data class Person(val name: String, var age: Int) fun main() { val person1 = Person("Murali", 21) val person2 = person1.copy() } Now my question is do the fields in both person1 and person2 refer to the same objects? I mean person1.age === person2.age ?

Hey there, I've been messing with kotlin trying to create a class that will be used by an Apache Spark enabled application. so previously I had a class that had a method:

override fun getFiles(path: String, sc: SparkContext): RDD<*> {
        sc.hadoopConfiguration().set("fs.file.impl", org.apache.hadoop.fs.LocalFileSystem::class.java.name)
        return sc.binaryFiles(path, 1)
    }

And that was fine, It all worked properly. But now I had to add a .filter() to that returning RDD, and I'm struggling to get the code to compile, even though I don't get any errors in the IDE The smallest example I can give is:

override fun getFiles(path: String, sc: SparkContext): RDD<*> {
        sc.hadoopConfiguration().set("fs.file.impl", org.apache.hadoop.fs.LocalFileSystem::class.java.name)
        return sc.binaryFiles(path, 1).filter { true }
    }

Which should just return true from the filter and not do anything But I get this error when trying to build:

Error:(56, 47) Kotlin: Type mismatch: inferred type is () -> Boolean but Function1<Tuple2<String!, PortableDataStream!>!, Any!>! was expected

The closest I have got to making it work was:

override fun getFiles(path: String, sc: SparkContext): RDD<*> {
        sc.hadoopConfiguration().set("fs.file.impl", org.apache.hadoop.fs.LocalFileSystem::class.java.name)
        return sc.binaryFiles(path, 1).filter(getFilterFunction())
    }

    private fun getFilterFunction(): scala.Function1<Tuple2<String, PortableDataStream>, Any> {
        return Function1<Tuple2<String, PortableDataStream>, Any> { tuple: Tuple2<String, PortableDataStream> ->
            return@Function1 true
        }
    }

But I get

Error:(60, 16) Kotlin: Interface Function1 does not have constructors

Does anyone have experience with interfacing with Apache Spark from kotlin?

Hey guys, I've been using kts scratches file for a while in Intellij CE and Android Studio and everything used to work perfectly. However since I had to delete my

~/.gradle/caches

, scripts don't work anymore if I try to run them from the IDE I get this :

Primary constructor not found for script template class ScriptTemplateWithArgs

Any idea how to fix that ?

why

inline

classes allow only one constructor param? it would be nice to have

inline class Pair

to avoid extra allocations

Is there some publicly published way to kill the kotlin compiler daemon?

Alright so, its also the case that if A depends on B statically, and B encounters an exception in its static initializer, and the runtime calls

A.main

as its entry point, the only thing you'll see is

NoClassDefFoundError: Cannot find 'com.you.A'

correct? without a caused-by

ExceptionInInitializer

?

Correct, what I actually have is this list initialization which of course happens outside of the constructor of MyClass