@annyce typically, we use Egyptian curly braces, like in Java, not in C. A question to developers of Kotlin. Should constants be

const val

or not?

Was

for (x in a until b)

ever optimized by compiler?

constructors must be as quick and simple as possible

No, there will be an unsuccessful cast.

Hi guys. Does anybody know, kotlin compiler uses ANTLR under the hood? Or jetbrains wrote compiler from the ground up?

Is there a way to expose a property as List outside of the class but access it as MutableList inside the class?

Is there a reason why kotlin doesn't have "regular looking" bitwise operators? (&, |, ~, >>, <<), I find it pretty annoying...

is there a specific Kotlin library people are using for parsing XML ?

Why "don't work"? I have

@XStreamAlias

annotations attached to Kotlin data classes

do I need my class to implement or extend some specific interface or class to support destructuring?

what am I doing wrong here guys?

class Test() {
    var l: List<Int> = mutableListOf()

    init {
        l.add(4) // Unresolved
    }
}

Any way to write this in funcitonal fashion?

controls.mapValues {
    val ans = EnumSet.noneOf(NotificationTarget::class.java)
    if (it.value.pushSwitch.isChecked) ans += NotificationTarget.PUSH
    if (it.value.emailSwitch.isChecked) ans += NotificationTarget.EMAIL
    ans
}

Is there any less-allocative way to do this? Make User mutable?

var user = state.user
sendToBackend(diff.mapValues { when (it.key) {
    "name" -> (it.value as String).also { user = user.copy(name = it) }
    "sex" -> ((it.value as Sex).also { user = user.copy(sex = it) }).name
    "birth" -> ((it.value as Calendar).also { user = user.copy(birth = it.time) }.timeInMillis / 1000L).toString()
    else -> throw AssertionError()
} })

Something like this?

val errors = torrent.error?.let { listOf(it) }

what could an error such as

java.lang.AbstractMethodError

indicate?

Is it possible to call inline kotlin functions from java code?

@robsonj Generic types are erased at runtime, so both are actually just

Remove(List)

. You could resolve it by giving them separate JVM names, but for more clarification on that, you should check SO. 😒tackoverflow:

thanks in advance

Hi I’ve a vararg of

Car

and I’ve to pass it to a function that accepts vararg but it says the time that needs si `Nothing!`… but in Java is getting the correct type, any suggestions?

In the meantime you can swap out the interface with a lambda reference (i.e.

public void callingMethod(TestInterface interface)

to

fun callingMethod(lambda: (string) -> String)

@north don’t really know if it’s ok, but this works:

interface TestInterface {
    fun apply(str: String): String
}

fun TestInterface(lambda: (String) -> String): TestInterface {
    return object : TestInterface {
        override fun apply(str: String): String = lambda(str)
    }
}

fun main(args: Array<String>) {
    var test = TestInterface { str: String -> str.apply { println(str) } }
    test.apply("test")
}

You can throw some inlines in there.

a while back i wrote a library to learn kotlin. when i try to use it in another project, it throws

java.lang.NoClassDefFoundError: com/beust/klaxon/Parser

on this line: https://github.com/danneu/reddit/blob/master/src/main/kotlin/com/danneu/reddit/extensions.kt#L44 i'm not very experienced in java/kotlin, any pointers on what might cause this when using a library from another project?

Hi....how to create below equivalent in kotlin public final class Constants { public static final String TWO_PANE_KEY = "is_two_pane"; private Constants() { } public static class DetailActivityKeys { public static final String STORY_URL_KEY = "storyURL"; public static final String IMAGE_URL_KEY = "imageURL"; public static final String SUMMARY_KEY = "summary"; public static final String TITLE_KEY = "title"; } public static class API { public static final String BASE_URL = "https://api.myjson.com/"; } } I know I can make on companion class to hold all constants .....but how to group constants in inner classes

Hi. I have a data class with three properties:

MyClass(groupId, datetime, someValue)

Next, I have a

Set<MyClass>

, which can contain multiple entries with the same groupId. I want to turn this into a

Set<MyClass>

that contains the latest(by datetime) entry for each groupId. What’s a good functional/stream-like way of achieving this?

Hi. Can someone tell me how to get a reference to the class container from the companion object? https://www.screencast.com/t/Txhuy9WiQ

Simple question about Kotlin JS: I am in a project folder with a local node_modules directory. I want to create a script.kt that does an import of a module within the node_modules. I am using the command-line compiler kotlinc-js, but nothing is found. What is the magic to allow the compiler to pull in JS from the node_modules? Do I have to run the ts2kt converter? Do I need a package.json of some sort? Thank you!

I guess I puted my question the wrong way lets say I have class that have some fields and methods and inside it I have a companion object that need to access the fields and methods of the outer class

no way to `return`/`break` the

init{ }

?

There is also

Character.digit(ch: Char, radix: Int)

, so you can simply do it straight away with:

fun String.calc() = map { Character.digit(it, 10) }.reduce(Int::times)