Does a combination of

data class

and builder pattern exist, or is it even possible? I'd like the simplicity of a data class, but with setters that return

this

... Anyone?

I’m tired of being told that I can’t compare

someByte == 13u

. Is it possible to implement an unbalanced equals override that will let me compare these without having to put toUByte() or toUInt() in everywhere. I tried something like: fun UInt.equals(b:UByte) : Boolean { return this == b.toUInt() } (and the reverse as well) But == sites still complain

Is there a way I could solve this issue?

Cause in Kotlin there is no point to write event.eventSource == null test, as at Kotlin level the event.eventSource will always be non-null

if I set java 11 as the target of kotlin, will java files also be able to use things like

var

(from java 10)?

Can anyone solve issue in #ktor i asked around 4 hours ago still no response...

any idea when kotlin 1.3.60 will be released officially?

Why every class in kotlin by default "final"?

Hi, I plan to participate to the Github annual Game Jam, and with my team we want to try Kotlin multi-platform to make the game running on Android, iOS and Web. Can I create and code the project into Android Studio or I need to use Intellij ? Also, if you have heard of some people who have do some little games with Kotlin multi-platform, I'm interested.

Could someone help me find the source code of hashCode for data classes in Kotlin?

Seems like a silly question, but where can I find what is the latest version of kotlin and release notes? https://kotlinlang.org/ says "Kotlin 1.3 Released" and is a link to release notes but that is not exactly the latest version (seems like there is a 1.3.50... but where can I find this info with release notes)?

Why is this not allowed?

val map: Map<String, Int>? = mutableMapOf("one" to 3)
        map?.["one"] // <- Why is this not allowed?
        map?.get("one") // <- Which is equivalent to this, which works

anyone ever wish there was a clean way to do

else ""

,

else 0

, etc?:

return myStr + if (myCondition) myPostfix else ""

return myVal + if (myCondition) myAddition else 0

obviously the nicest syntax would probably simple exclude the

else

, but that of course does not compile

I have a

List<Pair<A,B?>>

Is there an easy way to filter out all where

second==null

and make the type be

List<Pair<A,B>>

?

Anyone know why:

val t = '\u223C'  // TILDE
val a = "A" + t + "B" + t + "C"
val b = "A~B~C"
val c = "A${t}B${t}C"
println (a == b)    // false
println (b == c)    // true

?

Which libraries have the following: 1. Trees, B-Trees, Black/Red Trees, traversing them leafs first and root first. Balanced search trees and rebalancing. 2. All permutations (same as CROSS JOIN in SQL)

Hey, at what point is the value converted to Int in Kotlin? AS is showing a warning that Byte is expected but found Int even though in the Java version of the code it is picked up as byte. Kotlin: var r = byteArray[3 + i] If (r > 0) r += 255 //the warning is shown here Java: byte r = byteArray[3 + i] If (r > 0) r += 255; //the warning is not shown

This is a question on Type Inference that I posted on StackOverflow. First guess the answer and then look at the SO answer. I understand that Kotlin is a statically-typed language, and all the types are defined/inferred at the compile time itself. Here is a

when

expression that returns different types:

fun main(){

        val x = readLine()?.toInt() ?: 0

        val y = when(x){
            1 -> 42
            2 -> "Hello"
            else -> 3.14F
        }

        println(y::class.java)
}

During runtime (Kotlin 1.3.41 on JVM 1.8) this is the output: When

x

= 1, it prints

class java.lang.Integer

When

x

= 2, it prints

class java.lang.String

Otherwise, it prints

class java.lang.Float

When does the compiler determine the type of

y

? Or, how does the compiler infers the type of

y

during compile-time? Question on StackOverflow: https://stackoverflow.com/q/58479824/816416

Does anyone have a good resource for learning collections in Kotlin? That is the one place I seem to really be struggling

Can anybody think why this resolves to type

Any?

instead of

Number?

fun String.toNumber(): Number? = toIntOrNull() ?: toLongOrNull() ?: toBigIntegerOrNull()

@h0tk3y where is better-parse used in? i see it's on life support, would love to know more

Is there any way to do reflection at compile time? I want to dynamically create an interface. Use case is as follows: I have a base class (Let's call it foo) and I want to get all the subclasses of foo. Then I want to create an interface which creates a method (all with the same paramters and return type) for each and every subclass of foo

Why is JB reluctant to add sum/union types? e.g.

fun <N: Int | Byte> foo(n : N) = n.toDouble() / 4.5

TypeScript has them, so I'd imagine JB would want to have it for Kotlin/JS.

i'd imagine it'd be better if

fizz

returned nullable, then

foo.fizz()?.log()

Is there a kotlin function to scope an object on a condition? Something like

withIf(myObject.propertyToFiler == true) { myObject -> ... }

Hey Kotlin devs, I just released my first open source kotlin library for string case conversion and detection, which can be useful for things like generating code. It's stable as I have used it for other projects already. I'd love any feedback from the community! https://github.com/dotCipher/kase-format

Which is better, a

val

with a backing property, or a public property with a private setter? Is there any difference? For example,

class Foo {

    // (1) - public property with a private setter
    var isSyncing = false
        private set
    
    // (2) - val with a backing property
    private var isSyncing_ = false
    val isSyncing get() = isSyncing_
}

Hello, I’ve a question regarding

inline functions

. How can I make an inline function stopping/returning the calling function?

Basically, I would like this :

//This method should return the calling function
inline fun onUserNull() = run {
  Timber.e("User is null")
  return
}

fun fetchUserIdentity() {
  val currentUser = userDataSource.currentUser ?: onUserNull()

  presenter.displayUserIdentity(currentUser)
}

Would do the same as:

fun fetchUserIdentity() {
  val currentUser = userDataSource.currentUser ?: run {
    Timber.e("User is null")
    return
  }

  presenter.displayUserIdentity(currentUser)
}