Well, and I don’t understand Slack formatting, too… 😉

I'm kinda stuck when the compiler said that this function:

fun a(items: Array<Item>)

cannot be invoked like this:

fun b(vararg items: Item) {
    a(items)
}

because...

items

is

Array<out Item>

, not

Array<Item>

. This also means that I can't write to this array. Why? This may lead to situations when some code cannot be converted from Java.

whats the correct way to pass ‘this’ to a property in a constructor?

Hi, any clue why my main function no longer works after updating to 1.1.1? Using Idea and gradle. Trying to run main from the IDE spits out this error:

Exception in thread "main" java.lang.NoClassDefFoundError: kotlin/jvm/internal/Intrinsics
	at com.mypackage.something.MainKt.main(Main.kt)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Caused by: java.lang.ClassNotFoundException: kotlin.jvm.internal.Intrinsics
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 6 more

Looks like it struggles with the runtime or stdlib, but I'm not sure. It worked before, and I have applied kotlin as a gradle plugin, and the stdlib is in my dependencies.

strange, lots of extension methods on String, like toShortOrNull... I would like to have str.toNotEmptyOrNull()?:"replacement" but shorter

In fact, the opposite. I'm trying to have a really strong reason to always have them match. So, when I distribute a JAR for 64-bit machines, I want all integers and fractions to be 64-bit. On the other hand, when I distribute the 32-bit, I want all integers and fractions to be 32-bit. I don't like this mixed approach.

Hi, I'm playing around with Kotlin and am using Gson too. I'm trying to use Gson to convert an object that has a reference to a property with type KClass. Gson throws a Stackoverflow exception for this, does anyone have an idea why please?

Ok. So it's just a matter of personal preference. Thanks,

Why won't this compile?

fun String.differingCharacters(other: String): List<Char> {
    var endList: MutableList<Char> = mutableListOf()
    (0..min(this.length, other.length)).forEach { index ->
        val thisChar = this[index]
        val otherChar = other[index]
        if (thisChar != otherChar) {
            endList += thisChar
        }
    }
    if (this.length < other.length) {
        endList += other.substring(this.length).toCharArray().asList()
    } else if (other.length > this.length) {
        endList += other.substring(this.length).toCharArray().asList()
    }
    return endList
}

Errors:

Error:(123, 21) Kotlin: Assignment operators ambiguity:

public operator fun <T> Collection<Char>.plus(element: Char): List<Char> defined in kotlin.collections

@InlineOnly public operator inline fun <T> MutableCollection<in Char>.plusAssign(element: Char): Unit defined in kotlin.collections

Error:(127, 17) Kotlin: Assignment operators ambiguity:

public operator fun <T> Collection<Char>.plus(elements: Iterable<Char>): List<Char> defined in kotlin.collections

@InlineOnly public operator inline fun <T> MutableCollection<in Char>.plusAssign(elements: Iterable<Char>): Unit defined in kotlin.collections

Error:(129, 17) Kotlin: Assignment operators ambiguity:

public operator fun <T> Collection<Char>.plus(elements: Iterable<Char>): List<Char> defined in kotlin.collections

@InlineOnly public operator inline fun <T> MutableCollection<in Char>.plusAssign(elements: Iterable<Char>): Unit defined in kotlin.collections

I’ve noticed @Throws annotation being added to some auto-translated Java -> Kotlin code. Given that Kotlin does not use checked exceptions, is this annotation optional; i.e. only required if I need exception inter-op with Java code?

@ra1nmak3r different standard library from java

Why do I get this error?

java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    org/bh/tools/base/strings/TestUtils.concat(Ljava/lang/Object;Ljava/lang/CharSequence;)Ljava/lang/CharSequence; @28: invokevirtual
  Reason:
    Type 'java/lang/Object' (current frame, stack[1]) is not assignable to 'java/lang/String'
  Current Frame:
    bci: @28
    flags: { }
    locals: { 'java/lang/Object', 'java/lang/CharSequence' }
    stack: { 'java/lang/StringBuilder', 'java/lang/Object' }
  Bytecode:
    0x0000000: 2a12 59b8 0012 2b12 43b8 0012 2ac1 005b
    0x0000010: 9900 1a2a bb00 1659 b700 1a5f b600 512b
    0x0000020: b600 5eb6 0052 c000 23b0 2ac1 0016 9900
    0x0000030: 152a c000 162b b600 5e59 1260 b800 63c0
    0x0000040: 0023 b0bb 0016 59b7 001a 2ab6 0047 2bb6
    0x0000050: 005e 5912 65b8 0063 c000 23b0          
  Stackmap Table:
    same_frame(@42)
    same_frame(@67)


	at org.bh.tools.base.math.NumberConversionKtTestKt.assertNumbersClose(NumberConversionKtTest.kt:488)
	at org.bh.tools.base.math.NumberConversionKtTest.Number_float32Value(NumberConversionKtTest.kt:47)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runners.Suite.runChild(Suite.java:128)
	at org.junit.runners.Suite.runChild(Suite.java:27)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
	at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:58)
	at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:237)
	at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

At this line: https://github.com/BlueHuskyStudios/Blue-Base/blob/dev/JVM/test/org/bh/tools/base/math/NumberConversionKtTest.kt#L47

Hi there! Am I right in assuming it’s not possible to declare a custom setter for a field initialized in the primary constructor?

Anyone else have any ideas?

tried

infix fun (() -> Unit).shallThrow(java: Class<*>)

but it doesn't work

fun fromActivity(activity: Activity?): Source = when {
                activity != null && activity is FooActivity -> Source.FOO
                else -> Source.UNKNOWN
            }

Something tells me I don’t need the null check in the above code. Can I get rid of it and have the same exact behavior?

Does kotlin have any classes for observable lists? Kind of like

Delegates.observable

, but for

add

and

remove

I have no experience with the JavaScript interoperability. So can somebody confirm that you can call Kotlin code from JavaScript and vice versa like it works with Java and Kotlin?

cool. Is this preferable?

fun sql(colb : Int?) = "SELECT * FROM TABLE WHERE A=3 ${colb?.let {" AND B=$it"}.orEmpty()}"

I'd like to check if a

lateinit

has been initialized, according to https://youtrack.jetbrains.com/issue/KT-9327#comment=27-1845509 there should be a

javaField

but I have nothing like that

@Andreas Sinz Yes, IDEA 2017.1

Is anybody available to give me a bit of a hand?

is it possible to have

inline fun <T, R> binding(pair: Pair<Int, Int>, block: T.() -> R) {

where

T

is decided based on

pair.second

?

You're right, subject expression is inaccessible in

when

. This feature is being discussed.

I’ve encountered other similar issues where the only way around it was having a

/src/main/java

and a

/src/main/kotlin

. So now I just default to that to save me hours of troubleshooting in the future.

Is there a good way to deal with data classes and inheritance? Is the best way to do this to make the Parent's

a

open and the Childrens'

a

override? I'd really just like for the

a

of the children not to be a

val

.

sealed class Parent(val a: Int)
data class Child1(val a: Int, val b: Int) : Parent(a)
data class Child2(val a: Int, val c: Int): Parent(a)

This is my use case: https://github.com/czyzby/ktx/blob/master/style/src/main/kotlin/ktx/style/style.kt I'd like to prohibit users from using the API like this:

skin {
  label {
    label { // Should not compile: not a direct child of skin.
    }
  }
}

If you do not control types used in your dsl, you can apply dsl annotation to the receiver type of function-with-receiver parameter, something like this:

fun skin(init: (@MyStyleDsl Skin).() -> Unit): Skin

where

MyStyleDsl

is an annotation, annotated with

@DslMarker

Hi, is it supposed to work? named@for() { synchronized(obj) { ... continue@named; } } ? I was under impression that synchronized is inline function, and therefore there's no restrictions on control flow statements inside passed lambda, but compiler gives an error.