kotlinlang #announcements

var recipients: MutableList<String> = mutableListOf()
    var recipient: String
        set(recipient: String) {
            recipients.add(recipient)
        }

dumptruckman

02/07/2019, 4:23 PM

that would expose the property as a public field though, right?

dumptruckman

02/07/2019, 4:53 PM

is it possible to use a property for ONLY setting another property - like it has no getter in java or kotlin

diesieben07

02/07/2019, 4:55 PM

var foo: String
    @JvmSynthetic
    @Deprecated(message = "unused getter", level = DeprecationLevel.HIDDEN)
    get() = throw RuntimeException()
    set(value) {
        
    }

dumptruckman

02/07/2019, 6:13 PM

Does Kotlin have any secret feature for automatically overriding the return type of builder methods in subclasses?

Michael

02/07/2019, 8:11 PM

I have a lambda and I’m trying to have it return null from within an if statement; but it seems that it just exits the if and moves on to the last line:

{ .....some lines.... if (condition) { null } ..... final value }

groostav

02/07/2019, 8:40 PM

hey, can I have this?

sealed inline class Token{}
object UnixNewline: Token()
object WindowsNewline: Token()
inline class Character(val impl: Char): Token()

it would make one of my tokenizers run a whole lot faster

dumptruckman

02/07/2019, 9:40 PM

trying to do

() -> Unit

but it is expecting a return value

dumptruckman

02/07/2019, 10:09 PM

How can I user an optional generic type?

ursus

02/08/2019, 3:54 AM

is anyone using the Result monad in production?

antonis

02/08/2019, 8:55 AM

Hello, I was wondering if there is a way to pass an operator (like >, =< etc) as a parameter to a function. Since e.g. comparison operators are translated to a.compareTo(b) function calls how is it possible to pass the actual operator in a function like: fun someFunction(operator: Int.(Int) -> Boolean)

thana

02/08/2019, 8:57 AM

What is the rationale behind the decision not to provide a "package private" visibilty? (i think even better would be something like a "friend" visibility)

karelpeeters

02/08/2019, 10:29 AM

class Env {
    fun sub() = SubEnv(this)
}

class SubEnv(val parent: Env)

Is there a nice way to make

sub()

the only possible way to construct a

SubEnv

instance? Making the constructor of

SubEnv

private

isn't allowed. Making

SubEnv

an inner class doesn't help either, you're still not allowed to make the constructor private.

svenjacobs

02/08/2019, 11:19 AM

Does Kotlin provide some kind of annotation for public functions that are however considered "internal" API and should not be used? As a library developer I provide a public inline function. However this func references another "internal" utility function. The utility function should actually not be used outside of the library but since the inline function is public I cannot declare this utility function as

internal

. So I just want to warn users if they are accidentally using the internal function.

dumptruckman

02/08/2019, 4:42 PM

grrr, I will always be upset about the decision to remove package-private and stopping protected from being visible in package scope

👍 1

HaSH

02/08/2019, 7:01 PM

The if would be here

kevinmost

02/08/2019, 7:43 PM

internal

public

in Java, but they mangle the name in bytecode so it's not that bad. Nobody will look at that method name and want to call it.

dumptruckman

02/08/2019, 8:16 PM

Is there a more idiomatic way to write this?

val contentBodyP2MessageKey = template.contentBodyP2MessageKey
        val contentBodyP2MessageArgs = template.contentBodyP2MessageArgs
        if (contentBodyP2MessageKey != null && contentBodyP2MessageArgs != null) {
            val contentBodyP2 =
                messageSource.getMessage(contentBodyP2MessageKey, contentBodyP2MessageArgs(environment), locale!!)
            context.setVariable("contentBodyP2", contentBodyP2)
        }

tianhao

02/09/2019, 12:14 AM

Does Kotlin support catch multiple exceptions similar to Java now?

🇳🇴 2

tianhao

02/09/2019, 2:24 AM

How can I check that two lambdas are the same operations? For example, the argument of a function is a lambda:

op: (Double, Double) -> Double

and the parameters I will pass could be:

{ op1, op2 -> op1 + op2 }

{ op1, op2 -> op1 - op2 }

{ op1, op2 -> op1 / op2 }

. So how can I check

op

is equals

operation I passed in inside of the method?

Hexa

02/09/2019, 10:21 AM

We still use Java in our codebase but we are slowly migrating to Kotlin

Jakub Aniola

02/09/2019, 6:40 PM

What virtual machine is used by IntelliJ when I compile Kotlin code? Is it connected with configured JRE/JDK 1.8 etc? Is it Oracle HotSpot?

GarouDan

02/10/2019, 12:14 AM

I don’t know where I can file an issue about this but I had verified that there is an

error in the "Kotlin (Mobile Android/iOS)" template

in IntelliJ to create a new project. The android

buid.gradle

is not correct configured since it is prepared to copy a

app.framework

but the build process is generating a

main.framework

. Also, the references in the

iosApp

, specially in the

project.pbxproj

are wrong, pointing the the

app.framework

. I tried several variations trying to change the

main.framework

to the

app.framework

but it wasn’t working. What worked was the opposite, change the references from

app.framework

main.framework

. I think this worked because the module exported is

main

but not

app

. So I needed to fix the imports in the project too. Ufa! I had a hard time trying to put this to work, since this was my first project using android and ios.

tipsy

02/10/2019, 9:18 AM

i heard there was a compiler option to enable SAM conversion, can anyone point me to the docs for that?

Jakub Aniola

02/10/2019, 2:43 PM

Can someone recommend me place where I can read more about Kotlin JVM compiler? Is it the same JIT compiler which is a part of JRE? I assume not because I can check out compiler codebase on Github 😛

GarouDan

02/10/2019, 2:46 PM

I’m working on a project in IntelliJ but it keeps doing background operations when I’m editing a build.gradle.kts file. Is is possible to disable this behavior so we could hit this background process only after we save the file?

Dalinar

02/10/2019, 3:16 PM

what is the kotlin way to use

.use

if it is used on the next line? should it be indented or should it be flush with the object on the line above?

Title

Dalinar

02/10/2019, 3:16 PM

what is the kotlin way to use

.use

if it is used on the next line? should it be indented or should it be flush with the object on the line above?

Dominaezzz

02/10/2019, 3:30 PM

Next line if the line is too long. Up to developer to define too long.

Dalinar

02/10/2019, 3:31 PM

yeah, line is very long, multiple lines actually for this code - but the question is - if it is on the next line should it be

.use {

(tab).use {

(indented)? .. it seems to look better non-indented to me

Dominaezzz

02/10/2019, 3:34 PM

Ah I misread.

I think it should be flush.

Czar

02/10/2019, 3:36 PM

someObject
    .use {
        //logic
    }

karelpeeters

02/10/2019, 5:45 PM

Just look at what Idea autoformats it to?

Dalinar

02/11/2019, 5:28 PM

sure I saw that already, but I wasn't sure if it specifically knew it was a .use or just formatting it according to some general rule (more likely)

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