Does Array<Int> always translate to Integer[] on the JVM?

Hello ! Is there a good way to manage API errors on call in Kotlin? I'm writin a small API library and I'm wondering Should I do: -

fun getData(): Data?

-> catch all exceptions and return

null

-

fun getData(): Data

->

throw

exceptions depending on the situation and have the user of the library catch them -

fun getData(): Outcome<S: Success, F: Failure>

-> create a custom class to wrap the result I'm very much a beginner, and I have no clue what would be the best pratice. Btw I'm using

retrofit2

with kotlin's coroutines, so the REST requests might return exceptions.

I have a data class that I’ve printed to logs using default

toString

. Now I am doing some log manipulation and need to go from that String representation to the data class itself. Is there a simple way to do that?

Hi, i' studying Kotlin and want to make a simple web CRUD application for a book store. Can someone give me some resources to achieve this? I have little experience with web applications, i only did some simple servlets stuff before.

Yes, it's just a representation you can't actually declare intersection types like that yourself.

Hi! I have strange problem with Kotlin 1.3.40. Can anybody explain this?

hi!

list.filter { it.field != null }
    .associateBy({ it.id }, { it.field!! })

is there a way to avoid

!!

on the second line?

list

is a list of:

data class Person(val id: String, val field: Field?)

This message was deleted.

Can anyone give a link to the docs where this syntax is described? Can't find it here - https://kotlinlang.org/docs/reference/typecasts.html I mean how "other" is smart-casted in place, not assigned to another var.

Is there a way to get all the properties on an object (for example to print them out)? In Python, I would do

my_obj.__dir__

in an if check,

in

is the same as

contains

. What is the operator function for

in

when we use it in a loop?

Are Int/Long/CharProgression the only progression in the stdlib?

Is it possible to generate functions with Kotlin? I would like to take a list of endpoints from an API and their arguments and then build those into methods during runtime. So for example:

{
  "api.test": [],
  "<http://apps.permissions.info|apps.permissions.info>": [
    "token"
  ],
  "apps.permissions.request": [
    "token",
    "scopes",
    "trigger_id"
  ],

So in the end I could call my method with myApp.api.test('Bearer s0met0ken') and myApp.apps.permissions.request('Bearer s0met0ken', 'user.write', 'aTrigger') Is this possible with some functional magic?

Or could I also return, say, a String (theoretically)?

why are many functions in the stdlib extension-functions and not put directly into the corresponding class?

How do inline functions exactly execute multiple lines of code. As an example

with

inline function has a receiver and another function that behaves as extension function, so that receiver is able to execute that function on it self. My question is how does that inline function accept multiple lines of code that need to be executed?

What effects does the version of the jvm you target have on kotlin code? I've never written kotlin/jvm that isn't targetting 1.8

best I can do is manually Bar(foo.a, foo.b) right?

and on that note, is it possible to add default params to the abstract vals somehow? if I make them open nonabstract and add defaults there, it wont get applied to subclasses right?

Hi guys, a quick question...Do I need the (value == null) here? Or when the value is null, the "when" expression will trigger the else statement

i want to create a usually/sometimes statement for use with mock data. currently i have:

usually({

}, sometimes {

})

is it possible to get rid of the parens for

usually

somehow, so i just get:

usually {

} sometimes {

}

?

is there a variant of

associateBy

that would throw if a key should have more than one value?

I'm wondering if it's possible to define a type that would like a collection of either a String or another collection of possibly strings or Collections

I started Koans (and will still finish them) but the bugs were eating up enough time it's distracting me from learning, lol

why does this not run, but

test1.equals(test2)

does?

Also, if I don't override

equals

it compares the pointer by default, correct?

i've got a mutable list of <Any>. would like to iterate through it in a for loop.

What exactly is happening with the

.count

lambda inside this function; it looks to me like a lambda is being passed to an

Int

? What?

fun bingo(ticket: Array<Pair<String, Int>>, win: Int) =
    if (ticket.count { it.second.toChar() in it.first } >= win) "Winner!" else "Loser!"

I’m on https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/count.html and don’t see anything like a closure happening for

Array.count

Hi, I'm just starting to learn Kotlin and I'm a little confused by something. How come if I assign a function to a varibale, I am able to pass it in to map like this:

fun main() {
  val strings = listOf("Hello", "World", "!")
  val getLengthOfString = fun(str: String) : Int {
    return str.length
  }
  val lengths = strings.map(getLengthOfString)
  println(lengths)
}

But if the function is a regular function, I cant pass in the function name like so:

fun main() {
  val strings = listOf("Hello", "World", "!")
  fun getLengthOfString(str: String): Int {
    return str.length
  }
  val lengths = strings.map(getLengthOfString)
  println(lengths)
}