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  • n

    natpryce

    01/21/2019, 9:27 AM
    I use it occasionally, but I find star projections a bit “icky”. If I need one, I feel I’ve messed up my design somewhere.
  • a

    Andrew S

    01/21/2019, 9:30 AM
    I don't care for the complexities of the more flexible but layered aspects of some type systems, and I was hoping this stuff doesn't come up too much in normal code. Though it does seem a tad better than Java's wildcard types
  • n

    natpryce

    01/21/2019, 9:38 AM
    It’s far better than Java’s generics.
  • l

    LeoColman

    01/21/2019, 12:00 PM
    Hey guys! Is there anyway to use an experimental feature in a lib without forcing users to use 
    kotlin.experimental
    compiler option?
  • c

    Czar

    12/14/2019, 12:59 PM
    I hate this kind of hibernate mappings - the string literals all over my code:
    Copy code
    @Column
@Type(type = "org.hibernate.type.TextType")
val myText: String
    So currently I have:
    Copy code
    object Types {
  const val TEXT_TYPE = "org.hibernate.type.TextType"
  // other types
}
    Is there a better way? I mean this is better than using the literals everywhere, but the source of the type is still a literal and I can't change this into: 
    const val TEXT_TYPE = TextType.INSTANCE.name
    because then Kotlin complains that annotation value is not a compile time constant. Any solution?
    ➕ 1
  • v

    Vinicius Carvalho

    12/15/2019, 1:00 AM
    Hi folks, I have a silly question on Generics I have the following class hierarchy:
  • v

    Vinicius Carvalho

    12/15/2019, 1:01 AM
    Copy code
    interface Scrapper<T : Any> 
abstract class AbstractSiteScrapper<T: Any> : Scrapper<T>
class SiteScrapper<Site>
class PageScrapper<Page>
  • v

    Vinicius Carvalho

    12/15/2019, 1:02 AM
    I then have declared a map: 
    mutableMapOf<Class<*>, AbstractSiteScrapper<*>
  • v

    Vinicius Carvalho

    12/15/2019, 1:02 AM
    Idea is to fetch a scrapper given any class my method receives
  • v

    Vinicius Carvalho

    12/15/2019, 1:03 AM
    but then I get an error saying the method I invoke: is 
    page: Nothing
  • v

    Vinicius Carvalho

    12/15/2019, 1:04 AM
    Copy code
    interface Scraper<T : Any> {
    fun visit(page: T)
    fun accept(value: Any) : Boolean
}
  • v

    Vinicius Carvalho

    12/15/2019, 1:04 AM
    the visit method is the one I'm invoking
  • v

    Vinicius Carvalho

    12/15/2019, 1:06 AM
    Copy code
    val payload = queue.take()
                val scraper = scrapers[payload::class.java]
                scraper?.visit(payload)
  • v

    Vinicius Carvalho

    12/15/2019, 1:06 AM
    I was reading about Generics in Kotlin and thought I could use the * projection for a safe write, but does not seems to work
  • v

    Vinicius Carvalho

    12/15/2019, 1:07 AM
    declaring the map using 
    AbstractSiteScraper<Any>
    fails because it says 
    SiteScraper
    is not the same type as 
    AbstractSiteScraper<Any>
  • v

    Vinicius Carvalho

    12/15/2019, 1:07 AM
    The funny thing is that I can actually do
  • v

    Vinicius Carvalho

    12/15/2019, 1:09 AM
    Copy code
    val scrapers = mutableMapOf<Class<*>, AbstractSiteScraper<Any>>()
    scrapers[Site::class.java] = SiteScraper() as AbstractSiteScraper<Any>
    scrapers[Page::class.java] = PageScraper() as AbstractSiteScraper<Any>
  • v

    Vinicius Carvalho

    12/15/2019, 1:09 AM
    and that works, but looks so wrong 😞
  • n

    Nikky

    12/15/2019, 9:17 AM
    seems like smartcasting on 
    when
    only works when the selaed class type is casted to outside broken:

    https://i.imgur.com/tUusyIE.png▾

    working:
    Copy code
    val reducer: Reducer<MultiplayerState> = { state, action ->
    action as Actions
    when(action) {
        is Actions.AddObserver -> {
            state.copy(observers = state.observers + action.observer)
        }
        is Actions.RemoveObserver -> {
            state.copy(observers = state.observers - action.observer)
        }
        is Actions.SetConnectionState -> TODO()
    }.exhaustive
}
  • a

    Ashutosh Panda

    12/15/2019, 12:23 PM
    How to remove all elements in a list in Kotlin
  • a

    Ashutosh Panda

    12/15/2019, 12:25 PM
    This is my code
  • s

    steenooo

    12/16/2019, 8:50 AM
    (I know I can just do “Optional#ofNullable, but, maybe theres something different)
  • m

    Madera Jan

    12/16/2019, 12:58 PM
    Hi is there some way in kotlin create array as compile-time constant. I need to pass array in annotation and i need to access array from diffrent places?
    🚫 1
  • b

    bjonnh

    12/16/2019, 6:12 PM
    Videos of KotlinConf19 are starting to get published: https://www.youtube.com/channel/UCGp4UBwpTNegd_4nCpuBcow
    🎉 9
  • m

    Maciej Grzeszczak

    12/16/2019, 7:40 PM
    Does anybody else find Char.toInt() method behavior weird? I know in languages such as C/C++ chars were just bytes so you might be interested in that value, but two times already while doing adventofcode task I found myself looking for a bug when converting Char digit to its Integer value, which has to be done by first converting to a String.
    ➕ 3
  • e

    ephemient

    12/16/2019, 7:47 PM
    on JVM there's Character.digit()
  • c

    commanderpepper

    12/16/2019, 7:51 PM
    Char.toInt() casts the Char to the corresponding Int ASCII value
  • j

    jef

    12/16/2019, 8:06 PM
    anyone know kotlinx.serialization extensively?
  • a

    alexsimo

    12/17/2019, 10:30 AM
    Why while reading a file (json content) from a test resource, it escapes all characters?
  • s

    ShootingStar

    12/17/2019, 1:04 PM
    The other chapter the author expalin safe call oeprator lie this
    Copy code
    A better way to handle this situation is to use the safe call operator (?.). Safe call short-circuits
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