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  • k

    karelpeeters

    11/07/2018, 8:05 PM
    Kotlin protects you from mistakenly operating on nullable types
    Copy code
    fun foo(): String {
    null?.let {
        return it
    }
}

println(foo().length) //NullPointerException
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  • k

    Kevin Huang

    11/08/2018, 2:25 AM
    Do you like "Return at Labels" ? Specially in lambdas. It is too similar to 
    goto
    . And in lambdas,can't call "return" directly. In some complex cases , can't return a value immediately , need some ugly code to solve. Any suggests for this situation? Thanks.
    g
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  • s

    stevecstian

    11/08/2018, 2:49 AM
    Should we have kotl.in/maven and kotl.in/gradle?
    👌 2
    s
    h
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  • c

    cygnus

    11/08/2018, 3:51 AM
    in documentation, how would i reference a specific parameter of a method?
    g
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  • m

    Massimo Carli

    11/08/2018, 11:24 AM
    Hi all, just a curiosity. Why the type of 
    String::class
    is 
    KClass<String>
    while the type of 
    "Hello"::class
    is 
    KClass<out String>
    ? This means that what 
    "Hello"::class
    returns is a 
    KClass<T>
    where 
    T
    is a subtype of 
    String
    . But 
    String
    is final and it doesn't have subtypes. 🤔
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  • b

    bartvh

    11/08/2018, 2:44 PM
    I'm trying to implement a custom property delegate, but the compiler complains that it doesn't have a 
    getValue(receiver, property)
    method. While that's true, I only have a 
    var value: Boolean
    , I've looked into the source code for Lazy an it also only has a 
    var value: T
    . Why can't I do it like this in my custom class?
    y
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  • v

    vkuznetsov

    11/08/2018, 3:28 PM
    it compiles just fine at playground
    a
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  • m

    Massimo Carli

    11/08/2018, 3:29 PM
    I think the validate function should return 
    String?
    🚫 1
    a
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  • a

    arekolek

    11/08/2018, 3:39 PM
    but in runtime it prints that result is null, that’s what I’m saying
    🧵 1
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  • v

    vkuznetsov

    11/08/2018, 3:40 PM
    yes, in runtime it print's null despite function return type is String
    h
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  • d

    dagguh

    11/08/2018, 3:58 PM
    Today we encountered 
    Inheritance from an interface with ‘@JvmDefault’ members is only allowed with -Xjvm-default option
    I tried Googling and searching in this Slack, but came up short. I understand why the interface compilation needs this flag. But why do the implementations need this flag too? Can't the compiler see that the interface is compiled on JVM target 8 and uses the 
    default
    Java 8 in the method and simply compile as if you implemented in Java? Here's a concrete incarnation of this problem: https://ecosystem.atlassian.net/browse/JPERF-260
    🤔 1
    m
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  • i

    igor.wojda

    11/08/2018, 5:47 PM
    Can somebody give me good example of using 
    CharSequence.reduce
    function?
    d
    h
    +2
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  • m

    marcelo

    11/08/2018, 7:47 PM
    When trying to do a 
    File.copyTo
    and setting 
    overwrite = true
    it still throws a 
    FileAlreadyExistsException
    . I check the file permissions and so far can't write nor can't read. Is there anything that I can do to force a file to be updated? I tried deleting but nope.
    d
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  • j

    jlleitschuh

    11/08/2018, 10:01 PM
    The Kotlin compiler is blowing up with an unusual exception if I try to compile a file with a ~2300 multi-line pretty printed JSON string. Is there a known limitation on the max number of lines that a multi-line string supports in Kotlin? Update: Trying to cut (cmd-x) this string out of IntelliJ has caused intelliJ to hang. Update: The hang is reproducible after restart of IJ. I might report this issue privately in youtrack, if that's possible.
    d
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  • c

    camkadev

    11/09/2018, 10:08 AM
    kotlin bug?
    b
    e
    +2
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  • b

    BillKarv

    11/09/2018, 10:12 AM
    Hi I am testing coroutines. I want my code to run in parallel, not waiting for a result. How am I suppose to do that? I 've searched the internet with no luck..
    b
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  • j

    jmfayard

    11/09/2018, 11:03 AM
    Which kotlin equivalent exist to make our terminals more lively like this? https://dev.to/ryanwhocodes/artii-lolcat-colorls-catpix-and-other-ruby-gems-to-add-color-to-your-terminal-572g
    m
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  • i

    igor.wojda

    11/09/2018, 11:54 AM
    I want to make sublist that contains last element of my original list, however 
    list.subList()
    2nd param 
    toIndex
    is not end inclusive 🤔
    Copy code
    //have
val list = listOf(1,2,3,4)

//want sublist
listOf(3,4)
    g
    a
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  • d

    dalexander

    11/09/2018, 3:54 PM
    I’m running in to an interesting issue with generics and nested classes. For some reason changing the type parameter’s variance to in/out from invariant changes the visibility of a property using that type parameter.
    -.txt
    c
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  • c

    coder82

    11/09/2018, 5:19 PM
    With kotlin 1.3.0 it looks like a jvm subproject cannot depende anymore on a js subproject
    n
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  • c

    coder82

    11/09/2018, 5:21 PM
    mmm it was nice to depend my backend jvm on the frontend js
    😱 1
    😞 1
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  • c

    coder82

    11/09/2018, 6:05 PM
    it used to work perfectly, the output.jar from the frontend contains a bunch of transpiled .js and web resources
    k
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  • i

    igor.wojda

    11/09/2018, 6:45 PM
    I have general question about regular expressions In Javascript we can do this 
    const matches = str.match(/[aei]/gi)
    to check if string contains 
    a
    , 
    e
    or 
    i
    character. However In kotlin this does not work. I wonder are the regular expression general cross-language concept or each language has own implementation (similar to other languages yet different)?
    h
    b
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  • j

    jeggy

    11/09/2018, 6:53 PM
    How can I achieve something like this without using 
    out
    ?
    k
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  • a

    Alowaniak

    11/09/2018, 7:36 PM
    how can I easily get a (sorted) frequency map of a LongArray? is there something neater than 
    longArray.toList().groupingBy{ it }.eachCountTo(sortedMapOf())
    ?
    i
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    • 1
  • m

    Marcel Overdijk

    11/09/2018, 9:11 PM
    What are people using for checkstyle style/lint, findbugs for Kotlin (using Gradle build tool chain)?
    m
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  • d

    dharrigan

    11/09/2018, 9:26 PM
    Oh dear, I think I've found a nasty bug in Kotlin 1.3, with ArraysJvm...https://youtrack.jetbrains.net/issue/KT-28113. Anyone else notice this?
    K 1
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  • k

    kevinherron

    11/10/2018, 12:17 AM
    is there a Kotlin book that covers 1.2, or one coming that will cover 1.3 + coroutines?
    n
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  • c

    chansek

    11/10/2018, 11:38 AM
    I am correct in understanding how anonymous functions works in Kotlin?
    i
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  • b

    Bernhard

    11/10/2018, 4:15 PM
    does kotlin support anon union types (e.g. String | Int)
    👍 1
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