https://kotlinlang.org logo
Channels
Powered by
#announcements
  • h

    hastebrot

    12/29/2015, 11:52 PM
    Syntax rules for 
    fun foo...
    were so much simpler. It just needed the tokens 
    Keyword
    , 
    Text
    and 
    Name::Function
    and pop the state back to the root rules. 
    fun <T...> foo(...)
    is much more complicated, because we need to copy a subset of the root rules for the tokens between 
    Keyword
    (fun) and 
    Name::Function
    .
  • h

    hastebrot

    12/29/2015, 11:54 PM
    Hmm, I see. There were cases where one needed 
    fun <T> foo()
    and two different declaration styles were too many.
  • h

    hastebrot

    12/30/2015, 12:08 AM
    It is possible to mixin the rules of other states in lexer files for the Rough syntax highlighter. This makes it easier to follow DRY principle and allows syntax like 
    fun <reified T : Any> ...
    .
  • b

    benny_wang

    12/30/2015, 5:46 AM
  • r

    rokee

    12/30/2015, 9:29 AM
    Copy code
    module.itemsType?.length > 0) <- occurs an error
  • r

    rokee

    12/30/2015, 9:29 AM
    hey guys, what’s wrong with this?
  • r

    rokee

    12/30/2015, 9:30 AM
    Copy code
    Use ?. qualified instead, what’s the ?.qualified ?
  • r

    rokee

    12/30/2015, 9:31 AM
    ah, i understand, sorry.
  • r

    rokee

    12/30/2015, 9:32 AM
    hey guys, why does kotlin treat property of java class as a non-nullable? it has enough case to be null.
  • r

    rokee

    12/30/2015, 9:33 AM
    because all of property of java can be null.
  • d

    dmitry.petrov

    12/30/2015, 9:35 AM
    short answer: think of it as of an implicit 
    !!
    for values that come from Java and used as non-nullable
  • d

    dmitry.petrov

    12/30/2015, 9:36 AM
    long answer:

    https://www.youtube.com/watch?v=2IhT8HACc2E▾

  • k

    krtko

    12/30/2015, 10:24 AM
    Kotlin has null safety
  • k

    krtko

    12/30/2015, 10:24 AM
    basically they view nulls as a cause of a lot of bugs
  • k

    krtko

    12/30/2015, 10:25 AM
    so if a value has the possibility of being null it gets special attention
  • k

    krtko

    12/30/2015, 10:25 AM
    its pretty neat
  • k

    krtko

    12/30/2015, 10:25 AM
  • m

    mg6maciej

    12/30/2015, 10:53 AM
    In code:
    Copy code
    class Person(
        private val name: String,
        private val surname: String) {

    val fullName1 by lazy { "$name $surname" }
    val fullName2 = "$name $surname"
    val fullName3: String get() = "$name $surname"
}
    why would 1 and 2 throw 
    java.lang.IllegalArgumentException: Parameter specified as non-null is null: method kotlin.jvm.internal.Intrinsics.checkParameterIsNotNull
    while 3 is working fine?
  • m

    mg6maciej

    12/30/2015, 10:55 AM
    Debugging this fullName1 and fullName2 are null despite being shown as non-null in IDE.
  • m

    mg6maciej

    12/30/2015, 10:56 AM
    The exception is when assigning fullNameX to a String field in a different data class, that's why is saying parameter in the error message.
  • r

    rokee

    12/30/2015, 10:56 AM
    @dmitry.petrov: yes, thank you. But, since i think an operator 
    !!
    makes my code to be have less readability and make more crashable, I prefer to use 
    ?
    . but i’m sad that i can’t use 
    ?
    for property of java.
  • d

    dmitry.petrov

    12/30/2015, 10:58 AM
    I suppose you are talking about 
    module.itemsType
    , right? How is 
    itemsType
    declared?
  • r

    rokee

    12/30/2015, 10:58 AM
    Copy code
    String itemsType;
  • r

    rokee

    12/30/2015, 10:58 AM
    yes
  • r

    rokee

    12/30/2015, 11:00 AM
    and that’s initialized as a 
    null
    .
  • r

    rokee

    12/30/2015, 11:00 AM
    that’s nullable
  • r

    rokee

    12/30/2015, 11:00 AM
    i want to handle them as nullable property.
  • d

    dmitry.petrov

    12/30/2015, 11:00 AM
    So far I couldn't reproduce that with a toy example. What message do you get from the compiler (or from IDEA)?
  • r

    rokee

    12/30/2015, 11:00 AM
    but kotlin made them as non-nullable.
  • r

    rokee

    12/30/2015, 11:03 AM
    My question is how to handle them as a nullable (natural way)
1...146314641465...3338Latest