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#announcements
- h
Hexa
11/10/2018, 5:53 PMyep this functionfun <A> List<A>.k(): ListK<A> = ListK(this) - s
Shawn
11/10/2018, 5:54 PMoh okay, you’re asking about an #arrow thing here. https://arrow-kt.io/docs/datatypes/listk/👍 1 - h
Hullaballoonatic
11/10/2018, 7:31 PMi apologize because i imagine that this is asked a lot, but why does kotlin not autocast numbers to more expensive types? e.g. int to float, float to double? - h
Hullaballoonatic
11/10/2018, 7:32 PMis that a deliberate choice or a limitation of the language? - h
Hullaballoonatic
11/10/2018, 7:33 PMi consider that the only thing about kotlin that is more verbose than java - h
Hullaballoonatic
11/10/2018, 7:34 PMbecause floating point is messy and not precise like integers? - h
Hullaballoonatic
11/10/2018, 7:36 PMe.g. this kind of issue?Copy codeval a = 3 val b = 0.1f val c = 0.2f println(a == (b + c) * 10)
?false - k
karelpeeters
11/10/2018, 7:37 PMWell
is supposed to be an int, right?3/10 - h
Hullaballoonatic
11/10/2018, 7:37 PMi mean... it wouldn't be - k
karelpeeters
11/10/2018, 7:37 PMAnd then for
there's a deeper issue because that actually calls the==
function..equals() - h
Hullaballoonatic
11/10/2018, 7:37 PMi could rewrite to multiply the decimals by 10 to make them ints compared to 3 - h
Hullaballoonatic
11/10/2018, 7:38 PMmy point simply being that in floating point0.1 + 0.2 != 0.3 - h
Hullaballoonatic
11/10/2018, 7:39 PMi'm just wondering if JB wrote kotlin without autocasting to more expensive number types to protect devs from hidden stuff like that - k
karelpeeters
11/10/2018, 7:39 PMAre you saying it's annoying that
doesn't compile or do you actually want3 + .3
?3 / 2 == 1.5 - j
jdemeulenaere
11/11/2018, 7:20 PMIs there any way to make IntelliJ perform its syntax highlighting on a String that is Kotlin code ? i.e. the equivalent of
or@Language("JAVA")
for Kotlin// language=JAVA - k
karelpeeters
11/11/2018, 7:43 PM@Language("kotlin") - k
karelpeeters
11/11/2018, 7:43 PMIn general just press
on a string literal,Alt+Enter
, search what you want.Inject Language/Reference - k
karelpeeters
11/11/2018, 7:44 PMThen press
again for the annotation.Alt+Enter - a
alexcouch
11/11/2018, 10:26 PMJust curious, is there any way I can enable hotswap for kotlin? Or is that not quite a feature yet? I tried googling for it but there doesn't seem to be anything on it. - c
cndkhuong
11/12/2018, 6:51 AM - a
APXEOLOG
11/12/2018, 2:33 PMGuys is there any chance to declare operators with generic number types? I want something like this:Copy code
But it'm not sure how to do itclass Vector2<T : Number>(val x: T, val y: T) { operator fun plus(vector2: Vector2<Number>): Vector2<T> { return Vector2(x + vector2.x, y + vector2.y) // Doesn't compile } } fun main(args: Array<String>) { Vector2(1, 1) + Vector2(2, 2) // Int Vector2(1.0, 1.0) + Vector2(2.0, 2.0) // Double Vector2(1, 1) + Vector2(2.0, 2.0) // Ideally second Vector2 type should be casted toInt() here } - m
mp
11/12/2018, 2:36 PMI don't think Kotlin's type system allows you to express that sort of thing. Unfortunately, you can't implement your own interfaces for existing types, so you can't make your own equivalent to https://doc.rust-lang.org/std/convert/trait.From.html - m
mp
11/12/2018, 2:37 PM(If you could, you could make a
interface and implementFrom
,From<Double>
, ... forFrom<Float>
and then something likeInt
could work)T.from(vector2.x) - m
mp
11/12/2018, 2:39 PMHowever, the wrinkle here is how the resulting type would now be dependent on the order of operands, which is pretty confusing for numeric types where programmers are generally used to widening conversions being order-insensitive - m
mp
11/12/2018, 2:40 PMSo, even if you could do it, I'm not sure you'd want to. Add a
member function that maps both members to make it easy to make amap
from aVector2<Int>
, etc, and then you canVector2<Double>
without type issues.add - a
APXEOLOG
11/12/2018, 2:42 PMYea, that's what i will probably do. I just though if there is a way to do not copypaste all operators for all vector classes i need - m
Marc Knaup
11/12/2018, 4:53 PMJust had another
withClassCastException
in a generic context and quickly wanted to check first if there is a new Kotlin version which may have fixed it 😄inline class➕ 4 - u
user
11/12/2018, 5:52 PMhttps://twitter.com/kotlin/status/1062040333779984384 New in Kotlin 1.3: Enable progressive mode of the compiler (-progressive option) for a fast-track way to get fixes for compiler issues that affect language semantics. https://t.co/XkYuGlNROP ( Twitter - j
Javier
11/12/2018, 8:18 PMhttps://i.imgur.com/LgyKyDj.png▾
- j
jw
11/12/2018, 8:27 PMSuppress and file a bug👍 7