kotlinlang #stdlib

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brk

07/07/2017, 7:54 AM

~~Hopefully it will be added soon~~ It's in the public preview already! 1.2-M1 https://github.com/Kotlin/KEEP/issues/11 https://github.com/Kotlin/KEEP/blob/master/proposals/stdlib/window-sliding.md

enleur

07/07/2017, 7:56 AM

yeah, it says it’s already implemented in 1.2, but I can find the implementation 🙂

brk

07/07/2017, 7:59 AM

5fa79fa Sliding window implementation helper utilities 3 weeks ago Sergey Mashkov

👍 1

brk

07/07/2017, 8:01 AM

https://github.com/JetBrains/kotlin/blob/v1.2-M1/libraries/stdlib/common/src/generated/_Collections.kt#L1050

nkiesel

07/11/2017, 6:10 PM

Why does

List

have a

size

property but not an

empty

property?

ilya.gorbunov

07/11/2017, 6:15 PM

https://stackoverflow.com/questions/44316658/why-isnt-isempty-in-kotlin-collections-a-property

breandan

07/13/2017, 6:26 PM

Hi! I would like to propose the following extensions to `kotlin.reflect.K[Mutable]Property`:

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operator fun <T> KProperty0<T>.getValue(thisRef: Any?, property: KProperty<*>) = get()
operator fun <T> KMutableProperty0<T>.setValue(thisRef: Any?, property: KProperty<*>, value: T) = set(value)

This would let me use bound callable references as a property "alias". This enables me to write:

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var propertyAlias by property1::property2

Otherwise, in order to to get the same functionality, I would need to write a custom getter/setter:

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var propertyAlias
    get() = property1.property2
    set(value) {
      property1.property2 = value
    }

I believe this is a common enough scenario to warrant a

stdlib

addition. Thank you.

kirillrakhman

07/13/2017, 6:30 PM

there's been an issue for this on youtrack

kirillrakhman

07/13/2017, 6:31 PM

https://youtrack.jetbrains.com/issue/KT-8658

breandan

07/13/2017, 6:32 PM

Thanks! I should have checked first

kirillrakhman

07/13/2017, 6:32 PM

no worries

agomez

07/13/2017, 6:33 PM

there goes my vote

pavlospt

08/08/2017, 7:44 AM

there is also a blog post explaining the change https://medium.com/@trionkidnapper/kotlin-beware-the-silent-cast-5fed4f4c4aa6

👍 1

pavlospt

08/08/2017, 7:44 AM

But I was just wondering why this was needed, since the commit message is not very explanatory 😕

karelpeeters

08/08/2017, 8:10 AM

Where are

Float.toLongExactOrNull()

and friends even defined? A google search only results in the

_Ranges.kt

file.

pavlospt

08/08/2017, 8:39 AM

if you check the first link, you will find them at the last file of the Commit changes

👍 1

ilya.gorbunov

08/09/2017, 4:35 PM

Does anyone know the reasoning behind this commit and the changes it introduced? https://github.com/JetBrains/kotlin/commit/5773594412660af11357ac9adc6ffcb45138b840 4 replies The reason is that

ClosedRange.contains

is a virtual method, which can be implemented differently in inheritors. We've strived to reimplement

contains

extensions such that they delegated the check to the

contains

member. It turned out that could lead to some weird results related to rounding, as it was mentioned in the issue https://youtrack.jetbrains.com/issue/KT-18938. We're still to discuss what should be the correct behaviour in that case.

ilya.gorbunov

08/09/2017, 4:51 PM

Does anyone know the reasoning behind this commit and the changes it introduced? https://github.com/JetBrains/kotlin/commit/5773594412660af11357ac9adc6ffcb45138b840 8 replies An interesting case to consider here: should

3.5

be in an IntRange

1..4

given that it's never returned when we iterate values of that range?

08/09/2017, 4:52 PM

i wouldn't think you'd be able to do such a check without explicit conversion

➕ 4

kevinmost

08/09/2017, 4:53 PM

yeah, I don't think there's a clear expected behavior when checking if a Float is inside of an IntRange

dmcg

08/10/2017, 10:41 AM

Is there any work to add a standard Result type? We've been rolling our own per project, and it would be good to have a standard to get behind.

➕ 2

natpryce

08/10/2017, 1:26 PM

You mean something like:

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sealed class Result<T, ERR>
data class Success<T>(value: T): Result<T, Nothing>()
data class Failure<ERR>(failure: ERR): Result<Nothing,ERR>()

and associated extension functions like

map

flatMap

, etc.?

kirillrakhman

08/10/2017, 1:33 PM

https://youtrack.jetbrains.com/issue/KT-18608

dmcg

08/10/2017, 2:01 PM

Why yes @natpryce, that's exactly the sort of thing that I had in mind.

dmcg

08/10/2017, 2:03 PM

Thanks @kirillrakhman. That gist went off in an unexpected direction

08/10/2017, 11:17 PM

I'm curious as to why it doesn't follow the naming convention

karelpeeters

08/11/2017, 7:17 AM

Isn't

@Throws

also part of the documentation of a function?

08/11/2017, 2:05 PM

There's

@throws

for KDoc

karelpeeters

08/15/2017, 6:45 PM

Java's

Integer

and

Long

have methods for getting the sign of a value, can something like this be added to Kotlin's versions as well?

08/15/2017, 7:27 PM

wasn't that just added to 1.2?

👆 1