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#stdlib
- j
jw
08/17/2018, 3:31 PMyeah. right now it's basicallya.intersect(b).let { (a - it) to (b - it) } - e
evanchooly
08/17/2018, 3:32 PMi think i see what you’re getting at… - e
evanchooly
08/17/2018, 3:32 PMhrm. - j
jw
08/17/2018, 3:32 PMand then i destructure it at the call site - l
LeoColman
08/22/2018, 1:37 PMHiho peeps - l
LeoColman
08/22/2018, 1:37 PMI just created a PR. https://github.com/JetBrains/kotlin/pull/1824👍 2 - l
LeoColman
08/22/2018, 1:37 PMIf anyone wants to contribute with some code review, it'd be awesome! - m
mg6maciej
08/30/2018, 10:47 AMIs there no
function in stdlib?fun <T> T?.orElse(t: T): T - h
hho
08/30/2018, 10:52 AMthere is?:👍 1 - h
hho
08/30/2018, 10:52 AM - m
mg6maciej
08/30/2018, 10:56 AMOhh, didn't think that would work in
...x ?: 0 < 10 - m
mg6maciej
08/30/2018, 10:56 AMThanks. - m
miha-x64
08/30/2018, 12:30 PM
is more readable(x ?: 0) < 10👍 6👆 5 - l
littlelightcz
09/22/2018, 11:42 AMProposal: It would be nice if
andInt
types had extension functions:Long
andisOdd()
. I found myself doingisEven()
many times ... especially in tests.if (it % 2 == 0)🤔 1 - a
anstaendig
09/23/2018, 5:13 PMval Int.isOdd: Boolean = this % 2 == 0 - k
karelpeeters
09/23/2018, 5:18 PMForgot the `get()`:val Int.isOdd: Boolean get() = this % 2 == 0 - a
anstaendig
09/23/2018, 5:20 PMWhy do we need get() here? - a
anstaendig
09/23/2018, 5:20 PMBecause it could change - a
anstaendig
09/23/2018, 5:20 PMofc 🙂 - k
karelpeeters
09/23/2018, 5:22 PM"Because that just happens to be the syntax for extensions `val`s", but I think to emphasize that you're not actually defining a field and that this code will be run every time. - a
anstaendig
09/23/2018, 5:22 PMIf that val only ever needs to be computed once, then the get is redundant - k
kz
09/23/2018, 5:46 PMYou need the
because an extension property can't create a backing field. If you think about how this is implemented it makes sense. This just turns into a static function that acceptsget()
as a parameter. You can't add any state to the receiver that it doesn't already supportthis👍 3 - a
anstaendig
09/23/2018, 5:54 PMAh true, you’re right. - f
Fleshgrinder
09/24/2018, 6:12 PMI would love to see these extension function in the core for Kotlin JVM. Not sure how to go about that. Should one create a KEEP for discussion, even if it something simple like this, or simply go ahead and create a PR? - t
Tom Adam
10/31/2018, 4:26 PMHi, I wonder if Kotlin will have sumBy and sum for List<BigDecimal> in the future? Useful in banking systems, and one does not have to write his own:);)👍 2 - t
thomasnield
11/05/2018, 4:39 PM - t
thomasnield
11/05/2018, 4:39 PM@Tom Adam I'm just going to leave this right here... - d
dave08
11/07/2018, 3:05 PMThis is the current implementation in stdlib:Copy code
The problem is that ifpublic inline fun <K, V> ConcurrentMap<K, V>.getOrPut(key: K, defaultValue: () -> V): V { // Do not use computeIfAbsent on JVM8 as it would change locking behavior return this.get(key) ?: defaultValue().let { default -> this.putIfAbsent(key, default) ?: default } }
returnsdefaultValue
,null
will crash with an NPE... is there a way to ensure that it should not be able to receive nulls?putIfAbsent🤔 1 - d
dave08
11/07/2018, 3:06 PM
seems to accept `null`s...V - k
karelpeeters
11/07/2018, 3:14 PMThat's just a feature of the specific map you're using the, the docs for
(and for most of the other collections functions) says:putIfAbsentthrows
- if the specified key or value is null, and this map does not permit null keys or valuesNullPointerException