scala/scala

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daymo

@daymo

@BalmungSan Hmm, that actually works as it is supposed to and that narrows the problem down even more. Any idea why running it with Mill would make such a huge difference? I will consult the Mill channel anyway...

Luis Miguel Mejía Suárez

@BalmungSan

Yeah all I know about Mil is its name and the name of its creator lol.

So yeah, the best is to consult there.

:) :wave:

daymo

@daymo

@BalmungSan No worries and thank you for your help.

Derek Willingham

@DirtySoc

I am completely new to Scala and SBT. I am trying to setup a built.sbt file so that sbt publish will push the maven style project to one remote repository if the build agent is a Jenkins and a different remote repository if the build agent is a GitHub action. I've spent about 6 hours on this today and I don't feel like I really understand much more about SBT and how to modify the behavior of sbt publish. Does anyone here have good example sbt projects or suggestions for learning more in regard to what I am trying to do?

Also are Seq() and Some() special sbt functions? I see those throughout the build.sbt files I have been looking at and I don't really know what they do.

Luis Miguel Mejía Suárez

@BalmungSan

So you don't even know basic Scala and yet you want to do a custom publishing which seem very complex (if even possible) to do...

I think you would need more help.

Anyways, you may want to ask in the #tooling channel of the discord server.

https://stackoverflow.com/questions/68234835/covariant-type-a-accepted-in-contravariant-position-of-function-argument-a-b/68236182#68236182

Luis Miguel Mejía Suárez

@BalmungSan

BTW according to the docs you should be able to do something like this:

publishTo := { if (isJenkins) Some(...) else Some(...) }

Now, not sure how are you going to check which is the runner.

2 replies

Alex

@unthingable

Question about transparent inlining: I have a value x and a deserialized class object o fetched from a database. The fetch is polymorphic in that the object can be one of two distinct types, I don't know which one ahead of time. o has a method .foo(x) that expects a specific type of a value, depending on the type of o, and for that it has a safeguard method transparent inline cast[A](a: A) = inline erasedValue[A] match {...}. The question: given that the object is only known at runtime, is inlining going to do any good, or am I grossly misunderstanding it?

Luis Miguel Mejía Suárez

@BalmungSan

@DirtySoc so it seems you could do this:

publishTo := {
  scala.util.Properties
    .envOrNone(name = "GithubRunnerEnvVar")
    .fold(ifEmpty = Some(jenkinsRepository)) { _ =>
      Some(githubActionsRepository)
    }

southrivers

@southrivers

import java.lang.{Byte => JByte}

any one know what does this mean?

ml10

@ml10

I’m not sure ther precise name, but I’ve seen it referred to as a “rename import” or “import rename”. https://alvinalexander.com/scala/how-to-rename-members-import-scala-classes-methods-functions/

southrivers

@southrivers

thanks very much

Martin Egri

@megri

Is there a way to build a Map[K, V] by using the builders pattern, where I need to update a map key with a new value as I go along?

Basically what I want is items.foreach(item => mapBuilder.updateOrSet(item.key, set = 0, update = n => n + 1))

Luis Miguel Mejía Suárez

@BalmungSan

@megri you can do this:

items.foldLeft(Map.empty[K, V]) {
  case (acc, item) =>
    acc.updatedWith(key = item.key) {
      case Some(n) => Some(n + 1)
      case None => Some(0)
    }
}

No need to mutate.

Also, this seems it is doing some kind of word-count or something similar, right?

You should be able to just:

items.groupMapReduce(_.key)(_ => 1)(_ + _)

As I always say, the Scaladoc is your friend: https://www.scala-lang.org/api/current/scala/collection/immutable/Map.html

Bonus: If you have cats in scope, you can just do:

items.foldMap(item => Map(item.key -> 1))

Martin Egri

@megri

@BalmungSan Thanks, but I wanted a builder version specifically. I'm just coding for fun and part of that is exploring the standard library. Not having a way to build a map stumped me and I figured I had to be missing something, but maybe it's just an omission..

I think the underlying issue is that all collection builders return a base trait Builder, which has no specific knowledge of maps for instance. So when you do Map.newBuilder[String, Int] you end up with a Builder[(String, Int), Map[String, Int]], which has no knowledge of maps specifically.

Luis Miguel Mejía Suárez

@BalmungSan

@megri Well if you add a new key-value pair whose key was already present it overwrite the previous key.

Also, under the hood a MapBuilder is just a mutable map that also has a mutable version of the method I explained above,

Anyways, Builders are intended for the stdlib itself, not really for users.

So that is why there is no specific builder for Map with the method you want.

In any case, you should not wonder for this kind of low level details.

Martin Egri

@megri

Anyways, Builders are intended for the stdlib itself, not really for users.

I find that statement questionable.

And I understand that I can overwrite an already existing key with a new one. What I'm specifically looking for is a way to do it without recomputing the whole map every time I change a key. I know I can use something like mutable.Map or java.util.Map, but I was specifically looking for something to build an immutable map, but avoiding the overhead. And before you say "the overhead might not matter", then yes, you're right, but I was looking for a way to do it none the less :)

Luis Miguel Mejía Suárez

@BalmungSan

mutable.Map.updateWith

Or again, just look for something higher level like groupMapReduce which are optimized under the hood.

Matt Hicks

@darkfrog26

Anyone needing help migrating away from log4j to Scribe, just let me know, I'd be happy to help. ;)

lambook

@lambook

i'm looking for a library to handle HEX operations (hex String to byte array etc..), i have this library org.apache.commons.codec, is there any core scala library to do the same thing?

ritschwumm

@ritschwumm

@lambook i don't think the core lib has it - but imho that's one of the things that are too simple to be worth adding a third part dependency.

something like this is usually sufficient https://github.com/ritschwumm/scutil/blob/master/modules/core/src/main/scala/scutil/codec/Hex.scala

lambook

@lambook

@lambook i don't think the core lib has it - but imho that's one of the things that are too simple to be worth adding a third part dependency.

is this an official library ? i m looking for a library that is widely used

johannes karoff

@cornerman

Hi, I am trying to write a macro in scala 3, where I need to list all abstract methods of a trait - so I want to ignore all implemented member methods.
I am using TypeTree.of[T].memberMethods, but do not know how to filter.

ritschwumm

@ritschwumm

@lambook no, not at all. it's my personal collection of useful things. it's not even published to a public maven repo.

Hanns Holger Rutz

@Sciss

If I have

def augmentString (x: String) : Any = ()

can I disable the compiler warning:

parameter value x in method augmentString is never used

by annotating this method somehow?

Luis Miguel Mejía Suárez

@BalmungSan

@Sciss AFAIK you can do: def augmentString (@unused x: String) : Any = ()

Hanns Holger Rutz

@Sciss

@BalmungSan thanks, excellent

Luis Miguel Mejía Suárez

@BalmungSan

Did that worked?

Hanns Holger Rutz

@Sciss

yes

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