Mateusz Kubuszok
@kubuszok.com
Blog @ https://kubuszok.com
JVM-Scala Book @ https://leanpub.com/jvm-scala-book
Chimney @ https://chimney.scalaland.io
JVM-Scala Book @ https://leanpub.com/jvm-scala-book
Chimney @ https://chimney.scalaland.io
Reposted by Mateusz Kubuszok
This is probably the most complete tutorial on typeclasses in Scala 3, it's basically a short book. Bookmark it, as it has everything: givens, derivation, mirrors, inline defs, macros... you name it. #scala kubuszok.com//2025/sanely...
November 4, 2025 at 7:46 PM
This is probably the most complete tutorial on typeclasses in Scala 3, it's basically a short book. Bookmark it, as it has everything: givens, derivation, mirrors, inline defs, macros... you name it. #scala kubuszok.com//2025/sanely...
Chimney 2.0.0-M2 for 2.13.17+ and 3.7+ just landed!
* sanely-automatic derivation backported to 2.13
* aligned with featues/bugfixes up till 1.8.2
Try out, if you had any issues with semiauto on Scala 3.7 or if you want to test sanely-auto on 2.13!
github.com/scalalandio/...
* sanely-automatic derivation backported to 2.13
* aligned with featues/bugfixes up till 1.8.2
Try out, if you had any issues with semiauto on Scala 3.7 or if you want to test sanely-auto on 2.13!
github.com/scalalandio/...
Release v2.0.0-M2 · scalalandio/chimney
Important
Since Chimney got affected by 3.7.0 change in givens resolution we had to analyze the possible ways of fixing the issue.
While there is a temporary workaround the proper fix requires rele...
github.com
October 21, 2025 at 8:47 PM
Chimney 2.0.0-M2 for 2.13.17+ and 3.7+ just landed!
* sanely-automatic derivation backported to 2.13
* aligned with featues/bugfixes up till 1.8.2
Try out, if you had any issues with semiauto on Scala 3.7 or if you want to test sanely-auto on 2.13!
github.com/scalalandio/...
* sanely-automatic derivation backported to 2.13
* aligned with featues/bugfixes up till 1.8.2
Try out, if you had any issues with semiauto on Scala 3.7 or if you want to test sanely-auto on 2.13!
github.com/scalalandio/...
Great thanks to all organizers of @scalaio.bsky.social! It was a great experience I am happy I could be there.
October 18, 2025 at 10:21 AM
Great thanks to all organizers of @scalaio.bsky.social! It was a great experience I am happy I could be there.
Reposted by Mateusz Kubuszok
Can we have the Standard Library for Macros? (@kubuszok.com): makes simple things simple, and hard things (at least) possible 🚀
Event Sourcing is just a foldLeft on Events and a decide function! Or is it? (Matthieu Baechler & Thomas Hilaire): master of immutability but UPDATE db all day long ? 👀
Event Sourcing is just a foldLeft on Events and a decide function! Or is it? (Matthieu Baechler & Thomas Hilaire): master of immutability but UPDATE db all day long ? 👀
September 25, 2025 at 1:44 PM
Can we have the Standard Library for Macros? (@kubuszok.com): makes simple things simple, and hard things (at least) possible 🚀
Event Sourcing is just a foldLeft on Events and a decide function! Or is it? (Matthieu Baechler & Thomas Hilaire): master of immutability but UPDATE db all day long ? 👀
Event Sourcing is just a foldLeft on Events and a decide function! Or is it? (Matthieu Baechler & Thomas Hilaire): master of immutability but UPDATE db all day long ? 👀
Thank you everyone who came to my talk at @scaladays.org ! It was amazing to be here!
You can find my slides at mateuszkubuszok.github.io/ScalaStandar...
You can find my slides at mateuszkubuszok.github.io/ScalaStandar...
August 21, 2025 at 4:01 PM
Thank you everyone who came to my talk at @scaladays.org ! It was amazing to be here!
You can find my slides at mateuszkubuszok.github.io/ScalaStandar...
You can find my slides at mateuszkubuszok.github.io/ScalaStandar...
That #Scala code does something, that many considered impossible. Could you guess why?
github.com/MateuszKubus...
github.com/MateuszKubus...
hearth/hearth-tests/src/main/scala/hearth/demo/ShowMacrosImpl.scala at f4b7828eaecd6b154514832a51b1756f6a29fd37 · MateuszKubuszok/hearth
The first Scala macros' standard library. Contribute to MateuszKubuszok/hearth development by creating an account on GitHub.
github.com
August 10, 2025 at 6:13 PM
That #Scala code does something, that many considered impossible. Could you guess why?
github.com/MateuszKubus...
github.com/MateuszKubus...
Some time ago I made a presentation that wasn't recorded...
But at least some of the points from it could be showcased with this gist
gist.github.com/MateuszKubus...
But at least some of the points from it could be showcased with this gist
gist.github.com/MateuszKubus...
Newtypes and tagged types
Newtypes and tagged types. GitHub Gist: instantly share code, notes, and snippets.
gist.github.com
July 16, 2025 at 1:09 PM
Some time ago I made a presentation that wasn't recorded...
But at least some of the points from it could be showcased with this gist
gist.github.com/MateuszKubus...
But at least some of the points from it could be showcased with this gist
gist.github.com/MateuszKubus...
It seems #Scala folks are interested in macros once more!
So, let's meet at the @scaladays.org 2025 to talk why we would want some standard library for them and how!
So, let's meet at the @scaladays.org 2025 to talk why we would want some standard library for them and how!
May 30, 2025 at 10:46 AM
It seems #Scala folks are interested in macros once more!
So, let's meet at the @scaladays.org 2025 to talk why we would want some standard library for them and how!
So, let's meet at the @scaladays.org 2025 to talk why we would want some standard library for them and how!
I had hardly any exposure to Apache Spark, and Databricks is mostly irrelevant to me...
Still I am curious why nobody in my circle noticed that Databricks released runtime for Scala 2.13. Now only sbt is the reason to keep publishing for 2.12
docs.databricks.com/aws/en/relea...
Still I am curious why nobody in my circle noticed that Databricks released runtime for Scala 2.13. Now only sbt is the reason to keep publishing for 2.12
docs.databricks.com/aws/en/relea...
Databricks Runtime 16.4 LTS | Databricks Documentation
Release notes about Databricks Runtime 16.4 LTS, powered by Apache Spark.
docs.databricks.com
May 21, 2025 at 8:05 PM
I had hardly any exposure to Apache Spark, and Databricks is mostly irrelevant to me...
Still I am curious why nobody in my circle noticed that Databricks released runtime for Scala 2.13. Now only sbt is the reason to keep publishing for 2.12
docs.databricks.com/aws/en/relea...
Still I am curious why nobody in my circle noticed that Databricks released runtime for Scala 2.13. Now only sbt is the reason to keep publishing for 2.12
docs.databricks.com/aws/en/relea...
Reposted by Mateusz Kubuszok
🚀 Metals v1.5.3 is here!
Introducing:
- MCP server support for AI agents
- new inlay hints for named/by-name parameters
-improved test discovery for ZIO
- better auto-fill arguments
- using directives worksheet support.
Try it now! #Scala #IDE
scalameta.org/metals/blog...
Introducing:
- MCP server support for AI agents
- new inlay hints for named/by-name parameters
-improved test discovery for ZIO
- better auto-fill arguments
- using directives worksheet support.
Try it now! #Scala #IDE
scalameta.org/metals/blog...
May 13, 2025 at 3:02 PM
🚀 Metals v1.5.3 is here!
Introducing:
- MCP server support for AI agents
- new inlay hints for named/by-name parameters
-improved test discovery for ZIO
- better auto-fill arguments
- using directives worksheet support.
Try it now! #Scala #IDE
scalameta.org/metals/blog...
Introducing:
- MCP server support for AI agents
- new inlay hints for named/by-name parameters
-improved test discovery for ZIO
- better auto-fill arguments
- using directives worksheet support.
Try it now! #Scala #IDE
scalameta.org/metals/blog...
If you've been affected by Scala 3.7.0 given resolution change, and Chimney started failing in some case - try out 2.0.0-M1.
github.com/scalalandio/...
github.com/scalalandio/...
Release v2.0.0-M1 · scalalandio/chimney
Important
Since Chimney got affected by 3.7.0 change in givens resolution we had to analyze the possible ways of fixing the issue.
While there is a temporary workaround the proper fix requires rele...
github.com
May 8, 2025 at 1:02 PM
If you've been affected by Scala 3.7.0 given resolution change, and Chimney started failing in some case - try out 2.0.0-M1.
github.com/scalalandio/...
github.com/scalalandio/...
Reposted by Mateusz Kubuszok
Slow-Auto, Inconvenient-Semi: escaping false dichotomy with sanely-automatic derivation by @kubuszok.com
Subscribe to our our YouTube channel so you don't miss the rest of #scalarconf videos.
Subscribe to our our YouTube channel so you don't miss the rest of #scalarconf videos.
Slow-Auto, Inconvenient-Semi: escaping false dichotomy with sanely-automatic derivation
YouTube video by SoftwareMill
www.youtube.com
April 14, 2025 at 7:53 AM
Slow-Auto, Inconvenient-Semi: escaping false dichotomy with sanely-automatic derivation by @kubuszok.com
Subscribe to our our YouTube channel so you don't miss the rest of #scalarconf videos.
Subscribe to our our YouTube channel so you don't miss the rest of #scalarconf videos.
Reposted by Mateusz Kubuszok
Really interesting comparison between automatic vs. semi-automatic type class derivation and their impact on performance. #scala https://youtu.be/M54ux51H6Fo
Slow-Auto, Inconvenient-Semi: escaping false dichotomy with sanely-automatic derivation
youtu.be
April 11, 2025 at 2:44 PM
Really interesting comparison between automatic vs. semi-automatic type class derivation and their impact on performance. #scala https://youtu.be/M54ux51H6Fo
Reposted by Mateusz Kubuszok
As promised we are working hard on providing you with the Scala MCP server, we already have a WiP pull request ready and some courageous souls are actually testing it!
You can take a look and already give some feedback at github.com/scalameta/m...
You can take a look and already give some feedback at github.com/scalameta/m...
WIP: MCP support by kasiaMarek · Pull Request #7390 · scalameta/metals
resolves: scalameta/metals-feature-requests#430
github.com
April 10, 2025 at 4:00 PM
As promised we are working hard on providing you with the Scala MCP server, we already have a WiP pull request ready and some courageous souls are actually testing it!
You can take a look and already give some feedback at github.com/scalameta/m...
You can take a look and already give some feedback at github.com/scalameta/m...
Reposted by Mateusz Kubuszok
With our new Scala MCP server we are able to eliminate hallucinations and unproductive guesswork for code that LLMs aren't familiar with by exposing API shapes from the caches of Metals and the Scala compiler.
April 2, 2025 at 10:25 AM
With our new Scala MCP server we are able to eliminate hallucinations and unproductive guesswork for code that LLMs aren't familiar with by exposing API shapes from the caches of Metals and the Scala compiler.
Thank you @scalar-conf.com for yet another amazing conference and for having me there! See you next year!
March 28, 2025 at 6:17 PM
Thank you @scalar-conf.com for yet another amazing conference and for having me there! See you next year!
Scala 3.7.0-RC1: Expr.summonIgnoring works! (vide github.com/scala/scala3...)
I updated my benchmarks, now I'll have to update my slides for Scalar
I updated my benchmarks, now I'll have to update my slides for Scalar
Proposal: Add Expr.summonIgnoring method to use in macros · scala scala3 · Discussion #21909
Motivation: Typeclass derivation libraries have long been using the implicit resolution feature in scala. It: allows for easier developer experience where derivation library designers are able comp...
github.com
March 15, 2025 at 5:59 PM
Scala 3.7.0-RC1: Expr.summonIgnoring works! (vide github.com/scala/scala3...)
I updated my benchmarks, now I'll have to update my slides for Scalar
I updated my benchmarks, now I'll have to update my slides for Scalar
Reposted by Mateusz Kubuszok
Scala Projects Maintenance Survey results, still fresh from the oven are there! With over 100 responses from tech leaders and managers from our community to shed some light on how Scala fares. (1/4)
February 20, 2025 at 1:30 PM
Scala Projects Maintenance Survey results, still fresh from the oven are there! With over 100 responses from tech leaders and managers from our community to shed some light on how Scala fares. (1/4)
Chimney 1.7.0 with:
- transformation from more than 1 value
- recursive Patchers
- and much more!
Easily one of top 3 Chimney releases (next to 0.8.0 - with Scala 3 support - and 1.0.0 - with stable API)
github.com/scalalandio/...
- transformation from more than 1 value
- recursive Patchers
- and much more!
Easily one of top 3 Chimney releases (next to 0.8.0 - with Scala 3 support - and 1.0.0 - with stable API)
github.com/scalalandio/...
Release v1.7.0 · scalalandio/chimney
This big release bring some long-awaited features: transformations, which take more than 1 case class as input (well, not only case classes 😄 ) and improved Patchers which handle: recursive patchin...
github.com
January 23, 2025 at 6:50 PM
Chimney 1.7.0 with:
- transformation from more than 1 value
- recursive Patchers
- and much more!
Easily one of top 3 Chimney releases (next to 0.8.0 - with Scala 3 support - and 1.0.0 - with stable API)
github.com/scalalandio/...
- transformation from more than 1 value
- recursive Patchers
- and much more!
Easily one of top 3 Chimney releases (next to 0.8.0 - with Scala 3 support - and 1.0.0 - with stable API)
github.com/scalalandio/...
- I wonder why these functionalities takes them so long, it's just a few simple changes
- a few simple changes: github.com/scalalandio/...
- a few simple changes: github.com/scalalandio/...
January 23, 2025 at 12:37 PM
- I wonder why these functionalities takes them so long, it's just a few simple changes
- a few simple changes: github.com/scalalandio/...
- a few simple changes: github.com/scalalandio/...
Chimney 1.6.0 with some QoL improvements! github.com/scalalandio/...
Release v1.6.0 · scalalandio/chimney
Changelog:
now we are testing that macros in Scala 2.13 can read Scala 3 code and vice versa - while people might take it for granted, there are some differences in AST between both versions so s...
github.com
December 31, 2024 at 2:30 PM
Chimney 1.6.0 with some QoL improvements! github.com/scalalandio/...