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August 28th, 2025, ISSUE 596

READING

λÆS - Yet Another Effect System

Check out the new shiny website of λÆS, an experimental effect system in Scala inspired by the ideas behind Algebraic Effects.
Riccardo Cardin (@riccardo_cardin)
The Rebirth of Tagless Final: An Ergonomic Approach in Kyo

I recently went on a fun journey with Kyo, a new effect system for Scala, and stumbled upon a discovery. After initially trying to replace Tagless Final with custom effects, I found a novel approach that doesn't kill the pattern but revitalizes it, making it more intuitive and human-friendly than ever before.
Jonathan Winandy (@ahoy_jon)
Krop

Krop is a Scala 3 web framework. Its goal is to make it delightful to build delightful web applications.
Noel Welsh (@noelwelsh)
Hands on Capture Checking

I gave a live coding session on capture checking at Scala Days 2025. Let’s be honest: it was essentially a failure, mostly because I have very little live coding experience and woefully underestimated how long it’d take to go through the material. I was stopped maybe 10% in, much to my annoyance and that of Martin Odersky, who’d kindly agreed to be there and help with the questions I was likely to get. This article is a form of apology for my failure: at least the material is available somewhere!
Nicolas Rinaudo (@NicolasRinaudo)
PRE-SIP: Dedented Multiline String Literals

A discussion about shaping up a new proposal.

RELEASES

ox 1.0.0

Ox has reched stable 1.0.0 version.
ox contributors
sbt 2.0.0-RC3

Hi everyone. On behalf of the sbt project, I am happy to announce sbt 2.0.0-RC3, a beta version of sbt 2.x. sbt 2.0 is a new version of sbt, based on Scala 3 constructs and Bazel-compatible cache system.
Eugene Yokota (@eed3si9n)
Match Type simulator

Simulate match types and check provable disjointness.
Jamie Thompson (@bishabosha)
scafi3

A Scala 3 DSL for Aggregate Programming. Roots its foundations on the concept of computational fields: a distributed data structure manipulated by aggregate functions implementing the business logic for large-scale distributed systems.
Nicolas Farabegoli
kyo-test

API and adapters for testing Kyo effects using popular Scala testing frameworks.
johnhungerford
DingesAutomata

Group-theory-inspired cellular automata.
Daniel Karl Werner Maria Dinges

EVENTS

LLM4s Dev Hour – Sundays @ 9am London Time

Just finished another great hour of mob programming. We’re now doing this every Sunday — 60 minutes of live coding, debugging, and learning together in public.
LLM4s
The Scala Workshop, Oct 13th, Singapore

The Scala Workshop is the continuation of the Scala Symposium, providing a forum for researchers and practitioners to discuss the design, implementation, and applications of the Scala programming language. Topics include language features, compiler internals, type systems, libraries, tools, and industrial applications.
EPFL
Func Prog Conf, Oct 15th, Stockholm, Sweden

Func Prog Conf is a half-day conference about functional programming. Don't miss this unique opportunity to learn, network and have a good time!
Func Prog Conf
DEVJVM, Oct 25th, Barranquilla, Colombia

A conference uniting Java, Kotlin, and Scala developers.
DEVJVM





  1. Scala Times Issue #596

    The Rebirth of Tagless Final: An Ergonomic Approach in Kyo. Hands on Capture Checking. PRE-SIP: Dedented Multiline String Literals. Match Type simulator. LLM4s Dev Hour – Sundays @ 9am London Time.


  2. Scala Times Issue #595

    State of Scala 2025 Survey. Claude Code, Metals, and NVIM. Minimal Scala Container Images using Nix. IntelliJ Scala Plugin 2025.2. Release ducktape 0.2.10 · arainko/ducktape · GitHub.


  3. Scala Times Issue #594

    Golden Literal Testing in uTest 0.9.0. Nussknacker integration with Functional Programming. Type-safe vibe-coding a CRUD application. LLM4s Dev Hour – Sundays @ 9am London Time. Scala Days, Aug 19th - 21st, Lausanne, Switzerland.


  4. Scala Times Issue #593

    Understanding Scala Variance. LLM4s Dev Hour – Sundays @ 9am London Time. Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. DEVJVM, Oct 25th, Barranquilla, Colombia.


  5. Scala Times Issue #592

    LLM4s Dev Hour – Sundays @ 9am London Time. Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. DEVJVM, Oct 25th, Barranquilla, Colombia.


  6. Scala Times Issue #591

    Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. DEVJVM, Oct 25th, Barranquilla, Colombia. Mill Build Tool v1.0.0 Release Highlights. Business4s H1 2025 Highlights.


  7. Scala Times Issue #590

    Scalator: Stream Composition with Kyo & Community Revival!, Jul 9th, Toronto. Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. CFP for DEVJVM, Oct 25th, Barranquilla, Colombia. Anatomy of a Scala Game Server.


  8. Scala Times Issue #589

    Scala Highlights, June 2025 edition. ScalaWAW #35 - Summer hackathon, Jun 30th, Warsaw, Poland. Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. Making Capabilities Safe and Convenient.


  9. Scala Times Issue #588

    Fundamental Concurrency Problems and Solutions. Scala Days, Aug 19th - 21st, Lausanne, Switzerland. The Scala Workshop, Oct 13th, Singapore. S2D migrated to Scala Native.


  10. Scala Times Issue #587

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  11. Scala Times Issue #586

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  12. Scala Times Issue #585

    IntelliJ IDEA x Scala: How to clone carets. Scala Days 2025 - Functional Programming And The Real World. Developer Ecosystem Survey 2025. ScalaWAW #34, May 26th, Warsaw. Scala Hamburg: Recursion Schemes & Mill, Jun 2nd, Hamburg, Germany.


  13. Scala Times Issue #584

    Scala 3 migration Tips and Tricks. Learn Scala with Alvin Alexander . A Distributed System from scratch, with Scala 3 - Part 3. Can we ScalaSQL on Duckdb?. Unison, from a Scala perspective.


  14. Scala Times Issue #583

    Workflows4s Finally Released - You Might Hate Your Business Processes a Little Less. Business4s & GSoC 2025: 3 Exciting Projects and Not-So-Usual Approach. Unison, Scala, Distributed Systems and Delightful Programming. ScalaWAW #34 May 26th, Warsaw. Scala Hamburg: Recursion Schemes & Mill, Jun 2nd, Hamburg, Germany.


  15. Scala Times Issue #582

    How Scala Ruined My Java (in a good way). IntelliJ IDEA x Scala: Named Tuples. Random Scala Tip #624: The Pitfalls of Option Blindness. From JavaScript to Scala. Scala 3: The Evolution of a Macro.


  16. Scala Times Issue #581

    WORKSHOP: Principled Metaprogramming in Scala 3. The Scala Workshop 2025 - The Scala Workshop 2025. Programming a Language by Nicolas Rinaudo | Scalar Conference 2025.


  17. Scala Times Issue #580

    On vibe coding. Composing Independent Instruction Sets with Free Monads in Scala 3. Announcing Scala.js 1.19.0. Tagless Final for Humans by Noel Welsh | Scalar Conference 2025. Release v1.0.0-RC19 · zio/zio-dynamodb · GitHub.


  18. Scala Times Issue #579

    Scalar Conference 2025 - Summary & Highlights. Experimental Capture Checking: New Syntax for Explicit Capture Polymorphism. Whiteboxish Macro Powers with Named Tuples. IntelliJ Scala Plugin 2025.1 Is Out!. J On the Beach, May 14th - 16th, Málaga, Spain.


  19. Scala Times Issue #578

    Sttp client 4: the Scala HTTP client you always wanted, released!. London Scala User Group Meetup, Apr 16th, London. J On the Beach, May 14th - 16th, Málaga, Spain. 10% discount for Lambda Days, June 12th-13th, Kraków, Poland. Scala Days 2025 CFP, Aug 19th - 21st, Lausanne, Switzerland.


  20. Scala Times Issue #577

    Tagged vs Untagged Unions (in Scala). -XX:+UseCompactObjectHeaders is your new TURBO button for JDK 24+ . Scala Days proposal online hack, Apr 3rd, 8PM CEST, online event. London Scala User Group Meetup, Apr 16th, London. J On the Beach, May 14th - 16th, Málaga, Spain.


  21. Scala Times Issue #576

    API First Scala. Strategies for Efficiently Parallelizing JVM Test Suites. Publishing ZIP artifacts with SBT. London Scala User Group Meetup, Apr 16th, London. J On the Beach, May 14th - 16th, Málaga, Spain.


  22. Scala Times Issue #575

    Data Plumber - Data Integration Pipeline. 15% discount for Scalar, Mar 27th - 28th, Warsaw, Poland. London Scala User Group Meetup, Apr 16th, London. J On the Beach, May 14th - 16th, Málaga, Spain. CFP for Lambda Days, June 12th-13th, Kraków, Poland.


  23. Scala Times Issue #574

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  24. Scala Times Issue #573

    GSOC 2025: Call for contributors. Drawing Heighway’s Dragon - Recursive Function Rewrite. From Python to Scala: Rewriting 27k Lines of a CLI. Spotify FOSS Fund 2024. Functional World #16, Mar 11th, Online Event.


  25. Scala Times Issue #572

    Rock the JVM partners with the Scala Center. Typelevel Summer of Code 2025. Functional World #16, Mar 11th, Online Event. 15% discount for Scalar, Mar 27th - 28th, Warsaw, Poland. London Scala User Group Meetup, Apr 16th, London.


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