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November 26th, 2020, ISSUE 354


Scala 3 Developers Survey

The survey is for all developers, whether you’re a professional, a hobbyist, or a student who code in Scala. Share your experience and expectations, and win an Amazon Gift card!
SoftwareMill (@softwaremill)
A case for akka-coordination lease

Sure, using a singleton pattern has its drawbacks, but it’s a matter of choosing the right tool for the job. If you decide to use one, it’s required to understand the consequences and have strong guarantees that the singleton pattern is not violated as it may result in some hard to revert data corruption.
Michał Ostruszka (@mostruszka)
Monad transformers and cats  -  3 tips for beginners

Use the right factory method, help the compiler from time to time, and be consistent with error handling.
Krzysztof Atłasik
Forward Compatibility for the Scala 3 Transition

For maintainers of projects, the migration process may become easier with the recent release of Scala 2.13.4, which comes with a new preview feature: reading and compiling against Scala 3 dependencies.
Jamie Thompson (@bishabosha)
Mirror, Mirror on the Wall, Who’s the Genericioust of Them All?

Did you ever wonder how JSON libraries like circe derive codecs for you from case classes and sealed traits? Or how tapir generates a whole OpenAPI documentation from your endpoint definitions?
Philipp Martini (@maphiFP)

Use Python libraries from the comfort of Scala | ScalaPy
ScalaPy developers
Polymorphic Effects in Scala

Learn how Cats Effect 3 pushes Sync and Async to the bottom of the typeclass hierarchy so that you can introduce other CE3 typeclasses into scope without losing the ability to reason about effects.
Tim Spence
Enhanced Package Prefixes

Let’s see how the upcoming version of the Scala plugin combines package prefixes with chained package clauses and relative imports.
Pavel Fatin (@pavelfatin)
Showing Scaladoc and source code in the Scala REPL

What it would take to show Scala documentation in the REPL?
Alvin Alexander (@alvinalexander)


Programming in Scala for beginners - week 10: inheritance

Open Scala lectures in Swedish by Björn Regnell at Lund University, Sweden.
Björn Regnell


London Scala Open Source Saturday, November 28th, online event

Come and meet up with fellow contributors and maintainers to hack on their projects. We'll tackle good first issues in Scala, ScalaJS, and many more! First time contributors are especially welcome to help improve the https://www.lsug.co.uk/ website, written in functional Scala. Whether you're an experienced contributor or new to GitHub, we'll help you get your first taste of an open source project.
London Scala User Group (@londonscala)
Functional Scala, December 3th-4th, London

Learn the critical topics you need to excel as a Scala developer, and celebrate the Scala programming language and community. Every ticket holder to Functional Scala 2020 will receive an all-day Scala 3 course by John de Goes and a collectible T-shirt!
Ziverge (@zivergetech)
Scala 3 for Scala 2 developer, December 8th - 10th, Online training

In this course, developers who are already familiar with Scala 2.x will get a high-speed introduction to all the changes coming in Scala 3, including semantic changes, syntactic changes, new features, and dropped features. Use code "ScalaTimes10" to receive 10% off at the checkout.
John A. De Goes (@jdegoes)
Functional Scala Megapack (3 workshops)

Functional Design + Functional Data Modeling + Scala 3 for Scala 2 developers. Use our special link to get a 15% discount!
John A De Goes (@jdegoes)


Cats 2.3.0

Welcome to the first stable release of Cats on Scala 3… milestone 2! We will continue releasing minor versions within the 2.3.x lineage against Scala 3.0.0 until it reaches a final stable release. The decision to push a stable release of Cats in advance of this date was made in order to simplify versioning within the downstream ecosystem.
cats contributors
Scala 2.13.4

Restores default global ExecutionContext to 2.12 behavior, improves pattern matching, especially in exhaustivity checking, adds experimental support for consuming some libraries built by Scala 3.
Scala contributors
sbt 1.4.4

A patch release with bugfixes, updated dependencies and some improvements.
sbt contributors

Employ Scala for serverless applications.
Uwe Sommerlatt (@usommerl)

A plugin which represents my personal SBT project baseline.
Daniel Spiewak (@djspiewak)

To probe what we can't prove, so the unprovable may become probable.
Jon Pretty (@propensive)

A small, convenient, dependency-free library for command-line argument parsing in Scala.
Li Haoyi (@li_haoyi)

  1. Scala Times Issue #354

    Scala 3 Developers Survey. A case for akka-coordination lease. Monad transformers and cats  -  3 tips for beginners. Forward Compatibility for the Scala 3 Transition. Mirror, Mirror on the Wall, Who’s the Genericioust of Them All?.

  2. Scala Times Issue #353

    Scala 3 Developers Survey. Managing Database Migrations in Scala. One year with Akka 2.6. Best practice for natural Ordering. Event-driven railway network based on Pulsar.

  3. Scala Times Issue #352

    Domain-Driven Design with FP in Scala. Explicit term inference with Scala 3. Keep alive for JMS connections. Why You Should Learn Scala in 2020?. A step-by-step guide for debugging memory leaks in Spark Applications.

  4. Scala Times Issue #351

    Autorecovery for (JMS) Streams. ZIO-AWS with ZIO Query. Implementing Scala.js Support for Scala 3. Let’s Talk About the Scala 3 Indentation. Concurrency in Cats Effect 3.

  5. Scala Times Issue #350

    Designing tapir’s WebSockets support. BSP Support in sbt 1.4. Streaming With Probabilistic Data Structures: Why & How. Scala 3 Migration guide. ScalaZONE - Scala 3 Programming Language Courses.

  6. Scala Times Issue #349

    Generic IOApp alternative. Let's build a Scala mock library. How To Make Integration Tests Less Flaky. Option  - the null of our times. Top Link of September: Polynote, A better notebook for Scala.

  7. Scala Times Issue #348

    Java 15 through the eyes of a Scala programmer. Functional Design, October 20th - 22nd, Online training. Scale By the Bay, November 12th - 14th, online event. Functional Data Modeling, November 18th - 19th, Online training. ZIO Hackathon, November 20th-21st, online event.

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    A short guide to Blocker. Using: Did they forget something?. The assignment operator is broken!. Attending a hackathon with Scala and Akka (Streams) on Microsoft Azure. Programming Scala, Third Edition.

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    Getting Started with Knative in Scala. Tagless Final - Part 12 - delivery-http-http4s (The Big Rewrite). Programming in Scala for beginners - week 5: classes. Eyjafjallajökull Lecture 2019. Scala 3: Enums.

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    Tour of Scala. Polynote, A better notebook for Scala. Single command Scala setup. Dotty becomes Scala 3. Functional Effects with ZIO.

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  13. Scala Times Issue #342

    What’s coming up in sttp client 3?. FP in the City Virtual Conference, September 10th. Scala Castle, September 14th-17th. Scala micro.sphere.it, September 15th. Essential Effects EU, September 14th-16th, Online Course.

  14. Scala Times Issue #341

    Concurrency In Scala with Cats-Effect. Scala, React, and SSR (part 1). More Algebra of Algebraic Data Types. Akka HTTP 10.2 Release - Q/A with the Akka team. Type-Level Programming in Scala, Part 3.

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    SoftwareMilling around OSS - Scala Love. More Intuition on Optics. Type-Level Programming in Scala, Part 2. An Introduction to Functional Design. VimtelliJ: All the best of Vim in IntelliJ.

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    Scala Knowledge Bits Archives. Functional Effects with ZIO. Experiment with Loom. Auto publish sbt plugin from Travis CI. Scala String Interpolation.

  17. Scala Times Issue #338

    ZIO 1.0 Released. Retry Failing Tasks with Cats and Scala. An Intuition for Optics. Evoneering - Scala Bootcamp. How Does "20 seconds" Work in Scala?.

  18. Scala Times Issue #337

    Thinking With Types. IntelliJ Scala Plugin 2020.2 is released!. Announcing Dotty 0.26.0-RC1. A Dive into Configuring Metals · Metals. Life with fatal warnings.

  19. Scala Times Issue #336

    IntelliJ Scala Plugin 2020.2: Auto-import for Implicits. "First Class" Types in Scala 3. What is an Effect?. Writing Angular Services in Scala. Tagless Final - Part 4.2 - Why The F[_].

  20. Scala Times Issue #335

    Actors using Scala & Akka  - Part 2: AskPattern and SpawnProtocol. Railway Oriented Programming in Scala. Mocking endpoints with ZIO sttp. Top Link Of June: A Beginner's Guide to Scala 3.0. Tagless Final - Part 4.1 - Power to the Interpreters!.

  21. Scala Times Issue #334

    Scaling Event Bus. One-click install for Scala. Visual Scala reference. Functional, Type-safe, Testable Microservices with ZIO gRPC, July 16th, Online Webinar. Configuration management in Scala using zio-config, July 23rd, Online Webinar.

  22. Scala Times Issue #333

    Using akka and react to organize your single page scala.js application. Tagless Final - Part 2 - Introduction to the Expression Problem. Functional, Type-safe, Testable Microservices with ZIO gRPC, July 16th, Online Webinar. Configuration management in Scala using zio-config, July 23rd, Online Webinar. Functional Scala Fundamentals, September 1st-3rd, Online Course.

  23. Scala Times Issue #332

    Mastering modularity in ZIO with ZLayers. Scala/Mill: Step 1, Creating a new Mill project. Cats Concurrency basics with Ref and Deferred. Tagless Final - Part 1 - What is Tagless Final?. Getting started with ZIO.

  24. Scala Times Issue #331

    Managing dependencies using ZIO. Scala Programming - The State of Developer Ecosystem in 2020 Infographic. Announcing the Moving from Scala 2 to Scala 3 course. Streaming all the way with ZIO, Doobie, Quill, http4s and fs2. Playing With Scala - Slick.

  25. Scala Times Issue #330

    A Beginner's Guide to Scala 3.0. Opening the fridge with ZIO. Writing functional DSLs for business domains. What Functional Programming Is, What it Isn't, and Why it Matters. Dependent Types in Scala 3.

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