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November 26th, 2020, ISSUE 354

READING

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)
ScalaPy

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)

VIDEOS

Programming in Scala for beginners - week 10: inheritance

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

EVENTS

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)

RELEASES

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
graalnative4s

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

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

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

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





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