A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
September 19th, 2019, ISSUE 292

READING

Fixtures in Scala - three simple ways to reduce your test code boilerplate

Have you ever copied a very long test case just to change the name and few lines of code?
Jakub Dzikowski
Human-readable case class diffs

a short introduction to diffx library.
Kasper Kondzielski (@kkondzielski)
Why Parallel

Why someone using Cats should care about Parallel in the first place?
Travis Brown (@travisbrown)
Cats 2.0 migration guide

Which of the changes in the release 2.0 will affect users and what you can do about them?
Travis Brown (@travisbrown)
Top 10 Scala Libraries For Data Science

A tool-kit for every data science enthusiast.
Ambika Choudhury
Kenji Yoshida receives community award

The winner of the Phil Bagwell Memorial Scala Community Award.
Scala Lang Team
Kelley Robinson receives community award

The winner of the Phil Bagwell Memorial Scala Community Award.
Scala Lang Team
Considering Scala?

Find out if Scala is right for you and your team.
Oliver Winks (@OliWinks)
http4s: from Cats to ZIO

How http4s app runs with ZIO.
Alex Fruzenshtein (@Fruzenshtein)
Build your own Kafka in ZIO - ZIO Queues & ZIO Fibers

Queues & Fibers by example. A messaging system built step by step.
Mateusz Sokół
Functional tests with Scala, SBT, Play framework, Specs2 and one application per test suite

How to obtain an application using the WithApplication class of play-specs2 module?
Geovanny Junio
Cassandra scala client

How to use cassandra prepared statements with scala to do query operations?
λ.eranga (@itseranga)
Composing functions with Reader monad

A short tutorial on Reader Monad.
Alexander Zaidel
GoF design patterns in Scala: Visitor

The first episode from the classic patterns by the Gang of Four series.
Manuel Rodríguez
Top Link Of August: Scala Almost Succeeded

Sam's post really got our reader's attention last month, make sure you've read it too!
Sam Halliday (@fommil)

PRESENTATIONS

Getting started with Scalafmt

In this video we will install and play around with Scalafmt which is a code formatter for Scala.
DevInsideYou (@DevInsideYou)
The Traverse type class in Cats - Scala tutorial

In this video, you'll see what the Traverse type class is and what it allows you to do. You'll see some examples of traversable functors like List, Option and NonEmptyList, as well as applicative functors you can traverse to - IO, Option, Either, Validated and Map*.
Jakub Kozłowski (@kubukoz)

EVENTS

Scala.sphere.it, Kraków, Poland, October 7th-8th

Use special promo code 'media-partner-at-sphere.it' for a 20% discount.
ScalaSphere (@ScalaSphere)
Lambda World, Cádiz, Spain, October 17th - 18th

Use our link to get a special discount for Scala Times readers!
Lambda World (@lambda_world)
Code Mesh, London, November 7th - 8th

Get your tickets now!
CodeMesh (@CodeBEAMio)
BeeScala, Ljubljana, Slovenia, November 21st - 21rd

Don't miss your ticket for this unique conference!
BeeScala (@BeeScalaConf)
Tech Triveni, IIC Delhi, India, November 23rd - 24th

Grab special 10% discount code for Scala Times readers: TechTriveni10
Tech Triveni
CFP for ScalaConf.ru, Moscow, Russia, November 26th

Don't miss the CFP deadline which is September 26th!
ScalaConf.ru
Lambda Days, February 13th -14th 2020, Kraków, Poland

Call for talks and very early bird tickets are both open!
Lambda Days (@LambdaDays)
ScalaUA, April 3th-4th, 2020 Kyiv, Ukraine

CFP is on! Also: Super Early Bird tickets are available on website till 2019.12.31, and Wholesale 10+ tickets are available till 2020.04.02.
ScalaUA (@ScalaUA_Conf)

RELEASES

sbt-pgp 2.0.0

Breaking changes: Default to use GnuPG (useGpg := true); Bouncy Castle mode is now deprecated; camel case key name and package name change.
Eugene Yokota (@eed3si9n)
introprog-scalalib

Scala library with simple-to-use utilites for students of introductory programming.
Bjorn Regnell
Scala 2.13.1

The release fixes several regressions in 2.13.0.
Scala contributors

VARIA

Scala Times banners?

Want one? Click here
THE INTERNET
Scala Times stickers?

Want one? Let us know or tweet @scalatimes.
THE INTERNET
Scala experts?

Need some? SoftwareMill is here, ready to talk and dive deep into your code. .
SoftwareMill





  1. Scala Times Top Links of 2019

    January: Scala Best Practices. February: Is your Scala object always a singleton?. April: Did Functional Programming get it wrong?. May: The little gems of Scala standard library. June: The Evolution of a Scala Programmer.


  2. Scala Times Issue #310

    Git hooks in Scala projects  - the easy way!. Testing Doobie programs. Implementing typeclasses in Scala I. Effective testing with ZIO Test. Akka Streams: error handling in event processing pipelines.


  3. Scala Times Issue #309

    Towards more functional Play — Part 2. TMWL’ Dec 19 — Scala 3 overview, Scala hacks and DevOps hints. Scala etcd client with etcd4s and cats-effects. Boilerplate-free type class definition. GCP Cloud Functions with Scala.js in 10 lines(ish).


  4. Scala Times Issue #308

    Towards more functional Play  -  Part 1. ZIO environment meets constructor-based dependency injection. How-to run tests in parallel with sbt. Learn myself some Scala 3, episode 4: strict equality. 5 pitfalls to avoid when starting to work with ZIO.


  5. Scala Times Issue #307

    Standardizing IO Interfaces for Scala Libraries. WebSocket Streaming with Scala. State of Monocle. Scala tooling in 2019. How to Work with Scala Collections in Java.


  6. Scala Times Issue #306

    2019 Scala Developer Survey . Lessons Learned Building a Van Laarhoven Lens Library. A Glossary of Functional Programming. Tips for moving from tut to mdoc. Notes on Category Theory in Scala 3 (Dotty).


  7. Scala Times Issue #305

    Beyond Liskov: Type Safe Equality in Scala. Scala 2 Roadmap Update: the Road to Scala 3. Explicit nulls are in!. Functional Scala London 2019: Day 1. Leveraging Monoids for More Powerful Summarization.


  8. Scala Times Issue #304

    Akka references serialization with Protobufs (up to Akka 2.5). TMWL November’19 — ScalaTest, Medusa, PW-Sat2 cubesat. Implement your future with ZIO. Decouple the Program from its Implementation with ZIO modules. ZIO environment and modules pattern: zio, scala.js, react, query management.


  9. Scala Times Issue #303

    Write your own micro BDD test framework in one day. Monoid in the Category of Endofunctors. Introducing Scala Server Toolkit. How to write a command-line application with ZIO. Picking a Languages for Introductory CS  - The Argument Against Python.


  10. Scala Times Issue #302

    Regexp Replacement via Function in Java/Scala. Rationality in a Natural World: Arithmetic at the Type-Level. Transforming Data with Embedded Spark. Migrate a service getting 200KQPS from Jackson to Circe. Scala Type Classes comparison.


  11. Scala Times Issue #301

    Functors  - From Category Theory into Cats. Tour of Akka Typed: Cluster Sharding. The Future.await(s) for no one. Service architecture in Scala. Streaming the last few minutes from Kafka using Akka Streams.


  12. Scala Times Issue #300

    How an Optimizing Compiler Works. TMWL October’19  - Scala Steward, DB index and a React hack. Working with HTTP in Polynote. How I learned to stop worrying and love FP in Scala. A real life example of isomorphisms in Scala: POST request.


  13. Scala Times Issue #299

    Kleisli Category - From theory to Cats. Presto with Doobie. Lambda World 2019. Speeding up time with Zio TestClock. Simulating IoT Events - with Zio Streams.


  14. Scala Times Issue #298

    Scala application lifecycle, from pure Scala to FS2. Top 5 things that slow down your Scala build - Triplequote. ZIO, Http4s, Auth, Codecs and zio-test. Magnolia typeclass generation for Avro. Bird Operator in Scala.


  15. Scala Times Issue #297

    Websockets in Scala using sttp. Vim with Dotty (using coc vim). Sizeof in Scala. Scala Classes - Syntax, Declaration, Use case, Examples. How to structure your Scala application?.


  16. Scala Times Issue #296

    Travis Continuous deployment for your open source library. Publish open source project to Maven with Sonatype. My Way to Scala - part 1. Scala Tuples - Syntax, Declaration, Use case, Examples. Better management of transitive dependencies and conflicts.


  17. Scala Times Issue #295

    Tour of Akka Typed: Event Sourcing. Optional Is the New Mandatory. Visitors - a tale of generalization. Working with Databases using Scala and Quill. Proving Primality with GADTs.


  18. Scala Times Issue #294

    Scraping Websites using Scala and Jsoup. A quiet, attractive new programming language. Domain-driven event sourcing with Akka Typed. Crushing Design Patterns! - Chain of responsibility (Scala). Crushing Design Patterns! - Unnecessary Patterns.


  19. Scala Times Issue #293

    Painlessly passing message context through Akka Streams. Simple Web and Api Servers with Scala. From @Transactional to type-safe, reasonable transactions. 3 Layer Scala Cake. Illustrated guide to Types, Sets and Values.


  20. Scala Times Issue #292

    Human-readable case class diffs. Cats 2.0 migration guide. Top 10 Scala Libraries For Data Science. Kenji Yoshida receives community award. Kelley Robinson receives community award.


  21. Scala Times Issue #291

    Squeezing extra productivity out of Ammonite Scala REPL. Akka family build infrastructure. Learning Akka Typed from Classic. On Eliminating Error in Distributed Software Systems. Error Handling in Functional Applications - from Monad Transformers to ZIO.


  22. Scala Times Issue #290

    Easy Parallel Programming with Scala Futures. Permutive Community Engineering, August 2019. Key things I picked up while working with Scala. Typing the technical interview in Scala. Why Try? - Scala Error Handling.


  23. Scala Times Issue #289

    Dotty (Scala 3) adoption report: easy so far. Scraping and Storing Crypto-currency Prices with Scala and PostgreSQL. Scala Almost Succeeded. Allow significant indentation syntax. Jailbreak Oozie Spark action.


  24. Scala Times Issue #288

    Bootzooka 2019: functional Scala and React. The Science of Functional Programming book. Scala's isInstanceOf is an Anti-Pattern. A Scala “functional programming style” To-Do List application written with Cats. Minutes of the 13th meeting of the Scala Center, Q2 2019.


  25. Scala Times Issue #287

    When do you need Akka Cluster?. Hangman in FP Scala. Make your Google Spreadsheets Scala-ble. Understanding Monoids using real life examples. Scala in the City, London, Simply Business, August 28th.


Organizing an event?
Promote it with
Scala Times.
The Scala Times reader?
Get a banner!
Got a tip? Send it in!
Follow us on Twitter.
Curated by SoftwareMill.
We are hiring.
And taking on projects.