A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
December 6th, 2018, ISSUE 251

READING

Scala Numerical Performance with Scala Native and Graal

That post focused on the style of Scala code used and how that impacted the performance.
Mark Lewis
SBT Plugin - How to make it, debug it, improve it?

A detailed step-by-step guide.
Leo Benkel (@LeoBenkel)
Better than IO, part 1

This part covers MTL style.
Yuriy Netesov (@yuriynetesov)
Scala and Slick - An Introduction

In this article, I am going to explain working with Scala and slick, this is a tutorial to help beginners get a hang of slick as well as introduce to the concept of Scala Programming.
Adekunle Babatunde
EitherT

EitherT is a data type offered by cats, and despite the great documentation, I don’t think the EitherT docs do a great job explaining why something like this exists.
Ben Sheron
Category Theory for Programmers: Scala Edition 1.1-RC

First (pre)release of the Scala Edition! Contains code snippets in both Haskell and Scala (one after the other).
Bartosz Milewski (@BartoszMilewski)
Shape-dependent computations in Scala … and Agda!

In this post we will solve a little programming problem, mainly with the excuse of talking about dependent types.
Juan
Deploying Scala.js to the Web with Netlify

Last week I set up a Scala.js project to automatically deploy the master branch from github to a website running on Netlify, and was pleasantly surprised at how easy and straightforward it all was.
No Fun Allowed
Error handling in Http4s with classy optics – Part 2

I recently gave a 20 minutes talk on classy optics at the unconference of Scale by the Bay where I also talked about this error handling technique and on my way back home I was still thinking of different ways of doing this. So, after some exploratory work, I came up with a few different alternatives.
Gabriel Volpe (@volpegabriel87)
Scala exercises: cats-effect

Enjoy solving worker pool with load balancing and race for success to understand the practical side of cats-effects!
Oleg Pyzhcov
The Little Typer With Dan Friedman and David Christiansen

You can write more correct software and even rigorous mathematical proofs. Prepare for some mind stretching.
CoRecursive
Using Scala at the BBC

As part of the lead up to Scala eXchange London, we sat down with Phoebe Greig and Duncan Walker from BBC about their experience in adopting Scala. Read the interview here.
Skills Matter (@skillsmatter)
ScalaX2gether Community Day 2018

Following 2 days of awesome fun at Scala eXchange 2018, jump in right away with the latest technology on hand, join fellow ScalaX attendees and some of the most talented coders and experts, for ScalaX2gether and create something amazing! Register for FREE!
Skills Matter (@skillsmatter)
Imposing invariants in Scala

This post discusses different FP and OOP techniques to leverage types in order to model some constraints.
Carlos Teixeira
What Does an Ideal Data Scientist’s Profile Look Like?

Because of the need to implement algorithms from scratch and deploy ML models in big data environments, relevant languages such as C++ and Scala are also important.
George Liu
Top link of November: Explore Witnesses as an Alternative to Implicits

Martin's proposition has started quite a hot discussion, becoming the most visited link at Scala Times. Time to revisit!
Martin Odersky (@Odersky)
Aecor - Purely functional event sourcing in Scala

An introduction to the series.
Vladimir Pavkin (@vlpavkin)
Aecor - Purely functional event sourcing in Scala. Part 1

The first part focuses on defining entity behavior.
Vladimir Pavkin (@vlpavkin)

PRESENTATIONS

Homegrown Scala Collections - Part 16 - Stacks & related JVM flags

In this video we are going to start a conversation about advanced tail call elimination techniques.
DevInsideYou (@DevInsideYou)

EVENTS

Scalar, Warsaw, Poland April 5-6, 2019

Join the next edition of the largest Scala conference in central Europe!
SoftwareMill (@softwaremill)
Lambda Days, Kraków, Poland, February 21-22, 2019

Use promo code SCALArlz10 for a 10% discount for our readers!
LambdaDays (@LambdaDays)
$100 discount for Scala Times readers for "Functional Scala" training by John A De Goes in London

Use code "ScalaTimes" and join the training on Dec 10-12.
Signify Technology (@Signify_Tech)
What are the experts keen to share at Scala eXchange London 2018

“A conference is more than just a series of talks. It's about community, friendship, and having fun. You can't replicate that by watching videos." - Noel Welsh on why he is speaking at ScalaX again this year. Check out what others amazing speakers are most looking forward to the conference! Read more.
Skills Matter (@skillsmatter)

RELEASES

scala-typed-holes

This is a Scala compiler plugin to emulate the "typed holes" feature of Haskell, Idris, Agda, etc.
Chris Birchall (@cbirchall)
Announcing Dotty 0.11.0-RC1

Opaque Type Aliases, Worksheet Mode Support in Visual Studio Code, Various IDE improvements, and much more!
Dotty contributors

VARIA

Scala Times banners?

Want one? Click here
THE INTERNET
Scala Times stickers?

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





  1. Scala Times Issue #262

    Is your Scala object always a singleton?. Freer doesn’t come for free. Maintaining Binary Compatibility in Scala. Anatomy of functors and category theory. A little Scala 'sed' class.


  2. Scala Times Issue #261: from Scala with love

    Aecor — Purely functional event sourcing in Scala. Part 5. Homegrown #Scala Collections - Foldable Maps. Kubernetes Liveness and Readiness Probes Revisited. Streams and Resource Safety | Akka. Assemble messages from Akka Actors.


  3. Scala Times Issue #260

    Cats Ecosystem Community Survey 2018 Results. Thread Pool Best Practices with ZIO. Purely functional parallelism in Scala. Finatra meets Ammonite. Typed Supervision: why the changes?.


  4. Scala Times Issue #259

    State of Scala compilation time in 2018. Low-memory symbol indexing with bloom filters. Finally: Top-level Definitions. Why you should think about functional programming. Toward a polyglot James server….


  5. Scala Times Issue #258

    Scala Days 2019 - Celebrating Collaborative Success. Scala community build grows, adds Scala 2.13 and JDK 11. Type-checked triple equals: Scala test. Using Scala Plugins From Gradle. Exploring Explicit Nulls in Dotty.


  6. Scala Times Issue #257

    High-Performance Functional Programming Through Effect Rotation. Trampolines for Everything. This month at SoftwareMill we’ve learned — December’18. A Guide to Scala Collections: Exploring Monads in Scala Collections. Spark Custom Stream Sources.


  7. Scala Times Issue #256

    Where is the llama for FS2?. Scala Best Practices - Foreword. Aecor - Purely functional event sourcing in Scala. Part 4b. Postgresql from Spark, how to query?. Error Handling in Akka Actor (with Future).


  8. Scala Times Issue #255

    ADT through the looking glass - lenses, prims and other optics. Hpc with scala and akka Actors. Scala Type Classes - The Name Printer. Evolutionary Algorithms on the JVM via Scala  -  a minimal introduction. Aecor - Purely functional event sourcing in Scala. Part 4a.


  9. Scala Times Issue #254

    Cats Ecosystem Community Survey 2018. Scala Developer Suvey Results 2018. Minutes of the 11th meeting of the Scala Center, Q4 2018. Software as a Reflection of Values With Bryan Cantrill. Dotty: An Alternative to Implicits.


  10. Scala Times Issue #253

    Scala Variables - Syntax, Declaration, Use case, Examples - Leo Benkel. Fast goto definition with low memory footprint · Metals. New Akka Getting Started Guide. Different ways to understand a monad. MOOC: Introduction to programming with dependent types in Scala.


  11. Scala Times Issue #252

    The F-words: functor and friends. Grafter  -  a take on yet another DI library. Anatomy of a Scala quirk. Creating Work Queues with Apache Kafka and Apache Pulsar. Terminus - Cross Platform Terminal Emulator for Sublime Text.


  12. Scala Times Issue #251

    Scala Numerical Performance with Scala Native and Graal. SBT Plugin - How to make it, debug it, improve it?. Better than IO, part 1. Scala and Slick - An Introduction. Category Theory for Programmers: Scala Edition 1.1-RC.


  13. Scala Times Issue #250

    Correlation IDs in Scala using Monix. Further enhance `new` syntax to reduce boilerplate. Counting type inhabitants. Variances in Scala. SIP Meeting Minutes - November 1-3 2018.


  14. Scala Times Issue #249

    How To Exclude Scala Tests With Tagging?. Explore Witnesses as an Alternative to Implicits. Build code analyzers with Scalameta and Scalafix. Immutable State in Real World. A streaming library with a superpower: FS2 and functional programming.


  15. Scala Times Issue #248

    Minutes of the 10th meeting of the Scala Center, Q3 2018. Scala - faster and slimmer with GraalVM. 5 themes for Scala programming in 2019. Beyond the conference: Q&A with The Guardian’s Maria-Livia Chiorean. Homegrown Scala Collections - Part 13 - Growing Binary Search Trees.


  16. Scala Times Issue #247

    Getting started with recursion schemes using Matryoshka. Friendly Functional Programming. Building the Hangman Game using ScalaZ ZIO. Anatomy of semigroups and monoids. The Scala 2.12 / 2.13 Inliner and Optimizer.


  17. Scala Times Issue #246

    Don’t get mixed. Typed Functional Programming and Software Correctness. Scala compiler phases with pictures. A tale on Semirings. Scala Programming  -  A Skeptic’s Journey.


  18. Scala Times Issue #245

    Scala Center highlights June - October. Fastparse 2: Even Faster Scala Parser Combinators. God’s Programming Language With Philip Wadler. Algebraic Data Types in four languages. Finch Performance Lessons.


  19. Scala Times Issue #244

    Achieving stack and heap safety in recursive functions. A comprehensive introduction to Cats-mtl. Using Akka Http to create a test server. Skoda's new hatchback is called 'Scala'. Are you sure your AnyVals don’t instantiate?.


  20. Scala Times Issue #243

    Introducing Scaladoc Tables. This month at SoftwareMill we’ve learned. Backoff and Retry Error-Handling for Akka Streams. Anatomy of functional programming. Anatomy of an algebra.


  21. Scala Times Issue #242

    Using Monix with Kafka, Avro and Schema Registry. Scala is now on Apache License Version 2.0. Just Enough Scala for Spark Programmers. Giter8 Scala Microservice template. Homegrown Scala Collections - Part 7 - Parametric Polymorphism aka Generics.


  22. Scala Times Issue #241

    Model correctly and write less code, using Akka Streams. Elevator Control System using ZIO. Easing Into Cats, And The Case For Category Theory Inspired Abstractions. Get considered harmful. IO & Logging Capabilities.


  23. Scala Times Issue #240

    2018 Scala compilation time survey. How to Dockerise a Scala and Akka HTTP Application. Using Machine Learning to Predict the Weather in Basel. How We Found a Missing Scala Class. New proposal for extension method.


  24. Scala Times Issue #239

    Functional Programming for Mortals. Strings are not the type you are looking for. Choose Primitives for Typelevel and Meta Programming in Scala 3.0. To tag a type. Parallelize tests in SBT on Circle CI.


  25. Scala Times Issue #238

    How to translate your API with Shapeless. A case to introduce Scala in a Java world. Are Scala Futures the past?. Effect Extensions Pattern. Dotty Type classes.


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.