A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
November 9th, 2018, ISSUE 247


Getting started with recursion schemes using Matryoshka

Learn the basics of recursion schemes.
Wiem Zine
Friendly Functional Programming

An introduction to the functional paradigm.
Wiem Zine
Building the Hangman Game using ScalaZ ZIO

A summarization of a talk given by John A De Goes in Kiev, with code samples.
Abhishek Srivastava
Anatomy of semigroups and monoids

Discover important typeclasses.
Martin Menestret (@mmenestret)
The Scala 2.12 / 2.13 Inliner and Optimizer

The goal of this article was to explain why the Scala optimizer exists and give a rough explanation what it can and cannot do. It also showed how to configure and use the optimizer in your project.
Lukas Rytz (@lrytz)
Functional Programming and living past the edge of civilization

An interview, where John answers a few interesting questions, like How can Scala folks learn from Haskell and vice versa?
John A De Goes (@jdegoes)


Homegrown Scala Collections - Part 12 - Big O Notation

In this video we will learn how to determine the growth rate of your functions in order to see how they behave with respect to their input.
DevInsideYou (@DevInsideYou)
Task's Bracket, Cats-Effect's Resource and Streaming

A tutorial on usage of Task.bracket, Cats-Effect’s Resource and how that can be used in combination with streaming data types like Observable and Iterant.
Alex Nedelcu (@alexelcu)


Lambda Days, Kraków, PPoland, February 21-22, 2018

Use promo code SCALArlz10 for a 10% discount for our readers!
LambdaDays (@LambdaDays)
Win a ticket for Scala eXchange

We are running two competition simultaneously to give you all the best opportunity of winning, check them out!
Signify Technology (@Signify_Tech)
Tech Triveni, New Delhi, India, November 18th, 2018

Use code TechTriveni10 for a 10% discount for Scala Times readers!
Knoldus Inc. (@Knolspeak)
$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)



OS-Lib is a simple Scala interface to common OS filesystem and subprocess APIs.
Li Haoyi (@li_haoyi)

A frontend library for writing doobie queries.
Vadim Chelyshov (@_dos65)

A serverless proxy for Spark cluster. Mist provides a new functional programming framework and deployment model for Spark applications.
Mist contributors
Monix 3.0.0-RC2

The major theme of this release is compatibility with Cats-Effect 1.0.0.
Monix contributors
Spark 2.4.0

This release adds Barrier Execution Mode for better integration with deep learning frameworks, introduces 30+ built-in and higher-order functions to deal with complex data type easier, improves the K8s integration, along with experimental Scala 2.12 support.
Spark contributors


Scala Times banners?

Want one? Click here
Scala Times stickers?

Want one? Let us know or tweet @scalatimes.

  1. 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.

  2. 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.

  3. 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.

  4. 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?.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Scala Times Issue #237

    Instantiate case class with arbitrary values to reduce verbosity in tests. Homegrown Scala Collections - Part 2 - Unit Testing with ScalaTest. Lambda World Seattle, September 17th - 18th . Lambda World Cádiz, Spain, October 25th - 26th, 2018. Scala Wave, September 6th - 8th, 2018, Gdańsk, Poland.

  12. Scala Times Issue #236

    Streaming data from PostgreSQL using Akka Streams, Akka Http and Doobie. Lambda World Seattle, September 17th - 18th . Lambda World Cádiz, Spain, October 25th - 26th, 2018. Scala Wave, September 6th - 8th, 2018, Gdańsk, Poland. Scala Italy, September 14th-15th, Florence.

  13. Scala Times Issue #235

    Akka Http Websocket Example. Akka HTTP Request and Response models. Composable table updates in Slick. Cask: a Scala HTTP micro-framework. Actor Model Explained.

  14. Scala Times Issue #234

    Reverse State Monad in Scala. Is it possible?. Typedapi or how to derive your clients and servers from types. Testing in the wild. Akka HTTP request/response scope operations, vs. Deferred operations. Akka anti-patterns: too many actors.

  15. Scala Times Issue #233

    Akka HTTP and TCP streaming. Play Framework Action Composition. Scala 3 as a new Programming Language. [SPARK-14220] Build and test Spark against Scala 2.12 - ASF JIRA. How Curalate uses MXNet on AWS for some Deep Learning Magic.

  16. Scala Times Issue #232

    Akka anti-patterns: Java serialization. Practical Cats: Functor and Applicative. Why Scala Implicits. Implicits, type classes, and extension methods, part 4: understanding implicits. Scala FUD FAQ for newbies.

  17. Scala Times Issue #231

    Can someone explain to me the benefits of IO? . Shared State in Functional Programming. Demystifying Dependency Injection with Airframe. Scala Wars: FP-OOP vs FP. Lambda World Seattle, September 17th - 18th .

  18. Scala Times Issue #232

    Can someone explain to me the benefits of IO? . Shared State in Functional Programming. Demystifying Dependency Injection with Airframe. Scala Wars: FP-OOP vs FP. Lambda World Seattle, September 17th - 18th .

  19. Scala Times Issue #230

    Teaching Evolution With Genetic Algorithms. Rolling Your Own Monad To Deal With Nested Monads In Scala. Case Study - Solve Crosswords Puzzle. Scala Type Level – Part 4 : Way to the HigherKinds. Implicits, type classes, and extension methods, part 2: implicit derivation.

  20. Scala Times Issue #229

    How to turn ugly Java APIs into elegant, type-safe Scala APIs. Analyzing Pwned Passwords with Apache Spark. Understanding Parametricity in Scala. Are Scala Streams really lazy?. Convolutional LSTM for ocean temperature with Deeplearning4j.

  21. Scala Times Issue #228

    Compiling Scala Faster with GraalVM. Scala Compiler Options. Scalable read model updates in Akka Persistence. Are there exceptions in Scala?. Lambda World Seattle, September 17th - 18th .

  22. Scala Times Issue #227

    Compilation safety on Playframework’s i18n with Scala Macros. Reflections on using Typelevel Scala. A simple way to write parsers: using the State monad. Writing a simple Telegram bot with tagless final, http4s and fs2. Lambda World Seattle, September 17th - 18th .

  23. Scala Times Issue #226

    Scala in 2018 - The State of Developer Ecosystem by JetBrains. Combining ScalaCheck generators. Scalaz 8 IO vs Akka (typed) actors vs Monix (part 1). Use the decorator pattern for clean I/O boundaries. Scala - AnyVal meets Pattern Matching.

  24. Scala Times Issue #225

    Speeding Up Compilation Time with `scalac-profiling`. Partitioning Akka Streams for Scalability and High-Availability. Bringing back power assert with Expecty. Hot source dependencies using sbt-sriracha. Running akka-cluster on Kubernetes.

  25. Scala Times Issue #224

    Incorporating FaceNet into Play framework with Silhouette authentication. Futures in Scala Protips (part 5): Try more. Zero-Overhead Tree Processing with the Visitor Pattern. More Readable Code in Scala. Relearn your sbt.

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.