A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
March 29th, 2018, ISSUE 215

READING

Tour of Akka Cluster: Testing with the multi-node-testkit and a handful Raspberry PIs

It is time to look at one feature that is extremely useful when it comes to building production-quality systems based on Akka Cluster: the test support.
Manuel Bernhardt (@elmanu)
Akka anti-patterns: overusing ActorSelection

Learn how to avoid problems caused by the facts that ActorSelection is unverified and less performant than ActorRef.
Manuel Bernhardt (@elmanu)
Twilio guardrail: Principled Code-Generation for Type-Safe Languages

A framework for providing principled code-generation in typesafe language and frameworks. We’ve initially targeted the Scala language, as well as Lightbend’s akka-http web framework, although experimental support for http4s clients has been added recently.
Devon Stewart
Google Summer of Code 2018 Scala Projects

Want to get involved? Here are some projects waiting for contributions: Mill Build Tool, Scalafix in the editor, scalajs-bundler 1.0, various features of CBT and Scala Native, Web-based test UI for Bloop and REPL modernisation.
Sequential Traverse for managing parallel resource usage in Scala

Using free monads to control the execution of asynchronous tasks in Scala.
James Phillips
CoRecursive w/ Adam Bell: 009 - Throw Away the Irrelevant with John A De Goes

We talk about performance problems with monad transformer on the jvm, various flavours of IO monads and reasoning about polymorphic type signatures. On the lighter side of things, we discuss how to write technical articles well, flame wars and Zee vs Zed pronunciation.
John A. De Goes (@jdegoes)

PRESENTATIONS

Dependency Inversion | Inversion of Control (IoC) For Absolute Beginners

Learn the basics of DI using Scala.
DevInsideYou
Programming vs Math

In this video we are going to discuss the differences between mathematical functions and functions in programming, which in my humble opinion should rather be called subroutines or procedures to avoid confusion.
DevInsideYou

EVENTS

ScalaUA, April 20-21, 2018, Kyiv, Ukraine

Use promo code "ScalaTimes_ScalaUA-2018-20-04" for 5% discount!
ScalaUA
Scala Sphere, April 15-17, Kraków, Poland

Use promo code sphereit-2018-scalatimes for 10% discount for Scala Times readers!
Scala Sphere (@ScalaSphere)
Scalapeño 2018 CFP, July 2, Beer Sheva, Israel

Send your proposal before 2018.04.01.
Scalapeño
Blockyard Conference, April 13, Gdańsk, Poland

Use our promo link to get a 40% discount for Scala Times readers!
Blockyard
Scalar Conference, Apirl 6-7, Warsaw, Poland

There are still some tickets available for the conference and accompanying workshops, so don't hesitate!
SoftwareMill (@scalarconf)

RELEASES

RasterFrames 0.6.0

RasterFrames brings the power of Spark DataFrames to geospatial raster data.
RasterFrames contributors
Ammonite 1.1.0

The first version with experimental Java 9/10 support and Windows support in the REPL (using JLine3).
Li Haoyi (@li_haoyi)
Mill 0.1.7

A new, reinvented Scala build tool. Now with better Windows & Java 9 support & tons of bugfixes.
Mill contributors
Chimney

In the daily life of a strongly-typed language's programmer sometimes it happens we need to transform an object of one type to another object which contains a number of the same or similar fields in their definitions.
Chimney contributors
µPickle 0.6.2

A blazing fast Scala JSON library, ~3x faster than 0.5.1. uPickle now supports parsing to (and serializing) Other ASTs, from libraries such as Circe, Argonaut, Json4s or Play-Json.
uPickle contributors
IntelliJ Scala plugin 2018.1

Inline hints, better Structure View, improved refactoring, and greater usability | IntelliJ Scala plugin blog.
JetBrains (@jetbrains)
sbt 1.1.2 hotfix

A solid pack of improvements, bugfixes and internal changes.
sbt 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 #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.


  2. 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.


  3. 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.


  4. 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 .


  5. 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 .


  6. 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.


  7. 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.


  8. 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 .


  9. 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 .


  10. 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.


  11. 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.


  12. 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.


  13. Scala Times Issue #223

    Open Offer: Pair program with me. How well do you know your Akka trivia?. ScalaDays 2018 Berlin Takeaways. Scalar 2018 whiteboard voting results!. Implicit Implications (part 1): Implicit Parameters.


  14. Scala Times Issue #222

    Product with Serializable. Scala Enumerations hell. Running Play on GraalVM. Tagless Final algebras and Streaming. 10 Reasons to Learn Scala and FP - DZone Java.


  15. Scala Times Issue #221

    Akka Typed: Hello World in the new API. No More Transformers: High-Performance Effects in Scalaz 8. Writing Internal DSL in Scala. On Bifunctor IO and Java's Checked Exceptions. Partitioning Akka Streams to Maximize Throughput.


  16. Scala Times Issue #220

    Better logging with Monix 3, part 1: MDC. Learning how to code with Scala: Hello, World!. Responding to Incoming Text Messages with Scala and Finatra. Understanding F[_] in Scala. Macros: the Plan for Scala 3.


  17. Scala Times Issue #219

    A quick tour of build tools in Scala. Towards Scala 3. CoRecursive: Graphql And Sangria. Using Redux with Binding.scala. Testing Play Framework with H2 in-memory database.


  18. Scala Times Issue #218

    Cats: Safe Resource Acquisition and Release. An ode to the kind-projector and to the partial-unification of Scala. Models of Computation - Part 2 - How? (inspired by SICP). ScalaUA, April 20-21, 2018, Kyiv, Ukraine. WIN a ticket to Scala Days Berlin!.


  19. Scala Times Issue #217

    A Functional Interface for Key/Value Store. Defeat your 99th percentile with speculative task. Synchronous or asynchronous, and why wrestle with wrappers?. Running Spark on a Cluster: The Basics. Talks from Scalar Conference 2018.


  20. Scala Times Issue #216

    Boilerplate free testing with Scalacheck and Magnolia. ScalaUA, April 20-21, 2018, Kyiv, Ukraine. Scala Sphere, April 15-17, Kraków, Poland. Blockyard Conference, April 13, Gdańsk, Poland. Scala Native 0.3.7.


  21. Scala Times Issue #215

    Akka anti-patterns: overusing ActorSelection. Twilio guardrail: Principled Code-Generation for Type-Safe Languages. Google Summer of Code 2018 Scala Projects. Sequential Traverse for managing parallel resource usage in Scala. Dependency Inversion | Inversion of Control (IoC) For Absolute Beginners.


  22. Scala Times Issue #214

    Cats Effect: IO. Stepping down as the maintainer of scalamacros/paradise. Accessibility of the Scala Compiler. IO Monad and Monad Transformers for Rookies. Exploring Type Annotations in Scala.


  23. Scala Times Issue #213

    Generic Programming and Shapeless with Miles Sabin. Implementing an event-driven HTTP server with Scala Native. Survey on Swagger with Akka HTTP. AST-free JSON parsing. 5 steps of creating your very first Type Class in Scala.


  24. Scala Times Issue #212

    Scala-view: Animate streams of images. Creating forms on your Play application - Part 2. Typesafe Union-type folding in Scala. ManagedT: Compositional resource management. NeoVim + Scala.


  25. Scala Times Issue #211

    Top 15 Scala Libraries for Data Science in 2018. Static Sorting in Slick. Safe(r) mappings in Slick with Shapeless. Tour of Akka Cluster - Cluster Sharding. Akka cluster on kubernetes. Traps and pitfalls.


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.