Past Meetup

September meetup: Intro to Arrow + "The price we all pay"

This Meetup is past

56 people went

Location image of event venue


Talk #1: Intro to Λrrow
by Hubert Słojewski

After short introduction to type constructors, higher-kinded types and typeclasses you will see how they can be used in Kotlin. I will tell you why you might want to use Arrow and why you might not. It will be followed by a discussion about the library. The presentation is recommended for beginner and intermediate functional programmers, or basically for those who got used to maps and flatMaps.


Hubert - A functional programming enthusiast who despises nulls and throws, and on the other hand respects reactive systems and the actor model.

Talk #2: The price we all pay. Does Kotlin slow down our code?
by Krzysztof Romanowski

Kotlin, as well as other languages like Scala or Groovy is developed (echm, hacked, eckm) over JVM. We all enjoy features like extension methods or strict null management that does not have corresponding JVM operations. How does that affects performance?
Let’s run some benchmarks!


Krzysztof is Head of Dev & Scala Tooling @ Virtuslab where he has spent endless hours debugging Scala IDE, SBT, IntelliJ or even Scala compiler itself. Author of expression evaluator engine for Scala IDE and zinc contributor. Organizer of conference and Kotlin and Scala users groups in Kraków.

JetBrains provided free licence to rafle during the meetup.

VirtusLab is the founding sponsor of Kraków Kotlin User Group.