Rejmank's brain dump

Lambda days Krakow 2022

July 31, 2022

Lambda days Krakow 2022

Being a nodeJS developer at the functional programming conference is not easy. First of all, you are constantly being mocked for not programming in the real language (looking at you Roman!) and you often do not know if the speaker is cursing or describing some esoterical Haskell concept. But none of the difficulties should scare you from attending. Seven hours on the train means plenty of time for beers and reading. Our train even had a working air-conditioner... but working maybe too well so some of us had to shake off the hoarfrost before leaving the train. Nevertheless, We overcome all the difficulties, arrived in Krakow, and enjoyed the event.

Day 1

KEYNOTE: Building a Haskell-to-Hardware compiler: Theory & Practice

Two things I do not know anything about Haskell and the design of microchips... Cannot tell anything other than that the speaker was well prepared and with the knowledge of at least one I could see that it would be very interesting. I do not think that the topic was well suited for a keynote.

Attack Of The Clones: Multiplayer Online Game in Clojure

Introduction to Clojure that was not an introduction to Clojure. Walk through game code that runs on the backend. Well-chosen snippets and level of detail. Compared to the previous talk this one was really easy to grasp but on the other hand nothing new for me. I can imagine changing the talk to be a great introduction to Clojure. Nice talk nevertheless.

Debugging for math lover

With reduced complexity, you reduce the time and effort needed to debug the issues. This rather simple idea was spread into talk that covered different types and kinds of errors, debugging "strategies" and how they differ. Little too much Haskell(ish) but with takeaways even for us simple JavaScript programmers. I would be glad if the talk was more practical but the questions from the audience kind of fixed that. My takeaway is that there is to think more about the number of loops/ifs the speed of growth for them is not linear!

Teaching Functional Programmers Logic and Metatheory

Talk about a course at the university where they used a FP to teach the format logic concepts. I appreciate that he presented the results and feedback which was not that positive. I really, really appreciate that.

An Enigma Machine in Elm

Nice talk. Not really about elm but about cryptography and enigma itself. Well-spoken, funny, clear. The implementation was two slides but it showed the strength of simplicity in functional programming. This talk would make an awesome keynote.


So that was the end of day one. But not really because, you guessed it, after party! The venue was nice but the highlight was the 1 am kebab with a bottle of whiskey in the park. Great night, tough morning.

Day 2

Keynote: What every programmer should know about cognition

Do you know that you cannot teach teenagers programming in scratch? They just do not want to use something looking like a toy. The talk, based on the experience of teaching kids programming, was full of similar gems. A little reminder that we should think more about how we teach programming topics. Useful clear, great keynote! Note for me read the programmer's brain!

The work done by something else

Talk damaged by technical problems. The main idea was that the line between declarative and imperative is blurrier than we might think. Nice examples in Clojure. I liked the idea of Clojure in one slide, neat. Unfortunately, there was not possible to hear anything in the first third so I am sure I missed some ideas.

KEYNOTE: Sonic Pi - past, present & future

What an ending! Great, great talk with awesome delivery. Through teaching kids to program using music creation, principles of music the language itself... The only talk that forced me to download the software and play with it at the hotel.

Bitching about things

I did not write about all talks I attended (so my manager does not know how many I skipped :P ) and also because there were a few talks that were bad and writing that would help no one. Instead, I wrote down what mistakes I saw most frequently to avoid them myself.

  • Not good talk structure
    • The structure gives your talk rhythm, you can grab the audience's attention longer and it enables the listener to catch up if he/she gets distracted
  • BIG FONTS!!!
    • I cannot stress this enough. If you have code on your slides it must be big. It leaves you with just a few lines you can show at the time but nobody wants to read you 50 lines of code. If you want to show a larger portion of code do it step by step.


The conference was great. Cool venue, nice catering, stable wifi. The talks were interesting and I am bringing home some motivation and ideas. Thanks, CN for letting me go and the whole crew attending for the great atmosphere. Thank you Lambda Days!