Dutch Clojure Days 2018 round-up


As you may recall, I had enthusiastic expectations and resolutions for Dutch Clojure Days. My first Clojure-only conference, my first proper face-to-face with the community. How could I not be excited?

On Saturday 21st at 8:30 am sharp we were at the TQ building’s reception, greeted by Carlo Sciolla. A couple of words on the venue: a simple but elegant building, close to Dam Square and right in front of a fascinating flower market. The conference happened on the fourth floor, with a balcony to enjoy the outstanding view on the city, and food and drinks for everybody. My first, huge “thank you, DCD!” goes to the vegetarian option which was palatable for a vegan, but let’s keep the cheering and the hand-clapping for the end.

Eleven speakers were waiting for us. Vijay Kiran set the stage and the playful mood of the day, leaving soon room to Alex Yakushev. “Embrace the JVM” was a talk to treasure. Observability, performance profiling, memory inspection. I am by no means a JVM expert, however the tools Alex showed us will definitely help me get a better understanding of the machinery behind Clojure.

Simon Belak was up next talking about transducers and statistical analysis. This was probably the hardest one for me. I haven’t found a way to appreciate the value of transducers yet, and statistical analysis is not my strongest skill. But I still appreciated the concept of sketch algorithms and I will hunt histograms pretty soon.

Srihari Sriraman with “Practical Generative Testing Patterns” blew my mind and, if you fancy ratings and such, was the highlight of the day. We all know test.check is good, but the approach of Srihari to automation, seeding relevant data and testing plausible behaviours left me eager to grab my keyboard and implement something similar.

After lunch we were treated to one more talk before the lightning sessions. Wilker Lúcio explained the beauty and easy-of-use of GraphQL, an interesting alternative to REST for better APIs.

The lightning talks kicked off with some magical REPL-debugging from Valentin Waeselynck. scope-capture looked promising, and I can only hope for an integration with CIDER. Dr Roland Kay reminded us of the usefulness of clojure.spec, although if I had to base my opinion of clojure.spec on his talk, it roughly looked like the type-system Clojure is missing. No trolling intended. Thomas van der Veen hit the MQTT broker pedal, mixing Java and Clojure, but I am still not sure I got the purpose of the experiment aside from the sake of learning. Ray McDermott closed the lightning sessions with an amazing browser-driven, multi-user REPL he is devising which can make live pair-programming scattered around the world a breeze.

The last three talks reflected experiences of using Clojure for business. Josh Glover, Philip Mates and Pierre-Yves Ritschard shared with us the journeys of their companies and projects and how designing, developing and testing have only improved since their move to our beloved language.

Drinks followed before a bit of REPL-driven comedy courtesy of Ray McDermott. Suffice it to say we sang the Clojure version of Bowie’s “Rebel Rebel” aptly entitled “REPL REPL”. If you weren’t there, well, you don’t know what you missed.

Dutch Clojure Days left me with the impression that the Clojure community is alive and hard-working, and its heart is in the right place. Ideas flourish, projects boom, boundaries get stretched. We can only be thankful to the DCD staff for being able to set up such a pleasant event, asking us only to join them to share our passion.