ClojuTRE 2019

An amazing conference with amazing speakers

ClojuTRE 2019

September 30, 2019
Andrew Jackson

As ClojuTRE 2019 comes to a close, I am left with many different feelings - from joy and excitement to inspiration and massive appreciation. I think everyone that attended would agree with me when I say that this is one of the best conferences. I’d like to say a massive thank you to Metosin, the numerous other sponsors and to all the amazing speakers for putting the time and effort into making this conference such a success.

There were too many great talks to mention them all so I would like to highlight a few that I personally enjoyed a lot. Be sure to check out all the videos though when they are released over the coming week or two. There were also a lot of tweets so check out @clojuTRE and the #clojutre2019 hashtag.

Day 1

The first day started off with the FP track. Fabrizio Ferrai (@fabferrai) kicked things off with a talk on building and maintaining a package manager. His talk was a graceful blend of humour and insightful / painful lessons learned along the way. If you have some free time and you’re looking for a talk that will make you laugh and hopefully learn something about package management and why not to roll your own, then this is a great session to watch.

Fabrizio Ferrai talking about package managers
Figure 1: Fabrizio Ferrai talking about package managers

Nir Rubinstein from AppsFlyer chatted about the philosophy of language. I’ve always enjoy philosophy and studied language and literature so this talk resonated a lot with me. A large focal point of Nir’s talk were the seven principles outlined in Tractatus Logico-Philosophicus, a book by Ludwig Wittgenstein. If you like philosophy or the study of language or mathematics then you will enjoy this talk.

Nir Rubinstein talking about the philosophy of language
Figure 2: Nir Rubinstein talking about the philosophy of language

Daniel Slutsky has been working with the various maintainers of data science related Clojure libraries (go checkout scicloj). I’ve been silently following along over the past year as they have worked to bring Clojure and R closer together to improve the data science story for Clojure. Daniel spoke about some of these efforts and showed a few examples of calling R from Clojure and vice versa. If you’re into data science, then definitely watch this talk when the videos are out.

Daniel Slutsky talking about Clojure and R love
Figure 3: Daniel Slutsky on Clojure and R ❤️

Next up was an amazing talk on Computer Mathematics, AI and Functional Programming by Moa Johansson. Moa knows an incredible amount about the history in this domain, from the 1950’s through to the present day. She did a great job of highlighting the excitement and anticipation of the great minds of the 1960’s and how many of their predictions about computer programmes have come to pass (even though slightly later than originally anticipated). The talk included a demo of a programme discovering/solving mathematical proofs. A delightful talk worth watching.

Moa Johansson talking about computer mathematics
Figure 4: Moa Johansson talking about computer mathematics, AI and functional programming

Richard Feldman gave an entertaining talk entitled "Why Isn’t Functional Programming the Norm?" which centred around the evolution of mainstream programming languages which happen to be OO, but the reasons that he deduces for this are not quite what you’d expect. A fun and educational talk that goes into great depth about the history of programming languages.

Richard Feldman delving into why FP is not the norm
Figure 5: Richard Feldman delving into why FP isn’t the norm

Fotis Papadogeorgopoulos gave a talk on keeping websites accessible. This is definitely an area where many developers could put in that little bit of extra attention that would result in a better world for people that rely on assistive technologies such as screen readers. If you’d like to make their lives a little better, this talk is a great place to start and has many links to resources that can help.

Andrea Leopardi is one of the core maintainers of Elixir and gave a light hearted tour of the language and it’s features and about how decisions are made around the maintenance of the language and its evolution over time.

The after-parties were great fun and we were lucky enough to go to the speakers after-party at Nitor's offices. They were great hosts. Thank you all very much for having us there.

baltic sea

Day 2

Day 2 started with a Crux tutorial session where Johanna Antonelli helped attendees find and get started with the Crux tutorials, in particular the space adventure tutorial, A Tale of Time and Space. It was good to see so many people attend the session and we hope that they enjoy working through the series and become more familiar with using Crux.

Johanna Antonelli running the Crux tutorial session
Figure 6: Johanna Antonelli running the Crux tutorial session

Michiel Borkent showed the off some of the cool features of clj-kondo, "a linter that sparks joy". If you’ve ever watched Marie Kondo, you’ll understand where the inspiration for the project name comes from. You can see Michiel’s talk slides of the presentation here and I would highly recommend trying clj-kondo out and watching the video of his talk once it’s published online.

Michiel Borkent chatting about Clojure linters
Figure 7: Michiel Borkent chatting about Clojure linters

Tommi Reiman, the co-founder of Metosin, gave an interesting talk on strategies for analysing the performance of Clojure code using tools like flame graphs and shared some handy tips on ways to significantly improve the speed of your code. I highly recommend watching the video when it comes out. Metosin were also handing out some cool stickers, including the snow people captured in the image below. You can see the slides from Tommi’s talk here.

Tommi Reiman chatting about performant Clojure
Figure 8: Tommi Reiman chatting about performant Clojure

Jack Rusher was inspiring the creative side of the audience with his various designs and ideas about the creative mind. The presentation was a good mix of light hearted humour and funky visuals. I was so captivated that I forgot to capture any video of his generated animations (which were pretty awesome).

Jack Rusher displaying the results of creative computation
Figure 9: Jack Rusher displaying the results of creative computation

Dave Snowden's talk on dealing with unanticipated need was probably the highlight of the conference for me. The content of the talk was very thought provoking. I couldn’t do it justice trying to summarise it. If you watch only one video from ClojuTRE 2019, this should definitely be it.

Dave Snowden talking about unanticipated need
Figure 10: Dave Snowden talking about unanticipated need

Håkan Råberg is a still mind that is lightning sharp and full of knowledge. He spoke about the internals and design decisions around Crux and clearly had a solid understanding about it as he spoke at great speed to cover the breadth of information he was trying to share with the audience. Being a JUXT employee, I am obviously a bit biased towards this talk, but I think it’s fair to say that this is a talk worth watching. You can read the slides from Håkan’s talk here.

Håkan Råberg talking about the internals of Crux
Figure 11: Håkan Råberg talking about the internals of Crux

Finishing off the conference was Alex Miller from Cognitect. It was a delight to finally watch one of the Cognitect team give a talk in person. Alex started off talking about his path as a programmer, from childhood through to his interview process with Cognitect. Another light hearted talk with some good insights that were funny (because they were true). He also chatted about some of the processes that he and Rich Hickey use to plan and communicate with each other and about spec and some of the nice features coming to version 2. Another talk that is well worth the watch.

Alex Miller sharing lessons learned from a lifetime of programming
Figure 12: Alex Miller sharing lessons learned from a lifetime of programming

Once again, the after-party at Gofore's office was great fun. I’m sure everyone that attended would like to say thank you.


The main hall was filled with sponsor stands that included interesting games (like air ping pong) and various competitions to enter. Some examples include Solita, who had a code challenge where attendees could find three digit codes on their website, as well as code cracking challenges to find codes and win various prizes, and JUXT, who had a mystery word challenge to win flights, accommodation and a ticket to next year’s XT20 conference in London.

JUXT setting up in the hall
Figure 13: JUXT setting up in the hall

You may also be wondering who the nun is on the stage screen photo. She is Mary Kenneth Keller, one of the first two people to earn a doctorate in computer science in the United States.

A massive thank you

This has been an amazing two days and I have met so many great people, reconnected with old friends and made new ones. I hope that I have the privilege of coming to ClojuTRE 2020 and beyond. Thank you again to Metosin and all the sponsors and speakers for making this such a memorable experience. I’d also like to say an extra special thank you to the people behind the scenes that do so much to arrange everything, from organising the venue to the flights and accommodation and everything else in between. Events like this wouldn’t be possible without your help.

signing off laptop
Signing off until next time