Functional Scala London 2019

In December 2019 I attended the conference Functional Scala in London which was initiated and managed by John de Goes. See Skillsmatter about what happened to Scala Exchange. Of course a large part of the conference was related to ZIO, which seems to be a part of the eco system surrounding Scala with a lot of dynamic.

It was a single track conference with a lot of talks, so I have attended all of them:
Day 1 (2019-12-12)

  • KEYNOTE: XS — A Collections CLI [Paul Phillips] (Video)
  • Introduction to Interruption [Jakub Kozlowski] (Video)
  • Making Algorthms work with Functional Scala [Karl Brodowsky] (Video)
  • Solving the Scala Notebook Experience [Jeremy Smith & Jonathan Indig] (Video)
  • Mixing Scala & Kotlin [Alexey Soshin] (Video)
  • Prototyping the Future with Functional Scala [Mike Kotsur] (Video)
  • Test Effects: First Class [Adam Fraser] (Video)
  • Let’s Gossip! [Dejan Mijic & Przemyslaw Wierzbicki] (Video)
  • Ray Tracing with ZIO [Pierangelo Cecchetto] (Video)
  • Invertible Programs [Sergei Shabanau] (Video)
  • Hyper-pragmatic Pure FP Testing with DIStage-Testkit [Pavel Shirshov & Kai] (Video)
  • KEYNOTE: Unleash Your Fury [Jon Pretty] (Video)

Day 2 (2019-12-14)

  • Modern Data-Driven Applications with ZIO Streams [Itamar Ravid] (Video)
  • Functional Architecture [Piotr Golebiewski] (Video)
  • ZIO Chunk: A Fast, Pure Alternative to Arrays [Aleksandra A. Holubitska]
  • Caliban: Designing a Functional GraphQL Library [Pierre Ricadat] (Video)
  • Macros and Environmental Effects [Maxim Schuwalow] (Video)
  • Streaming Analytics with Scala and Spark [Bas Geerdink] (Video)
  • ZIO Actors [Mateusz Sokol] (Video)
  • Adventures in Type-safe Error Handling [Jacob Wang]
  • Composition using Arrows and Monoidal Categories [Oleg Nizhnik]
  • Practical Logic(al) Programming with Dotty [Lander Lopez]
  • Next-Level Type Safety: An Intro to Generalized Algebraic Data Types [Matthias Berndt]
  • KEYNOTE: The Many Faces of Modularity [Eric Torreborre]

See Agenda

Maybe I will write more about some topics.

Talks will be on youtube in the near future.


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Visit to reClojure in London 2019

On 2019-12-02 I visited the conference reClojure.

This was an admirable community effort to create a replacement for ScalaExchange, which simply did not happen because of the bankruptcy of Skillsmatter.

There was only one track, so the schedule is exactly what I visited.

I will just copy it below, because schedules from conference sites usually disappear after some time:

  • Building stuff with Clojure and 3D Printing. Clément Salaün.
    How to design objects with Clojure, OpenSCAD and then 3D print them. This talk covers the motivations, basic concepts and features with a live demo.
  • Clojure Art. Karl Brodowsky.
    Teaching or learning Clojure using images has been proven to be fun and beneficial! In this talk, learn how.
  • Growing Mobile Apps with ClojureScript and React Native. Daniel Neal.
    Starting things is fun, but growing them can be a real challenge – and mobile apps are no different…
  • Live Coding a Mandelbrot Renderer. Peter Westmacott.
    In this talk, Peter will demonstrate live coding of a fractal renderer, with the aim to show how complex beauty can emerge from simple mathematical rules and a little code.
  • Pizza Party Lunch (Thank You uSwitch!)
    Short 10 minute talks. Various Speakers.
  • Unleash the power of the REPL. Dana Borinski.
    Return to basics and dive into how to leverage the REPL to solve problems and debug more quickly – and with the added bonus of honing our Clojure skills!
  • Generating Generators. Andy Chambers.
    Generating data for use in tests can be laborious and boring. However, using the database’s information schema you can alleviate that! Discover the ways to achieve this.
  • Living in a Box. Life in Containers with the JVM. Matthew Gilliard.
    A focus on how containers and the JVM interact and what implications are there for Clojure Developers. Get the best results from the work gone into OpenJDK container support.
  • Closing Keynote – Code, meet data! Malcolm Sparks.
    Computers have 3 jobs: Input, process, output. How have we made such a mess of something so fundamental? Observations, opportunities for Clojurists and hope for the future.

There is a youtube channel for reClojure, where we can now find recordings of the talks.

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Devoxx UA and Devoxx BE 2019

In 2019 I visited Devoxx UA in Kiev and Devoxx BE in Antwerp.
Traveling was actually a little story by itself, so for now we can just assume that I magically was at the locations of DevoxxUA and DevoxxBE.

In Kiew I attended the following talks:

On Wednesday I attended the following talks in Antwerp:

On Thursday I attended the following talks in Antwerp:

On Friday I attended the following talks in Antwerp:

That’s it…
As always, a lot of these topics deserve an article in this blog. And a lot of video recordings from the conference are worth viewing.


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Travelling to Devoxx UA and Devoxx BE 2019

Travelling to this years Devoxx conferences is worth its own short article, even though it is not very IT oriented material…

On the last weekend in October I brought a bicycle to a place near Frankfurt, let’s call it FrankfurtE. I took the train to Karlruhe and then back from FrankfurtE, but cycled from Karlsruhe to FrankfurtE.

On Wednesday evening 2019-11-30 I took a night train from Basel to Hannover and then a day train to some place in North-Rhine-Westphalia for private reasons, then in the evening a flight from Düsseldorf to Vienna and from there to Kiev. There was a problem with the plane, so we returned to Vienna. Austrian Airlines did a good job on rebooking, because they told us that they would find different alternative connections for all of us and send them to our phone, if possible. So there was no need to stand in a line for hours. Plus a decent hotel was booked which was next to the terminal. I had to translate all this information to Russian, because many of the passengers were only comfortable with Ukrainian and Russian languages and the guys in the airport only with German and English.

Then on the 2019-11-31 I flew back from Vienna to Frankfurt and then finally to Kiev, where I could visit the second half of the first day of Devoxx UA and the second day.

On Sunday 2019-11-03 I flew from Kiev to Frankfurt, picked my bicycle in FrankfurtE and took a train to Trier, where I stayed for the night.

On Monday 2019-11-04 I cycled to Marche-en-Famenne.

On Tuesday 2019-11-05 I cycled to Antwerp, where I participated Devoxx Belgium.

On Friday 2019-11-08 I cycled to Lanaken.

On Saturday 2019-11-09 to Bastogne.

And on Sunday 2019-11-10 to Luxemburg, from where I took the train home to Switzerland.

Just to give an idea, it is absolutely possible to use a bicycle as a means of transport on a business trip, but it has to make sense by not consuming more than one or two working days plus weekends, so it is basically necessary to go relatively long distances of 150 to 200 km on a full day and not spend more time than necessary on breaks. And most of the time it is the right choice to use the bigger highways, at least the biggest that are not forbidden to use, because beautiful quite scenic route usually are longer and would be too time consuming. It is not a vacation, but it remains a business trip. Then, on the other hand, this is not such a bad idea, because it really gives some time for thinking about some of the more interesting talks while cycling.

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Company „Skillsmatter“ stops operations

The company Skillsmatter in London has been put „under administration“ and basically stopped its operations. The web site seems to suggest, that everything is still ok, but that is not the case and I have heard so from several sources. The owner Wendy Devolder writes on Twitter and on Linkedin. Or here are some more news from cbronline or from theregister. The adminstrator is Resolve. They had put a deadline on 2019-11-05 for potential buyers and nothing indicates that such a buyer could be found.

There are some hopes expressed, that either 10’000 people will donate 250 GPB each or that someone buys the company and keeps it afloat. Reasonably it is probably not going to happen.

Now it is hard to obtain further reliable information. Have the employees already been layed off? Have all conferences been cancelled, for example Clojure Exchange (ClojureX) and Scala Exchange (ScalaX)?

The websites mention nothing about it, but simply the fact that there is nothing mentioned indicates that the employees, who could update the site, are gone and that the conferences will probably not take place. Otherwise I would expect an update on the site mentioning that it is taking place in spite of the situation. In case of Clojure Exchange I have been informed by other participants that Clojure Exchange has been canceled and that there will probably be a „community conference“ instead. Being a speaker, I volunteered to perform my talk on this community conference instead.

In case of Scala Exchange there was a strange story. A keynote speaker, John de Goes, was „uninvited“ because of „inclusiveness“. As a result, he decided to create a competing conference, Functional Scala, at exactly the same time as Scala Exchange and also in London. Some speakers have reportedly decided to speak at Functional Scala instead of Scala Exchange and speakers were encouraged to do so. In the end this might come out as a good thing, because Functional Scala will probably take place and might be an option for those who have already booked their visit to Scala Exchange.

So what does all of this mean? If we are heading for bankruptcy of Skillsmatter and if the conferences (Clojure X for sure, Scala X probably) are canceled, we as speakers or simply visitors are entitled to refund for our ticket or our non refundable travel expenses as speakers to the extent that Skillsmatter would have covered them. But reasonably there will not be enough money left for this. A company can go bankrupt and still have funds that is hard to access, but in practice banks will help out if these funds can be documented. So in reality bankruptcy usually means that there are many debts and little money already. Now the salaries of the employees get the highest priority. When they have been paid, other open payments can be covered, according to the rules that apply in the country. Possibly the price for the ticket, that has already been paid, is simply lost. Possibly travel expenses are lost if they cannot be redirected to another event.

If you like to Donate 250 GBP and 10’000 people do so too, the company could continue. I do not think that this is going to happen.

I will keep you informed if I learn more about the issue that is interesting to potential conference visitors and speakers of events organized by skillsmatter.

Update 2019-11-12: I got in contact with the administrators. They did not want to confirm or deny that the conferences scheduled in December would take place. They just do not know, but it seems to be depending on finding a buyer. If a magical buyer appears and decides to reactivate the events, they might take place. Meanwhile all web pages of skillsmatter show a text that the company is „under administration“, so I guess each day it is getting less likely that there will be anything a buyer can reactivate. I know for sure that at least some employees have already been asked to leave.

Now the good news: The replacements for Scala Exchange and Clojure Exchange are already in place, meaning a conference about the same programming language at the same date and also in London. So if you have booked your hotel and your trip to London already, you might want to check them out:

Update 2019-12-09:
Scala Exchange is not going to happen. See web page.
And since so much time has passed, it is becoming unlikely that a buyer turns up, so the company will be gone.

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Scala Days 2019

Scala Days had a tenth anniversary in 2019. It is an annual conference about Scala, which I like to visit, when possible.

There is some confusion as to what is meant:

  • Where this the 9th, 10th or 11th Scala Days?
  • Where the first Scala Days 9, 10 or 11 years ago?

The truth is, that the first Scala Days were organized in 2010 and took place in Lausanne. So it was 9 years ago, but the tenth event. For this reason it was done in Lausanne again, but in a much larger venue.

Just for the completeness:

This is the opening keynote by Martin Odersky. A video will be on youtube soon.

I visited the following talks:

And on the last day I visited the following talks and the diversity panel and the closing panel:

Here is the whole schedule.

Btw., links might expire when the next Scala Days will start using the site in early 2020. Where it will be in 2020 is still unknown, but since 2014 it has been a habit to do the even years in Berlin. I will try to come, if there are Scala Days 2020 in Europe.

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ScalaUA 2019

In March 2019 I have visited ScalaUA in Kiev.

It was interesting. I attended the following talks:


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Clojure Exchange 2018

I visited Clojure Exchange 2018 in London.
Since there was only one track and I attended all talks, it is easy to just refer to the schedule.

Interesting topics, that came up multiple times in different flavors where immutability, stories of building real life applications, music, java and clojure and the transition, clojure script, emacs and cider…

I did a lightning talk myself about Some Thoughts about Immutability and its Limits.


  • Clojure
  • Clojure Exchange 2018
  • Clojure Exchange 2016
  • Clojure
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Devoxx Kiew 2018

In the end of 2018 the number of conferences is kind of high. A great highlight is the Devoxx BE in Antwerp. But it has now five partner conferences in London, Paris, Krakow, Morocco and Kiev. So I decided to have a look at the one in Kiev.

How was it in comparison to the one in Belgium? What was better in Kiev: The food was way better, the drinks in the first evening (Whisky and Long Drinks vs. Belgium Beer) might be considered better, there were more people engaged to help the organizers…
What was better in Belgium: There were still a bit more speeches. While the location in Kiev was really great, in Belgium the rooms were way better for the purpose of providing a projection visible for everybody and doing a video recording that did not disturb the audience.
The quality of the speeches was mostly great in both locations. In Kiev they gamified the event a bit more..

Generally there was a wide range of topics and the talks were sorted into the following thematic groups:

  • Methodology & Culture
  • JVM Languages
  • Server Side
  • Architecture & Security
  • Mobile & IoT
  • Machine Learning & AI
  • Big Data & Data Mining
  • Cloud, Containers & Infrastructure
  • Modern Web & UX

See the schedule for the distribution…

I attended on Friday:

I attended on Saturday:

A lot to learn.

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Devoxx Antwerp 2018

In 2018 I am visiting a few conferences. A great highlight is the Devoxx BE in Antwerp, which I had the privilege of visiting 2012, 2013, 2014, 2015, 2016 and 2017.

As it should be, it is not just the same every year, but content and speakers change a bit from year to year.

Some topics that got a lot of attention were functional programming, artificial intelligence, Big Data, Machine Learning, clouds, JVMs, Kotlin

There was less about other JVM languages (apart from Kotlin), so Scala, Clojure, Groovy or Ceylon were covered little or not at all and Android used to be more present in other years. I would say that Ceylon has become irrelevant, probably because Kotlin was too similar and came out the same time and won. Groovy has its niche, Clojure has its niche, Scala and Kotlin have become mature and are now the two mainstream alternatives to Java, but themselves much smaller than Java. This was represented in the conference, taking into account that Scala has its own large conferences, like Scala Days, Scala Exchange, Scala World and a lot more.

Some side issues that might worry some of us did come up occasionally. Was it bad, that IBM bought Red Hat? At least they paid around 34’000’000’000 USD, which is more than 2’500’000 USD per employee. There are probably no other assets in terms of buildings, patents, hardware or whatever, that would justify this price, so IBM probably will have an interest to keep a large number of these employees and not scare them away by too much „IBM-culture“. We will see, but no reason to get immediately worried. Oracle wants money for running their JVM in production after more than 6 months. This can be avoided by always switching to the newest version or by relying on the JDKs offered by alternative sources like Amazon, RedHat…

Microsoft was a sponsor and had a booth. Their topic was not MS-Windows and MS-Office and MS-SQL-Server, but Azure, which can be used with Linux and Java and PostgreSQL, for example. The company did change a bit since the days of Steve Ballmer and we will see if this is an excursion or a continuous direction.

And James Gosling was there at the opening, as a surprise.

Generally there was a wide range of topics and the talks were sorted into the following thematic groups:

  • Methodology & Culture
  • Java Language
  • Programming languages
  • Architecture & Security
  • Big Data & Machine Learning
  • Mind the Geek
  • Server Side Java
  • Modern Web & UX
  • Cloud, Containers & Infrastructure
  • Mobile & IoT

See the schedule for the distribution…

I attended on Wednesday:

I attended on Thursday:

I attended on Friday:

It was a great conference. A lot of new ideas.

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