Writings
Long-form essays and thoughts.
Building Collaborative Web Applications with the modelix Stack
In this post, we take a look at a sample application built on top of the modelix stack during my 20% time at itemis. The application allows for real-time collaboration between all clients. It doesn’t matter if a client is MPS or the web interface.
Feb 14, 2022
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Happy birthday mbeddr 🎉
Today marks the 10th birthday of the mbeddr open source project. Looking back on my experience with MPS and mbeddr and what is ahead of me.
Jan 18, 2022
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Meta Programming System Mentoring Experiment 2022
This year the JetBrains Meta Programming System (MPS) community has continued to grow. Many new names joined the MPS Slack and asked lots of questions. After years of almost stagnation, it motivates me to see growth in the community and adoption of MPS.
Dec 27, 2021
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Modelling in the Browser isn’t enough!
We need platforms for models in the cloud!
Jun 14, 2021
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Skadi Cloud - May Update
After the release about a month ago it’s time for the first bigger update. A couple of small fixes and major features found their way into skadi cloud!
May 8, 2021
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How JetBrains Meta Programming System (MPS) Identifies Things
How does MPS identify languages, solutions, models, concepts, nodes, or even properties? In this blog post, we take look at the details.
Apr 21, 2021
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Skadi Cloud - an Experiment with JetBrains Projector and MPS
Getting JetBrains MPS into the browser with Projector on Kubernetes.
Apr 8, 2021
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JetBrains Projector a Game Changer for MPS Projects?
My thoughts on the new Projector project by JetBrains, how we can use it with MPS and how it relates to modelix.
Mar 16, 2021
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Context Boundaries in Language Engineering Projects
How to scale your language engineering project beyond a single team without causing a communication and dependency hell.
Jan 8, 2021
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A new Home for my MPS Tutorials
For most of 2020 I was planning to create a dedicated website for my “language engineering with MPS” tutorials that I streamed on Twitch at the end of 2018 and early 2019. As part of creating a website for them I also wanted to update the tutorials to more recent MPS version as it was still stuck on 2019.1. Through 2020 I didn’t find the time to do it for various reasons but in November I finally got around doing it.
Jan 3, 2021
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Language Engineering Newsletter
In November I accidentally started a language engineering newsletter with a tweet. Here is how it came to be.
Dec 26, 2020
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Introducing Fernsprecher for IntelliJ IDEs
Fernsprecher is a plugin for IntelliJ based IDEs by JetBrains like Meta Programming System (MPS) that makes it easy to read IDE logs in the browser.
Dec 22, 2020
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JetBrains MPS Generators: Down the Rabbit Hole
How we tracked down a subtle JetBrains MPS generator bug after upgrading to 2019.3—property lookups failed due to constant unification missing the language ID—and contributed a one‑line upstream fix.
Aug 28, 2020
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Heavy Meta 2019
Last year I started a stream series about JetBrains Metaprogramming System called “Heavy Meta” on Twitch. In this blog post I would like to give you an update on my ideas for this year and look back on what worked well and what did not.
My goal with “Heavy Meta” was to do a slow paced tutorial on MPS, that is up to date with the current developments in MPS and its community.
Jan 14, 2019
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Update to MPS 2018.3: Behind the Scenes
In this post I‘m sharing some of our experiences from updating to MPS 2018.3 in various codebases. I did the migration in three projects: the MPS Extensions, mbeddr and IETS 3. The final version of MPS 2018.3 is now release for about a week.
The migration in all three projects is done. All projects compile against the lastest version of MPS and all migrations were executed. Some of the projects still contain model checking errors because of new checks introduced in the update but the generated code works.
Dec 10, 2018
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Testing in JetBrains Meta Programming System: What and Why?
There are a number of questions around testing in JetBrains Meta Programming System (MPS) that I get a lot. For example: How does MPS affect the way I do testing? How can I do TDD in MPS? Should I test this in MPS?
In this post I will try to answer these questions, but also enable you to answer these questions for yourself. To answer these questions we have to take a step back and reflect on why we do testing in the first place.
Nov 27, 2018
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Heavy Meta: A Streaming Series on JetBrains MPS
A while back I experimented with “streaming” about MPS. I didn’t do much more than a single, not even live streamed, video. It was basically me working on some extension to MPS while I explained what I was doing which I happened to record.
Recently I revived my efforts in that direction and starte with new series in Twitch. This time really live and with recordings available on twitch afterwards. The first two “episodes” focused on a more advanced topic that was requested by members of the MPS community: the command line build and integration in a continuous integration setup.
Nov 1, 2018
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MPS, Feature Branches and Language Migrations: DOs and DON’Ts
The MPS meet-up in Munich sprung some discussions about how feature branches and language migrations get along. It seems that there is quite some uncertainty how to approach this. In this blog post I shed some light on the topic and show what we found to work in practice. I assume that you already have some background in MPS. I won’t explain the details of how to write migrations or other aspects of MPS that play a role in the overall picture.
May 10, 2018
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Streaming, Contributing to MPS and Git Workflow
Today I tried something new: I streamed while I was programming. Well, actually … I didn’t live stream it. I recorded it on the weekend and uploaded the unedited video file to Twitch. Mostly because my MacBook seemed to be sluggish when recording and coding. I might have solved that problem and do real live streams in the future.
In the stream I added a small feature to one of MPSs languages: MPS and other JetBrains IDEs contain a webserver that allows you to interact with the IDE from other processes.
Feb 5, 2018
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Slack is not smart
I might be a bit late to the party since a bunch of people have already written about Slack and how awesome or awful it is. So I though I will give my two cents away how we use Slack and what I think about it
Over the past two and a half years our team has been using Slack quite heavily. Everything started relatively spontaneous as most of the team were abroad for a week and wanted to stay in touch with the others.
Jul 24, 2017
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My personal blockbuster 2016: Planet Earth II
Finally it’s there the continuation of the amazing Planet Earth documentary. I was excited when it was announced, because the first one was an amazing piece of documentary. I liked the first season (or however you want to call it) a lot but the second is taking it to a whole new level. The last documentary about nature that really got me stunned in a similar way was Wild Scandinavia (german).
Dec 20, 2016
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a Functional Approach to Asserts in Swift
While I was coding some tests for my side project I thought about if I can find a way to write my tests in a way that fits better to my way of thinking while I code.
When I write my tests my way of thinking is:
What do I want to test and what’s the expected result?
And I like it when my code and the way in which I write it reflects that.
Apr 30, 2016
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Some playgrounds to explore CIFilters on OSX
Swift playgrounds for experimenting with Core Image CIFilters on macOS—per‑category projects for fast, side‑by‑side testing (blur, color adjustment/effect, composite, distortion)—with a GitHub repo to explore and contribute.
Apr 16, 2016
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Home data: Arduino (part 1)
This is the first “real” post about my current side project. The first thing I will talk about is the Arduino I use to collect some date from my living room and outside of it. I will use two sensors one HDC1000 and a BME280. The BME will be placed outside because measuring the pressure in my flat does not make that much sense. Both sensors have a I²C interface so I can easily read their values from the Arduino.
Feb 25, 2016
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Home data (part 0)
This is the first post in a series of posts about my current side project. I wondered what to do with all the Arduinos, ESP8266s and a RaspberryPi that were floating around in my desks drawer. So I decided to use them to put lots of sensors in- and outside my home. I will start with the obvious ones like temperature, humidity and pressure. I also plan to add some air quality sensor, may be a VOC or CO2 sensor.
Feb 23, 2016
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Fsharp
On Friday I gave a about two hours long introduction to F# to my colleagues at itemis Stuttgart. The talk starts with a overview over F# and then dives into the features of the language. It also covers some of the meta programming capability that F# offers.
Most of the code samples have been taken from the wikibook “F# Programming”.
Here are the slides:
Aug 31, 2015
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Ghostbusters
I haven’t blogged for quite a while now. This was due two reasons, first I didn’t have that much time (read motivation) and second my old Octopress setup was horribly broken. But this weekend I choose to change this. I looked a round on the web which the new shiny blogging stuff is and stumbled up on ghost. Actually not. I know ghost for quite some time and I am running another blog which is focused on my hobby, kayaking.
Jun 7, 2015
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java extensions 101 with MPS
In the past years I have done lots of work in C# and recently came back to work with Java because I am
now working in a project that involves MPS. The Meta Programming System from JetBrains. Which is a
language workbench with a projectional editor. I got quite used to some of the features C# offers.
One of the features I love the most is implicit strong typed variables, expressed with the var keyword
as type in a variable declarations. Due to the extensible nature of MPS it is quite easy to extend existing
languages. So I decided to build this feature in MPS for Java.
Now you might think this ridiculously crazy since it is hard to change an existing language. But in MPS
everything is about modularization, extensibility and composition of languages. And It ships with a
Java implementation called baselanguage out of the box. For me it took 30 minutes of work to build
this extension. Though I have a lot of experience with MPS and a good knowledge of baselanguage
but even if you don’t have that it should take you not longer than an hour to do it on your own. And that is
what this tutorial is about. What I will show here is how to extend
baselanguage with a new kind of variable declaration that uses its initializer to calculate its type.
Mar 16, 2014
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mbeddr arduino release
After some month of low activity in the mbeddr.arduino repository I found more time to work on it in the past week. It is now in a state that it is reasonable to release a first version of it. This version contains a very fist look at the features available by mbeddr in combination with real hardware. If you find any issues please report them on the issue tracker or get in touch with me over the various social media links on the left or via Email.
Feb 1, 2014
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sleep modes with mbeddr.arduino
Here is a little status update on the mbeddr.arduino project. We are getting closer to the first “release”, which will be an early access version but we want to get it into the hands of people to try it. The main topic on this post is not the release ;-) it is about the opportunity to avoid common pitfalls in Arduino programing with Model Driven Software Development (MDSD). This weekend I have added support for sleep modes.
Oct 6, 2013
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jetbrains MPS debian package
Good news for all debian and ubuntu users using the Meta Programming System by JetBrains: I have just created a debain package for it. I have also setup a repository on this server to allow easy handling.
In order to use it open a root shell and run the following commands. Those will add the repository and import my public gpg key:
echo 'deb http://dl.logv.ws/repository ./' >> /etc/apt/sources.list wget http://logv.ws/files/kdummann.asc apt-key add kdummann.
Oct 4, 2013
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Trainmonitor: The API and why it sucks
Recently I have published my Trainmonitor app, that is using a backend server to get the train data and do the notifications. To communicate with the server I have an HTTP API, some people might call it a RESTful API, but we will see later that this is not the case. There are several issues with the API, part of the done intentionally done wrong and others not. So why would I do stuff wrong if I knew it was wrong?
Oct 1, 2013
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custom reporting with mbeddr
How to implement a custom serial-port reporting backend for mbeddr on Arduino: an overview of the reporting architecture (messages, tables, report statements, strategy) and generator rules for emitting messages—with and without parameters—plus counters and caveats.
Sep 15, 2013
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Building mbeddr projects with ant
This post is about setting up ant to build an mbeddr project. It enables you to do continues integration builds or other automated build scenarios. I assume that you have already installed mbeddr. If you haven’t, you should follow the instructions in the mbeddr user guide or this tutorial. It also assumes that you are using the source code distribution of mbeddr and have build it. If are using the binary distribution have a look at the end of this tutorial.
Jun 8, 2013
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installing mbeddr on ubuntu 13.04
This guide covers how to build and install mbeddr from source, it does not include how to install the fancy model checking tools.
After you have installed Ubuntu 13.04 you will notice that it already ships with Java 7. Since MPS only works with Java 6 you need to downgrade it. The problem is that the official package repository of Ubuntu does not contain a Oracle Java version anymore, there is OpenJDK 6 but it will not work with properly MPS.
Apr 6, 2013
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Trainmonitor goes open source
The trainmonitor / Zugmonitor Android App is now open source. Like I have planned from the beginning. Currently I only open sourceed the Android App. The server side will follow as soon as I have done some code clean ups! But it can take a while!
The App is licensed under the Apache 2 license and the source code can be found on Github.
I am developing with IntelliJ and the project has the folowing dependencies that are not part of the source code, but all open source or available from the Android SDK:
Jan 10, 2013
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EventBus for Android
Using greenrobot’s EventBus to simplify Android app startup and multi-threaded flows—replacing tangled callbacks with events to decouple logic, reduce boilerplate, and trigger shared actions from multiple sources.
Dec 31, 2012
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introducing logv.http - a event driven webserver for .net
While I was working on the trainmonitor project I need a back-end server that could handle the HTTP API. The normal .Net way would be to use ASP.Net and do it with MVC, but since my back-end should run on Mono I don’t wanted to go that painful road with Mono and decided to do some stuff on my own.
That’s when logv.http was born a simple webserver written in .
Dec 23, 2012
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event driven webserver with F#
I am always open to experiemt with new stuff, so this time I did something I wanted to do for a long time: play a bit with F#. I read some book about it in the past, but never had the chance to really do something with it. I was always fascinated by the expressiv code that you are able to create with it. Since my current spare time poject is using a webserver I thought it would be a nice idea to implement some stuff for it with F#.
Nov 21, 2012
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Trainmonitor
In meiner Freizeit habe ich ein kleine Projekt gestartet das ich nun endlich in die Freiheit entlassen möchte. Es richtet sich vorallem an deutschsprachige Pendler die die Deutsche Bahn nutzen. Mehr dazu findet ihr auf einer eigenen Seite hier im Blog, auf der ich den Status des Projekts immer aktuell halten werden. Zu Trainmonitor geht es hier.
Nov 17, 2012
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Forcing a HttpWebRequest to IPv6
How to get a HttpWebRequest to only use an IPv6 endpoint.
Nov 6, 2012
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Zugmonitor CSharp bindings
Da sich der Inhalt dieses Posts hauptsächlich an deutschsprachige Entwickler richtet verfasse ich diesen Post auf Deutsch. Es wird einer von mehreren sein, da ich dieses Thema in nacher Zukunft etwas ausführlicher bearbeiten werde. Durch Zufall bin ich bei der suche nach einer API für die Zugdaten der Deutschen Bahn auf ein sehr interessantes Projekt der Süddeutschen Zeitung (SZ) gestoßen. Es handelt sich um den Zugmonitor, der Verspätungen in nahe zu Echtzeit visualisiert und sehr erfreulicherweise auch eine API bereitstellt um mit diesen Daten zu arbeiten.
Sep 8, 2012
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Die Reiseauskunft der Deutschen Bahn
oder wie fickt man RESTful-HTTP richtig. Die Deutsche Bahn betreibt seit Jahren ein Auskunftsystem unter der Domain http://reiseauskunft.bahn.de/ dort kann man z.B. Tickets buchen, sich Verbindungen anzeigen lassen oder seit neustem auch einen Zug verfolgen. Damit kann z.B. rausfinden ob ein Zug pünktlich am Bahnhof ankommt. Eigentlich eine sinnvolle Sache, aber man kann sich keine Links auf einen Zug speichern. Denn das Webinterface der Bahn generiert immer neue URLs für die gleiche Zugnummer, diese sind auch nur eine bestimmte Zeit gültig, selbst ein einfacher refresh auf einer Ergebnisseite mit weiterführenden Links führt zu neugenerierten URLs.
Sep 7, 2012
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Get the size of an object graph at runtime
At first I have to put a big fat disclaimer up in here: what I am discribing below is totally undocumented and unsupported by microsoft. It is based on findings while I was investigating issues with the MemoryCache in the System.Runtime.Caching assembly. I would not recommend any useage of this in a production software. If you decide to do so that is up to you, but there is no support for this from anyone and it is likly to break in the future, since it is based on internals of the CLR.
Sep 7, 2012
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Encapsulate function calls with Reflection.Emit
My current spare time project YAAF had some requirement that I need to intercept calls to a function. The interceptor then decides if the function gets called or not. But I wanted to parameters to be encapsulated, so the interceptor does not have access to them. The easiest way to do this was a simple delegate that will be passed to the interceptor and represents the complete context needed to call the callee when the interceptor decides to do so.
Aug 6, 2012
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Decouple your dependencies
In my spare time I am working on a metro style app for geekli.st, which I wanted to write with CSharp. Since I don’t wanted to create hole REST API bindings by myself, I had a look at the official API-wrappers and found the CSharp bindings for geekli.st by Scott Smith. But there was a problem, there was no Windows Runtime version of it. This was not caused by the code itself, it where its dependencies.
Aug 6, 2012
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Happy Birthday omegatau
Well this is my first post on a non software development topic and I would like to say happy birthday to my favourite podcast omegatau for their 100th episode. And I would like to thank Markus and Nora for this awesome project. I think my first episode was number 22 about nuclear fission in late 2009 and felt in love with it right at that point. In the following years there were so many awesome episodes that I would recommend you to listen to each of them, but as always I have some favourites.
Aug 2, 2012
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Yet another AOP framework
In past years I was working with different aspect oriented frameworks. A lot with postsharp in its early days when it was open source and then changed its license to a more closed model. I have helped project to use aop to allow easier development and write less but expressive code that is just focused on the work it should do. I often used ready to use frameworks like postsharp or spring-aop to get that work done but those tools are pretty powerful and that might become a problem when the people in the project aren’t familiar with aop, then they start seeing nails everywhere and want to hammer them with aop.
Jul 27, 2012
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Typesafe interop with native function pointers
The current project I did for a customer faced me with tons of legancy code which was written in C++ years back. This code is supposed to die at some point, but due some requirements the code needed to interact with some .Net / C# with COM Interop. The code uses a lot of function pointers passed to the callee to supply callbacks for logging and user notification. Exposing events for interaction from .
Jul 18, 2012
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