March 31, 2022 - 6:00 pm CEST

Virtual Meetup Jennek Geels and Niko Stotz


Last week, Robert Deckers introduced MuDForM, a method that turns the art of domain modeling into engineering practice. This week Jennek Geels and Niko Stotz will apply this method to a real-world case, show MPS-based tools to facilitate the method and sketch status and plans. At Canon Production Printing, we applied MuDForM to Specification by Example, giving “MuDForm based Specification by Example”.

Internally this is known as “xSBD” which stands for “executable System Behavior Document”. The objective of xSBD is to turn the art of Specification by Example into engineering practice.

Topics are:

– why we work with Specification by Example

– how we use MuDForm to scale up Specification by Example (1000+ scenarios)

We will look at two aspects of combining MuDForm and Specification by Example

  1. integrating the underlying model and notation
  2. integrating the steps and guidelines

Moreover, we will look at the prototype of the “xSBD workbench”, built by Niko Stotz in JetBrains MPS. The xSBD workbench is a collection of tools to support the various steps of the xSBD method. We will discuss some of the solutions and some of the struggles when working with MPS.


Jennek has spent most of his working life at Océ-Technologies, since 2020 known as Canon Production Printing (CPP). He has had a large variety of roles, always bridging the gap between customers and R&D. Starting to work with Smalltalk in 1985, he was actively doing DSLs well before that was a thing. Looking for ways to engage domain experts, in 1996 he embraced KISS, a method that provides steps and guidelines to begin with the informal conversation among domain experts and turn it into a consistent and complete domain model. KISS was way ahead of its time and did not survive as a company. However, Jennek kept the KISS method alive within CPP. One application of KISS named Sheela has become a core part of multiple CPP products. Since 2018 Jennek is working with Robert Deckers to apply MuDForM, which may be considered a successor to KISS.

Niko is a long-time expert in Language Engineering. He has worked on designing and implementing DSLs, first based on EMF technologies and now mostly based on MPS. He is currently continuing his work on Language Engineering at F1RE in the Netherlands.

How to join the event:

To avoid security issues is now necessary to register for the meeting. The registration should be necessary just once and be valid for all the next meetings you will participate in. Follow these steps:

  1. Register yourself to the community on the Homepage
  2. You will receive a confirmation email containing all the information about joining the meeting.
  3. Add to your calendar
  4. Enjoy the talk and, if you feel like it, discuss it further on the community forum