Expressions of Change was a research project that aims to improve the tools for constructing ever-changing computer programs by putting the changes themselves central in the programming experience.

Below is a video with a 3-minute overview of the project.

Videos of longer talks are also available, as well as a textual explanation of the project’s status, motivation and goals.


NOTE: Klaas’ sabbatical ended May 2018 and he has returned to working life as a freelance software developer. Work on the project is paused until further notice.

The source code is available on Github (May 5, 2018)

The paper “Clef design: Thoughts on the Formalization of Program Construction” has been presented at the European Lisp Symposium 2018. (April 17, 2018)

I was honored to speak at the celebratory 100th edition of the Amsterdam Clojure Meetup. (March 14, 2018)

The video of the lightning talk at Lambda Days 2018 is up. (Febuary 20, 2018)