flatMap(Oslo) 2018
3-4 May 2018, Oslo Norway

Make your own meta-circular evaluator!


From building our own small evaluators we can learn about how programming languages are made and what kind of design decisions we can make when building languages, as well as about ideas and techniques that we can make use of in our everyday programming. More important: Making evaluators is lots of fun!

A meta-circular evaluator is an implementation of a programming language in an existing language, where the implementation “reuses” parts of the language it is implemented in. This lets us skip a lot of tedious plumbing, and we can quickly get a working new language implementation that we can play and experiment with.

In this workshop we will start with a simple evaluator for a “calculator-language” with basic arithmetic operations, and then gradually expand it into more and more sophisticated evaluators. We will end up with an evaluator for a language with special features for solving logic puzzles and constraint satisfaction problems, similar to the amb-evaluator in the book “Structure and Interpretation of Computer Programs.”

Jonas Winje

Jonas Winje


Jonas is a developer at Computas. He likes pretty animals and programming languages, and has an MSc in Computer Science from the University of Oslo. Dislikes things. (Also likes cute animals. (Some animals are pretty animals and are also cute animals.))

Heidi Mork

Heidi Mork


Heidi is a developer at NRK. She once studied mathematics and ended up with a PhD in algebraic geometry. But at some point she discovered programming and she has been enthusiastic about it ever since. Heidi finds most aspects of software development interesting, and is especially fond of functional programming and programming language theory.