Attendee preparation:
Bring a laptop with DrRacket (https://racket-lang.org/) installed.

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.”