Comment by lihaoyi

While this example is pretty dense, a "one page programming language interpreter" doesn't need to be so impenetrable. Here's a one-page (67 line) interpreter for a subset of the Jsonnet programming language, implemented in Scala:

- https://github.com/handsonscala/handsonscala/blob/v1/example...

From the top down, that snippet contains an AST definition, a parser, an object model, an evaluator, and an output serializer. This 67-line programming language interpreter is one of the projects in my book https://www.handsonscala.com/ (chapter 20), and while this example is minimal the same techniques were used for my production-ready Sjsonnet interpreter