I’m starting Tiny Interpreters, a new blog and newsletter about learning how programming languages work by building tiny interpreters in Elm, one language feature at a time.
The project grew out of my own attempts to study programming language design and implementation. What finally made the subject feel approachable was working through small interpreters that introduced one meaningful feature at a time. Instead of confronting an entire compiler at once, I could follow each change through the language’s syntax, parser, abstract syntax, evaluator, errors, and tests.
Tiny Interpreters will take that approach and make the progression even more gradual. For each language feature, we’ll begin by deciding what it should mean and then follow that decision through a complete implementation. The goal is to keep each interpreter small enough that the important ideas remain visible while still showing how the parts of a language work together.
I’m using Elm because its custom types and pattern matching make the structures inside an interpreter explicit, while elm/parser gives us the tools to build complete implementations. I also think the ideas involved—representing programs as data, separating description from execution, modelling domains precisely, and testing behaviour against an intended meaning—are useful well beyond interpreters and compilers.
I’ve written an introductory article explaining the experiences that led to the project and the teaching approach I plan to follow:
Introducing Tiny Interpreters: Learn How Programming Languages Work Without Fighting the Dragon
The first technical article will be published on August 3, 2026. It will begin with a tiny but complete interpreter and establish the structure that later interpreters will extend.
You can also subscribe to the Tiny Interpreters newsletter, and I’ll send you the first article when it goes live.
I’d be interested to hear which ideas from programming language design or implementation have influenced how you write ordinary Elm programs, libraries, or tools.