Io Dev Container

A Dev Container for experimenting with the Io programming language — no local setup required.

What is Io?

Io is a small, prototype-based language inspired by Smalltalk, Self, and Lisp. Everything is an object, and computation happens entirely through message passing. It's worth a look if you're curious about how far that idea can be taken.

"Hello, World!" println

What's inside

Component	Details
Io (CLI)	Built from source, runs via wasmtime as a WebAssembly binary
Io (browser REPL)	Served at http://localhost:8000, opens automatically on container start
WASI SDK v33	Used to compile Io to WASM
VS Code extensions	C/C++ tools, WebAssembly language support
Node.js / npm

Getting started

Prerequisites

• Docker
• VS Code with the Dev Containers extension

Open in Dev Container

1. Clone this repository
2. Open the folder in VS Code
3. When prompted, click Reopen in Container (or run Dev Containers: Reopen in Container from the command palette)

Or open it with DevPod for a IDE-agnostic alternative.

The browser REPL starts automatically and opens at http://localhost:8000.

Usage

Browser REPL — open http://localhost:8000 in your browser and start typing Io code.

CLI — open a terminal inside the container:

io

Io> 2 + 2
==> 4
Io> list(1, 2, 3) select(x, x > 1) println
==> list(2, 3)

Run a file:

io hello.io

License

MIT