Skip to content

An implementation of the Self programming language in Zig


Notifications You must be signed in to change notification settings


Repository files navigation


Discord badge

An implementation of the Self programming language with an actor model.

What is Self?

Self is a programming language designed in 1986 at Xerox PARC. It is an object-oriented programming language which uses prototype-based inheritance as its basis and message-passing as its execution method. It is dynamically (but strongly) typed.

Self uses an image-based approach for runtime. All the objects in the system are stored in a Self world and turned into a snapshot for saving. At runtime, objects can be interacted with, created and destroyed without losing state on other objects.

What is zigSelf?

zigSelf takes the good parts of Self (the global object hierarchy, the image-based workflow, the visual programming, behavior sharing with parent slots, ...), and leaves the bad parts behind (the ancient UI, cooperative scheduling, ...). It also introduces an actor system inspired by Erlang to replace the cooperative scheduling of the previous version and to bring some structure to the system.

zigSelf does not use the world provided with the original Self distribution, but instead has its own. It also has a few quality-of-life changes to the syntax that I've found to be useful, such as the ; operator that allows for easier chaining of keyword messages.

Currently, zigSelf doesn't have the visual programming environment nor the snapshot system, but they are planned.

Build-time requirements

You need the Zig compiler, preferably one built with the known-good version commit. You can find the source code, instructions for building, and more on the Zig repository.

Latest Zig commit known to work is 5cd7fef17. Earlier and later versions may work but there are no guarantees.

Building zigSelf

  1. Clone the repository: git clone
  2. Run the code: zig build run -- examples/fibonacci.self

That's it! If you want to build a release version, you can build one with zig build -Doptimize=ReleaseFast and the binary will be in zig-out/bin/.

There is an (experimental) REPL that you can run with zig build run -- repl.self.

Building for Wasm

ZigSelf is able to run as a WebAssembly module via WASI. To build it, add the wasm32-wasi target when building: zig build -Dtarget=wasm32-wasi

You can then run the resulting executable at zig-out/bin/self.wasm with Wasmtime. Currently ZigSelf does not support loading Self code via stdin, so you will need to give it filesystem access like so: wasmtime --mapdir=.::. zig-out/bin/self.wasm <script name>


All contributions are welcome! Please follow the contribution guidelines for details.


zigSelf is licensed under the GNU General Public License version 3, so that the VM implementation remains open for everyone including end-users to study, modify and share. See LICENSE for more details.