Ash

An ANS Forth implementation in C with a JIT compiler.

Why Ash?

Ash begins with a small C kernel and grows in Forth.

The C layer provides only what is necessary to make Forth exist. Everything else should be written in Forth whenever possible.

Like ash left after a fire, the kernel is what remains after everything unnecessary has been removed.

A small C kernel. The rest is Forth.

Platform

Ash is implemented in C11 and targets POSIX systems.

The threaded interpreter and core runtime are intended to be portable across supported POSIX environments.

JIT compilation is architecture-specific. The initial JIT target is x86_64.

Implementation language: C11
Runtime platform:        POSIX
Initial JIT target:      x86_64

Forth semantics remain independent of the underlying JIT architecture.

Design

Ash is built around three explicit boundaries: semantic, execution, and optimization.

See docs/ASH_DESIGN.md for the execution model, dictionary layout, threaded interpreter, and C/Forth bootstrapping boundary.

Development

A Nix development shell is recommended for a reproducible environment.

nix develop

Ash is built with make.

make

The default compiler is cc. Both GCC and Clang should be supported.

make CC=gcc
make CC=clang

The project targets C11 and POSIX and avoids compiler-specific extensions where possible.

License

Copyright KEI SAWAMURA 2026.
Ash is licensed under the MIT License. Copying and modifying is encouraged and appreciated.