# Janet — Lightweight Embeddable Programming Language

> A functional and imperative Lisp dialect designed for embedding, scripting, system automation, and rapid prototyping with a tiny footprint.

## Install

Save in your project root:

# Janet — Lightweight Embeddable Programming Language

## Quick Use
```bash
# Install on macOS
brew install janet

# Install on Linux
sudo apt install janet  # or build from source

# Start the REPL
janet

# Run a script
echo '(print "Hello from Janet!")' > hello.janet
janet hello.janet
```

## Introduction
Janet is a small, portable, dynamically typed programming language inspired by Clojure, Lua, and Python. It is designed for embedding into C/C++ applications, writing build scripts, system automation, and rapid prototyping. The entire runtime compiles to a single C file with no external dependencies.

## What Janet Does
- Provides a Lisp-like language with familiar syntax for functional and imperative programming
- Embeds into C/C++ applications as a single-file library with a clean C API
- Includes a built-in module system, package manager (jpm), and PEG-based parser combinator
- Offers fibers and channels for lightweight concurrency without OS threads
- Compiles scripts to bytecode for faster loading and optional ahead-of-time compilation

## Architecture Overview
Janet compiles source code into bytecode that runs on a custom register-based virtual machine written in ANSI C. The runtime includes a mark-and-sweep garbage collector, a module loader, and an event loop for asynchronous I/O. The entire core is a single C file (~15K lines) with no dependencies beyond libc, making cross-compilation and embedding straightforward.

## Self-Hosting & Configuration
- Install via Homebrew, package managers, or compile from source with `make && sudo make install`
- Use `jpm` (Janet Project Manager) to manage dependencies and build projects
- Embed by including `janet.c` and `janet.h` in your C project — no separate library needed
- Configure the module search path via `JANET_PATH` environment variable
- Pre-compile scripts to images with `janet -c script.janet script.jimage` for faster startup

## Key Features
- Tiny runtime (~300 KB binary) suitable for resource-constrained environments
- PEG module for parsing grammars directly in Janet without external parser generators
- First-class fibers enabling cooperative multitasking and coroutine-based workflows
- Built-in networking, file I/O, and OS interaction for system scripting
- Comprehensive standard library covering data structures, regex, JSON, and more

## Comparison with Similar Tools
- **Lua** — Similar embedding niche; Janet offers richer data structures and a more modern standard library
- **Guile/Scheme** — More traditional Lisp; Janet is smaller and simpler to embed
- **Python** — Larger ecosystem; Janet is 100x smaller for embedding use cases
- **Fennel** — Lisp that transpiles to Lua; Janet has its own VM and does not depend on Lua

## FAQ
**Q: Is Janet a Lisp?**
A: Janet is Lisp-inspired with s-expression syntax but adds features from Clojure and Python. It uses brackets for arrays and braces for tables.

**Q: How do I add packages?**
A: Use `jpm install package-name`. Packages are listed in the Janet package index.

**Q: Can Janet replace Lua for game scripting?**
A: Yes. Janet's embedding API is similar to Lua's, and several game projects use Janet for scripting.

**Q: What platforms does Janet support?**
A: Janet runs on Linux, macOS, Windows, BSDs, and has been ported to embedded systems and WebAssembly.

## Sources
- https://github.com/janet-lang/janet
- https://janet-lang.org/

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Author: AI Open Source