Cyclone Scheme is a brand-new compiler that allows real-world application development using the R7RS Scheme Language standard. We provide modern features and a stable system capable of generating fast native binaries.

Cheney on the MTA is used by Cyclone’s runtime to implement full tail recursion, continuations, and generational garbage collection. In addition, the Cheney on the MTA concept has been extended to allow execution of multiple native threads. An on-the-fly garbage collector is used to manage the second-generation heap and perform major collections without “stopping the world”.


Try in your Browser

You can run the Cyclone interpreter right in your browser. No installation required.


For the full user experience - compiling files, installing packages, running native code, etc - it is necessary to install a copy of Cyclone.

There are several installation options available:



Cyclone can be run from a Docker Image:

docker run -it cyclonescm/cyclone bash



Mac (and Linux!) users wanting to use Homebrew can do the following.

Note if Homebrew is not already installed: follow the instructions at to install the homebrew package manager.

brew tap cyclone-scheme/cyclone
brew install cyclone-scheme/cyclone/cyclone-bootstrap

Arch Linux

Arch Linux

Arch Linux users can install using the AUR:

git clone
cd cyclone-scheme
makepkg -si

Gentoo Linux

Gentoo Linux

Cyclone is available from the official Gentoo package repository.

Build from Source

Build from Source

To install Cyclone on your machine for the first time on Linux, Windows, FreeBSD, and for Mac users wanting to install without using Homebrew, use cyclone-bootstrap to build a set of binaries. Instructions are provided for Linux, Mac, Windows (via MSYS), and FreeBSD 12.

Getting Started

After installing you can run the cyclone command to compile a single Scheme file:

$ cyclone examples/fac.scm
$ examples/fac

And the icyc command to start an interactive interpreter. Note you can use rlwrap to make the interpreter more friendly, EG: rlwrap icyc:

$ icyc

       @@     @@     Cyclone Scheme->C compiler
       @@     #@     (c) 2014-2019 Justin Ethier
       `@@@#@@@.     Version 0.11
cyclone> (write 'hello-world)

Read the documentation below for more information on how to use Cyclone.

Package Manager

Cyclone Winds

The winds package manager provides the ability to install packaged libraries and programs for Cyclone. See the winds site for more information.


Example Programs

Cyclone provides several example programs, including:

Compiler Internals


Copyright (C) 2014 Justin Ethier.

Cyclone is available under the MIT license.

Recent News

Released Cyclone Scheme 0.35.0

August 25, 2022
Various bug fixes to core functionality.

Released Cyclone Scheme 0.34.0

January 2, 2022
Allow for more complete sandboxing when bootstrapping the compiler, and various bug fixes for libraries.

Released Cyclone Scheme 0.33.0

September 24, 2021
Allow easier macro debugging from the REPL using expand.