Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.
Latest commit message
Commit time
January 21, 2023 09:51
March 13, 2022 04:46
November 8, 2022 16:25
March 22, 2022 08:22
November 12, 2021 19:31
November 22, 2022 08:26
June 1, 2018 12:25
June 16, 2020 11:04
November 17, 2022 09:15
November 17, 2022 09:15

SICL: A new Common Lisp Implementation

This is the main source code repository for SICL. It contains the compiler, standard library, and documentation.

What is SICL?

SICL is a new implementation of Common Lisp. It is intentionally divided into many implementation-independent modules that are written in a totally or near-totally portable way, so as to allow other implementations to incorporate these modules from SICL, rather than having to maintain their own, perhaps implementation-specific versions.

Quick Start

  1. Make sure you have installed the dependencies:

The bash script will do this work for you.

  1. Clone the source with git:

    $ git clone
    $ cd SICL
  2. Make sure the top-level directory can be found by ASDF.

  3. Compile the boot system as follows:

    (asdf:load-system :sicl-boot)
  4. Change the package for convenience:

    (in-package #:sicl-boot)
  5. Create an instance of the BOOT class:

    (defparameter *b* (boot))

    Bootstrapping may take a few minutes.

  6. Start a REPL:

    (repl *e5*)


Check the Documentation directory for more information.

Getting Help and Contributing

The SICL community members are usually on various IRC channels. There is now a dedicated channel called #sicl, but discussion can also be found on #commonlisp, and #clasp. All these channels are on the network.

Keep up on SICL by reading the IRC logs

If you want to contribute SICL, please read


SICL is primarily distributed under the terms of the BSD license.

See LICENSE-BSD for more details.