Scheme 48 is an implementation of Scheme written by Richard Kelsey and Jonathan Rees. It is based on a byte-code interpreter and is designed to be used as a testbed for experiments in implementation techniques and as an expository tool.

The current version of Scheme 48 is 1.9.2 (released April 2014).

Kali is a distributed version of Scheme built on top of Scheme 48.

Instructions for getting the current development sources and building them are here.

Scsh (SCheme SHell) is a scripting and systems programming environment built on top of Scheme 48 and POSIX.

If you have questions about Scheme 48, please feel free to contact us at s48-info at s48 dot org.