LispMe - Newer versions here. Scheme system for the Palm Pilot PDA developed by Fred Bayer. KSM-Scheme - A R5RS Scheme interpreter which integrates with C, allowing calling of C functions and accessing C variables from Scheme. It provides a mechanism to load C shared libraries. It runs on x86 and PowerPC based Linux systems. QScheme - A fast, small Scheme interpreter which is mostly compliant with the R5RS standard. SXM, CXEMA - Portable Scheme implementation, conforms to IEEE/ANSI standard, supports all features of R5RS Report, many features of Chez Scheme and various SRFIs. Derived from XScheme: object system dropped, many changes, additions. Indiana University Scheme Repository: Implementations - Even more Scheme implementations freely available from the Indiana U. repository. T - Scheme-like language developed at Yale; is to Scheme rather as NIL is to Lisp; mainly of interest to historians and theoreticians. FTP for v3.1. Scheme 48 User's Guide - HTMLized by Margaret Fleck, one of the authors of Envision. 3DScheme - Two systems for Windows with built in "industrial-strength" solid modeler based on the ACIS solid modeler Geometric Modeling Kernel. EdScheme - Interpreter for Macintosh or Windows. Has "friendly and convenient interactive programming environment" with language sensitive editor, full documentation. [commercial, free 14 day download] The Ksi Scheme Interpreter - Ksi is a portable, embeddable Scheme implementation written in C. Unfortunately its documentation is all in Russian at this point. SIOD: Scheme in One Defun - Very small, portable implementation, has some database, Unix programming, CGI scripting extensions. Runs on DOS, Linux, Unix, Windows. Free source downloads. Scheme 48 - A small and portable implementation based on a bytecode interpreter designed to be used as a testbed for experiments in implementation techniques. TinyScheme - Based on Mini-Scheme, tiny implementation, almost a full R5RS Scheme. Goal: embedded scripting use, but works as standalone interpreter and extensible shell tool. Recent changes reduced executable size to about 64KB on Linux/x86. [BSD] Pocket Scheme - For MIPS, SH3, ARM-based Windows CE devices. Supports Aubrey Jaffer's SLIB, has initialization file for same, parenthesis-balancing text editor. Windows NT version exists. [Open Source, Artistic License] Inlab Scheme - A commercial Scheme which is freely available for non-commercial use on Linux and FreeBSD. It has support for several features like bitmap/greymap processing and can be used as a general tool for image processing, OCR or specialized optical object and pattern recognition. Bigloo - System with one goal: enable Scheme programming style where C(++) is usually needed; makes Scheme practical via features found in most normal languages but not Scheme and functional programming. Generators for C code, Java Virtual Machine, .NET bytecode. [Open Source, GPL] Chicken - A Scheme compiler which compiles a subset of R5RS into C. Uses the ideas presented in Baker's paper "Cheney on the MTA". It is highly portable, reasonably efficient and makes interfacing to C and C++ very easy. Kali Scheme - A distributed implementation of Scheme that permits efficient transmission of higher-order objects such as closures and continuations. Petite Chez Scheme - A complete Scheme system that is fully compatible with Chez Scheme but uses high-speed threaded interpreter technology in place of Chez Scheme's incremental native-code compiler. [Freeware] XLisp-Plus - Lisp version based on, and evolutionary improvement on, experimental XLisp. XLisp-Stat - Based on XLisp, but with built-in statistics support. Scheme 48 - Jonathan A. Rees's unofficial page: history, links, status. T Project - History with: downloads, contributors, timeline, publications, influence, users, successors, Olin history errata. By Jonathan A. Rees. T History - Fairly detailed, by Olin Shivers. Chez Scheme - Reliable, high performance implementation, by Cadence Research Systems. Free version exists. [Commercial] Elk: Scheme-based Extension Language Kit - Old site, last update 1997. Embeddable, reusable extension language subsystem for applications written in C/C++, also a useful standalone Scheme implementation with interfaces to POSIX, Unix, X11. Elk Scheme: The Extension Language Kit - New site. Embeddable, reusable extension language subsystem for programs coded in C/C++, also a useful standalone Scheme implementation with interfaces to POSIX, Unix, X11. CMU AI Repository Free/Shareware Scheme Implementations - Yet more Scheme implementations from the CMU AI Repository. Many of these are also available from the Indiana University Scheme Repository. Pico - Tiny, expressive; made to teach advanced computer science ideas to non-computer science students; mixes power of languages like Scheme, with standard infix notation known from calculus. Has: garbage collected tables (arrays), higher order functions, objects, meta programming, reflection. PC Scheme - Texas Instruments system for DOS OS; no longer maintained; download formats: source, executable/binary. EuScheme Sources - Small implementation of Level 0 EuLisp, downloads in formats: tar, tgz, zip. Pseudoscheme - Embeds Scheme in Common Lisp. Scsh FAQ - The FAQ for Scsh, the Scheme Shell. Scsh - Scheme Shell, broad-spectrum system programming environment for Unix, embedded in R5RS Scheme 48. Supports concurrent system programming, sophisticated I/O and automatic garbage collection for process resources. Pilo Visualization Tools for Scheme: PVTS - Simple interpreter, runs on Java VM, with 3 visual aids/tools to support learning functional programming via Scheme; has viewers (environment, function call, cons-cell), i.e., global environment, recursive trees, linked list. Description, thesis, screenshots, download. Open source, GPL. Schoca (Scheme for OCaml) - An implementation of the Scheme language in OCaml. The primary purpose of Schoca is the use as an embedded extension language in OCaml applications. [Open source, GPL] Gambit - A portable, high-performance implementation of Scheme based on an optimizing compiler by Marc Feeley. Developed at University of Montreal. Gauche - An R5RS Scheme implementation developed to be a handy script interpreter. Quick startup, built-in system interface, native multilingual support. [Open source, BSD license] Oaklisp - Object-oriented Scheme dialect with first-class types, multiple inheritance, lexically distributed method definitions. based on bytecode emulator, yet reasonably fast. Description, downloads, bibliography. [Open Source, GPL] MIT Scheme - From MIT, for many systems, has code library, includes most functionality of ANSI Standard Common Lisp (CLtL2), many low-level OS interactions. Distributed with system is LIAR (LIAR Imitates Apply Recursively), optimizing compiler that outputs native machine code, has Edwin interactive Emacs-derived editor written in pure Scheme and the subject of an MIT AI Lab Memo. Arguably one of the best Scheme systems available, unarguably one of largest. Major downfall: its not totally R5RS compliant, more so for hygienic macros and #f versus the empty list. Version 7.5 now available for x86 systems. SCM - A portable Scheme implementation written by Aubrey Jaffer. XLISP - A superset of the Scheme dialect of Lisp with extensions to support object-oriented programming. VSCM - A portable Scheme implementation written by Matthias Blume of Princeton University. No longer actively developed. Larceny Project - Simple, efficient Scheme run-time system, for SPARC architecture. Petit Larceny is portable and emits C, for Linux (Intel IA32), Macintosh OS X (PowerPC), Solaris (SPARC), Windows. Common Larceny runs on Microsoft Common Language Runtime (CLR), emits MS IL not native or C code.