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.
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.
MzScheme :
- Small, embeddable, scripting PLT Scheme implementation: R5RS compliant, full numerical tower, threads (all platforms), exceptions, modules, class-based objects, regular-expression matching, TCP/IP. For Macintosh, Unix, Windows 32-bit.
OScheme :
- Small, embeddable interpreter, mostly Scheme R4RS compliant, with extensions: supports prototype-based object model, some POSIX system calls, compilable in secure mode. Description, download, links.
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.
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.
Sketchy :
- Interpreter for pure functional applicative Scheme dialect, a variant of pure LISP plus global definitions (define), first-class continuations (call/cc), input/output functions (read, write, ...). Downloads: source, binaries. Sells: tutorial, reference manual.
STklos :
- Derived from STkn implementation based on an ad-hoc virtual machine, byte compiler; compilable as library to embed in other programs, has object system with MOP, multiple inheritance, generic functions, multimethods, module system, full R5RS tower of numbers, link to GTK+ X toolkit; almost R5RS compliant (in process), to support as many final SRFIs as possible, now supports SRFI-6.
T Revival Project :
- Scheme dialect and implementation, incompatible with R5RS, but an R3RS compatibility layer exists; to grow more compatible with R5RS over time. Description, manual, downloads, mail list, IRC, contacts, plans.