TinyScheme is a lightweight Scheme interpreter that implements as large a subset of R5RS as possible without getting very large and complicated. It is meant to be used as an embedded scripting interpreter for other programs. As such, it does not offer IDEs or extensive toolkits although it does sport a small top-level loop, included conditionally. A lot of functionality in TinyScheme is included conditionally, and it allows multiple interpreter states to coexist in the same program without any interference between them. Foreign functions in C can also be added and values can be defined in the Scheme environment.
CodeApplet is a Java-based client-server system that is meant to be used for teaching computer programming online. It may be used with any language for which an appropriate Java class is written, and adding a new interpreter requires no recompilation of the main binaries. Users connect to different coding sessions on the server. Every session has one editor at a time, elected by privileged operators or the current editor. This editor may control a shared language interpreter and edit source files while the other users watch in realtime. Some languages also support local interpreters for personal experiments.
SISC is an extensible Java-based interpreter of the algorithmic language Scheme. It uses modern interpretation techniques and handily outperforms all existing Java interpreters (often by more than an order of magnitude). In addition, SISC is a complete implementation of the language. The entire R5RS Scheme standard is supported. This includes a full number tower including complex number support and arbitrary precision integers and floating point numbers, proper tail recursion, hygienic macros, and full support for first-class continuations (not just the escaping continuations found in many other systems).
QuantLib is a cross-platform, quantitative finance C++ library for modeling, pricing, trading, and risk management in real-life. It is also wrapped as Python/Ruby/Scheme modules. Extensions for Excel, R, and Mathematica are available. Other such extensions are under consideration. QuantLib offers tools that are useful both for practical implementation and for advanced modeling. It features market conventions, yield curve models, solvers, PDEs, Monte Carlo (low-discrepancy included), exotic options, VAR, and so on.
Industria is a collection of portable R6RS Scheme libraries for cryptography (AES, DES, Blowfish, HMAC, MD5, SHA-1, SHA-2, RSA, DSA, etc.), zip/gzip/zlib decompression, disassembly of amd64 machine code, Off-The-Record messaging, bytevector pack/unpack syntax, TLS connections via custom binary ports, and more.
Momoko is a generic, object-oriented, modular, extensible environment for creating multi-user environments. It is suitable for writing MUDs, servers, and community-based Web sites. It is written in pure Java and supports Java and Python as internal scripting languages. Momoko provides facilities for organizing objects into tree-based hierarchies, orthogonal persistence, a transparent distributed objects system, remote access to source code and user files via WebDAV, a telnet-enabled shell for manipulating the object database, and an integrated build process which can be triggered remotely.