Gforth is a fast and portable implementation of the ANS Forth language. It works nicely with the Emacs editor, offers some nice features such as input completion and history and a powerful locals facility, and it even has (the beginnings of) a manual. Gforth employs traditional implementation techniques: its inner innerpreter is indirect or direct threaded. Gforth runs under Unix, Win95, OS/2, and DOS and should not be hard to port to other systems supported by GCC.
Bigloo is an implementation of the Scheme programming language. It relies on an optimizing compiler from Scheme to C. Bigloo enables connections between Scheme code and C code. It proposes many extensions to Scheme such as a regular parser compiler, an lalr parser compiler, pattern matching, an object layer, etc.
EGSL is a small interpreter which can execute Lua scripts. It includes some functions for fast and easy game development. These are image manipulation functions, functions for 2D drawing, sound and music, input via mouse, keyboard, and joypad, and some helper functions. The engine is based on SDL, SDL_gfx, and SDL_mixer, and additionally on SDL_image on Haiku-OS.
Pike is an interpreted, object-oriented, dynamic programming language with a syntax similar to C. It includes a powerful modules system that, for instance, has image manipulation, database connectivity and advanced cryptography. It is simple to learn, does not require long compilation passes and has powerful built-in data types allowing simple and fast data manipulation.
Steel Bank Common Lisp is a development environment for Common Lisp, with excellent support for the ANSI standard: garbage collection, lexical closures, powerful macros, strong dynamic typing, incremental compilation, and the famous Common Lisp Object System (multimethods and all). It also includes many extensions, such as native threads, socket support, a statistical profiler, programmable streams, and more. These are all available through an integrated, interactive native compiler which feels like an interpreter. SBCL is unique in being a multiplatform native compiler which bootstraps itself completely from source, using a C compiler and any other ANSI Common Lisp implementation.
ROOT is an OO framework for large-scale scientific data analysis and data mining. It contains an efficient hierarchical OO database, a C++ interpreter, advanced statistical analysis, visualization, introspection, documentation, networking, and GUI classes. The command/scripting language is C++, and large scripts can be compiled and dynamically linked in. Using the PROOF (Parallel ROOT Facility) extension, large databases can be analyzed in parallel. The system runs on all known POSIX platforms, Windows, and MacOS X.
AFNIX is a multi-threaded functional writing system with dynamic symbol bindings that support the object oriented paradigm. It has a rich set of features providing runtime compatibility with C++. The engine runs on both 32- and 64-bit platforms, and it is designed to be portable across platforms.