bigFORTH is a native code Forth. It was originally developed on the Atari ST for the Motorola 68k processor and was recently ported to Intel 386, running under a DOS extender (GO32). bigFORTH is available for Linux and Windows 95/98/NT in pre-beta-test. This version is available under GPL. The most striking new feature is the graphical user interface MINOS and the form editor Theseus. MINOS is a graphic user interface (GUI) for X, written for bigFORTH-Linux and bigFORTH-Win32. It includes a rapid GUI developement editor (Theseus).
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.
The Portable Forth Environment implements the ANSI Standard of the Forth programming language. It is fully written in C, and with gcc the virtual machine can be put into cpu registers. The newer development versions implement a set of modern features including modularization and multithreading. The terminal connection itself can be configured to work in an embedded environment.
4tH is a Forth compiler with a little difference. Instead of the standard Forth engine it features a conventional compiler. 4tH is a very small compiler that can create bytecode, C-embeddable bytecode, standalone executables, but also works fine as a scripting language. It supports about 95% of the ANS Forth CORE wordset and features conditional compilation, pipes, files, assertions, forward declarations, enumerations, structures, suspended execution, recursion, include files, etc. It comes with an RPN calculator, line editor, preprocessor, compiler, decompiler, C-source generator, a virtual machine, and a multitasking environment.
Factor is a dynamically-typed stack-based programming language. Factor runs on various OSes and CPU architectures, and provides an optimizing compiler, interactive development environment, powerful collections, higher order programming, continuations, and a growing library of contributed code.
RetroWeb is an extension for RetroForth intended to ease the task of creating Web pages. It is still close to HTML, but offers a more compact syntax. Most importantly, it allows you to work with the full power of Forth to generate HTML code. It can be used to create both static HTML files and simple dynamic CGI responses.