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.