ANSI/200x Forth interpreter and compiler
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, backtraces, a decompiler and a powerful locals facility, and it even has a manual. Gforth combines traditional implementation techniques with newer techniques for portability and performance: its inner interpreter is direct threaded with several optimizations, but you can also use a traditional-style indirect threaded interpreter.
Homepage: http://www.gnu.org/software/gforth/
Maintainer: Jasper Lievisse Adriaanse <jasper@openbsd.org>