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 innerpreter is direct threaded with
several optimizations, but you can also use a traditional-style indirect
threaded interpreter.
