The Vim editor provides a syntax file for Forth, but it has words and issues that are specific to other implementations of the language, and it was confusing to see them highlighted. That's why some time ago I started my own version, specific for Gforth. I think it can be useful to other Vim users, and I've published it:
http://programandala.net/en.program.gforth_vim_syntax_file.html -- Marcos Cruz http://programandala.net
