From the web site:
Tested on Linux and FreeBSD. Requires the S-Lang terminal library and Erlang/ OTP R7B or later.
Ermacs is now a part of the Jungerl, a “dense and chaotic Jungle of Erlang code” on Sourceforge.
The screenshot of the editor, which is all done in Erlang, should say it all.

Lisp:erlang-dired-mode.el – binding some key in dired mode if Emakefile is in current dired or parent dired . – by Joseph