GAP and Emacs users:
I have just finished writing a GAP process mode for running an interactive
GAP session in an Emacs buffer. This code is based on the GAP mode of Goetz
Pfeiffer, which I modified to use comint-mode instead of shell-mode.

GAP's command completion and help are available. Both the help and lists
of completions are shown in separate buffers from the GAP session, and help
can be evoked at any time (on any topic, defaulting to current command) by
pressing "?".

The file gap-process.el is available by anonymous ftp from pell.anu.edu.au
in directory pub/gnu/elisp. Note that it requires the comint-mode package
by Olin Shivers to work.

Follow the instructions in the comments at the start of the file for
installation instructions.

Cheers,
Michael.