There is my diff mode for JED.
To use this, download diffmode.zip, and put
diffmode.sl, treemode.sl, and walk.sl somewhere in your JED_LIBRARY_PATH.
Then add to you .jedrc something like:
autoload("diff_mode", "diffmode"); add_mode_for_extension("diff", "patch");
Last Updated : Mon Apr 16 22:58:12 CEST 2007