5 ==> Insert into your ~/.emacs or ~/.xemacs/init.el the following lines:
7 (autoload 'run-prolog "prolog" "Start a Prolog sub-process." t)
8 (autoload 'prolog-mode "prolog" "Major mode for editing Prolog programs." t)
9 (autoload 'mercury-mode "prolog" "Major mode for editing Mercury programs." t)
10 (setq prolog-system 'swi)
11 (setq auto-mode-alist (append '(("\\.pl$" . prolog-mode)
12 ("\\.m$" . mercury-mode))