I am enclosing some functions that I use quite a bit in my Lisp programming. They might be useful to include in SLIME. The first 2 are based on functions originally written by Paul Foley. If you want to include them, I would suggest binding insert-balanced-comments to "C-c C-;" and remove-balanced-comments to "C-c C-:". The third function uses font-lock to visually transform the word "lambda" to the Greek lambda character. Someone who wants to use this function would typically add it in for the specific mode. For example: (add-hook 'lisp-mode-hook (lambda () (slime-mode t) (pretty-lambdas))) Here are the 3 functions: (defun insert-balanced-comments (arg) "Insert a set of balanced comments around the s-expression containing the point. If this command is invoked repeatedly (without any other command occurring between invocations), the comment progressively moves outward over enclosing expressions. If invoked with a positive prefix argument, the s-expression arg expressions out is enclosed in a set of balanced comments." (interactive "*p") (save-excursion (when (eq last-command this-command) (when (search-backward "#|" nil t) (save-excursion (delete-char 2) (while (and (< (point) (point-max)) (not (looking-at " *|#"))) (forward-sexp)) (replace-match "")))) (while (> arg 0) (backward-char 1) (cond ((looking-at ")") (incf arg)) ((looking-at "(") (decf arg)))) (insert "#|") (forward-sexp) (insert "|#"))) (defun remove-balanced-comments () "Remove a set of balanced comments enclosing point." (interactive "*") (save-excursion (when (search-backward "#|" nil t) (delete-char 2) (while (and (< (point) (point-max)) (not (looking-at " *|#"))) (forward-sexp)) (replace-match "")))) (defun pretty-lambdas () (font-lock-add-keywords nil `(("(\\(lambda\\>\\)" (0 (progn (compose-region (match-beginning 1) (match-end 1) ,(make-char 'greek-iso8859-7 107)) nil))))))