When editing Lisp code, occasionally it\'s useful to entirely comment out a top-level definition, like this:
;(defun some-fn-which-is-broken (x)
; ...)
Just a side note:
The #+ and #- reader macros are pretty nice for commenting out sexps. They allow ignoring the following sexp, if the given symbol isn't/is found in *FEATURES*. Just pick a symbol not in *FEATURES*, and use it with #+ like this:
#+nil
(defun foo ()
...)
Now, the function definition will be ignored (unless NIL is in *FEATURES*, which is not very likely).