with a period or other punctuation.
It is occasionally useful to tell the user where an error originated,
-even if @code{debug-on-error} is nil. In such cases, a lower-case
-Lisp symbol can be prepended to the error message. For example, the
-error message ``Invalid input'' could be extended to say
+even if @code{debug-on-error} is @code{nil}. In such cases, a
+lower-case Lisp symbol can be prepended to the error message. For
+example, the error message ``Invalid input'' could be extended to say
``some-function: Invalid input''.
@item