extern int get_number_or_range (char **);
+/* Accept a number and a string-form list of numbers such as is
+ accepted by get_number_or_range. Return TRUE if the number is
+ in the list.
+
+ By definition, an empty list includes all numbers. This is to
+ be interpreted as typing a command such as "delete break" with
+ no arguments. */
+
+extern int number_is_in_list (char *list, int number);
+
/* Skip leading whitespace characters in INP, returning an updated
pointer. If INP is NULL, return NULL. */