node *get_link(int link_number) const;
//!< Returns the node that is connected to the specified "link_number".
- /*!< if the link is not set, then NIL is returned. */
+ /*!< if the link is not set, then NULL_POINTER is returned. */
void zap_link(int link_number);
//!< the specified link is removed from the node.
- void insert_link(int where, node *to_add = NIL);
+ void insert_link(int where, node *to_add = NULL_POINTER);
//!< adds a new link prior to the position specified in "where".
/*!< thus a "where" value of less than or equal to zero will add a new
link as the first element. a "where" value greater than or equal to