+/** Each mode is implemented by ONE ModeHandler class.
+ * You must derive ModeHandler and add the child class to
+ * the list of modes handled by the ircd, using
+ * ModeParser::AddMode. When the mode you implement is
+ * set by a user, the virtual function OnModeChange is
+ * called. If you specify a value greater than 0 for
+ * parameters_on or parameters_off, then when the mode is
+ * set or unset respectively, std::string ¶meter will
+ * contain the parameter given by the user, else it will
+ * contain an empty string. You may alter this parameter
+ * string, and if you alter it to an empty string, and your
+ * mode is expected to have a parameter, then this is
+ * equivalent to returning MODEACTION_DENY.
+ */