// base node class, to be used in a doubly linked list
var node:=class Value
(
	var dynamic datab;
	var dynamic nexti;
	var dynamic previ;
	
	var setdata:=method[toset]
	(
		datab:=toset;
	);
	
	var getdata:=method[] datab;
	
	var setnext:=method[tosetit]
	(
		nexti:=tosetit;
	);
	
	var getnext:=method[] nexti;
	
	var setprev:=method[toset]
	(
		previ:=toset;
	);
	
	var getprev:=method [] previ;
);