/**@constructor*/

function ChainNode(object, link) {

	this.value = object;

	this.link = link; // describes this node's relationship to the previous node

}

/**@constructor*/

function Chain(valueLinks) {

	this.nodes = [];

	this.cursor = -1;

	if (valueLinks && valueLinks.length > 0) {

		this.push(valueLinks[0], "//");

		for (var i = 1, l = valueLinks.length; i < l; i+=2) {

			this.push(valueLinks[i+1], valueLinks[i]);

		}

	}

}

Chain.prototype.push = function(o, link) {

	if (this.nodes.length > 0 && link) this.nodes.push(new ChainNode(o, link));

	else this.nodes.push(new ChainNode(o));

}

Chain.prototype.unshift = function(o, link) {

	if (this.nodes.length > 0 && link) this.nodes[0].link = link;

	this.nodes.unshift(new ChainNode(o));

	this.cursor++;

}

Chain.prototype.get = function() {

	if (this.cursor < 0 || this.cursor > this.nodes.length-1) return null;

	return this.nodes[this.cursor];

}

Chain.prototype.first = function() {

	this.cursor = 0;

	return this.get();

}

Chain.prototype.last = function() {

	this.cursor = this.nodes.length-1;

	return this.get();

}

Chain.prototype.next = function() {

	this.cursor++;

	return this.get();

}

Chain.prototype.prev = function() {

	this.cursor--;

	return this.get();

}

Chain.prototype.toString = function() {

	var string = "";

	for (var i = 0, l = this.nodes.length; i < l; i++) {

		if (this.nodes[i].link) string += " -("+this.nodes[i].link+")-> ";

		string += this.nodes[i].value.toString();

	}

	return string;

}

Chain.prototype.joinLeft = function() {

	var result = "";

	for (var i = 0, l = this.cursor; i < l; i++) {

		if (result && this.nodes[i].link) result += this.nodes[i].link;

		result += this.nodes[i].value.toString();

	}

	return result;

}

/* USAGE:

var path = "one/two/three.four/five-six";

var pathChain = new Chain(path.split(/([\/.-])/));

print(pathChain);

var lineage = new Chain();

lineage.push("Port");

lineage.push("Les", "son");

lineage.push("Dawn", "daughter");

lineage.unshift("Purdie", "son");

print(lineage);

// walk left

for (var node = lineage.last(); node !== null; node = lineage.prev()) {

	print("< "+node.value);

}

// walk right

var node = lineage.first()

while (node !== null) {

	print(node.value);

	node = lineage.next();

	if (node && node.link) print("had a "+node.link+" named");

}

*/