constructor( parent = null ) {

		super();

		/**
		 * List of nodes.
		 *
		 * @type {Array<Node>}
		 */
		this.nodes = [];

		/**
		 * The output node.
		 *
		 * @type {?Node}
		 * @default null
		 */
		this.outputNode = null;

		/**
		 * The parent stack node.
		 *
		 * @type {?StackNode}
		 * @default null
		 */
		this.parent = parent;

		/**
		 * The current conditional node.
		 *
		 * @private
		 * @type {ConditionalNode}
		 * @default null
		 */
		this._currentCond = null;

		/**
		 * The expression node. Only
		 * relevant for Switch/Case.
		 *
		 * @private
		 * @type {Node}
		 * @default null
		 */
		this._expressionNode = null;

		/**
		 * This flag can be used for type testing.
		 *
		 * @type {boolean}
		 * @readonly
		 * @default true
		 */
		this.isStackNode = true;

	}
Constructs a new stack node.

@param {?StackNode} [parent=null] - The parent stack node.