javascript设计模式之解释器模式详解(6)

for (var i = 0, len = tempNodeList.length; i < len; i++) {
                    if ((nowEle = tempNodeList[i]).nodeType === 1) {
                        if (nowEle.nodeName === eleName) {
                            elements.push(nowEle);
                        }
                    }
                }

return elements;
            },
            getPreEles: function () {
                return this.preEles;
            },
            setPreEles: function (nowEles) {
                this.preEles = nowEles;
            },
            getDocument: function () {
                return this.document;
            }
        };

// 工具对象
        // 解析xml，获取相应的Document对象
        var XmlUtil = {
            getRoot: function (filePathName) {
                var parser = new DOMParser();
                var xmldom = parser.parseFromString('<root><a><b><c>12345</c><d>d1</d><d>d2</d><d>d3</d><d>d4</d></b></a></root>', 'text/xml');

return xmldom;
            }
        };

/**
         * 元素作为非终结符对应的解释器，解释并执行中间元素
         * @param {String} eleName [元素的名称]
         */
        function ElementExpression(eleName) {
            this.eles = [];
            this.eleName = eleName;
        }

ElementExpression.prototype = {
            addEle: function (eleName) {
                this.eles.push(eleName);
                return true;
            },
            removeEle: function (ele) {
                for (var i = 0, len = this.eles.length; i < len; i++) {
                    if (ele === this.eles[i]) {
                        this.eles.splice(i--, 1);
                    }
                }
                return true;
            },
            interpret: function (context) {
                // 先取出上下文中的当前元素作为父级元素
                // 查找到当前元素名称所对应的xml元素，并设置回到上下文中
                var pEles = context.getPreEles();
                var ele = null;
                var nowEles = [];