对XPath模式定位能力的扩充

EXTENSION OF PATTERN LOCATING CAPABILITY IN XPATH

基于一般结构模式的定位手段对一个完备的面向 XML文档内容的定位机制来说是重要的 ,而 XPath在这方面还有所欠缺 .首先通过实例分析阐明了 XPath提供基于一般结构模式的定位手段的必要性 ,随后通过一些扩充定义来改善它的表示能力 .扩充从概念、语法描述和执行机制 3个方面展开 ,概念上 ,引入了结点序列模式和结点正则表达式的定义 ;语法描述上 ,为 XPath扩充了数据类型 N Regex Type和结点序列模式匹配函数 match;执行机制上 ,定义了一个用于分析结点序列模式匹配过程的形式化自动机 .

XPath is deficient in locating method based on general structures, which is important for a complete XML document oriented query mechanism. Examples first are illustrated to elucidate the need to make the extensions and then some extensions are made for XPath. The extensions are developed from three perspectives. From the perspective of concept, definitions of node sequence pattern and node regular expression are introduced. From the perspective of syntax description, a data type called “NRegexType” and a function called “match” are extended into XPath. From the perspective of execution mechanism, a formal automaton is defined, which is used to analyze the recognition process for node sequence patterns.