关键词: 可扩展标记语言（XML）, 树模式, XML树模式描述语言（XTPL）, 指称语义, 树模式提取

Abstract: As the core operation of XML (extensible markup language) query, tree pattern query has a broad application prospect. Its study has important significance. This paper presents a tree pattern description language XTPL (XML tree pattern language) for the GTP++ which is extended from generalized tree pattern, and uses denotational semantic to give the complete semantic description of XTPL. The denotational semantic of XTPL makes formal methods can be used for the analysis of tree pattern query in the behavior characteristic. It also conduces to verifying the correctness of XML query, and improves the reliability and robustness of query methods. Then, taking the path expression as an example, this paper presents a tree pattern extraction algorithm described by denotational semantic, which extracts tree pattern from path expressions.

Key words: extensible markup language (XML), tree pattern, XML tree pattern language (XTPL), denotational semantic, tree pattern extraction