Research On The Semantics Of XML Family Languages

XML technology has been the standard of interchanging data on internet. As the developing of XML application has increased, there are many challenges around XML technologies: many specifications are still working drafts now. The languages standardization and consistency between specifications are main challenges. These problems are caused by the dependence between specifications: XML related specifications all use the datatype system of XML Schema, and operation on the logic structure of XML document, and use uniform XPath expressions.The formal semantics of programming languages can provide concise and precise language definition. It helps people not only to understand well the language, but also to standardization of language. Formal specification languages Z and Object-Z have used to describe the semantics of programming language. Object-Z extends the Z language with Object, and includes class and inheritance features. The semantics described by Object-Z is not only concise and precise, but also composable and reusable. When the language is enhanced, the semantics of language can be easily extended.In this thesis, we specify the semantics of XML family languages from the view of Object-Oriented of programming languages. Based on the interdependence between XML family languages, after analyzing the XML core specifications, firstly we model the common semantic constructs of XML family languages, for instance: XML Schema datatype, XML document datamodel and XPath expressions, then reuse these common semantic constructs to describe the semantics of concrete XML family language , for instance: XSLT and XQuery. The formal description uses Z and Object-Z notation. This Object-Oriented semantic model describes abstract syntax, static and dynamic semantics of each language construct as single Object-Z class. This highly structured semantic model is concise, composable and reusable. It satisfies the requirement of continue evolution of XML family languages.As XML is used by many international organizations as a standard interchanging data form, the importance of the processing technologies of XML document is increased. In this thesis, we have developed a new XML programming language XWalk. The name came from the application "walks" XML document tree, and updates the structure and content of nodes. The process model is same with document object model (DOM). XWalk belongs to the XML family languages; its semantics is described by reusing the common semantic constructs of XML family languages. XWalk language uses XML syntax, and has precise formal semantics. XWalk applications run by transforming to Java program. XWalk is at least as powerful as DOM, and as convenient to use as XSLT.