Mark The Language To Explain The Design And Realization

Nowadays, the Internet is the most extensive system. And World Wide Web is the most widely used application. With the rapid development of WWW applications, more and more people want to fetch information from the Internet. Using embedded system, we can browse WWW easily. Normally, information spreaded on network is organized in various forms of Markup Languages. In this paper, we design and implement interpreters of several kinds of Markup Languages on embedded system.Firstly, we introduce the background of the project. Then clarify the general design. Finally, emphasize on the design and implementation of the browser's Markup Language interpreters. That is the key aspect of the browser design.An interpreter can be devided into parser and presentation. And Markup Language parser includes three parts: token, syntax and semantic analyzer. We use Flex to get a Tokenizer. And then, the realization of error tolerance function and later modification problem is simplified. Further, YACC is used to get a syntax analyzer. On one hand, it can correctly analyse the syntax of a document, on the other hand, all kinds of mistakes are considered. Semantic analysis is carried out during syntax analysis. An integrated UFO_syntax_tree is built. Moreover, all imformation expressed by the page is stored in the tree.The design of presentation part affects the impact of display directly. Accroding to the specifications of W3C and references of display results of the famous browsers IE and NETSCAPE, this system displays the pages elegantly and efficiently.We also discuss the rapidly developing language XML. Design and study one kind of XML interpreter. Referring to DTD, it can check the structure integrity and validness of the XML document simply.Finally, we conclude the thesis and list the future work.