Managing complex documents over the WWW: A case study for XML

The use of the World Wide Web as a communication medium for knowledge engin eers and software designers is limited by the lack of tools for writing, sh aring, and verifying documents written with design notations. For instance, the Z language has a rich set of mathematical characters, and requires gra phic-rich boxes and schemas for structuring a specification document. It is difficult to integrate Z specifications and text on WWW pages written with HTML, and traditional tools are not suited for the task. On the other hand , a newly proposed standard for markup languages, namely XML, allows one to define any set of markup elements; hence, it is suitable for describing an y kind of notation. Unfortunately, the proposed standard for rendering XML documents, namely XSL, provides for text-only (although sophisticated) rend ering of XML documents, and thus it cannot be used for more complex notatio ns. We present a Java-based tool for applying any notation to elements of X ML documents. These XML documents can thus be shown on current-generation W WW browsers with Java capabilities. A complete package for displaying Z spe cifications has been implemented and integrated with standard text parts. B eing a complete rendering engine, text parts and Z specifications can be fr eely intermixed, and all the standard features of XML (including HTML links and form elements) are available outside and inside Z specifications. Furt hermore, the extensibility of our engine allows any additional notations to be supported and integrated with the ones we describe here.