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STEP Modules
XML Repository Demo

Please send any comments or questions regarding these materials to Joshua Lubell at lubell@cme.nist.gov.

Overview | Instructions | Screen Shots | Related Sites


Overview

This modules repository demonstration prototype illustrates some of the benefits of representing modules using XML. In particular, it demonstrates how a module can be rendered dynamically in a Web browser environment in response to user input and independent of an HTTP server. The demo also includes a stylesheet which you can use to generate an HTML document from the XML.

The data used for the demo consists of the information requirements (ARM) from the 1999-05-11 draft of the Value_with_unit module. The information requirements are tagged in XML using a simple vocabulary for describing EXPRESS schemas. The XML tag set includes hooks for text descriptions of EXPRESS constructs and is thus able to represent all of the units of functionality and application objects in the module's "Information Requirements" clause.

Because the demo is completely client-driven, it exhibits the following desirable characteristics:

XML provides the following added benefits:

Simplified maintenance
Because XML allows for a STEP/EXPRESS-specific tag set, Value_with_unit can be represented as a single XML document. HTML, on the other hand, has a fixed non-application-specific tag set. If the demo had used HTML instead of XML for representing modules, achieving the same functionality would have required multiple HTML files per module and/or complicated scripting.
Ease of presentation
A single XML document can be easily presented in a variety of useful ways:

This demo requires a browser that supports XML, Level 2 Cascading Style Sheets, and the Document Object Model standard (see links). One such browser is Gecko, a developer preview of Netscape's next generation browser engine.

Instructions

To run the demo, do the following:

  1. View these screen shots to get a better idea of what the demo is about before attempting the subsequent steps.
  2. Download and install Gecko (see link) if it is not already on your system.
  3. Download demo.zip, a PKZIP-compatible file containing the XML, Javascript, and style sheet files needed for the demo. Unzip it, and look at the README file.
  4. Open arm.xml in Gecko. Click the various buttons on the web page to see the document's content change on the fly in response to user input.
  5. To convert arm.xml to HTML, use the XSL style sheet arm.xsl. You will need to use an XSL processor such as XT (see link).

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Last modified Mar 12, 2001.