Dynamically Generated XSL Revisited
By Michael Floyd
In the January installment of this column, I demonstrated how to dynamically generate XSL style-sheet transformations, which can then be applied to XML documents. In that column, I assumed that the developer has intrinsic knowledge of the structure and organization, or "schema," of the data being transformed. That knowledge is important because style-sheet transformations often use simple step patterns (or even full-blown XPath expressions) to locate a given element or attribute in the document tree, then use <xsl:value-of> to retrieve the item's content. So, XSL style sheets are highly reliant on a document's structure.
By moving from statically created style sheets to dynamically generated transformations, you shift responsibility from the style-sheet author to the DOM developer. However, if you can generalize the process, you can realize significant benefits from generating your XSL dynamically.
The key to generalizing this process lies in the schema. If you have a formal schema, such as a DTD or XML Schema document, you should be able to discover enough about the organization and structure to generate a reasonable XSL style-sheet document.
This month, I'll examine that process and discuss how far you can take it. I wrote this article with the assumption that you, the developer, are familiar with XML Data Reduced (XDR) schemas, the XSL Transformation language (XSLT), and the Document Object Model (DOM) (Visit www3.org for more information).<>
