With a sound foundation in XML theory behind you, it's now time to address the other half of the jigsaw - actually converting all that marked-up data into something useful. This first article in a two-part series examines the need, rationale and basic concepts of XSLT, the Extensible Stylesheet Language for Transformations, with sample code and examples.
Now, since this data follows a very simple structure, and moreover I'm not very concerned about the order in which the various records appear, I can format it and present it as HTML with just two XSLT template rules:
The first rule locates the document element and places the standard HTML headers and footers in the corresponding positions in the result tree. Next, the
instruction processes all the children of this node - in this case, these are
all "record" elements, for which there is a corresponding template rule. Each time a record is located via the "record" element, the template rule is invoked and a new fragment added to the result tree. At the end of the process, a composite tree is built out of all the different chunks - and it looks like this:
And that just about covers the essential concepts behind XSL transformations. In the second part of this article, I will be looking at a few of XSLT's more advanced constructs, demonstrating how to add loops and conditional tests to your XSLT templates.
Note: All examples in this article have been tested on Microsoft Internet Explorer 5.5 and Saxon 6.4.3. Examples are illustrative only, and are not meant for a production environment. YMMV!