XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition (14 page)

I expand further on this concept in the section on Computational Stylesheets in Chapter 17, page 985.

Example: Displaying a Poem

Let's see how we can use the rule-based approach to format a poem. Again, we haven't introduced all the concepts yet, and so I won't try to explain every detail of how this works, but it's useful to see what the template rules actually look like in practice.

Input

Let's take this poem as our XML source. The source file is called
poem.xml
, and the stylesheet is
poem.xsl
.

Output

Let's write a stylesheet such that this document appears in the browser, as shown in
Figure 1-8
.

Figure 1-8

Stylesheet

It starts with the standard header.

Now we write one template rule for each element type in the source document. The rule for the

element creates the skeleton of the HTML output, defining the ordering of the elements in the output (which doesn't have to be the same as the input order). The

instruction inserts the value of the selected element at this point in the output. The

instructions cause the selected child elements to be processed, each using its own template rule.

In XSLT 2.0 we could replace the four

instructions with one, written as follows:

This takes advantage of the fact that the type system for the language now supports ordered sequences. The
,
operator performs list concatenation and is used here to form a list containing the