XML - XSLT

What is XSLT?

XSLT is a language used to transform XML documents into other formats, like:

Another XML file
HTML (for web pages)
Plain text
Even PDF (via intermediate formats)

Think of it like this:

XML is your data (like student records).
XSLT is your template/stylesheet.
You apply the XSLT to the XML to produce a new result, like an HTML table or another structured XML file.

Why use XSLT?

To display XML in a browser as HTML.
To convert one XML structure into another.
To extract only part of the XML data.
To reformat data for different systems.

Key Concepts of XSLT

1. XML Input

The data you want to transform.

<students>
  <student>
    <name>Alice</name>
    <grade>A</grade>
  </student>
  <student>
    <name>Bob</name>
    <grade>B</grade>
  </student>
</students>

2. XSLT Stylesheet

Defines how to transform the XML. It's written in XML too!

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
      xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <!-- Output HTML -->
  <xsl:output method="html"/>

  <!-- Match the root element -->
  <xsl:template match="/students">
    <html>
      <body>
        <h2>Student Grades</h2>
        <ul>
          <xsl:for-each select="student">
            <li>
              <xsl:value-of select="name"/> - 
              <xsl:value-of select="grade"/>
            </li>
          </xsl:for-each>
        </ul>
      </body>
    </html>
  </xsl:template>

</xsl:stylesheet>

XSLT Elements

Element	Purpose
`<xsl:stylesheet>` or `<xsl:transform>`	Root of the XSLT file
`<xsl:template match="...">`	Matches parts of the XML to transform
`<xsl:value-of select="..."/>`	Extracts the value of a node
`<xsl:for-each select="...">`	Loops over a set of nodes
`<xsl:if>`	Conditional logic
`<xsl:choose>` / `<xsl:when>` / `<xsl:otherwise>`	More complex conditionals
`<xsl:apply-templates>`	Applies other templates (recursive processing)