Introduction

The XML Recursion Language, XRL, is a NetKernel service that supports the modular composition of structured XML documents.

XRL is a very powerful language that supports:

• Mapping public addresses onto internal private addresses,
• Reusable Widgets defined in separate XML documents,
• XML templating, and
• Structured XML document creation.

XRL may be used for regular XHTML web applications or for dynamic composition of arbitrary XML messages.

This tutorial provides a step-by-step guide which starts with address space mapping, introduces basic templating, examines push and pull widget design patterns, and ends with a demonstration of XRL as the foundation for an AJAX-style application.

All of the examples developed in this tutorial are available as source code in the directory[install]/modules/workbench/xrldemo/. Feel free to adapt and experiment with the code.

Table of Contents

Part 1: XRL Mapping Model

Part 2: XRL Template Recursion

Part 3: Composition

Part 4: XRL AJAX application example

XRL Reference Guide

A fast-track to XRL and a reference guide for the syntax is provided here.