to the main page... about these slides...

Motivation

- name clashes.

Consider an XML language WidgetML which uses XHTML as a sublanguage for help messages:

<widget type="gadget">
  <head size="medium"/>
  <big><subwidget ref="gizmo"/></big>
  <info>
    <head>
      <title>Description of gadget</title>
    </head>
    <body>
      <h1>Gadget</h1>
      A gadget contains a big gizmo
    </body>
  </info>
</widget>

Meaning of head and big depends on context!

This complicates things for processors and might even cause ambiguities.

The problem is: one common name-space.