XML Bombs

Here is an example inline DTD. Notice how the company declaration acts as a simple string substitution macro. This is a safe and helpful use of inline DTDs.

An XML file with an inline DTD

   <?xml version="1.0"?>
<!DOCTYPE employees [
  <!ELEMENT employees (employee)*>
  <!ELEMENT employee (#PCDATA)>
  <!ENTITY company "Rock and Gravel Company">
]>
<employees>
  <employee>
    Fred Flintstone, &company;
  </employee>
  <employee>
    Barney Rubble, &company;
  </employee>
</employees> 

The Expanded XML File

   <?xml version="1.0"?>
<employees>
  <employee>
    Fred Flintstone, Rock and Gravel Company
  </employee>
  <employee>
    Barney Rubble, Rock and Gravel Company
  </employee>
</employees> 