Rope, Anyone?

Back in a previous lifetime when I worked as a consultant for Digital Equipment Corporation, we all loved using the VMS operating system. However, we also joked that it was so capable and flexible that it gave us a thousand different ways to hang ourselves. The W3C XML Schema language is very similar. You can write a nearly infinite number of schemas to describe any particular instance document. Every one of these schemas can provide an accurate description of the document, be loaded into a parser, and validate the document.

XML Schemas and the Formal Study of Grammars

The situation of multiple schemas being able to validate the same instance document is very analogous to a situation in the formal study of languages and automata ...

Get Using XML with Legacy Business Applications now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.