RELAX NG

W3C XML Schema Type Library

W3C XML Schema simple types required several chapters in my XML Schema (O’Reilly) book to explain completely, but I’ll try to give a brief overview here so that you can use the basic features within RELAX NG schemas. You will find additional detail about the simple types’ definitions in Chapter 9 and Chapter 19, and you are of course welcome to read Chapter 4, Chapter 5, Chapter 6, and Chapter 16 of my XML Schema book to get a deeper understanding of their behavior.

The W3C XML Schema datatypes that can be used in a RELAX NG schema are the predefined W3C XML Schema types—those defined in the W3C XML Schema Recommendation itself as opposed to user-defined types, which are derived from the predefined types using the W3C XML Schema language and can’t be used from a RELAX NG schema. You’ll see that restrictions (called facets in the terminology of W3C XML Schema) can be applied to these datatypes using the RELAX NG param pattern, so some customization is possible.

Tip

RELAX NG’s support for named patterns makes it effectively possible to derive types from W3C XML Schema simple types despite RELAX NG’s lack of support for the W3C XML Schema type derivation system. This might be a bit confusing right now, but it will become clearer with examples; RELAX NG borrows the most basic part of W3C XML Schema datatypes without borrowing its syntax or its derivation methods.

The Datatypes

The W3C XML Schema predefined datatypes are divided into primitive and derived types. ...