XML Schema Complete Reference, The

14.1. Concepts and Observations

The Unicode Standard is the basis of the character set for XML. Further, most software in the United States makes use of the Latin character subset. The following sections contain guidelines for regular expressions. They also provide a comparison to regular expressions in the Perl language, because many programmers are familiar with Perl. Finally, there is a brief overview of how regular expressions integrate into base and derived types in an XML schema.

14.1.1. Unicode Regular Expression Guidelines

The Unicode Regular Expression Guidelines is a technical report associated with The Unicode Standard. The Schema Recommendation suggests that an XML validator should implement “Level 1” regular expressions as defined ...