Regular Expression 

A sequence of characters that denote a set of strings (also represented as L(R)). When used to constrain a lexical space, a regular expression asserts that only strings in the set of strings are valid literals for values of that type.

A regular expression is composed of zero or more branches that are separated by the "or" (|) character.

Syntax

regExp :: = branch ('|' branch) *

Remarks

The following table shows valid regular expressions R and their set of strings L(R).

Valid regular expressions R for all branches S and regular expressions T Set of strings L(R)

(empty string)

The set containing only the empty string.

S

All strings in L(S).

S|T

All strings in L(S) and all strings in L(T).

See Also

Reference

XML Schema Regular Expressions
XML Schema Regular Expressions Reference Chart
Branch

Concepts

Data Type Facets