Read XSLT 2.0 and XPath 2.0 Programmer's Reference, 4th Edition Online
Authors: Michael Kay
Atoms
Atoms are the parts of a regular expression that match specified characters. The various options are defined by the syntax below.
Construct | Syntax |
atom | Char | charClass | backReference | ( ( regex ) ) |
Char | Any XML character except . \ ? * + | ∧ $ { } ( ) [ ] |
charClass | charClassEsc | charClassExpr | . | ∧ | $ |
charClassExpr | [ charGroup ] |
backReference | \ [1-9] [0-9]* |