XML Schema Reference
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Select one of these online reference categories:
The XML Schema Complete Reference
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XML Schema - Regular ExpressionsA regular expression is a pattern for identifying a range of string values. This pattern conforms to a specific grammar. The Schema Recommendation suggests that an XML validator should implement "Level 1" regular expressions as defined in the Unicode Regular Expression Guidelines. In this text, the term expression (without "regular") indicates a regular expression snippet, or a subset of a regular expression. An expression may match one or many characters. An expression may comprise an entire regular expression. XML Schema regular expressions are similar to other well-known regular expressions, such as might be found in UNIX or Perl. Examples:
The following links (to this page) reference tables that contain information about all of the special regular expression characters: XML Schema - Regular Expression - Meta Characters
XML Schema - Regular Expressions - Individual CharactersXML Schema - Regular Expressions - Normal CharactersA regular expression that contains the majority of characters that one normally types into a keyboard (e.g., 'qwerty') matches exactly those characters. The rest of this page describes special escape sequences and more. Be aware that negating a regular expression with "normal" characters might provide surprising results. For example, The regular expression '[^A-Z]' matches, among other things, a Greek or Japanese letter. XML Schema - Regular Expressions - Single Character Escape Sequence
XML Schema - Regular Expressions - Multiple Character Escape Sequences
XML Schema - Regular Expressions - Character CategoriesA regular expression can match a character by using a character category. The expression can be inclusive or exclusive of the character category. A regular expression must escape a character category. An inclusive character category that represents any uppercase letter looks like the following:
\p{Lu}
An exclusive category that represents any character except an uppercase letter looks like the following:
\P{Lu}
Note that inclusive requires a lowercase 'p', whereas exclusive requires an uppercase 'P'.
XML Schema - Regular Expressions - Character BlocksThe Unicode Standard supports character blocks. A block is a range of characters set aside for a specific purpose. Some examples of these blocks are the characters for a language (such as Greek), the Braille character set, and various drawing symbols. The XML Schema Recommendation provides a regular expression mechanism for identifying characters that belong to a specific block of interest. The syntax for identifying a block is '\p{IsBlockName}', where 'BlockName' is a name from Table 14.13. Like the character categories, an uppercase 'P' (as in '\P{IsBlockName}') excludes the characters in that block. XML Schema - Regular Expressions - XML Character ReferencesAn expression may match a character by using the common XML character reference, which is a decimal number delimited by '&' and ';', or a hex number delimited by '&#' and ';'. For example, the uppercase letter 'Z' is referenced by the decimal representation 'Z' and the hex representation 'Z'. These numbers correspond directly to the characters documented in The Unicode Standard. |
