====== Appendix E. Regular Expressions. ======

=== Summary of regular-expression constructs ===

^Construct^Matches^
^  Characters  ^^
|X|The character x|
|\\|The backslash character|
|\0n|The character with octal value 0n <nowiki>(0 <= n <= 7)</nowiki>|
|\0nn|The character with octal value 0nn <nowiki>(0 <= n <= 7)</nowiki>)|
|\0mnn|The character with octal value 0mnn <nowiki>(0 <= m <= 3, 0 <= n <= 7)</nowiki>|
|\xhh|The character with hexadecimal value 0xhh|
|\uhhhh|The character with hexadecimal value 0xhhhh|
|\t|The tab character ('\u0009')|
|\n|The newline (line feed) character ('\u000A')|
|\r|The carriage-return character ('\u000D')|
|\f|The form-feed character ('\u000C')|
|\a|The alert (bell) character ('\u0007')|
|\e|The escape character ('\u001B')|
|\cx|The control character corresponding to x|
^  Character classes  ^^
|[abc]|a, b, or c (simple class)|
|[abc]|Any character except a, b, or c (negation)|
|[a-zA-Z]|a through z or A through Z, inclusive (range)|
|[a-d[m-p]]|a through d, or m through p: [a-dm-p] (union)|
|[a-z&&[def]]|d, e, or f (intersection)|
|<nowiki>[a-z&&[^bc]]</nowiki>|a through z, except for b and c: [ad-z] (subtraction)|
|<nowiki>[a-z&&[^m-p]]</nowiki>|a through z, and not m through p: [a-lq-z](subtraction)|
^  Predefined character classes  ^^
|.|Any character (may or may not match [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#lt|line terminators]])|
|\d|A digit: [0-9]|
|\D|A non-digit: <nowiki>[^0-9]</nowiki>|
|\s|A whitespace character: [ \t\n\x0B\f\r]|
|\S|A non-whitespace character: <nowiki>[^\s]</nowiki>|
|\w|A word character: [a-zA-Z_0-9]|
|\W|A non-word character: <nowiki>[^\w]</nowiki>|
^  POSIX character classes (US-ASCII only)  ^^
|\p{Lower}|A lower-case alphabetic character: [a-z]|
|\p{Upper}|An upper-case alphabetic character:[A-Z]|
|\p{ASCII}|All ASCII:[\x00-\x7F]|
|\p{Alpha}|An alphabetic character:[\p{Lower}\p{Upper}]|
|\p{Digit}|A decimal digit: [0-9]|
|\p{Alnum}|An alphanumeric character:[\p{Alpha}\p{Digit}]|
|\p{Punct}|Punctuation: One of <nowiki>!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~ </nowiki>|
|\p{Graph}|A visible character: [\p{Alnum}\p{Punct}]|
|\p{Print}|A printable character: [\p{Graph}]|
|\p{Blank}|A space or a tab: [ \t]|
|\p{Cntrl}|A control character: [\x00-\x1F\x7F]|
|\p{XDigit}|A hexadecimal digit: [0-9a-fA-F]|
|\p{Space}|A whitespace character: [ \t\n\x0B\f\r]|
^  Classes for Unicode blocks and categories  ^^
| \p{InGreek}|A character in the Greek block (simple [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#ubc|block]])|
| \p{Lu}|An uppercase letter (simple [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#ubc|category]])|
| \p{Sc}|A currency symbol|
| \P{InGreek}|Any character except one in the Greek block (negation)|
|<nowiki>[\p{L}&&[^\p{Lu}]]</nowiki>|Any letter except an uppercase letter (subtraction)|
^  Boundary matchers  ^^
|<nowiki>^</nowiki>|The beginning of a line|
|$|The end of a line|
|\b|A word boundary|
|\B|A non-word boundary|
|\A|The beginning of the input|
|\G|The end of the previous match|
|\Z|The end of the input but for the final [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#lt|terminator]], if any|
|\z|The end of the input|
^  Greedy quantifiers  ^^
|X?|X, once or not at all|
|X*|X, zero or more times|
|X+|X, one or more times|
|X{n}|X, exactly n times|
|X{n,}|X, at least n times|
|X{n,m}|X, at least n but not more than m times|
^  Reluctant quantifiers  ^^
|X??|X, once or not at all|
|X*?|X, zero or more times|
|X+?|X, one or more times|
|X{n}?|X, exactly n times|
|X{n,}?|X, at least n times|
|X{n,m}?|X, at least n but not more than m times|
^  Possessive quantifiers  ^^
|X?+|X, once or not at all|
|X*+|X, zero or more times|
|X++|X, one or more times|
|X{n}+|X, exactly n times|
|X{n,}+|X, at least n times|
|X{n,m}+|X, at least n but not more than m times|
^  Logical operators  ^^
|XY|X followed by Y|
|<nowiki>X|Y</nowiki>|Either X or Y|
|(X)|X, as a [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#cg|capturing group]]|
^  Back references  ^^
|\n|Whatever the n<sup>th</sup>[[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#cg|capturing group]] matched|
^  Quotation  ^^
|\|Nothing, but quotes the following character|
|\Q|Nothing, but quotes all characters until \E|
|\E|Nothing, but ends quoting started by \Q|
^  Special constructs (non-capturing)  ^^
|(?:X)|X, as a non-capturing group|
|(?idmsux-idmsux)|Nothing, but turns match flags on - off|
|(?idmsux-idmsux:X)|X, as a [[http://java.sun.com/j2se/1.4.2/docs/api/java/util/regex/#cg|non-capturing group]] with the given flags on - off|
|(?=X)|X, via zero-width positive lookahead|
|(?!X)|X, via zero-width negative lookahead|
|<nowiki>(?<=X)</nowiki>|X, via zero-width positive lookbehind|
|(?<!X)|X, via zero-width negative lookbehind|
|(?>X)|X, as an independent, non-capturing group|