Include RE2 library

third_party/re2/doc/syntax.txt

+RE2 regular expression syntax reference
+-------------------------­-------­-----
+
+Single characters:
+.       any character, including newline (s=true)
+[xyz]   character class
+[^xyz]  negated character class
+\d      Perl character class
+\D      negated Perl character class
+[:alpha:]       ASCII character class
+[:^alpha:]      negated ASCII character class
+\pN     Unicode character class (one-letter name)
+\p{Greek}       Unicode character class
+\PN     negated Unicode character class (one-letter name)
+\P{Greek}       negated Unicode character class
+
+Composites:
+xy      «x» followed by «y»
+x|y     «x» or «y» (prefer «x»)
+
+Repetitions:
+x*      zero or more «x», prefer more
+x+      one or more «x», prefer more
+x?      zero or one «x», prefer one
+x{n,m}  «n» or «n»+1 or ... or «m» «x», prefer more
+x{n,}   «n» or more «x», prefer more
+x{n}    exactly «n» «x»
+x*?     zero or more «x», prefer fewer
+x+?     one or more «x», prefer fewer
+x??     zero or one «x», prefer zero
+x{n,m}? «n» or «n»+1 or ... or «m» «x», prefer fewer
+x{n,}?  «n» or more «x», prefer fewer
+x{n}?   exactly «n» «x»
+x{}     (== x*) NOT SUPPORTED vim
+x{-}    (== x*?) NOT SUPPORTED vim
+x{-n}   (== x{n}?) NOT SUPPORTED vim
+x=      (== x?) NOT SUPPORTED vim
+
+Possessive repetitions:
+x*+     zero or more «x», possessive NOT SUPPORTED
+x++     one or more «x», possessive NOT SUPPORTED
+x?+     zero or one «x», possessive NOT SUPPORTED
+x{n,m}+ «n» or ... or «m» «x», possessive NOT SUPPORTED
+x{n,}+  «n» or more «x», possessive NOT SUPPORTED
+x{n}+   exactly «n» «x», possessive NOT SUPPORTED
+
+Grouping:
+(re)    numbered capturing group
+(?P<name>re)    named & numbered capturing group
+(?<name>re)     named & numbered capturing group NOT SUPPORTED
+(?'name're)     named & numbered capturing group NOT SUPPORTED
+(?:re)  non-capturing group
+(?flags)        set flags within current group; non-capturing
+(?flags:re)     set flags during re; non-capturing
+(?#text)        comment NOT SUPPORTED
+(?|x|y|z)       branch numbering reset NOT SUPPORTED
+(?>re)  possessive match of «re» NOT SUPPORTED
+re@>    possessive match of «re» NOT SUPPORTED vim
+%(re)   non-capturing group NOT SUPPORTED vim
+
+Flags:
+i       case-insensitive (default false)
+m       multi-line mode: ^ and $ match begin/end line in addition to begin/end text (default false)
+s       let «.» match «\n» (default false)
+U       ungreedy: swap meaning of «x*» and «x*?», «x+» and «x+?», etc (default false)
+Flag syntax is «xyz» (set) or «-xyz» (clear) or «xy-z» (set «xy», clear «z»).
+
+Empty strings:
+^       at beginning of text or line («m»=true)
+$       at end of text (like «\z» not «\Z») or line («m»=true)
+\A      at beginning of text
+\b      at word boundary («\w» on one side and «\W», «\A», or «\z» on the other)
+\B      not a word boundary
+\G      at beginning of subtext being searched NOT SUPPORTED pcre
+\G      at end of last match NOT SUPPORTED perl
+\Z      at end of text, or before newline at end of text NOT SUPPORTED
+\z      at end of text
+(?=re)  before text matching «re» NOT SUPPORTED
+(?!re)  before text not matching «re» NOT SUPPORTED
+(?<=re) after text matching «re» NOT SUPPORTED
+(?<!re) after text not matching «re» NOT SUPPORTED
+re&     before text matching «re» NOT SUPPORTED vim
+re@=    before text matching «re» NOT SUPPORTED vim
+re@!    before text not matching «re» NOT SUPPORTED vim
+re@<=   after text matching «re» NOT SUPPORTED vim
+re@<!   after text not matching «re» NOT SUPPORTED vim
+\zs     sets start of match (= \K) NOT SUPPORTED vim
+\ze     sets end of match NOT SUPPORTED vim
+\%^     beginning of file NOT SUPPORTED vim
+\%$     end of file NOT SUPPORTED vim
+\%V     on screen NOT SUPPORTED vim
+\%#     cursor position NOT SUPPORTED vim
+\%'m    mark «m» position NOT SUPPORTED vim
+\%23l   in line 23 NOT SUPPORTED vim
+\%23c   in column 23 NOT SUPPORTED vim
+\%23v   in virtual column 23 NOT SUPPORTED vim
+
+Escape sequences:
+\a      bell (== \007)
+\f      form feed (== \014)
+\t      horizontal tab (== \011)
+\n      newline (== \012)
+\r      carriage return (== \015)
+\v      vertical tab character (== \013)
+\*      literal «*», for any punctuation character «*»
+\123    octal character code (up to three digits)
+\x7F    hex character code (exactly two digits)
+\x{10FFFF}      hex character code
+\C      match a single byte even in UTF-8 mode
+\Q...\E literal text «...» even if «...» has punctuation
+
+\1      backreference NOT SUPPORTED
+\b      backspace NOT SUPPORTED (use «\010»)
+\cK     control char ^K NOT SUPPORTED (use «\001» etc)
+\e      escape NOT SUPPORTED (use «\033»)
+\g1     backreference NOT SUPPORTED
+\g{1}   backreference NOT SUPPORTED
+\g{+1}  backreference NOT SUPPORTED
+\g{-1}  backreference NOT SUPPORTED
+\g{name}        named backreference NOT SUPPORTED
+\g<name>        subroutine call NOT SUPPORTED
+\g'name'        subroutine call NOT SUPPORTED
+\k<name>        named backreference NOT SUPPORTED
+\k'name'        named backreference NOT SUPPORTED
+\lX     lowercase «X» NOT SUPPORTED
+\ux     uppercase «x» NOT SUPPORTED
+\L...\E lowercase text «...» NOT SUPPORTED
+\K      reset beginning of «$0» NOT SUPPORTED
+\N{name}        named Unicode character NOT SUPPORTED
+\R      line break NOT SUPPORTED
+\U...\E upper case text «...» NOT SUPPORTED
+\X      extended Unicode sequence NOT SUPPORTED
+
+\%d123  decimal character 123 NOT SUPPORTED vim
+\%xFF   hex character FF NOT SUPPORTED vim
+\%o123  octal character 123 NOT SUPPORTED vim
+\%u1234 Unicode character 0x1234 NOT SUPPORTED vim
+\%U12345678     Unicode character 0x12345678 NOT SUPPORTED vim
+
+Character class elements:
+x       single character
+A-Z     character range (inclusive)
+\d      Perl character class
+[:foo:] ASCII character class «foo»
+\p{Foo} Unicode character class «Foo»
+\pF     Unicode character class «F» (one-letter name)
+
+Named character classes as character class elements:
+[\d]    digits (== \d)
+[^\d]   not digits (== \D)
+[\D]    not digits (== \D)
+[^\D]   not not digits (== \d)
+[[:name:]]      named ASCII class inside character class (== [:name:])
+[^[:name:]]     named ASCII class inside negated character class (== [:^name:])
+[\p{Name}]      named Unicode property inside character class (== \p{Name})
+[^\p{Name}]     named Unicode property inside negated character class (== \P{Name})
+
+Perl character classes:
+\d      digits (== [0-9])
+\D      not digits (== [^0-9])
+\s      whitespace (== [\t\n\f\r ])
+\S      not whitespace (== [^\t\n\f\r ])
+\w      word characters (== [0-9A-Za-z_])
+\W      not word characters (== [^0-9A-Za-z_])
+
+\h      horizontal space NOT SUPPORTED
+\H      not horizontal space NOT SUPPORTED
+\v      vertical space NOT SUPPORTED
+\V      not vertical space NOT SUPPORTED
+
+ASCII character classes:
+[:alnum:]       alphanumeric (== [0-9A-Za-z])
+[:alpha:]       alphabetic (== [A-Za-z])
+[:ascii:]       ASCII (== [\x00-\x7F])
+[:blank:]       blank (== [\t ])
+[:cntrl:]       control (== [\x00-\x1F\x7F])
+[:digit:]       digits (== [0-9])
+[:graph:]       graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~])
+[:lower:]       lower case (== [a-z])
+[:print:]       printable (== [ -~] == [ [:graph:]])
+[:punct:]       punctuation (== [!-/:-@[-`{-~])
+[:space:]       whitespace (== [\t\n\v\f\r ])
+[:upper:]       upper case (== [A-Z])
+[:word:]        word characters (== [0-9A-Za-z_])
+[:xdigit:]      hex digit (== [0-9A-Fa-f])
+
+Unicode character class names--general category:
+C       other
+Cc      control
+Cf      format
+Cn      unassigned code points NOT SUPPORTED
+Co      private use
+Cs      surrogate
+L       letter
+LC      cased letter NOT SUPPORTED
+L&      cased letter NOT SUPPORTED
+Ll      lowercase letter
+Lm      modifier letter
+Lo      other letter
+Lt      titlecase letter
+Lu      uppercase letter
+M       mark
+Mc      spacing mark
+Me      enclosing mark
+Mn      non-spacing mark
+N       number
+Nd      decimal number
+Nl      letter number
+No      other number
+P       punctuation
+Pc      connector punctuation
+Pd      dash punctuation
+Pe      close punctuation
+Pf      final punctuation
+Pi      initial punctuation
+Po      other punctuation
+Ps      open punctuation
+S       symbol
+Sc      currency symbol
+Sk      modifier symbol
+Sm      math symbol
+So      other symbol
+Z       separator
+Zl      line separator
+Zp      paragraph separator
+Zs      space separator
+
+Unicode character class names--scripts:
+Arabic  Arabic
+Armenian        Armenian
+Balinese        Balinese
+Bengali Bengali
+Bopomofo        Bopomofo
+Braille Braille
+Buginese        Buginese
+Buhid   Buhid
+Canadian_Aboriginal     Canadian Aboriginal
+Carian  Carian
+Cham    Cham
+Cherokee        Cherokee
+Common  characters not specific to one script
+Coptic  Coptic
+Cuneiform       Cuneiform
+Cypriot Cypriot
+Cyrillic        Cyrillic
+Deseret Deseret
+Devanagari      Devanagari
+Ethiopic        Ethiopic
+Georgian        Georgian
+Glagolitic      Glagolitic
+Gothic  Gothic
+Greek   Greek
+Gujarati        Gujarati
+Gurmukhi        Gurmukhi
+Han     Han
+Hangul  Hangul
+Hanunoo Hanunoo
+Hebrew  Hebrew
+Hiragana        Hiragana
+Inherited       inherit script from previous character
+Kannada Kannada
+Katakana        Katakana
+Kayah_Li        Kayah Li
+Kharoshthi      Kharoshthi
+Khmer   Khmer
+Lao     Lao
+Latin   Latin
+Lepcha  Lepcha
+Limbu   Limbu
+Linear_B        Linear B
+Lycian  Lycian
+Lydian  Lydian
+Malayalam       Malayalam
+Mongolian       Mongolian
+Myanmar Myanmar
+New_Tai_Lue     New Tai Lue (aka Simplified Tai Lue)
+Nko     Nko
+Ogham   Ogham
+Ol_Chiki        Ol Chiki
+Old_Italic      Old Italic
+Old_Persian     Old Persian
+Oriya   Oriya
+Osmanya Osmanya
+Phags_Pa        'Phags Pa
+Phoenician      Phoenician
+Rejang  Rejang
+Runic   Runic
+Saurashtra      Saurashtra
+Shavian Shavian
+Sinhala Sinhala
+Sundanese       Sundanese
+Syloti_Nagri    Syloti Nagri
+Syriac  Syriac
+Tagalog Tagalog
+Tagbanwa        Tagbanwa
+Tai_Le  Tai Le
+Tamil   Tamil
+Telugu  Telugu
+Thaana  Thaana
+Thai    Thai
+Tibetan Tibetan
+Tifinagh        Tifinagh
+Ugaritic        Ugaritic
+Vai     Vai
+Yi      Yi
+
+Vim character classes:
+\i      identifier character NOT SUPPORTED vim
+\I      «\i» except digits NOT SUPPORTED vim
+\k      keyword character NOT SUPPORTED vim
+\K      «\k» except digits NOT SUPPORTED vim
+\f      file name character NOT SUPPORTED vim
+\F      «\f» except digits NOT SUPPORTED vim
+\p      printable character NOT SUPPORTED vim
+\P      «\p» except digits NOT SUPPORTED vim
+\s      whitespace character (== [ \t]) NOT SUPPORTED vim
+\S      non-white space character (== [^ \t]) NOT SUPPORTED vim
+\d      digits (== [0-9]) vim
+\D      not «\d» vim
+\x      hex digits (== [0-9A-Fa-f]) NOT SUPPORTED vim
+\X      not «\x» NOT SUPPORTED vim
+\o      octal digits (== [0-7]) NOT SUPPORTED vim
+\O      not «\o» NOT SUPPORTED vim
+\w      word character vim
+\W      not «\w» vim
+\h      head of word character NOT SUPPORTED vim
+\H      not «\h» NOT SUPPORTED vim
+\a      alphabetic NOT SUPPORTED vim
+\A      not «\a» NOT SUPPORTED vim
+\l      lowercase NOT SUPPORTED vim
+\L      not lowercase NOT SUPPORTED vim
+\u      uppercase NOT SUPPORTED vim
+\U      not uppercase NOT SUPPORTED vim
+\_x     «\x» plus newline, for any «x» NOT SUPPORTED vim
+
+Vim flags:
+\c      ignore case NOT SUPPORTED vim
+\C      match case NOT SUPPORTED vim
+\m      magic NOT SUPPORTED vim
+\M      nomagic NOT SUPPORTED vim
+\v      verymagic NOT SUPPORTED vim
+\V      verynomagic NOT SUPPORTED vim
+\Z      ignore differences in Unicode combining characters NOT SUPPORTED vim
+
+Magic:
+(?{code})       arbitrary Perl code NOT SUPPORTED perl
+(??{code})      postponed arbitrary Perl code NOT SUPPORTED perl
+(?n)    recursive call to regexp capturing group «n» NOT SUPPORTED
+(?+n)   recursive call to relative group «+n» NOT SUPPORTED
+(?-n)   recursive call to relative group «-n» NOT SUPPORTED
+(?C)    PCRE callout NOT SUPPORTED pcre
+(?R)    recursive call to entire regexp (== (?0)) NOT SUPPORTED
+(?&name)        recursive call to named group NOT SUPPORTED
+(?P=name)       named backreference NOT SUPPORTED
+(?P>name)       recursive call to named group NOT SUPPORTED
+(?(cond)true|false)     conditional branch NOT SUPPORTED
+(?(cond)true)   conditional branch NOT SUPPORTED
+(*ACCEPT)       make regexps more like Prolog NOT SUPPORTED
+(*COMMIT)       NOT SUPPORTED
+(*F)    NOT SUPPORTED
+(*FAIL) NOT SUPPORTED
+(*MARK) NOT SUPPORTED
+(*PRUNE)        NOT SUPPORTED
+(*SKIP) NOT SUPPORTED
+(*THEN) NOT SUPPORTED
+(*ANY)  set newline convention NOT SUPPORTED
+(*ANYCRLF)      NOT SUPPORTED
+(*CR)   NOT SUPPORTED
+(*CRLF) NOT SUPPORTED
+(*LF)   NOT SUPPORTED
+(*BSR_ANYCRLF)  set \R convention NOT SUPPORTED pcre
+(*BSR_UNICODE)  NOT SUPPORTED pcre
+