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diff --git a/fluent-bit/lib/onigmo/doc/RE b/fluent-bit/lib/onigmo/doc/RE new file mode 100644 index 000000000..4d2cdaba3 --- /dev/null +++ b/fluent-bit/lib/onigmo/doc/RE @@ -0,0 +1,569 @@ +Onigmo (Oniguruma-mod) Regular Expressions Version 6.1.0 2016/12/25 + +syntax: ONIG_SYNTAX_RUBY (default) + + +1. Syntax elements + + \ escape (enable or disable meta character) + | alternation + (...) group + [...] character class + + +2. Characters + + \t horizontal tab (0x09) + \v vertical tab (0x0B) + \n newline (line feed) (0x0A) + \r carriage return (0x0D) + \b backspace (0x08) + \f form feed (0x0C) + \a bell (0x07) + \e escape (0x1B) + \nnn octal char (encoded byte value) + \xHH hexadecimal char (encoded byte value) + \x{7HHHHHHH} wide hexadecimal char (character code point value) + \uHHHH wide hexadecimal char (character code point value) + \cx control char (character code point value) + \C-x control char (character code point value) + \M-x meta (x|0x80) (character code point value) + \M-\C-x meta control char (character code point value) + + (* \b as backspace is effective in character class only) + + * ONIG_SYNTAX_PERL: \o{nnn} (octal char) can be also used. + + +3. Character types + + . any character (except newline) + + \w word character + + Not Unicode: + alphanumeric and "_". + + Unicode: + General_Category -- (Letter|Mark|Number|Connector_Punctuation) + + It depends on ONIG_OPTION_ASCII_RANGE option that non-ASCII char + includes or not. + + \W non-word char + + \s whitespace char + + Not Unicode: + \t, \n, \v, \f, \r, \x20 + + Unicode: + 0009, 000A, 000B, 000C, 000D, 0085(NEL), + General_Category -- Line_Separator + -- Paragraph_Separator + -- Space_Separator + + It depends on ONIG_OPTION_ASCII_RANGE option that non-ASCII char + includes or not. + + \S non-whitespace char + + \d decimal digit char + + Unicode: General_Category -- Decimal_Number + + It depends on ONIG_OPTION_ASCII_RANGE option that non-ASCII char + includes or not. + + \D non-decimal-digit char + + \h hexadecimal-digit char [0-9a-fA-F] + + \H non-hexadecimal-digit char + + + Character Property + + * \p{property-name} + * \p{^property-name} (negative) + * \P{property-name} (negative) + + property-name: + + + works on all encodings + Alnum, Alpha, Blank, Cntrl, Digit, Graph, Lower, + Print, Punct, Space, Upper, XDigit, Word, ASCII + + + works on EUC_JP, Shift_JIS, CP932 + Hiragana, Katakana, Han, Latin, Greek, Cyrillic + + + works on UTF-8, UTF-16, UTF-32 + see UnicodeProps.txt + + \p{Punct} works slightly different on Unicode encodings and the other + encodings. It matches the nine characters "$+<=>^`|~" on non-Unicode + encodings (which is the same as [[:punct:]]), but not on Unicode encodings. + \p{XPosixPunct} matches the nine characters on Unicode encodings. + + + \R Linebreak + + Unicode: + (?>\x0D\x0A|[\x0A-\x0D\x{85}\x{2028}\x{2029}]) + + Not Unicode: + (?>\x0D\x0A|[\x0A-\x0D]) + + \X Extended Grapheme cluster + + Unicode: + See: Unicode Standard Annex #29 UNICODE TEXT SEGMENTATION + http://unicode.org/reports/tr29/ + + Not Unicode: + (?>\x0D\x0A|(?m:.)) + + + +4. Quantifier + + greedy + + ? 1 or 0 times + * 0 or more times + + 1 or more times + {n,m} at least n but no more than m times + {n,} at least n times + {,n} at least 0 but no more than n times ({0,n}) + {n} n times + + reluctant + + ?? 1 or 0 times + *? 0 or more times + +? 1 or more times + {n,m}? at least n but not more than m times + {n,}? at least n times + {,n}? at least 0 but not more than n times (== {0,n}?) + + possessive (greedy and does not backtrack once match) + + ?+ 1 or 0 times + *+ 0 or more times + ++ 1 or more times + + ({n,m}+, {n,}+, {n}+ are possessive op. in ONIG_SYNTAX_JAVA and + ONIG_SYNTAX_PERL only) + + ex. /a*+/ === /(?>a*)/ + + +5. Anchors + + ^ beginning of the line + $ end of the line + \b word boundary + \B non-word boundary + \A beginning of string + \Z end of string, or before newline at the end + \z end of string + \G where the current search attempt begins + + +6. Character class + + ^... negative class (lowest precedence) + x-y range from x to y + [...] set (character class in character class) + ..&&.. intersection (low precedence, only higher than ^) + + ex. [a-w&&[^c-g]z] ==> ([a-w] AND ([^c-g] OR z)) ==> [abh-w] + + * If you want to use '[', '-', or ']' as a normal character + in character class, you should escape them with '\'. + + + POSIX bracket ([:xxxxx:], negate [:^xxxxx:]) + + Not Unicode Case: + + alnum alphabet or digit char + alpha alphabet + ascii code value: [0 - 127] + blank \t, \x20 + cntrl + digit 0-9 + graph \x21-\x7E and all of multibyte encoded characters + lower + print \x20-\x7E and all of multibyte encoded characters + punct + space \t, \n, \v, \f, \r, \x20 + upper + xdigit 0-9, a-f, A-F + word alphanumeric, "_" and multibyte characters + + + Unicode Case: + + alnum Letter | Mark | Decimal_Number + alpha Letter | Mark + ascii 0000 - 007F + blank Space_Separator | 0009 + cntrl Control | Format | Unassigned | Private_Use | Surrogate + digit Decimal_Number + graph [[:^space:]] && ^Control && ^Unassigned && ^Surrogate + lower Lowercase_Letter + print [[:graph:]] | Space_Separator + punct Connector_Punctuation | Dash_Punctuation | Close_Punctuation | + Final_Punctuation | Initial_Punctuation | Other_Punctuation | + Open_Punctuation | 0024 | 002B | 003C | 003D | 003E | 005E | + 0060 | 007C | 007E + space Space_Separator | Line_Separator | Paragraph_Separator | + 0009 | 000A | 000B | 000C | 000D | 0085 + upper Uppercase_Letter + xdigit 0030 - 0039 | 0041 - 0046 | 0061 - 0066 + (0-9, a-f, A-F) + word Letter | Mark | Decimal_Number | Connector_Punctuation + + + It depends on ONIG_OPTION_ASCII_RANGE option and + ONIG_OPTION_POSIX_BRACKET_ALL_RANGE option that POSIX brackets + match non-ASCII char or not. + + + +7. Extended groups + + (?#...) comment + + (?imxdau-imx) option on/off + i: ignore case + m: multi-line (dot (.) also matches newline) + x: extended form + + character set option (character range option) + d: Default (compatible with Ruby 1.9.3) + \w, \d and \s doesn't match non-ASCII characters. + \b, \B and POSIX brackets use the each encoding's + rules. + a: ASCII + ONIG_OPTION_ASCII_RANGE option is turned on. + \w, \d, \s and POSIX brackets doesn't match + non-ASCII characters. + \b and \B use the ASCII rules. + u: Unicode + ONIG_OPTION_ASCII_RANGE option is turned off. + \w (\W), \d (\D), \s (\S), \b (\B) and POSIX + brackets use the each encoding's rules. + + (?imxdau-imx:subexp) + option on/off for subexp + + (?:subexp) non-capturing group + (subexp) capturing group + + (?=subexp) look-ahead + (?!subexp) negative look-ahead + (?<=subexp) look-behind + (?<!subexp) negative look-behind + + Subexp of look-behind must be fixed-width. + But top-level alternatives can be of various lengths. + ex. (?<=a|bc) is OK. (?<=aaa(?:b|cd)) is not allowed. + + In negative look-behind, capturing group isn't allowed, + but non-capturing group (?:) is allowed. + + \K keep + Another expression of look-behind. Keep the stuff left + of the \K, don't include it in the result. + + (?>subexp) atomic group + no backtracks in subexp. + + (?<name>subexp), (?'name'subexp) + define named group + (Each character of the name must be a word character.) + + Not only a name but a number is assigned like a capturing + group. + + Assigning the same name to two or more subexps is allowed. + + (?(cond)yes-subexp), (?(cond)yes-subexp|no-subexp) + conditional expression + Matches yes-subexp if (cond) yields a true value, matches + no-subexp otherwise. + Following (cond) can be used: + + (n) (n >= 1) + Checks if the numbered capturing group has matched + something. + + (<name>), ('name') + Checks if a group with the given name has matched + something. + + BUG: If the name is defined more than once, the + left-most group is checked, but it should be the + same as \k<name>. + + (?~subexp) absence operator (experimental) + Matches any string which doesn't contain any string which + matches subexp. + More precisely, (?~subexp) matches the complement set of + a set which .*subexp.* matches. This is regular in the + meaning of formal language theory. + Similar to (?:(?!subexp).)*, but easy to write. + + E.g.: + (?~abc) matches: "", "ab", "aab", "ccdd", etc. + It doesn't match: "abc", "aabc", "ccabcdd", etc. + + \/\*(?~\*\/)\*\/ matches C style comments: + "/**/", "/* foobar */", etc. + + \A\/\*(?~\*\/)\*\/\z doesn't match "/**/ */". + This is different from \A\/\*.*?\*\/\z which uses a + reluctant quantifier (.*?). + + Unlike (?:(?!abc).)*c, (?~abc)c matches "abc", because + (?~abc) matches "ab". + + (?~) never matches. + + Theoretical backgrounds are discussed in Tanaka Akira's + paper and slide (both Japanese): + + * Absent Operator for Regular Expression + https://staff.aist.go.jp/tanaka-akira/pub/prosym49-akr-paper.pdf + * 正規表現における非包含オペレータの提案 + https://staff.aist.go.jp/tanaka-akira/pub/prosym49-akr-presen.pdf + + +8. Backreferences + + When we say "backreference a group," it actually means, "re-match the same + text matched by the subexp in that group." + + \n \k<n> \k'n' (n >= 1) backreference the nth group in the regexp + \k<-n> \k'-n' (n >= 1) backreference the nth group counting + backwards from the referring position + \k<name> \k'name' backreference a group with the specified name + + When backreferencing with a name that is assigned to more than one groups, + the last group with the name is checked first, if not matched then the + previous one with the name, and so on, until there is a match. + + * Backreference by number is forbidden if any named group is defined and + ONIG_OPTION_CAPTURE_GROUP is not set. + + * ONIG_SYNTAX_PERL: \g{n}, \g{-n} and \g{name} can also be used. + If a name is defined more than once in Perl syntax, only the left-most + group is checked. + + + backreference with recursion level + + (n >= 1, level >= 0) + + \k<n+level> \k'n+level' + \k<n-level> \k'n-level' + \k<-n+level> \k'-n+level' + \k<-n-level> \k'-n-level' + + \k<name+level> \k'name+level' + \k<name-level> \k'name-level' + + Refer a group on the recursion level relative to the referring position. + + ex 1. + + /\A(?<a>|.|(?:(?<b>.)\g<a>\k<b>))\z/.match("reee") + /\A(?<a>|.|(?:(?<b>.)\g<a>\k<b+0>))\z/.match("reer") + + \k<b+0> refers to the (?<b>.) on the same recursion level with it. + + ex 2. + + r = Regexp.compile(<<'__REGEXP__'.strip, Regexp::EXTENDED) + (?<element> \g<stag> \g<content>* \g<etag> ){0} + (?<stag> < \g<name> \s* > ){0} + (?<name> [a-zA-Z_:]+ ){0} + (?<content> [^<&]+ (\g<element> | [^<&]+)* ){0} + (?<etag> </ \k<name+1> >){0} + \g<element> + __REGEXP__ + + p r.match("<foo>f<bar>bbb</bar>f</foo>").captures + + +9. Subexp calls ("Tanaka Akira special") + + When we say "call a group," it actually means, "re-execute the subexp in + that group." + + \g<0> \g'0' call the whole pattern recursively + \g<n> \g'n' (n >= 1) call the nth group + \g<-n> \g'-n' (n >= 1) call the nth group counting backwards from + the calling position + \g<+n> \g'+n' (n >= 1) call the nth group counting forwards from + the calling position + \g<name> \g'name' call the group with the specified name + + * Left-most recursive calls are not allowed. + + ex. (?<name>a|\g<name>b) => error + (?<name>a|b\g<name>c) => OK + + * Calls with a name that is assigned to more than one groups are not + allowed in ONIG_SYNTAX_RUBY. + + * Call by number is forbidden if any named group is defined and + ONIG_OPTION_CAPTURE_GROUP is not set. + + * The option status of the called group is always effective. + + ex. /(?-i:\g<name>)(?i:(?<name>a)){0}/.match("A") + + * ONIG_SYNTAX_PERL: + Use (?&name), (?n), (?-n), (?+n), (?R) or (?0) instead of \g<>. + Calls with a name that is assigned to more than one groups are allowed, + and the left-most subexp is used. + + +10. Captured group + + Behavior of an unnamed group (...) changes with the following conditions. + (But named group is not changed.) + + case 1. /.../ (named group is not used, no option) + + (...) is treated as a capturing group. + + case 2. /.../g (named group is not used, 'g' option) + + (...) is treated as a non-capturing group (?:...). + + case 3. /..(?<name>..)../ (named group is used, no option) + + (...) is treated as a non-capturing group. + numbered-backref/call is not allowed. + + case 4. /..(?<name>..)../G (named group is used, 'G' option) + + (...) is treated as a capturing group. + numbered-backref/call is allowed. + + where + g: ONIG_OPTION_DONT_CAPTURE_GROUP + G: ONIG_OPTION_CAPTURE_GROUP + + ('g' and 'G' options are argued in ruby-dev ML) + + + +----------------------------- +A-1. Syntax-dependent options + + + ONIG_SYNTAX_RUBY + (?m): dot (.) also matches newline + + + ONIG_SYNTAX_PERL, ONIG_SYNTAX_JAVA and ONIG_SYNTAX_PYTHON + (?s): dot (.) also matches newline + (?m): ^ matches after newline, $ matches before newline + + + ONIG_SYNTAX_PERL + (?d), (?l): same as (?u) + + +A-2. Original extensions + + + hexadecimal digit char type \h, \H + + named group (?<name>...), (?'name'...) + + named backref \k<name> + + subexp call \g<name>, \g<group-num> + + +A-3. Missing features compared with perl 5.18.0 + + + \N{name}, \N{U+xxxx}, \N + + \l,\u,\L,\U, \C + + \v, \V, \h, \H + + (?{code}) + + (??{code}) + + (?|...) + + (?[]) + + (*VERB:ARG) + + * \Q...\E + This is effective on ONIG_SYNTAX_PERL and ONIG_SYNTAX_JAVA. + + +A-4. Differences with Japanized GNU regex(version 0.12) of Ruby 1.8 + + + add character property (\p{property}, \P{property}) + + add hexadecimal digit char type (\h, \H) + + add look-behind + (?<=fixed-width-pattern), (?<!fixed-width-pattern) + + add possessive quantifier. ?+, *+, ++ + + add operations in character class. [], && + ('[' must be escaped as an usual char in character class.) + + add named group and subexp call. + + octal or hexadecimal number sequence can be treated as + a multibyte code char in character class if multibyte encoding + is specified. + (ex. [\xa1\xa2], [\xa1\xa7-\xa4\xa1]) + + allow the range of single byte char and multibyte char in character + class. + ex. /[a-<<any EUC-JP character>>]/ in EUC-JP encoding. + + effect range of isolated option is to next ')'. + ex. (?:(?i)a|b) is interpreted as (?:(?i:a|b)), not (?:(?i:a)|b). + + isolated option is not transparent to previous pattern. + ex. a(?i)* is a syntax error pattern. + + allowed unpaired left brace as a normal character. + ex. /{/, /({)/, /a{2,3/ etc... + + negative POSIX bracket [:^xxxx:] is supported. + + POSIX bracket [:ascii:] is added. + + repeat of look-ahead is not allowed. + ex. /(?=a)*/, /(?!b){5}/ + + Ignore case option is effective to escape sequence. + ex. /\x61/i =~ "A" + + In the range quantifier, the number of the minimum is optional. + /a{,n}/ == /a{0,n}/ + The omission of both minimum and maximum values is not allowed. + /a{,}/ + + /{n}?/ is not a reluctant quantifier. + /a{n}?/ == /(?:a{n})?/ + + invalid back reference is checked and raises error. + /\1/, /(a)\2/ + + Zero-width match in an infinite loop stops the repeat, + then changes of the capture group status are checked as stop condition. + /(?:()|())*\1\2/ =~ "" + /(?:\1a|())*/ =~ "a" + + +A-5. Features disabled in default syntax + + + capture history + + (?@...) and (?@<name>...) + + ex. /(?@a)*/.match("aaa") ==> [<0-1>, <1-2>, <2-3>] + + see sample/listcap.c file. + + +A-6. Problems + + + Invalid encoding byte sequence is not checked. + + ex. UTF-8 + + * Invalid first byte is treated as a character. + /./u =~ "\xa3" + + * Incomplete byte sequence is not checked. + /\w+/ =~ "a\xf3\x8ec" + +// END |