Lark 支持 RE2 语法，正则表达式默认区分大小写。
正则表达式示例
以下示例介绍了如何使用、构造简单的正则表达式。每个示例都包含要匹配的文本类型、用于匹配该文本的一个或几个正则表达式，以及一些注释（说明特殊字符和格式的使用方法）。
仅精确匹配短语
匹配列表中的字词或短语
匹配包含不同拼写或特殊字符的字词
匹配某个特定网域的所有电子邮件地址
匹配某个范围内的所有 IP 地址
匹配字母数字格式
语法附录
kinds of single-character expressions | examples |
any character, possibly including newline (s=true) | . |
character class | [xyz] |
negated character class | [^xyz] |
Perl character class | \d |
negated Perl character class | \D |
ASCII character class | [[:alpha:]] |
negated ASCII character class | [[:^alpha:]] |
Unicode character class (one-letter name) | \pN |
Unicode character class | \p{Greek} |
negated Unicode character class (one-letter name) | \PN |
negated Unicode character class | \P{Greek} |
| 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 |
Implementation restriction: The counting forms x{n,m}, x{n,}, and x{n} reject forms that create a minimum or maximum repetition count above 1000. Unlimited repetitions are not subject to this restriction.
| 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) |
| 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).
| Grouping |
(re) | numbered capturing group (submatch) |
(?P<name>re) | named & numbered capturing group (submatch) |
(?<name>re) | named & numbered capturing group (submatch) (NOT SUPPORTED) |
(?'name're) | named & numbered capturing group (submatch) (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 |
| 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 ASCII word boundary (\w on one side and \W, \A, or \z on the other) |
\B | not at ASCII 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}) |