-
Notifications
You must be signed in to change notification settings - Fork 94
/
RE
522 lines (366 loc) · 15.4 KB
/
RE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
Onigmo (Oniguruma-mod) Regular Expressions Version 5.13.0 2012/01/19
syntax: ONIG_SYNTAX_RUBY (default)
1. Syntax elements
\ escape (enable or disable meta character meaning)
| alternation
(...) group
[...] character class
2. Characters
\t horizontal tab (0x09)
\v vertical tab (0x0B)
\n newline (0x0A)
\r return (0x0D)
\b back space (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)
\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 is effective in character class [...] only)
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 UTF8, UTF16, UTF32
see UnicodeProps.txt
\R Linebreak
Unicode:
(?>\x0D\x0A|[\x0A-\x0D\x{85}\x{2028}\x{2029}])
Not Unicode:
(?>\x0D\x0A|[\x0A-\x0D])
\X eXtended grapheme cluster
Unicode:
(?>\P{M}\p{M}*)
Not Unicode:
(?m:.)
4. Quantifier
greedy
? 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})
{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 after repeated)
?+ 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 not word boundary
\A beginning of string
\Z end of string, or before newline at the end
\z end of string
\G matching start position
6. Character class
^... negative class (lowest precedence operator)
x-y range from x to y
[...] set (character class in character class)
..&&.. intersection (low precedence at the next of ^)
ex. [a-w&&[^c-g]z] ==> ([a-w] AND ([^c-g] OR z)) ==> [abh-w]
* If you want to use '[', '-', ']' as a normal character
in a character class, you should escape these characters by '\'.
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
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(.) match 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) not captured group
(subexp) captured group
(?=subexp) look-ahead
(?!subexp) negative look-ahead
(?<=subexp) look-behind
(?<!subexp) negative look-behind
Subexp of look-behind must be fixed character length.
But different character length is allowed in top level
alternatives only.
ex. (?<=a|bc) is OK. (?<=aaa(?:b|cd)) is not allowed.
In negative-look-behind, captured group isn't allowed,
but shy 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
don't backtrack in subexp.
(?<name>subexp), (?'name'subexp)
define named group
(All characters of the name must be a word character.)
Not only a name but a number is assigned like a captured
group.
Assigning the same name as two or more subexps is allowed.
In this case, a subexp call can not be performed although
the back reference is possible.
(ONIG_SYNTAX_PERL: a subexp call is allowed in this case.)
(?(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.
8. Back reference
\n back reference by group number (n >= 1)
\k<n> back reference by group number (n >= 1)
\k'n' back reference by group number (n >= 1)
\k<-n> back reference by relative group number (n >= 1)
\k'-n' back reference by relative group number (n >= 1)
\k<name> back reference by group name
\k'name' back reference by group name
In the back reference by the multiplex definition name,
a subexp with a large number is referred to preferentially.
(When not matched, a group of the small number is referred to.)
* Back reference by group number is forbidden if named group is defined
in the pattern and ONIG_OPTION_CAPTURE_GROUP is not set.
* ONIG_SYNTAX_PERL: \g{n}, \g{-n} and \g{name} can also be used.
back reference with nest level
level: 0, 1, 2, ...
\k<n+level> (n >= 1)
\k<n-level> (n >= 1)
\k'n+level' (n >= 1)
\k'n-level' (n >= 1)
\k<-n+level> (n >= 1)
\k<-n-level> (n >= 1)
\k'-n+level' (n >= 1)
\k'-n-level' (n >= 1)
\k<name+level>
\k<name-level>
\k'name+level'
\k'name-level'
Destinate relative nest level from back reference position.
ex 1.
/\A(?<a>|.|(?:(?<b>.)\g<a>\k<b+0>))\z/.match("reer")
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 call ("Tanaka Akira special")
\g<name> call by group name
\g'name' call by group name
\g<n> call by group number (n >= 1)
\g'n' call by group number (n >= 1)
\g<0> call the whole pattern recursively
\g'0' call the whole pattern recursively
\g<-n> call by relative group number (n >= 1)
\g'-n' call by relative group number (n >= 1)
\g<+n> call by relative group number (n >= 1)
\g'+n' call by relative group number (n >= 1)
* left-most recursive call is not allowed.
ex. (?<name>a|\g<name>b) => error
(?<name>a|b\g<name>c) => OK
* Call by group number is forbidden if named group is defined in the pattern
and ONIG_OPTION_CAPTURE_GROUP is not set.
* If the option status of called group is different from calling position
then the group's option is effective.
ex. (?-i:\g<name>)(?i:(?<name>a)){0} match to "A"
* ONIG_SYNTAX_PERL: use (?&name), (?n), (?-n), (?+n), (?R) or (?0) instead.
10. Captured group
Behavior of the no-named 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 captured group.
case 2. /.../g (named group is not used, 'g' option)
(...) is treated as a no-captured group (?:...).
case 3. /..(?<name>..)../ (named group is used, no option)
(...) is treated as a no-captured group (?:...).
numbered-backref/call is not allowed.
case 4. /..(?<name>..)../G (named group is used, 'G' option)
(...) is treated as a captured 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 depend options
+ ONIG_SYNTAX_RUBY
(?m): dot(.) match newline
+ ONIG_SYNTAX_PERL, ONIG_SYNTAX_JAVA and ONIG_SYNTAX_PYTHON
(?s): dot(.) match newline
(?m): ^ match after newline, $ match 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. Lacked features compare with perl 5.14.0
+ \N{name}, \N{U+xxxx}, \N
+ \l,\u,\L,\U, \C
+ \v, \V, \h, \H, \o{xxx}
+ (?{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-char-length-pattern), (?<!fixed-char-length-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 incomplete left brace as an usual string.
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 numbered character.
ex. /\x61/i =~ "A"
+ In the range quantifier, the number of the minimum is omissible.
/a{,n}/ == /a{0,n}/
The simultaneous abbreviation of the number of times of the minimum
and the maximum is not allowed. (/a{,}/)
+ /a{n}?/ is not a non-greedy operator.
/a{n}?/ == /(?:a{n})?/
+ invalid back reference is checked and cause error.
/\1/, /(a)\2/
+ Zero-length match in infinite repeat stops the repeat,
then changes of the capture group status are checked as stop condition.
/(?:()|())*\1\2/ =~ ""
/(?:\1a|())*/ =~ "a"
A-5. Disabled functions by 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