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1 PCRETEST(1) General Commands Manual PCRETEST(1)
2
3
4
5 NAME
6 pcretest - a program for testing Perl-compatible regular expressions.
7
8 SYNOPSIS
9
10 pcretest [options] [input file [output file]]
11
12 pcretest was written as a test program for the PCRE regular expression
13 library itself, but it can also be used for experimenting with regular
14 expressions. This document describes the features of the test program;
15 for details of the regular expressions themselves, see the pcrepattern
16 documentation. For details of the PCRE library function calls and their
17 options, see the pcreapi , pcre16 and pcre32 documentation.
18
19 The input for pcretest is a sequence of regular expression patterns and
20 strings to be matched, as described below. The output shows the result
21 of each match. Options on the command line and the patterns control
22 PCRE options and exactly what is output.
23
24 As PCRE has evolved, it has acquired many different features, and as a
25 result, pcretest now has rather a lot of obscure options for testing
26 every possible feature. Some of these options are specifically designed
27 for use in conjunction with the test script and data files that are
28 distributed as part of PCRE, and are unlikely to be of use otherwise.
29 They are all documented here, but without much justification.
30
31
32 PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
33
34 From release 8.30, two separate PCRE libraries can be built. The origi-
35 nal one supports 8-bit character strings, whereas the newer 16-bit
36 library supports character strings encoded in 16-bit units. From
37 release 8.32, a third library can be built, supporting character
38 strings encoded in 32-bit units. The pcretest program can be used to
39 test all three libraries. However, it is itself still an 8-bit program,
40 reading 8-bit input and writing 8-bit output. When testing the 16-bit
41 or 32-bit library, the patterns and data strings are converted to 16-
42 or 32-bit format before being passed to the PCRE library functions.
43 Results are converted to 8-bit for output.
44
45 References to functions and structures of the form pcre[16|32]_xx below
46 mean "pcre_xx when using the 8-bit library or pcre16_xx when using the
47 16-bit library".
48
49
50 COMMAND LINE OPTIONS
51
52 -8 If both the 8-bit library has been built, this option causes
53 the 8-bit library to be used (which is the default); if the
54 8-bit library has not been built, this option causes an
55 error.
56
57 -16 If both the 8-bit or the 32-bit, and the 16-bit libraries
58 have been built, this option causes the 16-bit library to be
59 used. If only the 16-bit library has been built, this is the
60 default (so has no effect). If only the 8-bit or the 32-bit
61 library has been built, this option causes an error.
62
63 -32 If both the 8-bit or the 16-bit, and the 32-bit libraries
64 have been built, this option causes the 32-bit library to be
65 used. If only the 32-bit library has been built, this is the
66 default (so has no effect). If only the 8-bit or the 16-bit
67 library has been built, this option causes an error.
68
69 -b Behave as if each pattern has the /B (show byte code) modi-
70 fier; the internal form is output after compilation.
71
72 -C Output the version number of the PCRE library, and all avail-
73 able information about the optional features that are
74 included, and then exit with zero exit code. All other
75 options are ignored.
76
77 -C option Output information about a specific build-time option, then
78 exit. This functionality is intended for use in scripts such
79 as RunTest. The following options output the value and set
80 the exit code as indicated:
81
82 ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
83 0x15 or 0x25
84 0 if used in an ASCII environment
85 exit code is always 0
86 linksize the configured internal link size (2, 3, or 4)
87 exit code is set to the link size
88 newline the default newline setting:
89 CR, LF, CRLF, ANYCRLF, or ANY
90 exit code is always 0
91
92 The following options output 1 for true or 0 for false, and
93 set the exit code to the same value:
94
95 ebcdic compiled for an EBCDIC environment
96 jit just-in-time support is available
97 pcre16 the 16-bit library was built
98 pcre32 the 32-bit library was built
99 pcre8 the 8-bit library was built
100 ucp Unicode property support is available
101 utf UTF-8 and/or UTF-16 and/or UTF-32 support
102 is available
103
104 If an unknown option is given, an error message is output;
105 the exit code is 0.
106
107 -d Behave as if each pattern has the /D (debug) modifier; the
108 internal form and information about the compiled pattern is
109 output after compilation; -d is equivalent to -b -i.
110
111 -dfa Behave as if each data line contains the \D escape sequence;
112 this causes the alternative matching function,
113 pcre[16|32]_dfa_exec(), to be used instead of the standard
114 pcre[16|32]_exec() function (more detail is given below).
115
116 -help Output a brief summary these options and then exit.
117
118 -i Behave as if each pattern has the /I modifier; information
119 about the compiled pattern is given after compilation.
120
121 -M Behave as if each data line contains the \M escape sequence;
122 this causes PCRE to discover the minimum MATCH_LIMIT and
123 MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
124 repeatedly with different limits.
125
126 -m Output the size of each compiled pattern after it has been
127 compiled. This is equivalent to adding /M to each regular
128 expression. The size is given in bytes for both libraries.
129
130 -o osize Set the number of elements in the output vector that is used
131 when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
132 be osize. The default value is 45, which is enough for 14
133 capturing subexpressions for pcre[16|32]_exec() or 22 differ-
134 ent matches for pcre[16|32]_dfa_exec(). The vector size can
135 be changed for individual matching calls by including \O in
136 the data line (see below).
137
138 -p Behave as if each pattern has the /P modifier; the POSIX
139 wrapper API is used to call PCRE. None of the other options
140 has any effect when -p is set. This option can be used only
141 with the 8-bit library.
142
143 -q Do not output the version number of pcretest at the start of
144 execution.
145
146 -S size On Unix-like systems, set the size of the run-time stack to
147 size megabytes.
148
149 -s or -s+ Behave as if each pattern has the /S modifier; in other
150 words, force each pattern to be studied. If -s+ is used, all
151 the JIT compile options are passed to pcre[16|32]_study(),
152 causing just-in-time optimization to be set up if it is
153 available, for both full and partial matching. Specific JIT
154 compile options can be selected by following -s+ with a digit
155 in the range 1 to 7, which selects the JIT compile modes as
156 follows:
157
158 1 normal match only
159 2 soft partial match only
160 3 normal match and soft partial match
161 4 hard partial match only
162 6 soft and hard partial match
163 7 all three modes (default)
164
165 If -s++ is used instead of -s+ (with or without a following
166 digit), the text "(JIT)" is added to the first output line
167 after a match or no match when JIT-compiled code was actually
168 used.
169
170 Note that there are pattern options that can override -s,
171 either specifying no studying at all, or suppressing JIT com-
172 pilation.
173
174 If the /I or /D option is present on a pattern (requesting
175 output about the compiled pattern), information about the
176 result of studying is not included when studying is caused
177 only by -s and neither -i nor -d is present on the command
178 line. This behaviour means that the output from tests that
179 are run with and without -s should be identical, except when
180 options that output information about the actual running of a
181 match are set.
182
183 The -M, -t, and -tm options, which give information about
184 resources used, are likely to produce different output with
185 and without -s. Output may also differ if the /C option is
186 present on an individual pattern. This uses callouts to trace
187 the the matching process, and this may be different between
188 studied and non-studied patterns. If the pattern contains
189 (*MARK) items there may also be differences, for the same
190 reason. The -s command line option can be overridden for spe-
191 cific patterns that should never be studied (see the /S pat-
192 tern modifier below).
193
194 -t Run each compile, study, and match many times with a timer,
195 and output resulting time per compile or match (in millisec-
196 onds). Do not set -m with -t, because you will then get the
197 size output a zillion times, and the timing will be dis-
198 torted. You can control the number of iterations that are
199 used for timing by following -t with a number (as a separate
200 item on the command line). For example, "-t 1000" would iter-
201 ate 1000 times. The default is to iterate 500000 times.
202
203 -tm This is like -t except that it times only the matching phase,
204 not the compile or study phases.
205
206
207 DESCRIPTION
208
209 If pcretest is given two filename arguments, it reads from the first
210 and writes to the second. If it is given only one filename argument, it
211 reads from that file and writes to stdout. Otherwise, it reads from
212 stdin and writes to stdout, and prompts for each line of input, using
213 "re>" to prompt for regular expressions, and "data>" to prompt for data
214 lines.
215
216 When pcretest is built, a configuration option can specify that it
217 should be linked with the libreadline library. When this is done, if
218 the input is from a terminal, it is read using the readline() function.
219 This provides line-editing and history facilities. The output from the
220 -help option states whether or not readline() will be used.
221
222 The program handles any number of sets of input on a single input file.
223 Each set starts with a regular expression, and continues with any num-
224 ber of data lines to be matched against the pattern.
225
226 Each data line is matched separately and independently. If you want to
227 do multi-line matches, you have to use the \n escape sequence (or \r or
228 \r\n, etc., depending on the newline setting) in a single line of input
229 to encode the newline sequences. There is no limit on the length of
230 data lines; the input buffer is automatically extended if it is too
231 small.
232
233 An empty line signals the end of the data lines, at which point a new
234 regular expression is read. The regular expressions are given enclosed
235 in any non-alphanumeric delimiters other than backslash, for example:
236
237 /(a|bc)x+yz/
238
239 White space before the initial delimiter is ignored. A regular expres-
240 sion may be continued over several input lines, in which case the new-
241 line characters are included within it. It is possible to include the
242 delimiter within the pattern by escaping it, for example
243
244 /abc\/def/
245
246 If you do so, the escape and the delimiter form part of the pattern,
247 but since delimiters are always non-alphanumeric, this does not affect
248 its interpretation. If the terminating delimiter is immediately fol-
249 lowed by a backslash, for example,
250
251 /abc/\
252
253 then a backslash is added to the end of the pattern. This is done to
254 provide a way of testing the error condition that arises if a pattern
255 finishes with a backslash, because
256
257 /abc\/
258
259 is interpreted as the first line of a pattern that starts with "abc/",
260 causing pcretest to read the next line as a continuation of the regular
261 expression.
262
263
264 PATTERN MODIFIERS
265
266 A pattern may be followed by any number of modifiers, which are mostly
267 single characters, though some of these can be qualified by further
268 characters. Following Perl usage, these are referred to below as, for
269 example, "the /i modifier", even though the delimiter of the pattern
270 need not always be a slash, and no slash is used when writing modi-
271 fiers. White space may appear between the final pattern delimiter and
272 the first modifier, and between the modifiers themselves. For refer-
273 ence, here is a complete list of modifiers. They fall into several
274 groups that are described in detail in the following sections.
275
276 /8 set UTF mode
277 /? disable UTF validity check
278 /+ show remainder of subject after match
279 /= show all captures (not just those that are set)
280
281 /A set PCRE_ANCHORED
282 /B show compiled code
283 /C set PCRE_AUTO_CALLOUT
284 /D same as /B plus /I
285 /E set PCRE_DOLLAR_ENDONLY
286 /F flip byte order in compiled pattern
287 /f set PCRE_FIRSTLINE
288 /G find all matches (shorten string)
289 /g find all matches (use startoffset)
290 /I show information about pattern
291 /i set PCRE_CASELESS
292 /J set PCRE_DUPNAMES
293 /K show backtracking control names
294 /L set locale
295 /M show compiled memory size
296 /m set PCRE_MULTILINE
297 /N set PCRE_NO_AUTO_CAPTURE
298 /P use the POSIX wrapper
299 /S study the pattern after compilation
300 /s set PCRE_DOTALL
301 /T select character tables
302 /U set PCRE_UNGREEDY
303 /W set PCRE_UCP
304 /X set PCRE_EXTRA
305 /x set PCRE_EXTENDED
306 /Y set PCRE_NO_START_OPTIMIZE
307 /Z don't show lengths in /B output
308
309 /<any> set PCRE_NEWLINE_ANY
310 /<anycrlf> set PCRE_NEWLINE_ANYCRLF
311 /<cr> set PCRE_NEWLINE_CR
312 /<crlf> set PCRE_NEWLINE_CRLF
313 /<lf> set PCRE_NEWLINE_LF
314 /<bsr_anycrlf> set PCRE_BSR_ANYCRLF
315 /<bsr_unicode> set PCRE_BSR_UNICODE
316 /<JS> set PCRE_JAVASCRIPT_COMPAT
317
318
319 Perl-compatible modifiers
320
321 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
322 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
323 pcre[16|32]_compile() is called. These four modifier letters have the
324 same effect as they do in Perl. For example:
325
326 /caseless/i
327
328
329 Modifiers for other PCRE options
330
331 The following table shows additional modifiers for setting PCRE com-
332 pile-time options that do not correspond to anything in Perl:
333
334 /8 PCRE_UTF8 ) when using the 8-bit
335 /? PCRE_NO_UTF8_CHECK ) library
336
337 /8 PCRE_UTF16 ) when using the 16-bit
338 /? PCRE_NO_UTF16_CHECK ) library
339
340 /8 PCRE_UTF32 ) when using the 32-bit
341 /? PCRE_NO_UTF32_CHECK ) library
342
343 /A PCRE_ANCHORED
344 /C PCRE_AUTO_CALLOUT
345 /E PCRE_DOLLAR_ENDONLY
346 /f PCRE_FIRSTLINE
347 /J PCRE_DUPNAMES
348 /N PCRE_NO_AUTO_CAPTURE
349 /U PCRE_UNGREEDY
350 /W PCRE_UCP
351 /X PCRE_EXTRA
352 /Y PCRE_NO_START_OPTIMIZE
353 /<any> PCRE_NEWLINE_ANY
354 /<anycrlf> PCRE_NEWLINE_ANYCRLF
355 /<cr> PCRE_NEWLINE_CR
356 /<crlf> PCRE_NEWLINE_CRLF
357 /<lf> PCRE_NEWLINE_LF
358 /<bsr_anycrlf> PCRE_BSR_ANYCRLF
359 /<bsr_unicode> PCRE_BSR_UNICODE
360 /<JS> PCRE_JAVASCRIPT_COMPAT
361
362 The modifiers that are enclosed in angle brackets are literal strings
363 as shown, including the angle brackets, but the letters within can be
364 in either case. This example sets multiline matching with CRLF as the
365 line ending sequence:
366
367 /^abc/m<CRLF>
368
369 As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
370 causes all non-printing characters in output strings to be printed
371 using the \x{hh...} notation. Otherwise, those less than 0x100 are out-
372 put in hex without the curly brackets.
373
374 Full details of the PCRE options are given in the pcreapi documenta-
375 tion.
376
377 Finding all matches in a string
378
379 Searching for all possible matches within each subject string can be
380 requested by the /g or /G modifier. After finding a match, PCRE is
381 called again to search the remainder of the subject string. The differ-
382 ence between /g and /G is that the former uses the startoffset argument
383 to pcre[16|32]_exec() to start searching at a new point within the
384 entire string (which is in effect what Perl does), whereas the latter
385 passes over a shortened substring. This makes a difference to the
386 matching process if the pattern begins with a lookbehind assertion
387 (including \b or \B).
388
389 If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
390 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
391 PCRE_ANCHORED flags set in order to search for another, non-empty,
392 match at the same point. If this second match fails, the start offset
393 is advanced, and the normal match is retried. This imitates the way
394 Perl handles such cases when using the /g modifier or the split() func-
395 tion. Normally, the start offset is advanced by one character, but if
396 the newline convention recognizes CRLF as a newline, and the current
397 character is CR followed by LF, an advance of two is used.
398
399 Other modifiers
400
401 There are yet more modifiers for controlling the way pcretest operates.
402
403 The /+ modifier requests that as well as outputting the substring that
404 matched the entire pattern, pcretest should in addition output the
405 remainder of the subject string. This is useful for tests where the
406 subject contains multiple copies of the same substring. If the + modi-
407 fier appears twice, the same action is taken for captured substrings.
408 In each case the remainder is output on the following line with a plus
409 character following the capture number. Note that this modifier must
410 not immediately follow the /S modifier because /S+ and /S++ have other
411 meanings.
412
413 The /= modifier requests that the values of all potential captured
414 parentheses be output after a match. By default, only those up to the
415 highest one actually used in the match are output (corresponding to the
416 return code from pcre[16|32]_exec()). Values in the offsets vector cor-
417 responding to higher numbers should be set to -1, and these are output
418 as "<unset>". This modifier gives a way of checking that this is hap-
419 pening.
420
421 The /B modifier is a debugging feature. It requests that pcretest out-
422 put a representation of the compiled code after compilation. Normally
423 this information contains length and offset values; however, if /Z is
424 also present, this data is replaced by spaces. This is a special fea-
425 ture for use in the automatic test scripts; it ensures that the same
426 output is generated for different internal link sizes.
427
428 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
429 that is, both the /B and the /I modifiers.
430
431 The /F modifier causes pcretest to flip the byte order of the 2-byte
432 and 4-byte fields in the compiled pattern. This facility is for testing
433 the feature in PCRE that allows it to execute patterns that were com-
434 piled on a host with a different endianness. This feature is not avail-
435 able when the POSIX interface to PCRE is being used, that is, when the
436 /P pattern modifier is specified. See also the section about saving and
437 reloading compiled patterns below.
438
439 The /I modifier requests that pcretest output information about the
440 compiled pattern (whether it is anchored, has a fixed first character,
441 and so on). It does this by calling pcre[16|32]_fullinfo() after com-
442 piling a pattern. If the pattern is studied, the results of that are
443 also output.
444
445 The /K modifier requests pcretest to show names from backtracking con-
446 trol verbs that are returned from calls to pcre[16|32]_exec(). It
447 causes pcretest to create a pcre[16|32]_extra block if one has not
448 already been created by a call to pcre[16|32]_study(), and to set the
449 PCRE_EXTRA_MARK flag and the mark field within it, every time that
450 pcre[16|32]_exec() is called. If the variable that the mark field
451 points to is non-NULL for a match, non-match, or partial match,
452 pcretest prints the string to which it points. For a match, this is
453 shown on a line by itself, tagged with "MK:". For a non-match it is
454 added to the message.
455
456 The /L modifier must be followed directly by the name of a locale, for
457 example,
458
459 /pattern/Lfr_FR
460
461 For this reason, it must be the last modifier. The given locale is set,
462 pcre[16|32]_maketables() is called to build a set of character tables
463 for the locale, and this is then passed to pcre[16|32]_compile() when
464 compiling the regular expression. Without an /L (or /T) modifier, NULL
465 is passed as the tables pointer; that is, /L applies only to the
466 expression on which it appears.
467
468 The /M modifier causes the size in bytes of the memory block used to
469 hold the compiled pattern to be output. This does not include the size
470 of the pcre[16|32] block; it is just the actual compiled data. If the
471 pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
472 the size of the JIT compiled code is also output.
473
474 The /S modifier causes pcre[16|32]_study() to be called after the
475 expression has been compiled, and the results used when the expression
476 is matched. There are a number of qualifying characters that may follow
477 /S. They may appear in any order.
478
479 If S is followed by an exclamation mark, pcre[16|32]_study() is called
480 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
481 pcre_extra block, even when studying discovers no useful information.
482
483 If /S is followed by a second S character, it suppresses studying, even
484 if it was requested externally by the -s command line option. This
485 makes it possible to specify that certain patterns are always studied,
486 and others are never studied, independently of -s. This feature is used
487 in the test files in a few cases where the output is different when the
488 pattern is studied.
489
490 If the /S modifier is followed by a + character, the call to
491 pcre[16|32]_study() is made with all the JIT study options, requesting
492 just-in-time optimization support if it is available, for both normal
493 and partial matching. If you want to restrict the JIT compiling modes,
494 you can follow /S+ with a digit in the range 1 to 7:
495
496 1 normal match only
497 2 soft partial match only
498 3 normal match and soft partial match
499 4 hard partial match only
500 6 soft and hard partial match
501 7 all three modes (default)
502
503 If /S++ is used instead of /S+ (with or without a following digit), the
504 text "(JIT)" is added to the first output line after a match or no
505 match when JIT-compiled code was actually used.
506
507 Note that there is also an independent /+ modifier; it must not be
508 given immediately after /S or /S+ because this will be misinterpreted.
509
510 If JIT studying is successful, the compiled JIT code will automatically
511 be used when pcre[16|32]_exec() is run, except when incompatible run-
512 time options are specified. For more details, see the pcrejit documen-
513 tation. See also the \J escape sequence below for a way of setting the
514 size of the JIT stack.
515
516 Finally, if /S is followed by a minus character, JIT compilation is
517 suppressed, even if it was requested externally by the -s command line
518 option. This makes it possible to specify that JIT is never to be used
519 for certain patterns.
520
521 The /T modifier must be followed by a single digit. It causes a spe-
522 cific set of built-in character tables to be passed to pcre[16|32]_com-
523 pile(). It is used in the standard PCRE tests to check behaviour with
524 different character tables. The digit specifies the tables as follows:
525
526 0 the default ASCII tables, as distributed in
527 pcre_chartables.c.dist
528 1 a set of tables defining ISO 8859 characters
529
530 In table 1, some characters whose codes are greater than 128 are iden-
531 tified as letters, digits, spaces, etc.
532
533 Using the POSIX wrapper API
534
535 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
536 rather than its native API. This supports only the 8-bit library. When
537 /P is set, the following modifiers set options for the regcomp() func-
538 tion:
539
540 /i REG_ICASE
541 /m REG_NEWLINE
542 /N REG_NOSUB
543 /s REG_DOTALL )
544 /U REG_UNGREEDY ) These options are not part of
545 /W REG_UCP ) the POSIX standard
546 /8 REG_UTF8 )
547
548 The /+ modifier works as described above. All other modifiers are
549 ignored.
550
551
552 DATA LINES
553
554 Before each data line is passed to pcre[16|32]_exec(), leading and
555 trailing white space is removed, and it is then scanned for \ escapes.
556 Some of these are pretty esoteric features, intended for checking out
557 some of the more complicated features of PCRE. If you are just testing
558 "ordinary" regular expressions, you probably don't need any of these.
559 The following escapes are recognized:
560
561 \a alarm (BEL, \x07)
562 \b backspace (\x08)
563 \e escape (\x27)
564 \f form feed (\x0c)
565 \n newline (\x0a)
566 \qdd set the PCRE_MATCH_LIMIT limit to dd
567 (any number of digits)
568 \r carriage return (\x0d)
569 \t tab (\x09)
570 \v vertical tab (\x0b)
571 \nnn octal character (up to 3 octal digits); always
572 a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
573 \xhh hexadecimal byte (up to 2 hex digits)
574 \x{hh...} hexadecimal character (any number of hex digits)
575 \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
576 or pcre[16|32]_dfa_exec()
577 \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
578 or pcre[16|32]_dfa_exec()
579 \Cdd call pcre[16|32]_copy_substring() for substring dd
580 after a successful match (number less than 32)
581 \Cname call pcre[16|32]_copy_named_substring() for substring
582 "name" after a successful match (name termin-
583 ated by next non alphanumeric character)
584 \C+ show the current captured substrings at callout
585 time
586 \C- do not supply a callout function
587 \C!n return 1 instead of 0 when callout number n is
588 reached
589 \C!n!m return 1 instead of 0 when callout number n is
590 reached for the nth time
591 \C*n pass the number n (may be negative) as callout
592 data; this is used as the callout return value
593 \D use the pcre[16|32]_dfa_exec() match function
594 \F only shortest match for pcre[16|32]_dfa_exec()
595 \Gdd call pcre[16|32]_get_substring() for substring dd
596 after a successful match (number less than 32)
597 \Gname call pcre[16|32]_get_named_substring() for substring
598 "name" after a successful match (name termin-
599 ated by next non-alphanumeric character)
600 \Jdd set up a JIT stack of dd kilobytes maximum (any
601 number of digits)
602 \L call pcre[16|32]_get_substringlist() after a
603 successful match
604 \M discover the minimum MATCH_LIMIT and
605 MATCH_LIMIT_RECURSION settings
606 \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
607 or pcre[16|32]_dfa_exec(); if used twice, pass the
608 PCRE_NOTEMPTY_ATSTART option
609 \Odd set the size of the output vector passed to
610 pcre[16|32]_exec() to dd (any number of digits)
611 \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
612 or pcre[16|32]_dfa_exec(); if used twice, pass the
613 PCRE_PARTIAL_HARD option
614 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
615 (any number of digits)
616 \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
617 \S output details of memory get/free calls during matching
618 \Y pass the PCRE_NO_START_OPTIMIZE option to
619 pcre[16|32]_exec()
620 or pcre[16|32]_dfa_exec()
621 \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
622 or pcre[16|32]_dfa_exec()
623 \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
624 pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
625 \>dd start the match at offset dd (optional "-"; then
626 any number of digits); this sets the startoffset
627 argument for pcre[16|32]_exec() or
628 pcre[16|32]_dfa_exec()
629 \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
630 or pcre[16|32]_dfa_exec()
631 \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
632 or pcre[16|32]_dfa_exec()
633 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
634 or pcre[16|32]_dfa_exec()
635 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
636 or pcre[16|32]_dfa_exec()
637 \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
638 or pcre[16|32]_dfa_exec()
639
640 The use of \x{hh...} is not dependent on the use of the /8 modifier on
641 the pattern. It is recognized always. There may be any number of hexa-
642 decimal digits inside the braces; invalid values provoke error mes-
643 sages.
644
645 Note that \xhh specifies one byte rather than one character in UTF-8
646 mode; this makes it possible to construct invalid UTF-8 sequences for
647 testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
648 character in UTF-8 mode, generating more than one byte if the value is
649 greater than 127. When testing the 8-bit library not in UTF-8 mode,
650 \x{hh} generates one byte for values less than 256, and causes an error
651 for greater values.
652
653 In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
654 possible to construct invalid UTF-16 sequences for testing purposes.
655
656 In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
657 makes it possible to construct invalid UTF-32 sequences for testing
658 purposes.
659
660 The escapes that specify line ending sequences are literal strings,
661 exactly as shown. No more than one newline setting should be present in
662 any data line.
663
664 A backslash followed by anything else just escapes the anything else.
665 If the very last character is a backslash, it is ignored. This gives a
666 way of passing an empty line as data, since a real empty line termi-
667 nates the data input.
668
669 The \J escape provides a way of setting the maximum stack size that is
670 used by the just-in-time optimization code. It is ignored if JIT opti-
671 mization is not being used. Providing a stack that is larger than the
672 default 32K is necessary only for very complicated patterns.
673
674 If \M is present, pcretest calls pcre[16|32]_exec() several times, with
675 different values in the match_limit and match_limit_recursion fields of
676 the pcre[16|32]_extra data structure, until it finds the minimum num-
677 bers for each parameter that allow pcre[16|32]_exec() to complete with-
678 out error. Because this is testing a specific feature of the normal
679 interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
680 tion that might have been set up by the /S+ qualifier of -s+ option is
681 disabled.
682
683 The match_limit number is a measure of the amount of backtracking that
684 takes place, and checking it out can be instructive. For most simple
685 matches, the number is quite small, but for patterns with very large
686 numbers of matching possibilities, it can become large very quickly
687 with increasing length of subject string. The match_limit_recursion
688 number is a measure of how much stack (or, if PCRE is compiled with
689 NO_RECURSE, how much heap) memory is needed to complete the match
690 attempt.
691
692 When \O is used, the value specified may be higher or lower than the
693 size set by the -O command line option (or defaulted to 45); \O applies
694 only to the call of pcre[16|32]_exec() for the line in which it
695 appears.
696
697 If the /P modifier was present on the pattern, causing the POSIX wrap-
698 per API to be used, the only option-setting sequences that have any
699 effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
700 REG_NOTEOL, respectively, to be passed to regexec().
701
702
703 THE ALTERNATIVE MATCHING FUNCTION
704
705 By default, pcretest uses the standard PCRE matching function,
706 pcre[16|32]_exec() to match each data line. PCRE also supports an
707 alternative matching function, pcre[16|32]_dfa_test(), which operates
708 in a different way, and has some restrictions. The differences between
709 the two functions are described in the pcrematching documentation.
710
711 If a data line contains the \D escape sequence, or if the command line
712 contains the -dfa option, the alternative matching function is used.
713 This function finds all possible matches at a given point. If, however,
714 the \F escape sequence is present in the data line, it stops after the
715 first match is found. This is always the shortest possible match.
716
717
718 DEFAULT OUTPUT FROM PCRETEST
719
720 This section describes the output when the normal matching function,
721 pcre[16|32]_exec(), is being used.
722
723 When a match succeeds, pcretest outputs the list of captured substrings
724 that pcre[16|32]_exec() returns, starting with number 0 for the string
725 that matched the whole pattern. Otherwise, it outputs "No match" when
726 the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
727 partially matching substring when pcre[16|32]_exec() returns
728 PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
729 inspected during the partial match; it may include characters before
730 the actual match start if a lookbehind assertion, \K, \b, or \B was
731 involved.) For any other return, pcretest outputs the PCRE negative
732 error number and a short descriptive phrase. If the error is a failed
733 UTF string check, the offset of the start of the failing character and
734 the reason code are also output, provided that the size of the output
735 vector is at least two. Here is an example of an interactive pcretest
736 run.
737
738 $ pcretest
739 PCRE version 8.13 2011-04-30
740
741 re> /^abc(\d+)/
742 data> abc123
743 0: abc123
744 1: 123
745 data> xyz
746 No match
747
748 Unset capturing substrings that are not followed by one that is set are
749 not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
750 the following example, there are two capturing substrings, but when the
751 first data line is matched, the second, unset substring is not shown.
752 An "internal" unset substring is shown as "<unset>", as for the second
753 data line.
754
755 re> /(a)|(b)/
756 data> a
757 0: a
758 1: a
759 data> b
760 0: b
761 1: <unset>
762 2: b
763
764 If the strings contain any non-printing characters, they are output as
765 \xhh escapes if the value is less than 256 and UTF mode is not set.
766 Otherwise they are output as \x{hh...} escapes. See below for the defi-
767 nition of non-printing characters. If the pattern has the /+ modifier,
768 the output for substring 0 is followed by the the rest of the subject
769 string, identified by "0+" like this:
770
771 re> /cat/+
772 data> cataract
773 0: cat
774 0+ aract
775
776 If the pattern has the /g or /G modifier, the results of successive
777 matching attempts are output in sequence, like this:
778
779 re> /\Bi(\w\w)/g
780 data> Mississippi
781 0: iss
782 1: ss
783 0: iss
784 1: ss
785 0: ipp
786 1: pp
787
788 "No match" is output only if the first match attempt fails. Here is an
789 example of a failure message (the offset 4 that is specified by \>4 is
790 past the end of the subject string):
791
792 re> /xyz/
793 data> xyz\>4
794 Error -24 (bad offset value)
795
796 If any of the sequences \C, \G, or \L are present in a data line that
797 is successfully matched, the substrings extracted by the convenience
798 functions are output with C, G, or L after the string number instead of
799 a colon. This is in addition to the normal full list. The string length
800 (that is, the return from the extraction function) is given in paren-
801 theses after each string for \C and \G.
802
803 Note that whereas patterns can be continued over several lines (a plain
804 ">" prompt is used for continuations), data lines may not. However new-
805 lines can be included in data by means of the \n escape (or \r, \r\n,
806 etc., depending on the newline sequence setting).
807
808
809 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
810
811 When the alternative matching function, pcre[16|32]_dfa_exec(), is used
812 (by means of the \D escape sequence or the -dfa command line option),
813 the output consists of a list of all the matches that start at the
814 first point in the subject where there is at least one match. For exam-
815 ple:
816
817 re> /(tang|tangerine|tan)/
818 data> yellow tangerine\D
819 0: tangerine
820 1: tang
821 2: tan
822
823 (Using the normal matching function on this data finds only "tang".)
824 The longest matching string is always given first (and numbered zero).
825 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
826 lowed by the partially matching substring. (Note that this is the
827 entire substring that was inspected during the partial match; it may
828 include characters before the actual match start if a lookbehind asser-
829 tion, \K, \b, or \B was involved.)
830
831 If /g is present on the pattern, the search for further matches resumes
832 at the end of the longest match. For example:
833
834 re> /(tang|tangerine|tan)/g
835 data> yellow tangerine and tangy sultana\D
836 0: tangerine
837 1: tang
838 2: tan
839 0: tang
840 1: tan
841 0: tan
842
843 Since the matching function does not support substring capture, the
844 escape sequences that are concerned with captured substrings are not
845 relevant.
846
847
848 RESTARTING AFTER A PARTIAL MATCH
849
850 When the alternative matching function has given the PCRE_ERROR_PARTIAL
851 return, indicating that the subject partially matched the pattern, you
852 can restart the match with additional subject data by means of the \R
853 escape sequence. For example:
854
855 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
856 data> 23ja\P\D
857 Partial match: 23ja
858 data> n05\R\D
859 0: n05
860
861 For further information about partial matching, see the pcrepartial
862 documentation.
863
864
865 CALLOUTS
866
867 If the pattern contains any callout requests, pcretest's callout func-
868 tion is called during matching. This works with both matching func-
869 tions. By default, the called function displays the callout number, the
870 start and current positions in the text at the callout time, and the
871 next pattern item to be tested. For example:
872
873 --->pqrabcdef
874 0 ^ ^ \d
875
876 This output indicates that callout number 0 occurred for a match
877 attempt starting at the fourth character of the subject string, when
878 the pointer was at the seventh character of the data, and when the next
879 pattern item was \d. Just one circumflex is output if the start and
880 current positions are the same.
881
882 Callouts numbered 255 are assumed to be automatic callouts, inserted as
883 a result of the /C pattern modifier. In this case, instead of showing
884 the callout number, the offset in the pattern, preceded by a plus, is
885 output. For example:
886
887 re> /\d?[A-E]\*/C
888 data> E*
889 --->E*
890 +0 ^ \d?
891 +3 ^ [A-E]
892 +8 ^^ \*
893 +10 ^ ^
894 0: E*
895
896 If a pattern contains (*MARK) items, an additional line is output when-
897 ever a change of latest mark is passed to the callout function. For
898 example:
899
900 re> /a(*MARK:X)bc/C
901 data> abc
902 --->abc
903 +0 ^ a
904 +1 ^^ (*MARK:X)
905 +10 ^^ b
906 Latest Mark: X
907 +11 ^ ^ c
908 +12 ^ ^
909 0: abc
910
911 The mark changes between matching "a" and "b", but stays the same for
912 the rest of the match, so nothing more is output. If, as a result of
913 backtracking, the mark reverts to being unset, the text "<unset>" is
914 output.
915
916 The callout function in pcretest returns zero (carry on matching) by
917 default, but you can use a \C item in a data line (as described above)
918 to change this and other parameters of the callout.
919
920 Inserting callouts can be helpful when using pcretest to check compli-
921 cated regular expressions. For further information about callouts, see
922 the pcrecallout documentation.
923
924
925 NON-PRINTING CHARACTERS
926
927 When pcretest is outputting text in the compiled version of a pattern,
928 bytes other than 32-126 are always treated as non-printing characters
929 are are therefore shown as hex escapes.
930
931 When pcretest is outputting text that is a matched part of a subject
932 string, it behaves in the same way, unless a different locale has been
933 set for the pattern (using the /L modifier). In this case, the
934 isprint() function to distinguish printing and non-printing characters.
935
936
937 SAVING AND RELOADING COMPILED PATTERNS
938
939 The facilities described in this section are not available when the
940 POSIX interface to PCRE is being used, that is, when the /P pattern
941 modifier is specified.
942
943 When the POSIX interface is not in use, you can cause pcretest to write
944 a compiled pattern to a file, by following the modifiers with > and a
945 file name. For example:
946
947 /pattern/im >/some/file
948
949 See the pcreprecompile documentation for a discussion about saving and
950 re-using compiled patterns. Note that if the pattern was successfully
951 studied with JIT optimization, the JIT data cannot be saved.
952
953 The data that is written is binary. The first eight bytes are the
954 length of the compiled pattern data followed by the length of the
955 optional study data, each written as four bytes in big-endian order
956 (most significant byte first). If there is no study data (either the
957 pattern was not studied, or studying did not return any data), the sec-
958 ond length is zero. The lengths are followed by an exact copy of the
959 compiled pattern. If there is additional study data, this (excluding
960 any JIT data) follows immediately after the compiled pattern. After
961 writing the file, pcretest expects to read a new pattern.
962
963 A saved pattern can be reloaded into pcretest by specifying < and a
964 file name instead of a pattern. The name of the file must not contain a
965 < character, as otherwise pcretest will interpret the line as a pattern
966 delimited by < characters. For example:
967
968 re> </some/file
969 Compiled pattern loaded from /some/file
970 No study data
971
972 If the pattern was previously studied with the JIT optimization, the
973 JIT information cannot be saved and restored, and so is lost. When the
974 pattern has been loaded, pcretest proceeds to read data lines in the
975 usual way.
976
977 You can copy a file written by pcretest to a different host and reload
978 it there, even if the new host has opposite endianness to the one on
979 which the pattern was compiled. For example, you can compile on an i86
980 machine and run on a SPARC machine. When a pattern is reloaded on a
981 host with different endianness, the confirmation message is changed to:
982
983 Compiled pattern (byte-inverted) loaded from /some/file
984
985 The test suite contains some saved pre-compiled patterns with different
986 endianness. These are reloaded using "<!" instead of just "<". This
987 suppresses the "(byte-inverted)" text so that the output is the same on
988 all hosts. It also forces debugging output once the pattern has been
989 reloaded.
990
991 File names for saving and reloading can be absolute or relative, but
992 note that the shell facility of expanding a file name that starts with
993 a tilde (~) is not available.
994
995 The ability to save and reload files in pcretest is intended for test-
996 ing and experimentation. It is not intended for production use because
997 only a single pattern can be written to a file. Furthermore, there is
998 no facility for supplying custom character tables for use with a
999 reloaded pattern. If the original pattern was compiled with custom
1000 tables, an attempt to match a subject string using a reloaded pattern
1001 is likely to cause pcretest to crash. Finally, if you attempt to load
1002 a file that is not in the correct format, the result is undefined.
1003
1004
1005 SEE ALSO
1006
1007 pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1008 pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1009
1010
1011 AUTHOR
1012
1013 Philip Hazel
1014 University Computing Service
1015 Cambridge CB2 3QH, England.
1016
1017
1018 REVISION
1019
1020 Last updated: 22 February 2013
1021 Copyright (c) 1997-2013 University of Cambridge.

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