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3 pcretest - a program for testing Perl-compatible regular expressions.
5 .rs
6 .sp
7 .B pcretest "[options] [input file [output file]]"
8 .sp
9 \fBpcretest\fP was written as a test program for the PCRE regular expression
10 library itself, but it can also be used for experimenting with regular
11 expressions. This document describes the features of the test program; for
12 details of the regular expressions themselves, see the
13 .\" HREF
14 \fBpcrepattern\fP
15 .\"
16 documentation. For details of the PCRE library function calls and their
17 options, see the
18 .\" HREF
19 \fBpcreapi\fP
20 .\"
21 and
22 .\" HREF
23 \fBpcre16\fP
24 .\"
25 documentation. The input for \fBpcretest\fP is a sequence of regular expression
26 patterns and strings to be matched, as described below. The output shows the
27 result of each match. Options on the command line and the patterns control PCRE
28 options and exactly what is output.
29 .
30 .
31 .SH "PCRE's 8-BIT and 16-BIT LIBRARIES"
32 .rs
33 .sp
34 From release 8.30, two separate PCRE libraries can be built. The original one
35 supports 8-bit character strings, whereas the newer 16-bit library supports
36 character strings encoded in 16-bit units. The \fBpcretest\fP program can be
37 used to test both libraries. However, it is itself still an 8-bit program,
38 reading 8-bit input and writing 8-bit output. When testing the 16-bit library,
39 the patterns and data strings are converted to 16-bit format before being
40 passed to the PCRE library functions. Results are converted to 8-bit for
41 output.
42 .P
43 References to functions and structures of the form \fBpcre[16]_xx\fP below
44 mean "\fBpcre_xx\fP when using the 8-bit library or \fBpcre16_xx\fP when using
45 the 16-bit library".
46 .
47 .
49 .rs
50 .TP 10
51 \fB-16\fP
52 If both the 8-bit and the 16-bit libraries have been built, this option causes
53 the 16-bit library to be used. If only the 16-bit library has been built, this
54 is the default (so has no effect). If only the 8-bit library has been built,
55 this option causes an error.
56 .TP 10
57 \fB-b\fP
58 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the
59 internal form is output after compilation.
60 .TP 10
61 \fB-C\fP
62 Output the version number of the PCRE library, and all available information
63 about the optional features that are included, and then exit. All other options
64 are ignored.
65 .TP 10
66 \fB-C\fP \fIoption\fP
67 Output information about a specific build-time option, then exit. This
68 functionality is intended for use in scripts such as \fBRunTest\fP. The
69 following options output the value indicated:
70 .sp
71 linksize the internal link size (2, 3, or 4)
72 newline the default newline setting:
74 .sp
75 The following options output 1 for true or zero for false:
76 .sp
77 jit just-in-time support is available
78 pcre16 the 16-bit library was built
79 pcre8 the 8-bit library was built
80 ucp Unicode property support is available
81 utf UTF-8 and/or UTF-16 support is available
82 .TP 10
83 \fB-d\fP
84 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal
85 form and information about the compiled pattern is output after compilation;
86 \fB-d\fP is equivalent to \fB-b -i\fP.
87 .TP 10
88 \fB-dfa\fP
89 Behave as if each data line contains the \eD escape sequence; this causes the
90 alternative matching function, \fBpcre[16]_dfa_exec()\fP, to be used instead of
91 the standard \fBpcre[16]_exec()\fP function (more detail is given below).
92 .TP 10
93 \fB-help\fP
94 Output a brief summary these options and then exit.
95 .TP 10
96 \fB-i\fP
97 Behave as if each pattern has the \fB/I\fP modifier; information about the
98 compiled pattern is given after compilation.
99 .TP 10
100 \fB-M\fP
101 Behave as if each data line contains the \eM escape sequence; this causes
102 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
103 calling \fBpcre[16]_exec()\fP repeatedly with different limits.
104 .TP 10
105 \fB-m\fP
106 Output the size of each compiled pattern after it has been compiled. This is
107 equivalent to adding \fB/M\fP to each regular expression. The size is given in
108 bytes for both libraries.
109 .TP 10
110 \fB-o\fP \fIosize\fP
111 Set the number of elements in the output vector that is used when calling
112 \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP to be \fIosize\fP. The
113 default value is 45, which is enough for 14 capturing subexpressions for
114 \fBpcre[16]_exec()\fP or 22 different matches for \fBpcre[16]_dfa_exec()\fP.
115 The vector size can be changed for individual matching calls by including \eO
116 in the data line (see below).
117 .TP 10
118 \fB-p\fP
119 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is
120 used to call PCRE. None of the other options has any effect when \fB-p\fP is
121 set. This option can be used only with the 8-bit library.
122 .TP 10
123 \fB-q\fP
124 Do not output the version number of \fBpcretest\fP at the start of execution.
125 .TP 10
126 \fB-S\fP \fIsize\fP
127 On Unix-like systems, set the size of the run-time stack to \fIsize\fP
128 megabytes.
129 .TP 10
130 \fB-s\fP or \fB-s+\fP
131 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each
132 pattern to be studied. If \fB-s+\fP is used, the PCRE_STUDY_JIT_COMPILE flag is
133 passed to \fBpcre[16]_study()\fP, causing just-in-time optimization to be set
134 up if it is available. If the \fB/I\fP or \fB/D\fP option is present on a
135 pattern (requesting output about the compiled pattern), information about the
136 result of studying is not included when studying is caused only by \fB-s\fP and
137 neither \fB-i\fP nor \fB-d\fP is present on the command line. This behaviour
138 means that the output from tests that are run with and without \fB-s\fP should
139 be identical, except when options that output information about the actual
140 running of a match are set.
141 .sp
142 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about
143 resources used, are likely to produce different output with and without
144 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an
145 individual pattern. This uses callouts to trace the the matching process, and
146 this may be different between studied and non-studied patterns. If the pattern
147 contains (*MARK) items there may also be differences, for the same reason. The
148 \fB-s\fP command line option can be overridden for specific patterns that
149 should never be studied (see the \fB/S\fP pattern modifier below).
150 .TP 10
151 \fB-t\fP
152 Run each compile, study, and match many times with a timer, and output
153 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
154 \fB-t\fP, because you will then get the size output a zillion times, and the
155 timing will be distorted. You can control the number of iterations that are
156 used for timing by following \fB-t\fP with a number (as a separate item on the
157 command line). For example, "-t 1000" would iterate 1000 times. The default is
158 to iterate 500000 times.
159 .TP 10
160 \fB-tm\fP
161 This is like \fB-t\fP except that it times only the matching phase, not the
162 compile or study phases.
163 .
164 .
166 .rs
167 .sp
168 If \fBpcretest\fP is given two filename arguments, it reads from the first and
169 writes to the second. If it is given only one filename argument, it reads from
170 that file and writes to stdout. Otherwise, it reads from stdin and writes to
171 stdout, and prompts for each line of input, using "re>" to prompt for regular
172 expressions, and "data>" to prompt for data lines.
173 .P
174 When \fBpcretest\fP is built, a configuration option can specify that it should
175 be linked with the \fBlibreadline\fP library. When this is done, if the input
176 is from a terminal, it is read using the \fBreadline()\fP function. This
177 provides line-editing and history facilities. The output from the \fB-help\fP
178 option states whether or not \fBreadline()\fP will be used.
179 .P
180 The program handles any number of sets of input on a single input file. Each
181 set starts with a regular expression, and continues with any number of data
182 lines to be matched against the pattern.
183 .P
184 Each data line is matched separately and independently. If you want to do
185 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
186 etc., depending on the newline setting) in a single line of input to encode the
187 newline sequences. There is no limit on the length of data lines; the input
188 buffer is automatically extended if it is too small.
189 .P
190 An empty line signals the end of the data lines, at which point a new regular
191 expression is read. The regular expressions are given enclosed in any
192 non-alphanumeric delimiters other than backslash, for example:
193 .sp
194 /(a|bc)x+yz/
195 .sp
196 White space before the initial delimiter is ignored. A regular expression may
197 be continued over several input lines, in which case the newline characters are
198 included within it. It is possible to include the delimiter within the pattern
199 by escaping it, for example
200 .sp
201 /abc\e/def/
202 .sp
203 If you do so, the escape and the delimiter form part of the pattern, but since
204 delimiters are always non-alphanumeric, this does not affect its interpretation.
205 If the terminating delimiter is immediately followed by a backslash, for
206 example,
207 .sp
208 /abc/\e
209 .sp
210 then a backslash is added to the end of the pattern. This is done to provide a
211 way of testing the error condition that arises if a pattern finishes with a
212 backslash, because
213 .sp
214 /abc\e/
215 .sp
216 is interpreted as the first line of a pattern that starts with "abc/", causing
217 pcretest to read the next line as a continuation of the regular expression.
218 .
219 .
221 .rs
222 .sp
223 A pattern may be followed by any number of modifiers, which are mostly single
224 characters. Following Perl usage, these are referred to below as, for example,
225 "the \fB/i\fP modifier", even though the delimiter of the pattern need not
226 always be a slash, and no slash is used when writing modifiers. White space may
227 appear between the final pattern delimiter and the first modifier, and between
228 the modifiers themselves.
229 .P
230 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
231 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
232 \fBpcre[16]_compile()\fP is called. These four modifier letters have the same
233 effect as they do in Perl. For example:
234 .sp
235 /caseless/i
236 .sp
237 The following table shows additional modifiers for setting PCRE compile-time
238 options that do not correspond to anything in Perl:
239 .sp
240 \fB/8\fP PCRE_UTF8 ) when using the 8-bit
241 \fB/?\fP PCRE_NO_UTF8_CHECK ) library
242 .sp
243 \fB/8\fP PCRE_UTF16 ) when using the 16-bit
244 \fB/?\fP PCRE_NO_UTF16_CHECK ) library
245 .sp
253 \fB/W\fP PCRE_UCP
257 \fB/<cr>\fP PCRE_NEWLINE_CR
258 \fB/<lf>\fP PCRE_NEWLINE_LF
259 \fB/<crlf>\fP PCRE_NEWLINE_CRLF
260 \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
261 \fB/<any>\fP PCRE_NEWLINE_ANY
262 \fB/<bsr_anycrlf>\fP PCRE_BSR_ANYCRLF
263 \fB/<bsr_unicode>\fP PCRE_BSR_UNICODE
264 .sp
265 The modifiers that are enclosed in angle brackets are literal strings as shown,
266 including the angle brackets, but the letters within can be in either case.
267 This example sets multiline matching with CRLF as the line ending sequence:
268 .sp
269 /^abc/m<CRLF>
270 .sp
271 As well as turning on the PCRE_UTF8/16 option, the \fB/8\fP modifier causes
272 all non-printing characters in output strings to be printed using the
273 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without
274 the curly brackets.
275 .P
276 Full details of the PCRE options are given in the
277 .\" HREF
278 \fBpcreapi\fP
279 .\"
280 documentation.
281 .
282 .
283 .SS "Finding all matches in a string"
284 .rs
285 .sp
286 Searching for all possible matches within each subject string can be requested
287 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
288 again to search the remainder of the subject string. The difference between
289 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
290 \fBpcre[16]_exec()\fP to start searching at a new point within the entire
291 string (which is in effect what Perl does), whereas the latter passes over a
292 shortened substring. This makes a difference to the matching process if the
293 pattern begins with a lookbehind assertion (including \eb or \eB).
294 .P
295 If any call to \fBpcre[16]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches
296 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
297 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
298 same point. If this second match fails, the start offset is advanced, and the
299 normal match is retried. This imitates the way Perl handles such cases when
300 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start
301 offset is advanced by one character, but if the newline convention recognizes
302 CRLF as a newline, and the current character is CR followed by LF, an advance
303 of two is used.
304 .
305 .
306 .SS "Other modifiers"
307 .rs
308 .sp
309 There are yet more modifiers for controlling the way \fBpcretest\fP
310 operates.
311 .P
312 The \fB/+\fP modifier requests that as well as outputting the substring that
313 matched the entire pattern, \fBpcretest\fP should in addition output the
314 remainder of the subject string. This is useful for tests where the subject
315 contains multiple copies of the same substring. If the \fB+\fP modifier appears
316 twice, the same action is taken for captured substrings. In each case the
317 remainder is output on the following line with a plus character following the
318 capture number. Note that this modifier must not immediately follow the /S
319 modifier because /S+ has another meaning.
320 .P
321 The \fB/=\fP modifier requests that the values of all potential captured
322 parentheses be output after a match. By default, only those up to the highest
323 one actually used in the match are output (corresponding to the return code
324 from \fBpcre[16]_exec()\fP). Values in the offsets vector corresponding to
325 higher numbers should be set to -1, and these are output as "<unset>". This
326 modifier gives a way of checking that this is happening.
327 .P
328 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
329 output a representation of the compiled code after compilation. Normally this
330 information contains length and offset values; however, if \fB/Z\fP is also
331 present, this data is replaced by spaces. This is a special feature for use in
332 the automatic test scripts; it ensures that the same output is generated for
333 different internal link sizes.
334 .P
335 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
336 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
337 .P
338 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
339 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
340 the feature in PCRE that allows it to execute patterns that were compiled on a
341 host with a different endianness. This feature is not available when the POSIX
342 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
343 specified. See also the section about saving and reloading compiled patterns
344 below.
345 .P
346 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
347 compiled pattern (whether it is anchored, has a fixed first character, and
348 so on). It does this by calling \fBpcre[16]_fullinfo()\fP after compiling a
349 pattern. If the pattern is studied, the results of that are also output.
350 .P
351 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking
352 control verbs that are returned from calls to \fBpcre[16]_exec()\fP. It causes
353 \fBpcretest\fP to create a \fBpcre[16]_extra\fP block if one has not already
354 been created by a call to \fBpcre[16]_study()\fP, and to set the
355 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that
356 \fBpcre[16]_exec()\fP is called. If the variable that the \fBmark\fP field
357 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP
358 prints the string to which it points. For a match, this is shown on a line by
359 itself, tagged with "MK:". For a non-match it is added to the message.
360 .P
361 The \fB/L\fP modifier must be followed directly by the name of a locale, for
362 example,
363 .sp
364 /pattern/Lfr_FR
365 .sp
366 For this reason, it must be the last modifier. The given locale is set,
367 \fBpcre[16]_maketables()\fP is called to build a set of character tables for
368 the locale, and this is then passed to \fBpcre[16]_compile()\fP when compiling
369 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is
370 passed as the tables pointer; that is, \fB/L\fP applies only to the expression
371 on which it appears.
372 .P
373 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold
374 the compiled pattern to be output. This does not include the size of the
375 \fBpcre[16]\fP block; it is just the actual compiled data. If the pattern is
376 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
377 JIT compiled code is also output.
378 .P
379 If the \fB/S\fP modifier appears once, it causes \fBpcre[16]_study()\fP to be
380 called after the expression has been compiled, and the results used when the
381 expression is matched. If \fB/S\fP appears twice, it suppresses studying, even
382 if it was requested externally by the \fB-s\fP command line option. This makes
383 it possible to specify that certain patterns are always studied, and others are
384 never studied, independently of \fB-s\fP. This feature is used in the test
385 files in a few cases where the output is different when the pattern is studied.
386 .P
387 If the \fB/S\fP modifier is immediately followed by a + character, the call to
388 \fBpcre[16]_study()\fP is made with the PCRE_STUDY_JIT_COMPILE option,
389 requesting just-in-time optimization support if it is available. Note that
390 there is also a \fB/+\fP modifier; it must not be given immediately after
391 \fB/S\fP because this will be misinterpreted. If JIT studying is successful, it
392 will automatically be used when \fBpcre[16]_exec()\fP is run, except when
393 incompatible run-time options are specified. These include the partial matching
394 options; a complete list is given in the
395 .\" HREF
396 \fBpcrejit\fP
397 .\"
398 documentation. See also the \fB\eJ\fP escape sequence below for a way of
399 setting the size of the JIT stack.
400 .P
401 The \fB/T\fP modifier must be followed by a single digit. It causes a specific
402 set of built-in character tables to be passed to \fBpcre[16]_compile()\fP. It
403 is used in the standard PCRE tests to check behaviour with different character
404 tables. The digit specifies the tables as follows:
405 .sp
406 0 the default ASCII tables, as distributed in
407 pcre_chartables.c.dist
408 1 a set of tables defining ISO 8859 characters
409 .sp
410 In table 1, some characters whose codes are greater than 128 are identified as
411 letters, digits, spaces, etc.
412 .
413 .
414 .SS "Using the POSIX wrapper API"
415 .rs
416 .sp
417 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
418 API rather than its native API. This supports only the 8-bit library. When
419 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP
420 function:
421 .sp
422 /i REG_ICASE
425 /s REG_DOTALL )
426 /U REG_UNGREEDY ) These options are not part of
427 /W REG_UCP ) the POSIX standard
428 /8 REG_UTF8 )
429 .sp
430 The \fB/+\fP modifier works as described above. All other modifiers are
431 ignored.
432 .
433 .
435 .rs
436 .sp
437 Before each data line is passed to \fBpcre[16]_exec()\fP, leading and trailing
438 white space is removed, and it is then scanned for \e escapes. Some of these
439 are pretty esoteric features, intended for checking out some of the more
440 complicated features of PCRE. If you are just testing "ordinary" regular
441 expressions, you probably don't need any of these. The following escapes are
442 recognized:
443 .sp
444 \ea alarm (BEL, \ex07)
445 \eb backspace (\ex08)
446 \ee escape (\ex27)
447 \ef form feed (\ex0c)
448 \en newline (\ex0a)
449 .\" JOIN
450 \eqdd set the PCRE_MATCH_LIMIT limit to dd
451 (any number of digits)
452 \er carriage return (\ex0d)
453 \et tab (\ex09)
454 \ev vertical tab (\ex0b)
455 \ennn octal character (up to 3 octal digits); always
456 a byte unless > 255 in UTF-8 or 16-bit mode
457 \exhh hexadecimal byte (up to 2 hex digits)
458 \ex{hh...} hexadecimal character (any number of hex digits)
459 .\" JOIN
460 \eA pass the PCRE_ANCHORED option to \fBpcre[16]_exec()\fP
461 or \fBpcre[16]_dfa_exec()\fP
462 .\" JOIN
463 \eB pass the PCRE_NOTBOL option to \fBpcre[16]_exec()\fP
464 or \fBpcre[16]_dfa_exec()\fP
465 .\" JOIN
466 \eCdd call pcre[16]_copy_substring() for substring dd
467 after a successful match (number less than 32)
468 .\" JOIN
469 \eCname call pcre[16]_copy_named_substring() for substring
470 "name" after a successful match (name termin-
471 ated by next non alphanumeric character)
472 .\" JOIN
473 \eC+ show the current captured substrings at callout
474 time
475 \eC- do not supply a callout function
476 .\" JOIN
477 \eC!n return 1 instead of 0 when callout number n is
478 reached
479 .\" JOIN
480 \eC!n!m return 1 instead of 0 when callout number n is
481 reached for the nth time
482 .\" JOIN
483 \eC*n pass the number n (may be negative) as callout
484 data; this is used as the callout return value
485 \eD use the \fBpcre[16]_dfa_exec()\fP match function
486 \eF only shortest match for \fBpcre[16]_dfa_exec()\fP
487 .\" JOIN
488 \eGdd call pcre[16]_get_substring() for substring dd
489 after a successful match (number less than 32)
490 .\" JOIN
491 \eGname call pcre[16]_get_named_substring() for substring
492 "name" after a successful match (name termin-
493 ated by next non-alphanumeric character)
494 .\" JOIN
495 \eJdd set up a JIT stack of dd kilobytes maximum (any
496 number of digits)
497 .\" JOIN
498 \eL call pcre[16]_get_substringlist() after a
499 successful match
500 .\" JOIN
501 \eM discover the minimum MATCH_LIMIT and
503 .\" JOIN
504 \eN pass the PCRE_NOTEMPTY option to \fBpcre[16]_exec()\fP
505 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
507 .\" JOIN
508 \eOdd set the size of the output vector passed to
509 \fBpcre[16]_exec()\fP to dd (any number of digits)
510 .\" JOIN
511 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre[16]_exec()\fP
512 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
514 .\" JOIN
515 \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
516 (any number of digits)
517 \eR pass the PCRE_DFA_RESTART option to \fBpcre[16]_dfa_exec()\fP
518 \eS output details of memory get/free calls during matching
519 .\" JOIN
520 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16]_exec()\fP
521 or \fBpcre[16]_dfa_exec()\fP
522 .\" JOIN
523 \eZ pass the PCRE_NOTEOL option to \fBpcre[16]_exec()\fP
524 or \fBpcre[16]_dfa_exec()\fP
525 .\" JOIN
526 \e? pass the PCRE_NO_UTF[8|16]_CHECK option to
527 \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
528 .\" JOIN
529 \e>dd start the match at offset dd (optional "-"; then
530 any number of digits); this sets the \fIstartoffset\fP
531 argument for \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
532 .\" JOIN
533 \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre[16]_exec()\fP
534 or \fBpcre[16]_dfa_exec()\fP
535 .\" JOIN
536 \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre[16]_exec()\fP
537 or \fBpcre[16]_dfa_exec()\fP
538 .\" JOIN
539 \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre[16]_exec()\fP
540 or \fBpcre[16]_dfa_exec()\fP
541 .\" JOIN
542 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16]_exec()\fP
543 or \fBpcre[16]_dfa_exec()\fP
544 .\" JOIN
545 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre[16]_exec()\fP
546 or \fBpcre[16]_dfa_exec()\fP
547 .sp
548 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on
549 the pattern. It is recognized always. There may be any number of hexadecimal
550 digits inside the braces; invalid values provoke error messages.
551 .P
552 Note that \exhh specifies one byte rather than one character in UTF-8 mode;
553 this makes it possible to construct invalid UTF-8 sequences for testing
554 purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in
555 UTF-8 mode, generating more than one byte if the value is greater than 127.
556 When testing the 8-bit library not in UTF-8 mode, \ex{hh} generates one byte
557 for values less than 256, and causes an error for greater values.
558 .P
559 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it
560 possible to construct invalid UTF-16 sequences for testing purposes.
561 .P
562 The escapes that specify line ending sequences are literal strings, exactly as
563 shown. No more than one newline setting should be present in any data line.
564 .P
565 A backslash followed by anything else just escapes the anything else. If
566 the very last character is a backslash, it is ignored. This gives a way of
567 passing an empty line as data, since a real empty line terminates the data
568 input.
569 .P
570 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is
571 used by the just-in-time optimization code. It is ignored if JIT optimization
572 is not being used. Providing a stack that is larger than the default 32K is
573 necessary only for very complicated patterns.
574 .P
575 If \eM is present, \fBpcretest\fP calls \fBpcre[16]_exec()\fP several times,
576 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
577 fields of the \fBpcre[16]_extra\fP data structure, until it finds the minimum
578 numbers for each parameter that allow \fBpcre[16]_exec()\fP to complete without
579 error. Because this is testing a specific feature of the normal interpretive
580 \fBpcre[16]_exec()\fP execution, the use of any JIT optimization that might
581 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled.
582 .P
583 The \fImatch_limit\fP number is a measure of the amount of backtracking
584 that takes place, and checking it out can be instructive. For most simple
585 matches, the number is quite small, but for patterns with very large numbers of
586 matching possibilities, it can become large very quickly with increasing length
587 of subject string. The \fImatch_limit_recursion\fP number is a measure of how
588 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
589 needed to complete the match attempt.
590 .P
591 When \eO is used, the value specified may be higher or lower than the size set
592 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
593 the call of \fBpcre[16]_exec()\fP for the line in which it appears.
594 .P
595 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
596 API to be used, the only option-setting sequences that have any effect are \eB,
597 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
598 to be passed to \fBregexec()\fP.
599 .
600 .
602 .rs
603 .sp
604 By default, \fBpcretest\fP uses the standard PCRE matching function,
605 \fBpcre[16]_exec()\fP to match each data line. PCRE also supports an
606 alternative matching function, \fBpcre[16]_dfa_test()\fP, which operates in a
607 different way, and has some restrictions. The differences between the two
608 functions are described in the
609 .\" HREF
610 \fBpcrematching\fP
611 .\"
612 documentation.
613 .P
614 If a data line contains the \eD escape sequence, or if the command line
615 contains the \fB-dfa\fP option, the alternative matching function is used.
616 This function finds all possible matches at a given point. If, however, the \eF
617 escape sequence is present in the data line, it stops after the first match is
618 found. This is always the shortest possible match.
619 .
620 .
622 .rs
623 .sp
624 This section describes the output when the normal matching function,
625 \fBpcre[16]_exec()\fP, is being used.
626 .P
627 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings
628 that \fBpcre[16]_exec()\fP returns, starting with number 0 for the string that
629 matched the whole pattern. Otherwise, it outputs "No match" when the return is
630 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
631 substring when \fBpcre[16]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that
632 this is the entire substring that was inspected during the partial match; it
633 may include characters before the actual match start if a lookbehind assertion,
634 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs
635 the PCRE negative error number and a short descriptive phrase. If the error is
636 a failed UTF string check, the offset of the start of the failing character and
637 the reason code are also output, provided that the size of the output vector is
638 at least two. Here is an example of an interactive \fBpcretest\fP run.
639 .sp
640 $ pcretest
641 PCRE version 8.13 2011-04-30
642 .sp
643 re> /^abc(\ed+)/
644 data> abc123
645 0: abc123
646 1: 123
647 data> xyz
648 No match
649 .sp
650 Unset capturing substrings that are not followed by one that is set are not
651 returned by \fBpcre[16]_exec()\fP, and are not shown by \fBpcretest\fP. In the
652 following example, there are two capturing substrings, but when the first data
653 line is matched, the second, unset substring is not shown. An "internal" unset
654 substring is shown as "<unset>", as for the second data line.
655 .sp
656 re> /(a)|(b)/
657 data> a
658 0: a
659 1: a
660 data> b
661 0: b
662 1: <unset>
663 2: b
664 .sp
665 If the strings contain any non-printing characters, they are output as \exhh
666 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
667 are output as \ex{hh...} escapes. See below for the definition of non-printing
668 characters. If the pattern has the \fB/+\fP modifier, the output for substring
669 0 is followed by the the rest of the subject string, identified by "0+" like
670 this:
671 .sp
672 re> /cat/+
673 data> cataract
674 0: cat
675 0+ aract
676 .sp
677 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
678 matching attempts are output in sequence, like this:
679 .sp
680 re> /\eBi(\ew\ew)/g
681 data> Mississippi
682 0: iss
683 1: ss
684 0: iss
685 1: ss
686 0: ipp
687 1: pp
688 .sp
689 "No match" is output only if the first match attempt fails. Here is an example
690 of a failure message (the offset 4 that is specified by \e>4 is past the end of
691 the subject string):
692 .sp
693 re> /xyz/
694 data> xyz\e>4
695 Error -24 (bad offset value)
696 .P
697 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
698 data line that is successfully matched, the substrings extracted by the
699 convenience functions are output with C, G, or L after the string number
700 instead of a colon. This is in addition to the normal full list. The string
701 length (that is, the return from the extraction function) is given in
702 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
703 .P
704 Note that whereas patterns can be continued over several lines (a plain ">"
705 prompt is used for continuations), data lines may not. However newlines can be
706 included in data by means of the \en escape (or \er, \er\en, etc., depending on
707 the newline sequence setting).
708 .
709 .
710 .
712 .rs
713 .sp
714 When the alternative matching function, \fBpcre[16]_dfa_exec()\fP, is used (by
715 means of the \eD escape sequence or the \fB-dfa\fP command line option), the
716 output consists of a list of all the matches that start at the first point in
717 the subject where there is at least one match. For example:
718 .sp
719 re> /(tang|tangerine|tan)/
720 data> yellow tangerine\eD
721 0: tangerine
722 1: tang
723 2: tan
724 .sp
725 (Using the normal matching function on this data finds only "tang".) The
726 longest matching string is always given first (and numbered zero). After a
727 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
728 partially matching substring. (Note that this is the entire substring that was
729 inspected during the partial match; it may include characters before the actual
730 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)
731 .P
732 If \fB/g\fP is present on the pattern, the search for further matches resumes
733 at the end of the longest match. For example:
734 .sp
735 re> /(tang|tangerine|tan)/g
736 data> yellow tangerine and tangy sultana\eD
737 0: tangerine
738 1: tang
739 2: tan
740 0: tang
741 1: tan
742 0: tan
743 .sp
744 Since the matching function does not support substring capture, the escape
745 sequences that are concerned with captured substrings are not relevant.
746 .
747 .
749 .rs
750 .sp
751 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
752 indicating that the subject partially matched the pattern, you can restart the
753 match with additional subject data by means of the \eR escape sequence. For
754 example:
755 .sp
756 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
757 data> 23ja\eP\eD
758 Partial match: 23ja
759 data> n05\eR\eD
760 0: n05
761 .sp
762 For further information about partial matching, see the
763 .\" HREF
764 \fBpcrepartial\fP
765 .\"
766 documentation.
767 .
768 .
770 .rs
771 .sp
772 If the pattern contains any callout requests, \fBpcretest\fP's callout function
773 is called during matching. This works with both matching functions. By default,
774 the called function displays the callout number, the start and current
775 positions in the text at the callout time, and the next pattern item to be
776 tested. For example:
777 .sp
778 --->pqrabcdef
779 0 ^ ^ \ed
780 .sp
781 This output indicates that callout number 0 occurred for a match attempt
782 starting at the fourth character of the subject string, when the pointer was at
783 the seventh character of the data, and when the next pattern item was \ed. Just
784 one circumflex is output if the start and current positions are the same.
785 .P
786 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
787 result of the \fB/C\fP pattern modifier. In this case, instead of showing the
788 callout number, the offset in the pattern, preceded by a plus, is output. For
789 example:
790 .sp
791 re> /\ed?[A-E]\e*/C
792 data> E*
793 --->E*
794 +0 ^ \ed?
795 +3 ^ [A-E]
796 +8 ^^ \e*
797 +10 ^ ^
798 0: E*
799 .sp
800 If a pattern contains (*MARK) items, an additional line is output whenever
801 a change of latest mark is passed to the callout function. For example:
802 .sp
803 re> /a(*MARK:X)bc/C
804 data> abc
805 --->abc
806 +0 ^ a
807 +1 ^^ (*MARK:X)
808 +10 ^^ b
809 Latest Mark: X
810 +11 ^ ^ c
811 +12 ^ ^
812 0: abc
813 .sp
814 The mark changes between matching "a" and "b", but stays the same for the rest
815 of the match, so nothing more is output. If, as a result of backtracking, the
816 mark reverts to being unset, the text "<unset>" is output.
817 .P
818 The callout function in \fBpcretest\fP returns zero (carry on matching) by
819 default, but you can use a \eC item in a data line (as described above) to
820 change this and other parameters of the callout.
821 .P
822 Inserting callouts can be helpful when using \fBpcretest\fP to check
823 complicated regular expressions. For further information about callouts, see
824 the
825 .\" HREF
826 \fBpcrecallout\fP
827 .\"
828 documentation.
829 .
830 .
831 .
833 .rs
834 .sp
835 When \fBpcretest\fP is outputting text in the compiled version of a pattern,
836 bytes other than 32-126 are always treated as non-printing characters are are
837 therefore shown as hex escapes.
838 .P
839 When \fBpcretest\fP is outputting text that is a matched part of a subject
840 string, it behaves in the same way, unless a different locale has been set for
841 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
842 function to distinguish printing and non-printing characters.
843 .
844 .
845 .
847 .rs
848 .sp
849 The facilities described in this section are not available when the POSIX
850 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
851 specified.
852 .P
853 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
854 compiled pattern to a file, by following the modifiers with > and a file name.
855 For example:
856 .sp
857 /pattern/im >/some/file
858 .sp
859 See the
860 .\" HREF
861 \fBpcreprecompile\fP
862 .\"
863 documentation for a discussion about saving and re-using compiled patterns.
864 Note that if the pattern was successfully studied with JIT optimization, the
865 JIT data cannot be saved.
866 .P
867 The data that is written is binary. The first eight bytes are the length of the
868 compiled pattern data followed by the length of the optional study data, each
869 written as four bytes in big-endian order (most significant byte first). If
870 there is no study data (either the pattern was not studied, or studying did not
871 return any data), the second length is zero. The lengths are followed by an
872 exact copy of the compiled pattern. If there is additional study data, this
873 (excluding any JIT data) follows immediately after the compiled pattern. After
874 writing the file, \fBpcretest\fP expects to read a new pattern.
875 .P
876 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file
877 name instead of a pattern. The name of the file must not contain a < character,
878 as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
879 characters.
880 For example:
881 .sp
882 re> </some/file
883 Compiled pattern loaded from /some/file
884 No study data
885 .sp
886 If the pattern was previously studied with the JIT optimization, the JIT
887 information cannot be saved and restored, and so is lost. When the pattern has
888 been loaded, \fBpcretest\fP proceeds to read data lines in the usual way.
889 .P
890 You can copy a file written by \fBpcretest\fP to a different host and reload it
891 there, even if the new host has opposite endianness to the one on which the
892 pattern was compiled. For example, you can compile on an i86 machine and run on
893 a SPARC machine. When a pattern is reloaded on a host with different
894 endianness, the confirmation message is changed to:
895 .sp
896 Compiled pattern (byte-inverted) loaded from /some/file
897 .sp
898 The test suite contains some saved pre-compiled patterns with different
899 endianness. These are reloaded using "<!" instead of just "<". This suppresses
900 the "(byte-inverted)" text so that the output is the same on all hosts. It also
901 forces debugging output once the pattern has been reloaded.
902 .P
903 File names for saving and reloading can be absolute or relative, but note that
904 the shell facility of expanding a file name that starts with a tilde (~) is not
905 available.
906 .P
907 The ability to save and reload files in \fBpcretest\fP is intended for testing
908 and experimentation. It is not intended for production use because only a
909 single pattern can be written to a file. Furthermore, there is no facility for
910 supplying custom character tables for use with a reloaded pattern. If the
911 original pattern was compiled with custom tables, an attempt to match a subject
912 string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
913 Finally, if you attempt to load a file that is not in the correct format, the
914 result is undefined.
915 .
916 .
917 .SH "SEE ALSO"
918 .rs
919 .sp
920 \fBpcre\fP(3), \fBpcre16\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
921 \fBpcrejit\fP, \fBpcrematching\fP(3), \fBpcrepartial\fP(d),
922 \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
923 .
924 .
926 .rs
927 .sp
928 .nf
929 Philip Hazel
930 University Computing Service
931 Cambridge CB2 3QH, England.
932 .fi
933 .
934 .
936 .rs
937 .sp
938 .nf
939 Last updated: 14 January 2012
940 Copyright (c) 1997-2012 University of Cambridge.
941 .fi


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