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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, all the JIT compile options are
133 passed to \fBpcre[16]_study()\fP, causing just-in-time optimization to be set
134 up if it is available, for both full and partial matching. Specific JIT compile
135 options can be selected by following \fB-s+\fP with a digit in the range 1 to
136 7, which selects the JIT compile modes as follows:
137 .sp
138 1 normal match only
139 2 soft partial match only
140 3 normal match and soft partial match
141 4 hard partial match only
142 6 soft and hard partial match
143 7 all three modes (default)
144 .sp
145 If \fB-s++\fP is used instead of \fB-s+\fP (with or without a following digit),
146 the text "(JIT)" is added to the first output line after a match or no match
147 when JIT-compiled code was actually used.
148 .P
149 If the \fB/I\fP or \fB/D\fP option is present on a pattern (requesting output
150 about the compiled pattern), information about the result of studying is not
151 included when studying is caused only by \fB-s\fP and neither \fB-i\fP nor
152 \fB-d\fP is present on the command line. This behaviour means that the output
153 from tests that are run with and without \fB-s\fP should be identical, except
154 when options that output information about the actual running of a match are
155 set.
156 .sp
157 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about
158 resources used, are likely to produce different output with and without
159 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an
160 individual pattern. This uses callouts to trace the the matching process, and
161 this may be different between studied and non-studied patterns. If the pattern
162 contains (*MARK) items there may also be differences, for the same reason. The
163 \fB-s\fP command line option can be overridden for specific patterns that
164 should never be studied (see the \fB/S\fP pattern modifier below).
165 .TP 10
166 \fB-t\fP
167 Run each compile, study, and match many times with a timer, and output
168 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
169 \fB-t\fP, because you will then get the size output a zillion times, and the
170 timing will be distorted. You can control the number of iterations that are
171 used for timing by following \fB-t\fP with a number (as a separate item on the
172 command line). For example, "-t 1000" would iterate 1000 times. The default is
173 to iterate 500000 times.
174 .TP 10
175 \fB-tm\fP
176 This is like \fB-t\fP except that it times only the matching phase, not the
177 compile or study phases.
178 .
179 .
181 .rs
182 .sp
183 If \fBpcretest\fP is given two filename arguments, it reads from the first and
184 writes to the second. If it is given only one filename argument, it reads from
185 that file and writes to stdout. Otherwise, it reads from stdin and writes to
186 stdout, and prompts for each line of input, using "re>" to prompt for regular
187 expressions, and "data>" to prompt for data lines.
188 .P
189 When \fBpcretest\fP is built, a configuration option can specify that it should
190 be linked with the \fBlibreadline\fP library. When this is done, if the input
191 is from a terminal, it is read using the \fBreadline()\fP function. This
192 provides line-editing and history facilities. The output from the \fB-help\fP
193 option states whether or not \fBreadline()\fP will be used.
194 .P
195 The program handles any number of sets of input on a single input file. Each
196 set starts with a regular expression, and continues with any number of data
197 lines to be matched against the pattern.
198 .P
199 Each data line is matched separately and independently. If you want to do
200 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
201 etc., depending on the newline setting) in a single line of input to encode the
202 newline sequences. There is no limit on the length of data lines; the input
203 buffer is automatically extended if it is too small.
204 .P
205 An empty line signals the end of the data lines, at which point a new regular
206 expression is read. The regular expressions are given enclosed in any
207 non-alphanumeric delimiters other than backslash, for example:
208 .sp
209 /(a|bc)x+yz/
210 .sp
211 White space before the initial delimiter is ignored. A regular expression may
212 be continued over several input lines, in which case the newline characters are
213 included within it. It is possible to include the delimiter within the pattern
214 by escaping it, for example
215 .sp
216 /abc\e/def/
217 .sp
218 If you do so, the escape and the delimiter form part of the pattern, but since
219 delimiters are always non-alphanumeric, this does not affect its interpretation.
220 If the terminating delimiter is immediately followed by a backslash, for
221 example,
222 .sp
223 /abc/\e
224 .sp
225 then a backslash is added to the end of the pattern. This is done to provide a
226 way of testing the error condition that arises if a pattern finishes with a
227 backslash, because
228 .sp
229 /abc\e/
230 .sp
231 is interpreted as the first line of a pattern that starts with "abc/", causing
232 pcretest to read the next line as a continuation of the regular expression.
233 .
234 .
236 .rs
237 .sp
238 A pattern may be followed by any number of modifiers, which are mostly single
239 characters. Following Perl usage, these are referred to below as, for example,
240 "the \fB/i\fP modifier", even though the delimiter of the pattern need not
241 always be a slash, and no slash is used when writing modifiers. White space may
242 appear between the final pattern delimiter and the first modifier, and between
243 the modifiers themselves.
244 .P
245 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
246 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
247 \fBpcre[16]_compile()\fP is called. These four modifier letters have the same
248 effect as they do in Perl. For example:
249 .sp
250 /caseless/i
251 .sp
252 The following table shows additional modifiers for setting PCRE compile-time
253 options that do not correspond to anything in Perl:
254 .sp
255 \fB/8\fP PCRE_UTF8 ) when using the 8-bit
256 \fB/?\fP PCRE_NO_UTF8_CHECK ) library
257 .sp
258 \fB/8\fP PCRE_UTF16 ) when using the 16-bit
259 \fB/?\fP PCRE_NO_UTF16_CHECK ) library
260 .sp
268 \fB/W\fP PCRE_UCP
272 \fB/<cr>\fP PCRE_NEWLINE_CR
273 \fB/<lf>\fP PCRE_NEWLINE_LF
274 \fB/<crlf>\fP PCRE_NEWLINE_CRLF
275 \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
276 \fB/<any>\fP PCRE_NEWLINE_ANY
277 \fB/<bsr_anycrlf>\fP PCRE_BSR_ANYCRLF
278 \fB/<bsr_unicode>\fP PCRE_BSR_UNICODE
279 .sp
280 The modifiers that are enclosed in angle brackets are literal strings as shown,
281 including the angle brackets, but the letters within can be in either case.
282 This example sets multiline matching with CRLF as the line ending sequence:
283 .sp
284 /^abc/m<CRLF>
285 .sp
286 As well as turning on the PCRE_UTF8/16 option, the \fB/8\fP modifier causes
287 all non-printing characters in output strings to be printed using the
288 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without
289 the curly brackets.
290 .P
291 Full details of the PCRE options are given in the
292 .\" HREF
293 \fBpcreapi\fP
294 .\"
295 documentation.
296 .
297 .
298 .SS "Finding all matches in a string"
299 .rs
300 .sp
301 Searching for all possible matches within each subject string can be requested
302 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
303 again to search the remainder of the subject string. The difference between
304 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
305 \fBpcre[16]_exec()\fP to start searching at a new point within the entire
306 string (which is in effect what Perl does), whereas the latter passes over a
307 shortened substring. This makes a difference to the matching process if the
308 pattern begins with a lookbehind assertion (including \eb or \eB).
309 .P
310 If any call to \fBpcre[16]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches
311 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
312 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
313 same point. If this second match fails, the start offset is advanced, and the
314 normal match is retried. This imitates the way Perl handles such cases when
315 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start
316 offset is advanced by one character, but if the newline convention recognizes
317 CRLF as a newline, and the current character is CR followed by LF, an advance
318 of two is used.
319 .
320 .
321 .SS "Other modifiers"
322 .rs
323 .sp
324 There are yet more modifiers for controlling the way \fBpcretest\fP
325 operates.
326 .P
327 The \fB/+\fP modifier requests that as well as outputting the substring that
328 matched the entire pattern, \fBpcretest\fP should in addition output the
329 remainder of the subject string. This is useful for tests where the subject
330 contains multiple copies of the same substring. If the \fB+\fP modifier appears
331 twice, the same action is taken for captured substrings. In each case the
332 remainder is output on the following line with a plus character following the
333 capture number. Note that this modifier must not immediately follow the /S
334 modifier because /S+ and /S++ have other meanings.
335 .P
336 The \fB/=\fP modifier requests that the values of all potential captured
337 parentheses be output after a match. By default, only those up to the highest
338 one actually used in the match are output (corresponding to the return code
339 from \fBpcre[16]_exec()\fP). Values in the offsets vector corresponding to
340 higher numbers should be set to -1, and these are output as "<unset>". This
341 modifier gives a way of checking that this is happening.
342 .P
343 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
344 output a representation of the compiled code after compilation. Normally this
345 information contains length and offset values; however, if \fB/Z\fP is also
346 present, this data is replaced by spaces. This is a special feature for use in
347 the automatic test scripts; it ensures that the same output is generated for
348 different internal link sizes.
349 .P
350 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
351 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
352 .P
353 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
354 2-byte and 4-byte fields in the compiled pattern. This facility is for testing
355 the feature in PCRE that allows it to execute patterns that were compiled on a
356 host with a different endianness. This feature is not available when the POSIX
357 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
358 specified. See also the section about saving and reloading compiled patterns
359 below.
360 .P
361 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
362 compiled pattern (whether it is anchored, has a fixed first character, and
363 so on). It does this by calling \fBpcre[16]_fullinfo()\fP after compiling a
364 pattern. If the pattern is studied, the results of that are also output.
365 .P
366 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking
367 control verbs that are returned from calls to \fBpcre[16]_exec()\fP. It causes
368 \fBpcretest\fP to create a \fBpcre[16]_extra\fP block if one has not already
369 been created by a call to \fBpcre[16]_study()\fP, and to set the
370 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that
371 \fBpcre[16]_exec()\fP is called. If the variable that the \fBmark\fP field
372 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP
373 prints the string to which it points. For a match, this is shown on a line by
374 itself, tagged with "MK:". For a non-match it is added to the message.
375 .P
376 The \fB/L\fP modifier must be followed directly by the name of a locale, for
377 example,
378 .sp
379 /pattern/Lfr_FR
380 .sp
381 For this reason, it must be the last modifier. The given locale is set,
382 \fBpcre[16]_maketables()\fP is called to build a set of character tables for
383 the locale, and this is then passed to \fBpcre[16]_compile()\fP when compiling
384 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is
385 passed as the tables pointer; that is, \fB/L\fP applies only to the expression
386 on which it appears.
387 .P
388 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold
389 the compiled pattern to be output. This does not include the size of the
390 \fBpcre[16]\fP block; it is just the actual compiled data. If the pattern is
391 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the
392 JIT compiled code is also output.
393 .P
394 If the \fB/S\fP modifier appears once, it causes \fBpcre[16]_study()\fP to be
395 called after the expression has been compiled, and the results used when the
396 expression is matched. If \fB/S\fP appears twice, it suppresses studying, even
397 if it was requested externally by the \fB-s\fP command line option. This makes
398 it possible to specify that certain patterns are always studied, and others are
399 never studied, independently of \fB-s\fP. This feature is used in the test
400 files in a few cases where the output is different when the pattern is studied.
401 .P
402 If the \fB/S\fP modifier is immediately followed by a + character, the call to
403 \fBpcre[16]_study()\fP is made with all the JIT study options, requesting
404 just-in-time optimization support if it is available, for both normal and
405 partial matching. If you want to restrict the JIT compiling modes, you can
406 follow \fB/S+\fP with a digit in the range 1 to 7:
407 .sp
408 1 normal match only
409 2 soft partial match only
410 3 normal match and soft partial match
411 4 hard partial match only
412 6 soft and hard partial match
413 7 all three modes (default)
414 .sp
415 If \fB/S++\fP is used instead of \fB/S+\fP (with or without a following digit),
416 the text "(JIT)" is added to the first output line after a match or no match
417 when JIT-compiled code was actually used.
418 .P
419 Note that there is also an independent \fB/+\fP modifier; it must not be given
420 immediately after \fB/S\fP or \fB/S+\fP because this will be misinterpreted.
421 .P
422 If JIT studying is successful, the compiled JIT code will automatically be used
423 when \fBpcre[16]_exec()\fP is run, except when incompatible run-time options
424 are specified. For more details, see the
425 .\" HREF
426 \fBpcrejit\fP
427 .\"
428 documentation. See also the \fB\eJ\fP escape sequence below for a way of
429 setting the size of the JIT stack.
430 .P
431 The \fB/T\fP modifier must be followed by a single digit. It causes a specific
432 set of built-in character tables to be passed to \fBpcre[16]_compile()\fP. It
433 is used in the standard PCRE tests to check behaviour with different character
434 tables. The digit specifies the tables as follows:
435 .sp
436 0 the default ASCII tables, as distributed in
437 pcre_chartables.c.dist
438 1 a set of tables defining ISO 8859 characters
439 .sp
440 In table 1, some characters whose codes are greater than 128 are identified as
441 letters, digits, spaces, etc.
442 .
443 .
444 .SS "Using the POSIX wrapper API"
445 .rs
446 .sp
447 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
448 API rather than its native API. This supports only the 8-bit library. When
449 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP
450 function:
451 .sp
452 /i REG_ICASE
455 /s REG_DOTALL )
456 /U REG_UNGREEDY ) These options are not part of
457 /W REG_UCP ) the POSIX standard
458 /8 REG_UTF8 )
459 .sp
460 The \fB/+\fP modifier works as described above. All other modifiers are
461 ignored.
462 .
463 .
465 .rs
466 .sp
467 Before each data line is passed to \fBpcre[16]_exec()\fP, leading and trailing
468 white space is removed, and it is then scanned for \e escapes. Some of these
469 are pretty esoteric features, intended for checking out some of the more
470 complicated features of PCRE. If you are just testing "ordinary" regular
471 expressions, you probably don't need any of these. The following escapes are
472 recognized:
473 .sp
474 \ea alarm (BEL, \ex07)
475 \eb backspace (\ex08)
476 \ee escape (\ex27)
477 \ef form feed (\ex0c)
478 \en newline (\ex0a)
479 .\" JOIN
480 \eqdd set the PCRE_MATCH_LIMIT limit to dd
481 (any number of digits)
482 \er carriage return (\ex0d)
483 \et tab (\ex09)
484 \ev vertical tab (\ex0b)
485 \ennn octal character (up to 3 octal digits); always
486 a byte unless > 255 in UTF-8 or 16-bit mode
487 \exhh hexadecimal byte (up to 2 hex digits)
488 \ex{hh...} hexadecimal character (any number of hex digits)
489 .\" JOIN
490 \eA pass the PCRE_ANCHORED option to \fBpcre[16]_exec()\fP
491 or \fBpcre[16]_dfa_exec()\fP
492 .\" JOIN
493 \eB pass the PCRE_NOTBOL option to \fBpcre[16]_exec()\fP
494 or \fBpcre[16]_dfa_exec()\fP
495 .\" JOIN
496 \eCdd call pcre[16]_copy_substring() for substring dd
497 after a successful match (number less than 32)
498 .\" JOIN
499 \eCname call pcre[16]_copy_named_substring() for substring
500 "name" after a successful match (name termin-
501 ated by next non alphanumeric character)
502 .\" JOIN
503 \eC+ show the current captured substrings at callout
504 time
505 \eC- do not supply a callout function
506 .\" JOIN
507 \eC!n return 1 instead of 0 when callout number n is
508 reached
509 .\" JOIN
510 \eC!n!m return 1 instead of 0 when callout number n is
511 reached for the nth time
512 .\" JOIN
513 \eC*n pass the number n (may be negative) as callout
514 data; this is used as the callout return value
515 \eD use the \fBpcre[16]_dfa_exec()\fP match function
516 \eF only shortest match for \fBpcre[16]_dfa_exec()\fP
517 .\" JOIN
518 \eGdd call pcre[16]_get_substring() for substring dd
519 after a successful match (number less than 32)
520 .\" JOIN
521 \eGname call pcre[16]_get_named_substring() for substring
522 "name" after a successful match (name termin-
523 ated by next non-alphanumeric character)
524 .\" JOIN
525 \eJdd set up a JIT stack of dd kilobytes maximum (any
526 number of digits)
527 .\" JOIN
528 \eL call pcre[16]_get_substringlist() after a
529 successful match
530 .\" JOIN
531 \eM discover the minimum MATCH_LIMIT and
533 .\" JOIN
534 \eN pass the PCRE_NOTEMPTY option to \fBpcre[16]_exec()\fP
535 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
537 .\" JOIN
538 \eOdd set the size of the output vector passed to
539 \fBpcre[16]_exec()\fP to dd (any number of digits)
540 .\" JOIN
541 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre[16]_exec()\fP
542 or \fBpcre[16]_dfa_exec()\fP; if used twice, pass the
544 .\" JOIN
545 \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
546 (any number of digits)
547 \eR pass the PCRE_DFA_RESTART option to \fBpcre[16]_dfa_exec()\fP
548 \eS output details of memory get/free calls during matching
549 .\" JOIN
550 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16]_exec()\fP
551 or \fBpcre[16]_dfa_exec()\fP
552 .\" JOIN
553 \eZ pass the PCRE_NOTEOL option to \fBpcre[16]_exec()\fP
554 or \fBpcre[16]_dfa_exec()\fP
555 .\" JOIN
556 \e? pass the PCRE_NO_UTF[8|16]_CHECK option to
557 \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
558 .\" JOIN
559 \e>dd start the match at offset dd (optional "-"; then
560 any number of digits); this sets the \fIstartoffset\fP
561 argument for \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP
562 .\" JOIN
563 \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre[16]_exec()\fP
564 or \fBpcre[16]_dfa_exec()\fP
565 .\" JOIN
566 \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre[16]_exec()\fP
567 or \fBpcre[16]_dfa_exec()\fP
568 .\" JOIN
569 \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre[16]_exec()\fP
570 or \fBpcre[16]_dfa_exec()\fP
571 .\" JOIN
572 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16]_exec()\fP
573 or \fBpcre[16]_dfa_exec()\fP
574 .\" JOIN
575 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre[16]_exec()\fP
576 or \fBpcre[16]_dfa_exec()\fP
577 .sp
578 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on
579 the pattern. It is recognized always. There may be any number of hexadecimal
580 digits inside the braces; invalid values provoke error messages.
581 .P
582 Note that \exhh specifies one byte rather than one character in UTF-8 mode;
583 this makes it possible to construct invalid UTF-8 sequences for testing
584 purposes. On the other hand, \ex{hh} is interpreted as a UTF-8 character in
585 UTF-8 mode, generating more than one byte if the value is greater than 127.
586 When testing the 8-bit library not in UTF-8 mode, \ex{hh} generates one byte
587 for values less than 256, and causes an error for greater values.
588 .P
589 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it
590 possible to construct invalid UTF-16 sequences for testing purposes.
591 .P
592 The escapes that specify line ending sequences are literal strings, exactly as
593 shown. No more than one newline setting should be present in any data line.
594 .P
595 A backslash followed by anything else just escapes the anything else. If
596 the very last character is a backslash, it is ignored. This gives a way of
597 passing an empty line as data, since a real empty line terminates the data
598 input.
599 .P
600 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is
601 used by the just-in-time optimization code. It is ignored if JIT optimization
602 is not being used. Providing a stack that is larger than the default 32K is
603 necessary only for very complicated patterns.
604 .P
605 If \eM is present, \fBpcretest\fP calls \fBpcre[16]_exec()\fP several times,
606 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
607 fields of the \fBpcre[16]_extra\fP data structure, until it finds the minimum
608 numbers for each parameter that allow \fBpcre[16]_exec()\fP to complete without
609 error. Because this is testing a specific feature of the normal interpretive
610 \fBpcre[16]_exec()\fP execution, the use of any JIT optimization that might
611 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled.
612 .P
613 The \fImatch_limit\fP number is a measure of the amount of backtracking
614 that takes place, and checking it out can be instructive. For most simple
615 matches, the number is quite small, but for patterns with very large numbers of
616 matching possibilities, it can become large very quickly with increasing length
617 of subject string. The \fImatch_limit_recursion\fP number is a measure of how
618 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
619 needed to complete the match attempt.
620 .P
621 When \eO is used, the value specified may be higher or lower than the size set
622 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
623 the call of \fBpcre[16]_exec()\fP for the line in which it appears.
624 .P
625 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
626 API to be used, the only option-setting sequences that have any effect are \eB,
627 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
628 to be passed to \fBregexec()\fP.
629 .
630 .
632 .rs
633 .sp
634 By default, \fBpcretest\fP uses the standard PCRE matching function,
635 \fBpcre[16]_exec()\fP to match each data line. PCRE also supports an
636 alternative matching function, \fBpcre[16]_dfa_test()\fP, which operates in a
637 different way, and has some restrictions. The differences between the two
638 functions are described in the
639 .\" HREF
640 \fBpcrematching\fP
641 .\"
642 documentation.
643 .P
644 If a data line contains the \eD escape sequence, or if the command line
645 contains the \fB-dfa\fP option, the alternative matching function is used.
646 This function finds all possible matches at a given point. If, however, the \eF
647 escape sequence is present in the data line, it stops after the first match is
648 found. This is always the shortest possible match.
649 .
650 .
652 .rs
653 .sp
654 This section describes the output when the normal matching function,
655 \fBpcre[16]_exec()\fP, is being used.
656 .P
657 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings
658 that \fBpcre[16]_exec()\fP returns, starting with number 0 for the string that
659 matched the whole pattern. Otherwise, it outputs "No match" when the return is
660 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
661 substring when \fBpcre[16]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that
662 this is the entire substring that was inspected during the partial match; it
663 may include characters before the actual match start if a lookbehind assertion,
664 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs
665 the PCRE negative error number and a short descriptive phrase. If the error is
666 a failed UTF string check, the offset of the start of the failing character and
667 the reason code are also output, provided that the size of the output vector is
668 at least two. Here is an example of an interactive \fBpcretest\fP run.
669 .sp
670 $ pcretest
671 PCRE version 8.13 2011-04-30
672 .sp
673 re> /^abc(\ed+)/
674 data> abc123
675 0: abc123
676 1: 123
677 data> xyz
678 No match
679 .sp
680 Unset capturing substrings that are not followed by one that is set are not
681 returned by \fBpcre[16]_exec()\fP, and are not shown by \fBpcretest\fP. In the
682 following example, there are two capturing substrings, but when the first data
683 line is matched, the second, unset substring is not shown. An "internal" unset
684 substring is shown as "<unset>", as for the second data line.
685 .sp
686 re> /(a)|(b)/
687 data> a
688 0: a
689 1: a
690 data> b
691 0: b
692 1: <unset>
693 2: b
694 .sp
695 If the strings contain any non-printing characters, they are output as \exhh
696 escapes if the value is less than 256 and UTF mode is not set. Otherwise they
697 are output as \ex{hh...} escapes. See below for the definition of non-printing
698 characters. If the pattern has the \fB/+\fP modifier, the output for substring
699 0 is followed by the the rest of the subject string, identified by "0+" like
700 this:
701 .sp
702 re> /cat/+
703 data> cataract
704 0: cat
705 0+ aract
706 .sp
707 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
708 matching attempts are output in sequence, like this:
709 .sp
710 re> /\eBi(\ew\ew)/g
711 data> Mississippi
712 0: iss
713 1: ss
714 0: iss
715 1: ss
716 0: ipp
717 1: pp
718 .sp
719 "No match" is output only if the first match attempt fails. Here is an example
720 of a failure message (the offset 4 that is specified by \e>4 is past the end of
721 the subject string):
722 .sp
723 re> /xyz/
724 data> xyz\e>4
725 Error -24 (bad offset value)
726 .P
727 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
728 data line that is successfully matched, the substrings extracted by the
729 convenience functions are output with C, G, or L after the string number
730 instead of a colon. This is in addition to the normal full list. The string
731 length (that is, the return from the extraction function) is given in
732 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
733 .P
734 Note that whereas patterns can be continued over several lines (a plain ">"
735 prompt is used for continuations), data lines may not. However newlines can be
736 included in data by means of the \en escape (or \er, \er\en, etc., depending on
737 the newline sequence setting).
738 .
739 .
740 .
742 .rs
743 .sp
744 When the alternative matching function, \fBpcre[16]_dfa_exec()\fP, is used (by
745 means of the \eD escape sequence or the \fB-dfa\fP command line option), the
746 output consists of a list of all the matches that start at the first point in
747 the subject where there is at least one match. For example:
748 .sp
749 re> /(tang|tangerine|tan)/
750 data> yellow tangerine\eD
751 0: tangerine
752 1: tang
753 2: tan
754 .sp
755 (Using the normal matching function on this data finds only "tang".) The
756 longest matching string is always given first (and numbered zero). After a
757 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
758 partially matching substring. (Note that this is the entire substring that was
759 inspected during the partial match; it may include characters before the actual
760 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)
761 .P
762 If \fB/g\fP is present on the pattern, the search for further matches resumes
763 at the end of the longest match. For example:
764 .sp
765 re> /(tang|tangerine|tan)/g
766 data> yellow tangerine and tangy sultana\eD
767 0: tangerine
768 1: tang
769 2: tan
770 0: tang
771 1: tan
772 0: tan
773 .sp
774 Since the matching function does not support substring capture, the escape
775 sequences that are concerned with captured substrings are not relevant.
776 .
777 .
779 .rs
780 .sp
781 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
782 indicating that the subject partially matched the pattern, you can restart the
783 match with additional subject data by means of the \eR escape sequence. For
784 example:
785 .sp
786 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
787 data> 23ja\eP\eD
788 Partial match: 23ja
789 data> n05\eR\eD
790 0: n05
791 .sp
792 For further information about partial matching, see the
793 .\" HREF
794 \fBpcrepartial\fP
795 .\"
796 documentation.
797 .
798 .
800 .rs
801 .sp
802 If the pattern contains any callout requests, \fBpcretest\fP's callout function
803 is called during matching. This works with both matching functions. By default,
804 the called function displays the callout number, the start and current
805 positions in the text at the callout time, and the next pattern item to be
806 tested. For example:
807 .sp
808 --->pqrabcdef
809 0 ^ ^ \ed
810 .sp
811 This output indicates that callout number 0 occurred for a match attempt
812 starting at the fourth character of the subject string, when the pointer was at
813 the seventh character of the data, and when the next pattern item was \ed. Just
814 one circumflex is output if the start and current positions are the same.
815 .P
816 Callouts numbered 255 are assumed to be automatic callouts, inserted as a
817 result of the \fB/C\fP pattern modifier. In this case, instead of showing the
818 callout number, the offset in the pattern, preceded by a plus, is output. For
819 example:
820 .sp
821 re> /\ed?[A-E]\e*/C
822 data> E*
823 --->E*
824 +0 ^ \ed?
825 +3 ^ [A-E]
826 +8 ^^ \e*
827 +10 ^ ^
828 0: E*
829 .sp
830 If a pattern contains (*MARK) items, an additional line is output whenever
831 a change of latest mark is passed to the callout function. For example:
832 .sp
833 re> /a(*MARK:X)bc/C
834 data> abc
835 --->abc
836 +0 ^ a
837 +1 ^^ (*MARK:X)
838 +10 ^^ b
839 Latest Mark: X
840 +11 ^ ^ c
841 +12 ^ ^
842 0: abc
843 .sp
844 The mark changes between matching "a" and "b", but stays the same for the rest
845 of the match, so nothing more is output. If, as a result of backtracking, the
846 mark reverts to being unset, the text "<unset>" is output.
847 .P
848 The callout function in \fBpcretest\fP returns zero (carry on matching) by
849 default, but you can use a \eC item in a data line (as described above) to
850 change this and other parameters of the callout.
851 .P
852 Inserting callouts can be helpful when using \fBpcretest\fP to check
853 complicated regular expressions. For further information about callouts, see
854 the
855 .\" HREF
856 \fBpcrecallout\fP
857 .\"
858 documentation.
859 .
860 .
861 .
863 .rs
864 .sp
865 When \fBpcretest\fP is outputting text in the compiled version of a pattern,
866 bytes other than 32-126 are always treated as non-printing characters are are
867 therefore shown as hex escapes.
868 .P
869 When \fBpcretest\fP is outputting text that is a matched part of a subject
870 string, it behaves in the same way, unless a different locale has been set for
871 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
872 function to distinguish printing and non-printing characters.
873 .
874 .
875 .
877 .rs
878 .sp
879 The facilities described in this section are not available when the POSIX
880 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
881 specified.
882 .P
883 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
884 compiled pattern to a file, by following the modifiers with > and a file name.
885 For example:
886 .sp
887 /pattern/im >/some/file
888 .sp
889 See the
890 .\" HREF
891 \fBpcreprecompile\fP
892 .\"
893 documentation for a discussion about saving and re-using compiled patterns.
894 Note that if the pattern was successfully studied with JIT optimization, the
895 JIT data cannot be saved.
896 .P
897 The data that is written is binary. The first eight bytes are the length of the
898 compiled pattern data followed by the length of the optional study data, each
899 written as four bytes in big-endian order (most significant byte first). If
900 there is no study data (either the pattern was not studied, or studying did not
901 return any data), the second length is zero. The lengths are followed by an
902 exact copy of the compiled pattern. If there is additional study data, this
903 (excluding any JIT data) follows immediately after the compiled pattern. After
904 writing the file, \fBpcretest\fP expects to read a new pattern.
905 .P
906 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file
907 name instead of a pattern. The name of the file must not contain a < character,
908 as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
909 characters.
910 For example:
911 .sp
912 re> </some/file
913 Compiled pattern loaded from /some/file
914 No study data
915 .sp
916 If the pattern was previously studied with the JIT optimization, the JIT
917 information cannot be saved and restored, and so is lost. When the pattern has
918 been loaded, \fBpcretest\fP proceeds to read data lines in the usual way.
919 .P
920 You can copy a file written by \fBpcretest\fP to a different host and reload it
921 there, even if the new host has opposite endianness to the one on which the
922 pattern was compiled. For example, you can compile on an i86 machine and run on
923 a SPARC machine. When a pattern is reloaded on a host with different
924 endianness, the confirmation message is changed to:
925 .sp
926 Compiled pattern (byte-inverted) loaded from /some/file
927 .sp
928 The test suite contains some saved pre-compiled patterns with different
929 endianness. These are reloaded using "<!" instead of just "<". This suppresses
930 the "(byte-inverted)" text so that the output is the same on all hosts. It also
931 forces debugging output once the pattern has been reloaded.
932 .P
933 File names for saving and reloading can be absolute or relative, but note that
934 the shell facility of expanding a file name that starts with a tilde (~) is not
935 available.
936 .P
937 The ability to save and reload files in \fBpcretest\fP is intended for testing
938 and experimentation. It is not intended for production use because only a
939 single pattern can be written to a file. Furthermore, there is no facility for
940 supplying custom character tables for use with a reloaded pattern. If the
941 original pattern was compiled with custom tables, an attempt to match a subject
942 string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
943 Finally, if you attempt to load a file that is not in the correct format, the
944 result is undefined.
945 .
946 .
947 .SH "SEE ALSO"
948 .rs
949 .sp
950 \fBpcre\fP(3), \fBpcre16\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
951 \fBpcrejit\fP, \fBpcrematching\fP(3), \fBpcrepartial\fP(d),
952 \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
953 .
954 .
956 .rs
957 .sp
958 .nf
959 Philip Hazel
960 University Computing Service
961 Cambridge CB2 3QH, England.
962 .fi
963 .
964 .
966 .rs
967 .sp
968 .nf
969 Last updated: 21 February 2012
970 Copyright (c) 1997-2012 University of Cambridge.
971 .fi


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