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PCRE documentation changes. Fixes #657
[exim.git] / doc / doc-txt / pcretest.txt
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8ac170f3
PH		 1This file contains the PCRE man page that described the pcretest program. Note
2that not all of the features of PCRE are available in the limited version that
495ae4b0
PH		 3is built with Exim.
4-------------------------------------------------------------------------------
5
6PCRETEST(1) PCRETEST(1)
7
8
495ae4b0
PH		 9NAME
10 pcretest - a program for testing Perl-compatible regular expressions.
11
92e772ff 12
495ae4b0
PH		 13SYNOPSIS
14
aa41d2de 15 pcretest [options] [source] [destination]
495ae4b0
PH		 16
17 pcretest was written as a test program for the PCRE regular expression
18 library itself, but it can also be used for experimenting with regular
19 expressions. This document describes the features of the test program;
20 for details of the regular expressions themselves, see the pcrepattern
21 documentation. For details of the PCRE library function calls and their
22 options, see the pcreapi documentation.
23
24
25OPTIONS
26
6bf342e1
PH		 27 -b Behave as if each regex has the /B (show bytecode) modifier;
28 the internal form is output after compilation.
29
495ae4b0 30 -C Output the version number of the PCRE library, and all avail-
6bf342e1 31 able information about the optional features that are
495ae4b0
PH		 32 included, and then exit.
33
6bf342e1
PH		 34 -d Behave as if each regex has the /D (debug) modifier; the
35 internal form and information about the compiled pattern is
36 output after compilation; -d is equivalent to -b -i.
495ae4b0 37
8ac170f3
PH		 38 -dfa Behave as if each data line contains the \D escape sequence;
39 this causes the alternative matching function,
40 pcre_dfa_exec(), to be used instead of the standard
41 pcre_exec() function (more detail is given below).
42
6bf342e1
PH		 43 -help Output a brief summary these options and then exit.
44
8ac170f3 45 -i Behave as if each regex has the /I modifier; information
495ae4b0
PH		 46 about the compiled pattern is given after compilation.
47
8ac170f3
PH		 48 -m Output the size of each compiled pattern after it has been
49 compiled. This is equivalent to adding /M to each regular
50 expression. For compatibility with earlier versions of
495ae4b0
PH		 51 pcretest, -s is a synonym for -m.
52
8ac170f3 53 -o osize Set the number of elements in the output vector that is used
6bf342e1
PH		 54 when calling pcre_exec() or pcre_dfa_exec() to be osize. The
55 default value is 45, which is enough for 14 capturing subex-
56 pressions for pcre_exec() or 22 different matches for
57 pcre_dfa_exec(). The vector size can be changed for individ-
58 ual matching calls by including \O in the data line (see
59 below).
495ae4b0 60
8ac170f3
PH		 61 -p Behave as if each regex has the /P modifier; the POSIX wrap-
62 per API is used to call PCRE. None of the other options has
63 any effect when -p is set.
495ae4b0 64
aa41d2de
PH		 65 -q Do not output the version number of pcretest at the start of
66 execution.
67
68 -S size On Unix-like systems, set the size of the runtime stack to
69 size megabytes.
70
8ac170f3
PH		 71 -t Run each compile, study, and match many times with a timer,
72 and output resulting time per compile or match (in millisec-
73 onds). Do not set -m with -t, because you will then get the
74 size output a zillion times, and the timing will be dis-
6bf342e1
PH		 75 torted. You can control the number of iterations that are
76 used for timing by following -t with a number (as a separate
77 item on the command line). For example, "-t 1000" would iter-
78 ate 1000 times. The default is to iterate 500000 times.
79
80 -tm This is like -t except that it times only the matching phase,
81 not the compile or study phases.
495ae4b0
PH		 82
83
84DESCRIPTION
85
8ac170f3 86 If pcretest is given two filename arguments, it reads from the first
495ae4b0 87 and writes to the second. If it is given only one filename argument, it
8ac170f3
PH		 88 reads from that file and writes to stdout. Otherwise, it reads from
89 stdin and writes to stdout, and prompts for each line of input, using
495ae4b0
PH		 90 "re>" to prompt for regular expressions, and "data>" to prompt for data
91 lines.
92
93 The program handles any number of sets of input on a single input file.
8ac170f3 94 Each set starts with a regular expression, and continues with any num-
495ae4b0
PH		 95 ber of data lines to be matched against the pattern.
96
8ac170f3 97 Each data line is matched separately and independently. If you want to
aa41d2de 98 do multi-line matches, you have to use the \n escape sequence (or \r or
6bf342e1
PH		 99 \r\n, etc., depending on the newline setting) in a single line of input
100 to encode the newline sequences. There is no limit on the length of
101 data lines; the input buffer is automatically extended if it is too
102 small.
495ae4b0 103
6bf342e1
PH		 104 An empty line signals the end of the data lines, at which point a new
105 regular expression is read. The regular expressions are given enclosed
aa41d2de 106 in any non-alphanumeric delimiters other than backslash, for example:
495ae4b0
PH		 107
108 /(a|bc)x+yz/
109
6bf342e1
PH		 110 White space before the initial delimiter is ignored. A regular expres-
111 sion may be continued over several input lines, in which case the new-
112 line characters are included within it. It is possible to include the
495ae4b0
PH		 113 delimiter within the pattern by escaping it, for example
114
115 /abc\/def/
116
6bf342e1
PH		 117 If you do so, the escape and the delimiter form part of the pattern,
118 but since delimiters are always non-alphanumeric, this does not affect
119 its interpretation. If the terminating delimiter is immediately fol-
495ae4b0
PH		 120 lowed by a backslash, for example,
121
122 /abc/\
123
6bf342e1
PH		 124 then a backslash is added to the end of the pattern. This is done to
125 provide a way of testing the error condition that arises if a pattern
495ae4b0
PH		 126 finishes with a backslash, because
127
128 /abc\/
129
6bf342e1 130 is interpreted as the first line of a pattern that starts with "abc/",
495ae4b0
PH		 131 causing pcretest to read the next line as a continuation of the regular
132 expression.
133
134
135PATTERN MODIFIERS
136
6bf342e1
PH		 137 A pattern may be followed by any number of modifiers, which are mostly
138 single characters. Following Perl usage, these are referred to below
139 as, for example, "the /i modifier", even though the delimiter of the
140 pattern need not always be a slash, and no slash is used when writing
141 modifiers. Whitespace may appear between the final pattern delimiter
495ae4b0
PH		 142 and the first modifier, and between the modifiers themselves.
143
144 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
6bf342e1
PH		 145 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com-
146 pile() is called. These four modifier letters have the same effect as
495ae4b0
PH		 147 they do in Perl. For example:
148
149 /caseless/i
150
151 The following table shows additional modifiers for setting PCRE options
152 that do not correspond to anything in Perl:
153
64f2600a
PH		 154 /A PCRE_ANCHORED
155 /C PCRE_AUTO_CALLOUT
156 /E PCRE_DOLLAR_ENDONLY
157 /f PCRE_FIRSTLINE
158 /J PCRE_DUPNAMES
159 /N PCRE_NO_AUTO_CAPTURE
160 /U PCRE_UNGREEDY
161 /X PCRE_EXTRA
162 /<cr> PCRE_NEWLINE_CR
163 /<lf> PCRE_NEWLINE_LF
164 /<crlf> PCRE_NEWLINE_CRLF
165 /<anycrlf> PCRE_NEWLINE_ANYCRLF
166 /<any> PCRE_NEWLINE_ANY
6bf342e1
PH		 167
168 Those specifying line ending sequencess are literal strings as shown.
169 This example sets multiline matching with CRLF as the line ending
170 sequence:
aa41d2de 171
6bf342e1
PH		 172 /^abc/m<crlf>
173
174 Details of the meanings of these PCRE options are given in the pcreapi
175 documentation.
aa41d2de
PH		 176
177 Finding all matches in a string
178
179 Searching for all possible matches within each subject string can be
180 requested by the /g or /G modifier. After finding a match, PCRE is
495ae4b0
PH		 181 called again to search the remainder of the subject string. The differ-
182 ence between /g and /G is that the former uses the startoffset argument
aa41d2de
PH		 183 to pcre_exec() to start searching at a new point within the entire
184 string (which is in effect what Perl does), whereas the latter passes
185 over a shortened substring. This makes a difference to the matching
495ae4b0
PH		 186 process if the pattern begins with a lookbehind assertion (including \b
187 or \B).
188
aa41d2de
PH		 189 If any call to pcre_exec() in a /g or /G sequence matches an empty
190 string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
191 flags set in order to search for another, non-empty, match at the same
192 point. If this second match fails, the start offset is advanced by
193 one, and the normal match is retried. This imitates the way Perl han-
495ae4b0
PH		 194 dles such cases when using the /g modifier or the split() function.
195
aa41d2de
PH		 196 Other modifiers
197
495ae4b0
PH		 198 There are yet more modifiers for controlling the way pcretest operates.
199
aa41d2de
PH		 200 The /+ modifier requests that as well as outputting the substring that
201 matched the entire pattern, pcretest should in addition output the
202 remainder of the subject string. This is useful for tests where the
495ae4b0
PH		 203 subject contains multiple copies of the same substring.
204
6bf342e1 205 The /B modifier is a debugging feature. It requests that pcretest out-
64f2600a
PH		 206 put a representation of the compiled byte code after compilation. Nor-
207 mally this information contains length and offset values; however, if
208 /Z is also present, this data is replaced by spaces. This is a special
209 feature for use in the automatic test scripts; it ensures that the same
210 output is generated for different internal link sizes.
6bf342e1
PH		 211
212 The /L modifier must be followed directly by the name of a locale, for
495ae4b0
PH		 213 example,
214
215 /pattern/Lfr_FR
216
217 For this reason, it must be the last modifier. The given locale is set,
6bf342e1
PH		 218 pcre_maketables() is called to build a set of character tables for the
219 locale, and this is then passed to pcre_compile() when compiling the
220 regular expression. Without an /L modifier, NULL is passed as the
221 tables pointer; that is, /L applies only to the expression on which it
495ae4b0
PH		 222 appears.
223
6bf342e1
PH		 224 The /I modifier requests that pcretest output information about the
225 compiled pattern (whether it is anchored, has a fixed first character,
226 and so on). It does this by calling pcre_fullinfo() after compiling a
227 pattern. If the pattern is studied, the results of that are also out-
495ae4b0
PH		 228 put.
229
6bf342e1
PH		 230 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
231 that is, both the /B and the /I modifiers.
495ae4b0
PH		 232
233 The /F modifier causes pcretest to flip the byte order of the fields in
6bf342e1
PH		 234 the compiled pattern that contain 2-byte and 4-byte numbers. This
235 facility is for testing the feature in PCRE that allows it to execute
495ae4b0 236 patterns that were compiled on a host with a different endianness. This
6bf342e1
PH		 237 feature is not available when the POSIX interface to PCRE is being
238 used, that is, when the /P pattern modifier is specified. See also the
495ae4b0
PH		 239 section about saving and reloading compiled patterns below.
240
6bf342e1 241 The /S modifier causes pcre_study() to be called after the expression
495ae4b0
PH		 242 has been compiled, and the results used when the expression is matched.
243
6bf342e1 244 The /M modifier causes the size of memory block used to hold the com-
495ae4b0
PH		 245 piled pattern to be output.
246
6bf342e1
PH		 247 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
248 rather than its native API. When this is done, all other modifiers
249 except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
250 and REG_NEWLINE is set if /m is present. The wrapper functions force
251 PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
495ae4b0 252
6bf342e1
PH		 253 The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
254 set. This turns on support for UTF-8 character handling in PCRE, pro-
255 vided that it was compiled with this support enabled. This modifier
495ae4b0
PH		 256 also causes any non-printing characters in output strings to be printed
257 using the \x{hh...} notation if they are valid UTF-8 sequences.
258
6bf342e1
PH		 259 If the /? modifier is used with /8, it causes pcretest to call
260 pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
495ae4b0
PH		 261 checking of the string for UTF-8 validity.
262
263
264DATA LINES
265
6bf342e1
PH		 266 Before each data line is passed to pcre_exec(), leading and trailing
267 whitespace is removed, and it is then scanned for \ escapes. Some of
268 these are pretty esoteric features, intended for checking out some of
269 the more complicated features of PCRE. If you are just testing "ordi-
270 nary" regular expressions, you probably don't need any of these. The
495ae4b0
PH		 271 following escapes are recognized:
272
6bf342e1
PH		 273 \a alarm (BEL, \x07)
274 \b backspace (\x08)
275 \e escape (\x27)
276 \f formfeed (\x0c)
277 \n newline (\x0a)
aa41d2de
PH		 278 \qdd set the PCRE_MATCH_LIMIT limit to dd
279 (any number of digits)
6bf342e1
PH		 280 \r carriage return (\x0d)
281 \t tab (\x09)
282 \v vertical tab (\x0b)
495ae4b0
PH		 283 \nnn octal character (up to 3 octal digits)
284 \xhh hexadecimal character (up to 2 hex digits)
285 \x{hh...} hexadecimal character, any number of digits
286 in UTF-8 mode
287 \A pass the PCRE_ANCHORED option to pcre_exec()
aa41d2de 288 or pcre_dfa_exec()
495ae4b0 289 \B pass the PCRE_NOTBOL option to pcre_exec()
aa41d2de 290 or pcre_dfa_exec()
495ae4b0
PH		 291 \Cdd call pcre_copy_substring() for substring dd
292 after a successful match (number less than 32)
293 \Cname call pcre_copy_named_substring() for substring
294 "name" after a successful match (name termin-
295 ated by next non alphanumeric character)
296 \C+ show the current captured substrings at callout
297 time
298 \C- do not supply a callout function
299 \C!n return 1 instead of 0 when callout number n is
300 reached
301 \C!n!m return 1 instead of 0 when callout number n is
302 reached for the nth time
303 \C*n pass the number n (may be negative) as callout
304 data; this is used as the callout return value
8ac170f3
PH		 305 \D use the pcre_dfa_exec() match function
306 \F only shortest match for pcre_dfa_exec()
495ae4b0
PH		 307 \Gdd call pcre_get_substring() for substring dd
308 after a successful match (number less than 32)
309 \Gname call pcre_get_named_substring() for substring
310 "name" after a successful match (name termin-
311 ated by next non-alphanumeric character)
312 \L call pcre_get_substringlist() after a
313 successful match
aa41d2de
PH		 314 \M discover the minimum MATCH_LIMIT and
315 MATCH_LIMIT_RECURSION settings
495ae4b0 316 \N pass the PCRE_NOTEMPTY option to pcre_exec()
aa41d2de 317 or pcre_dfa_exec()
495ae4b0
PH		 318 \Odd set the size of the output vector passed to
319 pcre_exec() to dd (any number of digits)
320 \P pass the PCRE_PARTIAL option to pcre_exec()
8ac170f3 321 or pcre_dfa_exec()
aa41d2de
PH		 322 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
323 (any number of digits)
8ac170f3 324 \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
495ae4b0
PH		 325 \S output details of memory get/free calls during matching
326 \Z pass the PCRE_NOTEOL option to pcre_exec()
aa41d2de 327 or pcre_dfa_exec()
495ae4b0 328 \? pass the PCRE_NO_UTF8_CHECK option to
aa41d2de 329 pcre_exec() or pcre_dfa_exec()
495ae4b0
PH		 330 \>dd start the match at offset dd (any number of digits);
331 this sets the startoffset argument for pcre_exec()
aa41d2de
PH		 332 or pcre_dfa_exec()
333 \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec()
334 or pcre_dfa_exec()
335 \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec()
336 or pcre_dfa_exec()
337 \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec()
338 or pcre_dfa_exec()
64f2600a
PH		 339 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
340 or pcre_dfa_exec()
6bf342e1
PH		 341 \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec()
342 or pcre_dfa_exec()
495ae4b0 343
6bf342e1
PH		 344 The escapes that specify line ending sequences are literal strings,
345 exactly as shown. No more than one newline setting should be present in
346 any data line.
347
348 A backslash followed by anything else just escapes the anything else.
349 If the very last character is a backslash, it is ignored. This gives a
350 way of passing an empty line as data, since a real empty line termi-
351 nates the data input.
495ae4b0 352
8ac170f3 353 If \M is present, pcretest calls pcre_exec() several times, with dif-
aa41d2de
PH		 354 ferent values in the match_limit and match_limit_recursion fields of
355 the pcre_extra data structure, until it finds the minimum numbers for
356 each parameter that allow pcre_exec() to complete. The match_limit num-
357 ber is a measure of the amount of backtracking that takes place, and
358 checking it out can be instructive. For most simple matches, the number
359 is quite small, but for patterns with very large numbers of matching
360 possibilities, it can become large very quickly with increasing length
361 of subject string. The match_limit_recursion number is a measure of how
362 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap)
363 memory is needed to complete the match attempt.
364
365 When \O is used, the value specified may be higher or lower than the
495ae4b0
PH		 366 size set by the -O command line option (or defaulted to 45); \O applies
367 only to the call of pcre_exec() for the line in which it appears.
368
aa41d2de
PH		 369 If the /P modifier was present on the pattern, causing the POSIX wrap-
370 per API to be used, the only option-setting sequences that have any
371 effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
372 to be passed to regexec().
495ae4b0 373
8ac170f3
PH		 374 The use of \x{hh...} to represent UTF-8 characters is not dependent on
375 the use of the /8 modifier on the pattern. It is recognized always.
376 There may be any number of hexadecimal digits inside the braces. The
377 result is from one to six bytes, encoded according to the UTF-8 rules.
378
379
380THE ALTERNATIVE MATCHING FUNCTION
381
382 By default, pcretest uses the standard PCRE matching function,
383 pcre_exec() to match each data line. From release 6.0, PCRE supports an
384 alternative matching function, pcre_dfa_test(), which operates in a
385 different way, and has some restrictions. The differences between the
386 two functions are described in the pcrematching documentation.
387
388 If a data line contains the \D escape sequence, or if the command line
389 contains the -dfa option, the alternative matching function is called.
390 This function finds all possible matches at a given point. If, however,
391 the \F escape sequence is present in the data line, it stops after the
392 first match is found. This is always the shortest possible match.
495ae4b0
PH		 393
394
8ac170f3
PH		 395DEFAULT OUTPUT FROM PCRETEST
396
397 This section describes the output when the normal matching function,
398 pcre_exec(), is being used.
495ae4b0
PH		 399
400 When a match succeeds, pcretest outputs the list of captured substrings
401 that pcre_exec() returns, starting with number 0 for the string that
402 matched the whole pattern. Otherwise, it outputs "No match" or "Partial
403 match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
404 TIAL, respectively, and otherwise the PCRE negative error number. Here
405 is an example of an interactive pcretest run.
406
407 $ pcretest
6bf342e1 408 PCRE version 7.0 30-Nov-2006
495ae4b0
PH		 409
410 re> /^abc(\d+)/
411 data> abc123
412 0: abc123
413 1: 123
414 data> xyz
415 No match
416
417 If the strings contain any non-printing characters, they are output as
418 \0x escapes, or as \x{...} escapes if the /8 modifier was present on
6bf342e1
PH		 419 the pattern. See below for the definition of non-printing characters.
420 If the pattern has the /+ modifier, the output for substring 0 is fol-
421 lowed by the the rest of the subject string, identified by "0+" like
422 this:
495ae4b0
PH		 423
424 re> /cat/+
425 data> cataract
426 0: cat
427 0+ aract
428
6bf342e1 429 If the pattern has the /g or /G modifier, the results of successive
495ae4b0
PH		 430 matching attempts are output in sequence, like this:
431
432 re> /\Bi(\w\w)/g
433 data> Mississippi
434 0: iss
435 1: ss
436 0: iss
437 1: ss
438 0: ipp
439 1: pp
440
441 "No match" is output only if the first match attempt fails.
442
6bf342e1
PH		 443 If any of the sequences \C, \G, or \L are present in a data line that
444 is successfully matched, the substrings extracted by the convenience
495ae4b0
PH		 445 functions are output with C, G, or L after the string number instead of
446 a colon. This is in addition to the normal full list. The string length
6bf342e1 447 (that is, the return from the extraction function) is given in paren-
495ae4b0
PH		 448 theses after each string for \C and \G.
449
6bf342e1 450 Note that whereas patterns can be continued over several lines (a plain
495ae4b0 451 ">" prompt is used for continuations), data lines may not. However new-
6bf342e1
PH		 452 lines can be included in data by means of the \n escape (or \r, \r\n,
453 etc., depending on the newline sequence setting).
495ae4b0
PH		 454
455
8ac170f3
PH		 456OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
457
6bf342e1
PH		 458 When the alternative matching function, pcre_dfa_exec(), is used (by
459 means of the \D escape sequence or the -dfa command line option), the
460 output consists of a list of all the matches that start at the first
8ac170f3
PH		 461 point in the subject where there is at least one match. For example:
462
463 re> /(tang|tangerine|tan)/
464 data> yellow tangerine\D
465 0: tangerine
466 1: tang
467 2: tan
468
6bf342e1
PH		 469 (Using the normal matching function on this data finds only "tang".)
470 The longest matching string is always given first (and numbered zero).
8ac170f3 471
6bf342e1
PH		 472 If /g is present on the pattern, the search for further matches resumes
473 at the end of the longest match. For example:
8ac170f3
PH		 474
475 re> /(tang|tangerine|tan)/g
476 data> yellow tangerine and tangy sultana\D
477 0: tangerine
478 1: tang
479 2: tan
480 0: tang
481 1: tan
482 0: tan
483
6bf342e1
PH		 484 Since the matching function does not support substring capture, the
485 escape sequences that are concerned with captured substrings are not
8ac170f3
PH		 486 relevant.
487
488
489RESTARTING AFTER A PARTIAL MATCH
490
491 When the alternative matching function has given the PCRE_ERROR_PARTIAL
6bf342e1
PH		 492 return, indicating that the subject partially matched the pattern, you
493 can restart the match with additional subject data by means of the \R
8ac170f3
PH		 494 escape sequence. For example:
495
64f2600a 496 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
8ac170f3
PH		 497 data> 23ja\P\D
498 Partial match: 23ja
499 data> n05\R\D
500 0: n05
501
6bf342e1 502 For further information about partial matching, see the pcrepartial
8ac170f3
PH		 503 documentation.
504
505
495ae4b0
PH		 506CALLOUTS
507
6bf342e1
PH		 508 If the pattern contains any callout requests, pcretest's callout func-
509 tion is called during matching. This works with both matching func-
8ac170f3 510 tions. By default, the called function displays the callout number, the
6bf342e1 511 start and current positions in the text at the callout time, and the
8ac170f3 512 next pattern item to be tested. For example, the output
495ae4b0
PH		 513
514 --->pqrabcdef
515 0 ^ ^ \d
516
6bf342e1
PH		 517 indicates that callout number 0 occurred for a match attempt starting
518 at the fourth character of the subject string, when the pointer was at
519 the seventh character of the data, and when the next pattern item was
520 \d. Just one circumflex is output if the start and current positions
495ae4b0
PH		 521 are the same.
522
523 Callouts numbered 255 are assumed to be automatic callouts, inserted as
6bf342e1
PH		 524 a result of the /C pattern modifier. In this case, instead of showing
525 the callout number, the offset in the pattern, preceded by a plus, is
495ae4b0
PH		 526 output. For example:
527
528 re> /\d?[A-E]\*/C
529 data> E*
530 --->E*
531 +0 ^ \d?
532 +3 ^ [A-E]
533 +8 ^^ \*
534 +10 ^ ^
535 0: E*
536
6bf342e1
PH		 537 The callout function in pcretest returns zero (carry on matching) by
538 default, but you can use a \C item in a data line (as described above)
495ae4b0
PH		 539 to change this.
540
6bf342e1
PH		 541 Inserting callouts can be helpful when using pcretest to check compli-
542 cated regular expressions. For further information about callouts, see
495ae4b0
PH		 543 the pcrecallout documentation.
544
545
6bf342e1
PH		 546NON-PRINTING CHARACTERS
547
548 When pcretest is outputting text in the compiled version of a pattern,
549 bytes other than 32-126 are always treated as non-printing characters
550 are are therefore shown as hex escapes.
551
552 When pcretest is outputting text that is a matched part of a subject
553 string, it behaves in the same way, unless a different locale has been
554 set for the pattern (using the /L modifier). In this case, the
555 isprint() function to distinguish printing and non-printing characters.
556
557
495ae4b0
PH		 558SAVING AND RELOADING COMPILED PATTERNS
559
6bf342e1 560 The facilities described in this section are not available when the
495ae4b0
PH		 561 POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
562 ifier is specified.
563
564 When the POSIX interface is not in use, you can cause pcretest to write
6bf342e1 565 a compiled pattern to a file, by following the modifiers with > and a
495ae4b0
PH		 566 file name. For example:
567
568 /pattern/im >/some/file
569
6bf342e1 570 See the pcreprecompile documentation for a discussion about saving and
495ae4b0
PH		 571 re-using compiled patterns.
572
6bf342e1
PH		 573 The data that is written is binary. The first eight bytes are the
574 length of the compiled pattern data followed by the length of the
575 optional study data, each written as four bytes in big-endian order
576 (most significant byte first). If there is no study data (either the
495ae4b0 577 pattern was not studied, or studying did not return any data), the sec-
6bf342e1 578 ond length is zero. The lengths are followed by an exact copy of the
495ae4b0 579 compiled pattern. If there is additional study data, this follows imme-
6bf342e1 580 diately after the compiled pattern. After writing the file, pcretest
495ae4b0
PH		 581 expects to read a new pattern.
582
583 A saved pattern can be reloaded into pcretest by specifing < and a file
6bf342e1
PH		 584 name instead of a pattern. The name of the file must not contain a <
585 character, as otherwise pcretest will interpret the line as a pattern
495ae4b0
PH		 586 delimited by < characters. For example:
587
588 re> </some/file
589 Compiled regex loaded from /some/file
590 No study data
591
6bf342e1 592 When the pattern has been loaded, pcretest proceeds to read data lines
495ae4b0
PH		 593 in the usual way.
594
6bf342e1
PH		 595 You can copy a file written by pcretest to a different host and reload
596 it there, even if the new host has opposite endianness to the one on
597 which the pattern was compiled. For example, you can compile on an i86
495ae4b0
PH		 598 machine and run on a SPARC machine.
599
6bf342e1
PH		 600 File names for saving and reloading can be absolute or relative, but
601 note that the shell facility of expanding a file name that starts with
495ae4b0
PH		 602 a tilde (~) is not available.
603
6bf342e1
PH		 604 The ability to save and reload files in pcretest is intended for test-
605 ing and experimentation. It is not intended for production use because
606 only a single pattern can be written to a file. Furthermore, there is
607 no facility for supplying custom character tables for use with a
608 reloaded pattern. If the original pattern was compiled with custom
609 tables, an attempt to match a subject string using a reloaded pattern
610 is likely to cause pcretest to crash. Finally, if you attempt to load
495ae4b0
PH		 611 a file that is not in the correct format, the result is undefined.
612
613
6bf342e1
PH		 614SEE ALSO
615
616 pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d),
617 pcrepattern(3), pcreprecompile(3).
618
619
495ae4b0
PH		 620AUTHOR
621
8ac170f3 622 Philip Hazel
64f2600a 623 University Computing Service
6bf342e1 624 Cambridge CB2 3QH, England.
495ae4b0 625
64f2600a
PH		 626
627REVISION
628
629 Last updated: 24 April 2007
630 Copyright (c) 1997-2007 University of Cambridge.
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