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1 nigel 73 PCRETEST(1) PCRETEST(1)
2 nigel 41
3    
4 nigel 73 NAME
5     pcretest - a program for testing Perl-compatible regular expressions.
6    
7 nigel 79
8 nigel 53 SYNOPSIS
9 nigel 41
10 nigel 91 pcretest [options] [source] [destination]
11 nigel 75
12 nigel 73 pcretest was written as a test program for the PCRE regular expression
13     library itself, but it can also be used for experimenting with regular
14     expressions. This document describes the features of the test program;
15     for details of the regular expressions themselves, see the pcrepattern
16 nigel 75 documentation. For details of the PCRE library function calls and their
17     options, see the pcreapi documentation.
18 nigel 41
19    
20 nigel 63 OPTIONS
21 nigel 41
22 nigel 93 -b Behave as if each regex has the /B (show bytecode) modifier;
23     the internal form is output after compilation.
24    
25 nigel 73 -C Output the version number of the PCRE library, and all avail-
26 nigel 93 able information about the optional features that are
27 nigel 73 included, and then exit.
28 nigel 63
29 nigel 93 -d Behave as if each regex has the /D (debug) modifier; the
30     internal form and information about the compiled pattern is
31     output after compilation; -d is equivalent to -b -i.
32 nigel 41
33 nigel 77 -dfa Behave as if each data line contains the \D escape sequence;
34     this causes the alternative matching function,
35     pcre_dfa_exec(), to be used instead of the standard
36     pcre_exec() function (more detail is given below).
37    
38 nigel 93 -help Output a brief summary these options and then exit.
39    
40 nigel 77 -i Behave as if each regex has the /I modifier; information
41 nigel 73 about the compiled pattern is given after compilation.
42 nigel 41
43 nigel 77 -m Output the size of each compiled pattern after it has been
44     compiled. This is equivalent to adding /M to each regular
45     expression. For compatibility with earlier versions of
46 nigel 73 pcretest, -s is a synonym for -m.
47 nigel 41
48 nigel 77 -o osize Set the number of elements in the output vector that is used
49 nigel 93 when calling pcre_exec() or pcre_dfa_exec() to be osize. The
50     default value is 45, which is enough for 14 capturing subex-
51     pressions for pcre_exec() or 22 different matches for
52     pcre_dfa_exec(). The vector size can be changed for individ-
53     ual matching calls by including \O in the data line (see
54     below).
55 nigel 41
56 nigel 77 -p Behave as if each regex has the /P modifier; the POSIX wrap-
57     per API is used to call PCRE. None of the other options has
58     any effect when -p is set.
59 nigel 41
60 nigel 87 -q Do not output the version number of pcretest at the start of
61     execution.
62    
63 nigel 91 -S size On Unix-like systems, set the size of the runtime stack to
64     size megabytes.
65    
66     -t Run each compile, study, and match many times with a timer,
67     and output resulting time per compile or match (in millisec-
68     onds). Do not set -m with -t, because you will then get the
69     size output a zillion times, and the timing will be dis-
70 nigel 93 torted. You can control the number of iterations that are
71     used for timing by following -t with a number (as a separate
72     item on the command line). For example, "-t 1000" would iter-
73     ate 1000 times. The default is to iterate 500000 times.
74 nigel 49
75 nigel 93 -tm This is like -t except that it times only the matching phase,
76     not the compile or study phases.
77 nigel 49
78 nigel 93
79 nigel 63 DESCRIPTION
80 nigel 41
81 nigel 91 If pcretest is given two filename arguments, it reads from the first
82 nigel 73 and writes to the second. If it is given only one filename argument, it
83 nigel 91 reads from that file and writes to stdout. Otherwise, it reads from
84     stdin and writes to stdout, and prompts for each line of input, using
85 nigel 73 "re>" to prompt for regular expressions, and "data>" to prompt for data
86     lines.
87 nigel 41
88 ph10 289 When pcretest is built, a configuration option can specify that it
89     should be linked with the libreadline library. When this is done, if
90     the input is from a terminal, it is read using the readline() function.
91     This provides line-editing and history facilities. The output from the
92     -help option states whether or not readline() will be used.
93    
94 nigel 73 The program handles any number of sets of input on a single input file.
95 nigel 91 Each set starts with a regular expression, and continues with any num-
96 nigel 73 ber of data lines to be matched against the pattern.
97 nigel 41
98 nigel 91 Each data line is matched separately and independently. If you want to
99     do multi-line matches, you have to use the \n escape sequence (or \r or
100 nigel 93 \r\n, etc., depending on the newline setting) in a single line of input
101     to encode the newline sequences. There is no limit on the length of
102     data lines; the input buffer is automatically extended if it is too
103     small.
104 nigel 63
105 nigel 93 An empty line signals the end of the data lines, at which point a new
106     regular expression is read. The regular expressions are given enclosed
107 nigel 91 in any non-alphanumeric delimiters other than backslash, for example:
108 nigel 63
109 nigel 73 /(a|bc)x+yz/
110 nigel 41
111 nigel 93 White space before the initial delimiter is ignored. A regular expres-
112     sion may be continued over several input lines, in which case the new-
113     line characters are included within it. It is possible to include the
114 nigel 73 delimiter within the pattern by escaping it, for example
115 nigel 41
116 nigel 73 /abc\/def/
117 nigel 41
118 nigel 93 If you do so, the escape and the delimiter form part of the pattern,
119     but since delimiters are always non-alphanumeric, this does not affect
120     its interpretation. If the terminating delimiter is immediately fol-
121 nigel 73 lowed by a backslash, for example,
122 nigel 41
123 nigel 73 /abc/\
124 nigel 41
125 nigel 93 then a backslash is added to the end of the pattern. This is done to
126     provide a way of testing the error condition that arises if a pattern
127 nigel 73 finishes with a backslash, because
128 nigel 49
129 nigel 73 /abc\/
130 nigel 49
131 nigel 93 is interpreted as the first line of a pattern that starts with "abc/",
132 nigel 73 causing pcretest to read the next line as a continuation of the regular
133     expression.
134 nigel 49
135 nigel 41
136 nigel 63 PATTERN MODIFIERS
137 nigel 41
138 nigel 93 A pattern may be followed by any number of modifiers, which are mostly
139     single characters. Following Perl usage, these are referred to below
140     as, for example, "the /i modifier", even though the delimiter of the
141     pattern need not always be a slash, and no slash is used when writing
142     modifiers. Whitespace may appear between the final pattern delimiter
143 nigel 75 and the first modifier, and between the modifiers themselves.
144 nigel 41
145 nigel 75 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
146 nigel 93 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com-
147     pile() is called. These four modifier letters have the same effect as
148 nigel 75 they do in Perl. For example:
149    
150 nigel 73 /caseless/i
151 nigel 41
152 nigel 75 The following table shows additional modifiers for setting PCRE options
153     that do not correspond to anything in Perl:
154 nigel 41
155 ph10 231 /A PCRE_ANCHORED
156     /C PCRE_AUTO_CALLOUT
157     /E PCRE_DOLLAR_ENDONLY
158     /f PCRE_FIRSTLINE
159     /J PCRE_DUPNAMES
160     /N PCRE_NO_AUTO_CAPTURE
161     /U PCRE_UNGREEDY
162     /X PCRE_EXTRA
163 ph10 345 /<JS> PCRE_JAVASCRIPT_COMPAT
164 ph10 231 /<cr> PCRE_NEWLINE_CR
165     /<lf> PCRE_NEWLINE_LF
166     /<crlf> PCRE_NEWLINE_CRLF
167     /<anycrlf> PCRE_NEWLINE_ANYCRLF
168     /<any> PCRE_NEWLINE_ANY
169     /<bsr_anycrlf> PCRE_BSR_ANYCRLF
170     /<bsr_unicode> PCRE_BSR_UNICODE
171 nigel 75
172 ph10 227 Those specifying line ending sequences are literal strings as shown,
173     but the letters can be in either case. This example sets multiline
174     matching with CRLF as the line ending sequence:
175 nigel 91
176 nigel 93 /^abc/m<crlf>
177    
178     Details of the meanings of these PCRE options are given in the pcreapi
179     documentation.
180    
181 nigel 91 Finding all matches in a string
182    
183 nigel 87 Searching for all possible matches within each subject string can be
184     requested by the /g or /G modifier. After finding a match, PCRE is
185 nigel 73 called again to search the remainder of the subject string. The differ-
186     ence between /g and /G is that the former uses the startoffset argument
187 nigel 87 to pcre_exec() to start searching at a new point within the entire
188     string (which is in effect what Perl does), whereas the latter passes
189     over a shortened substring. This makes a difference to the matching
190 nigel 73 process if the pattern begins with a lookbehind assertion (including \b
191     or \B).
192 nigel 49
193 nigel 87 If any call to pcre_exec() in a /g or /G sequence matches an empty
194     string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
195     flags set in order to search for another, non-empty, match at the same
196     point. If this second match fails, the start offset is advanced by
197     one, and the normal match is retried. This imitates the way Perl han-
198 nigel 73 dles such cases when using the /g modifier or the split() function.
199 nigel 49
200 nigel 91 Other modifiers
201    
202 nigel 75 There are yet more modifiers for controlling the way pcretest operates.
203 nigel 49
204 nigel 87 The /+ modifier requests that as well as outputting the substring that
205     matched the entire pattern, pcretest should in addition output the
206     remainder of the subject string. This is useful for tests where the
207 nigel 73 subject contains multiple copies of the same substring.
208 nigel 41
209 nigel 93 The /B modifier is a debugging feature. It requests that pcretest out-
210 ph10 123 put a representation of the compiled byte code after compilation. Nor-
211     mally this information contains length and offset values; however, if
212     /Z is also present, this data is replaced by spaces. This is a special
213     feature for use in the automatic test scripts; it ensures that the same
214     output is generated for different internal link sizes.
215 nigel 93
216     The /L modifier must be followed directly by the name of a locale, for
217 nigel 73 example,
218 nigel 41
219 nigel 75 /pattern/Lfr_FR
220 nigel 41
221 nigel 75 For this reason, it must be the last modifier. The given locale is set,
222 nigel 93 pcre_maketables() is called to build a set of character tables for the
223     locale, and this is then passed to pcre_compile() when compiling the
224     regular expression. Without an /L modifier, NULL is passed as the
225     tables pointer; that is, /L applies only to the expression on which it
226 nigel 75 appears.
227 nigel 41
228 nigel 93 The /I modifier requests that pcretest output information about the
229     compiled pattern (whether it is anchored, has a fixed first character,
230     and so on). It does this by calling pcre_fullinfo() after compiling a
231     pattern. If the pattern is studied, the results of that are also out-
232 nigel 75 put.
233 nigel 63
234 nigel 93 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
235     that is, both the /B and the /I modifiers.
236 nigel 41
237 nigel 75 The /F modifier causes pcretest to flip the byte order of the fields in
238 nigel 93 the compiled pattern that contain 2-byte and 4-byte numbers. This
239     facility is for testing the feature in PCRE that allows it to execute
240 nigel 75 patterns that were compiled on a host with a different endianness. This
241 nigel 93 feature is not available when the POSIX interface to PCRE is being
242     used, that is, when the /P pattern modifier is specified. See also the
243 nigel 75 section about saving and reloading compiled patterns below.
244    
245 nigel 93 The /S modifier causes pcre_study() to be called after the expression
246 nigel 73 has been compiled, and the results used when the expression is matched.
247 nigel 41
248 nigel 93 The /M modifier causes the size of memory block used to hold the com-
249 nigel 73 piled pattern to be output.
250 nigel 41
251 nigel 93 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
252     rather than its native API. When this is done, all other modifiers
253     except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
254     and REG_NEWLINE is set if /m is present. The wrapper functions force
255     PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
256 nigel 41
257 nigel 93 The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
258     set. This turns on support for UTF-8 character handling in PCRE, pro-
259     vided that it was compiled with this support enabled. This modifier
260 nigel 73 also causes any non-printing characters in output strings to be printed
261     using the \x{hh...} notation if they are valid UTF-8 sequences.
262 nigel 41
263 nigel 93 If the /? modifier is used with /8, it causes pcretest to call
264     pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
265 nigel 73 checking of the string for UTF-8 validity.
266 nigel 41
267 nigel 71
268 nigel 53 DATA LINES
269 nigel 63
270 nigel 93 Before each data line is passed to pcre_exec(), leading and trailing
271     whitespace is removed, and it is then scanned for \ escapes. Some of
272     these are pretty esoteric features, intended for checking out some of
273     the more complicated features of PCRE. If you are just testing "ordi-
274     nary" regular expressions, you probably don't need any of these. The
275 nigel 73 following escapes are recognized:
276 nigel 49
277 nigel 93 \a alarm (BEL, \x07)
278     \b backspace (\x08)
279     \e escape (\x27)
280     \f formfeed (\x0c)
281     \n newline (\x0a)
282 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd
283     (any number of digits)
284 nigel 93 \r carriage return (\x0d)
285     \t tab (\x09)
286     \v vertical tab (\x0b)
287 nigel 73 \nnn octal character (up to 3 octal digits)
288     \xhh hexadecimal character (up to 2 hex digits)
289     \x{hh...} hexadecimal character, any number of digits
290     in UTF-8 mode
291     \A pass the PCRE_ANCHORED option to pcre_exec()
292 nigel 91 or pcre_dfa_exec()
293 nigel 73 \B pass the PCRE_NOTBOL option to pcre_exec()
294 nigel 91 or pcre_dfa_exec()
295 nigel 73 \Cdd call pcre_copy_substring() for substring dd
296 nigel 75 after a successful match (number less than 32)
297 nigel 73 \Cname call pcre_copy_named_substring() for substring
298     "name" after a successful match (name termin-
299     ated by next non alphanumeric character)
300     \C+ show the current captured substrings at callout
301     time
302     \C- do not supply a callout function
303     \C!n return 1 instead of 0 when callout number n is
304     reached
305     \C!n!m return 1 instead of 0 when callout number n is
306     reached for the nth time
307     \C*n pass the number n (may be negative) as callout
308 nigel 75 data; this is used as the callout return value
309 nigel 77 \D use the pcre_dfa_exec() match function
310     \F only shortest match for pcre_dfa_exec()
311 nigel 73 \Gdd call pcre_get_substring() for substring dd
312 nigel 75 after a successful match (number less than 32)
313 nigel 73 \Gname call pcre_get_named_substring() for substring
314     "name" after a successful match (name termin-
315     ated by next non-alphanumeric character)
316     \L call pcre_get_substringlist() after a
317     successful match
318 nigel 87 \M discover the minimum MATCH_LIMIT and
319     MATCH_LIMIT_RECURSION settings
320 nigel 73 \N pass the PCRE_NOTEMPTY option to pcre_exec()
321 nigel 91 or pcre_dfa_exec()
322 nigel 73 \Odd set the size of the output vector passed to
323 nigel 75 pcre_exec() to dd (any number of digits)
324     \P pass the PCRE_PARTIAL option to pcre_exec()
325 nigel 77 or pcre_dfa_exec()
326 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
327     (any number of digits)
328 nigel 77 \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
329 nigel 73 \S output details of memory get/free calls during matching
330     \Z pass the PCRE_NOTEOL option to pcre_exec()
331 nigel 91 or pcre_dfa_exec()
332 nigel 73 \? pass the PCRE_NO_UTF8_CHECK option to
333 nigel 91 pcre_exec() or pcre_dfa_exec()
334 nigel 75 \>dd start the match at offset dd (any number of digits);
335     this sets the startoffset argument for pcre_exec()
336 nigel 91 or pcre_dfa_exec()
337     \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec()
338     or pcre_dfa_exec()
339     \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec()
340     or pcre_dfa_exec()
341     \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec()
342     or pcre_dfa_exec()
343 ph10 150 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
344     or pcre_dfa_exec()
345 nigel 93 \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec()
346     or pcre_dfa_exec()
347 nigel 71
348 nigel 93 The escapes that specify line ending sequences are literal strings,
349     exactly as shown. No more than one newline setting should be present in
350     any data line.
351 nigel 75
352 nigel 93 A backslash followed by anything else just escapes the anything else.
353     If the very last character is a backslash, it is ignored. This gives a
354     way of passing an empty line as data, since a real empty line termi-
355     nates the data input.
356    
357 nigel 91 If \M is present, pcretest calls pcre_exec() several times, with dif-
358     ferent values in the match_limit and match_limit_recursion fields of
359     the pcre_extra data structure, until it finds the minimum numbers for
360 nigel 87 each parameter that allow pcre_exec() to complete. The match_limit num-
361 nigel 91 ber is a measure of the amount of backtracking that takes place, and
362 nigel 87 checking it out can be instructive. For most simple matches, the number
363 nigel 91 is quite small, but for patterns with very large numbers of matching
364     possibilities, it can become large very quickly with increasing length
365 nigel 87 of subject string. The match_limit_recursion number is a measure of how
366 nigel 91 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap)
367 nigel 87 memory is needed to complete the match attempt.
368 nigel 41
369 nigel 91 When \O is used, the value specified may be higher or lower than the
370 nigel 75 size set by the -O command line option (or defaulted to 45); \O applies
371     only to the call of pcre_exec() for the line in which it appears.
372 nigel 63
373 nigel 91 If the /P modifier was present on the pattern, causing the POSIX wrap-
374     per API to be used, the only option-setting sequences that have any
375     effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
376 nigel 87 to be passed to regexec().
377 nigel 41
378 nigel 91 The use of \x{hh...} to represent UTF-8 characters is not dependent on
379     the use of the /8 modifier on the pattern. It is recognized always.
380     There may be any number of hexadecimal digits inside the braces. The
381 ph10 211 result is from one to six bytes, encoded according to the original
382     UTF-8 rules of RFC 2279. This allows for values in the range 0 to
383     0x7FFFFFFF. Note that not all of those are valid Unicode code points,
384     or indeed valid UTF-8 characters according to the later rules in RFC
385     3629.
386 nigel 41
387 nigel 53
388 nigel 77 THE ALTERNATIVE MATCHING FUNCTION
389 nigel 53
390 ph10 211 By default, pcretest uses the standard PCRE matching function,
391 nigel 77 pcre_exec() to match each data line. From release 6.0, PCRE supports an
392 ph10 211 alternative matching function, pcre_dfa_test(), which operates in a
393     different way, and has some restrictions. The differences between the
394 nigel 77 two functions are described in the pcrematching documentation.
395    
396 ph10 211 If a data line contains the \D escape sequence, or if the command line
397     contains the -dfa option, the alternative matching function is called.
398 nigel 77 This function finds all possible matches at a given point. If, however,
399 ph10 211 the \F escape sequence is present in the data line, it stops after the
400 nigel 77 first match is found. This is always the shortest possible match.
401    
402    
403     DEFAULT OUTPUT FROM PCRETEST
404    
405 ph10 211 This section describes the output when the normal matching function,
406 nigel 77 pcre_exec(), is being used.
407    
408 nigel 73 When a match succeeds, pcretest outputs the list of captured substrings
409 ph10 211 that pcre_exec() returns, starting with number 0 for the string that
410 nigel 75 matched the whole pattern. Otherwise, it outputs "No match" or "Partial
411 ph10 211 match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
412     TIAL, respectively, and otherwise the PCRE negative error number. Here
413 nigel 75 is an example of an interactive pcretest run.
414 nigel 53
415 nigel 73 $ pcretest
416 nigel 93 PCRE version 7.0 30-Nov-2006
417 nigel 53
418 nigel 73 re> /^abc(\d+)/
419     data> abc123
420     0: abc123
421     1: 123
422     data> xyz
423     No match
424 nigel 53
425 ph10 286 Note that unset capturing substrings that are not followed by one that
426     is set are not returned by pcre_exec(), and are not shown by pcretest.
427     In the following example, there are two capturing substrings, but when
428     the first data line is matched, the second, unset substring is not
429     shown. An "internal" unset substring is shown as "<unset>", as for the
430     second data line.
431    
432     re> /(a)|(b)/
433     data> a
434     0: a
435     1: a
436     data> b
437     0: b
438     1: <unset>
439     2: b
440    
441     If the strings contain any non-printing characters, they are output as
442     \0x escapes, or as \x{...} escapes if the /8 modifier was present on
443     the pattern. See below for the definition of non-printing characters.
444     If the pattern has the /+ modifier, the output for substring 0 is fol-
445     lowed by the the rest of the subject string, identified by "0+" like
446 nigel 93 this:
447 nigel 53
448 nigel 73 re> /cat/+
449     data> cataract
450     0: cat
451     0+ aract
452 nigel 53
453 ph10 286 If the pattern has the /g or /G modifier, the results of successive
454 nigel 73 matching attempts are output in sequence, like this:
455 nigel 53
456 nigel 73 re> /\Bi(\w\w)/g
457     data> Mississippi
458     0: iss
459     1: ss
460     0: iss
461     1: ss
462     0: ipp
463     1: pp
464 nigel 53
465 nigel 73 "No match" is output only if the first match attempt fails.
466 nigel 53
467 ph10 286 If any of the sequences \C, \G, or \L are present in a data line that
468     is successfully matched, the substrings extracted by the convenience
469 nigel 73 functions are output with C, G, or L after the string number instead of
470     a colon. This is in addition to the normal full list. The string length
471 ph10 286 (that is, the return from the extraction function) is given in paren-
472 nigel 73 theses after each string for \C and \G.
473 nigel 53
474 nigel 93 Note that whereas patterns can be continued over several lines (a plain
475 nigel 73 ">" prompt is used for continuations), data lines may not. However new-
476 ph10 286 lines can be included in data by means of the \n escape (or \r, \r\n,
477 nigel 93 etc., depending on the newline sequence setting).
478 nigel 53
479    
480 nigel 77 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
481    
482 ph10 286 When the alternative matching function, pcre_dfa_exec(), is used (by
483     means of the \D escape sequence or the -dfa command line option), the
484     output consists of a list of all the matches that start at the first
485 nigel 77 point in the subject where there is at least one match. For example:
486    
487     re> /(tang|tangerine|tan)/
488     data> yellow tangerine\D
489     0: tangerine
490     1: tang
491     2: tan
492    
493 ph10 286 (Using the normal matching function on this data finds only "tang".)
494     The longest matching string is always given first (and numbered zero).
495 nigel 77
496 nigel 93 If /g is present on the pattern, the search for further matches resumes
497     at the end of the longest match. For example:
498 nigel 77
499     re> /(tang|tangerine|tan)/g
500     data> yellow tangerine and tangy sultana\D
501     0: tangerine
502     1: tang
503     2: tan
504     0: tang
505     1: tan
506     0: tan
507    
508 ph10 286 Since the matching function does not support substring capture, the
509     escape sequences that are concerned with captured substrings are not
510 nigel 77 relevant.
511    
512    
513     RESTARTING AFTER A PARTIAL MATCH
514    
515     When the alternative matching function has given the PCRE_ERROR_PARTIAL
516 ph10 286 return, indicating that the subject partially matched the pattern, you
517     can restart the match with additional subject data by means of the \R
518 nigel 77 escape sequence. For example:
519    
520 ph10 155 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
521 nigel 77 data> 23ja\P\D
522     Partial match: 23ja
523     data> n05\R\D
524     0: n05
525    
526 ph10 286 For further information about partial matching, see the pcrepartial
527 nigel 77 documentation.
528    
529    
530 nigel 75 CALLOUTS
531    
532 ph10 286 If the pattern contains any callout requests, pcretest's callout func-
533     tion is called during matching. This works with both matching func-
534 nigel 77 tions. By default, the called function displays the callout number, the
535 ph10 286 start and current positions in the text at the callout time, and the
536 nigel 77 next pattern item to be tested. For example, the output
537 nigel 75
538     --->pqrabcdef
539     0 ^ ^ \d
540    
541 ph10 286 indicates that callout number 0 occurred for a match attempt starting
542     at the fourth character of the subject string, when the pointer was at
543     the seventh character of the data, and when the next pattern item was
544     \d. Just one circumflex is output if the start and current positions
545 nigel 75 are the same.
546    
547     Callouts numbered 255 are assumed to be automatic callouts, inserted as
548 ph10 286 a result of the /C pattern modifier. In this case, instead of showing
549     the callout number, the offset in the pattern, preceded by a plus, is
550 nigel 75 output. For example:
551    
552     re> /\d?[A-E]\*/C
553     data> E*
554     --->E*
555     +0 ^ \d?
556     +3 ^ [A-E]
557     +8 ^^ \*
558     +10 ^ ^
559     0: E*
560    
561 ph10 286 The callout function in pcretest returns zero (carry on matching) by
562     default, but you can use a \C item in a data line (as described above)
563 nigel 75 to change this.
564    
565 ph10 286 Inserting callouts can be helpful when using pcretest to check compli-
566     cated regular expressions. For further information about callouts, see
567 nigel 75 the pcrecallout documentation.
568    
569    
570 nigel 93 NON-PRINTING CHARACTERS
571    
572 ph10 286 When pcretest is outputting text in the compiled version of a pattern,
573     bytes other than 32-126 are always treated as non-printing characters
574 nigel 93 are are therefore shown as hex escapes.
575    
576 ph10 286 When pcretest is outputting text that is a matched part of a subject
577     string, it behaves in the same way, unless a different locale has been
578     set for the pattern (using the /L modifier). In this case, the
579 nigel 93 isprint() function to distinguish printing and non-printing characters.
580    
581    
582 nigel 75 SAVING AND RELOADING COMPILED PATTERNS
583    
584 ph10 286 The facilities described in this section are not available when the
585 nigel 75 POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
586     ifier is specified.
587    
588     When the POSIX interface is not in use, you can cause pcretest to write
589 ph10 286 a compiled pattern to a file, by following the modifiers with > and a
590 nigel 75 file name. For example:
591    
592     /pattern/im >/some/file
593    
594 ph10 286 See the pcreprecompile documentation for a discussion about saving and
595 nigel 75 re-using compiled patterns.
596    
597 ph10 286 The data that is written is binary. The first eight bytes are the
598     length of the compiled pattern data followed by the length of the
599     optional study data, each written as four bytes in big-endian order
600     (most significant byte first). If there is no study data (either the
601 nigel 75 pattern was not studied, or studying did not return any data), the sec-
602 ph10 286 ond length is zero. The lengths are followed by an exact copy of the
603 nigel 75 compiled pattern. If there is additional study data, this follows imme-
604 ph10 286 diately after the compiled pattern. After writing the file, pcretest
605 nigel 75 expects to read a new pattern.
606    
607     A saved pattern can be reloaded into pcretest by specifing < and a file
608 ph10 286 name instead of a pattern. The name of the file must not contain a <
609     character, as otherwise pcretest will interpret the line as a pattern
610 nigel 75 delimited by < characters. For example:
611    
612     re> </some/file
613     Compiled regex loaded from /some/file
614     No study data
615    
616 ph10 286 When the pattern has been loaded, pcretest proceeds to read data lines
617 nigel 75 in the usual way.
618    
619 ph10 286 You can copy a file written by pcretest to a different host and reload
620     it there, even if the new host has opposite endianness to the one on
621     which the pattern was compiled. For example, you can compile on an i86
622 nigel 75 machine and run on a SPARC machine.
623    
624 ph10 286 File names for saving and reloading can be absolute or relative, but
625     note that the shell facility of expanding a file name that starts with
626 nigel 75 a tilde (~) is not available.
627    
628 ph10 286 The ability to save and reload files in pcretest is intended for test-
629     ing and experimentation. It is not intended for production use because
630     only a single pattern can be written to a file. Furthermore, there is
631     no facility for supplying custom character tables for use with a
632     reloaded pattern. If the original pattern was compiled with custom
633     tables, an attempt to match a subject string using a reloaded pattern
634     is likely to cause pcretest to crash. Finally, if you attempt to load
635 nigel 75 a file that is not in the correct format, the result is undefined.
636    
637    
638 nigel 93 SEE ALSO
639    
640 ph10 286 pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d),
641 nigel 93 pcrepattern(3), pcreprecompile(3).
642    
643    
644 nigel 63 AUTHOR
645 nigel 53
646 nigel 77 Philip Hazel
647 ph10 99 University Computing Service
648 nigel 93 Cambridge CB2 3QH, England.
649 nigel 53
650 ph10 99
651     REVISION
652    
653 ph10 345 Last updated: 12 April 2008
654     Copyright (c) 1997-2008 University of Cambridge.

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