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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 nigel 73 The program handles any number of sets of input on a single input file.
89 nigel 91 Each set starts with a regular expression, and continues with any num-
90 nigel 73 ber of data lines to be matched against the pattern.
91 nigel 41
92 nigel 91 Each data line is matched separately and independently. If you want to
93     do multi-line matches, you have to use the \n escape sequence (or \r or
94 nigel 93 \r\n, etc., depending on the newline setting) in a single line of input
95     to encode the newline sequences. There is no limit on the length of
96     data lines; the input buffer is automatically extended if it is too
97     small.
98 nigel 63
99 nigel 93 An empty line signals the end of the data lines, at which point a new
100     regular expression is read. The regular expressions are given enclosed
101 nigel 91 in any non-alphanumeric delimiters other than backslash, for example:
102 nigel 63
103 nigel 73 /(a|bc)x+yz/
104 nigel 41
105 nigel 93 White space before the initial delimiter is ignored. A regular expres-
106     sion may be continued over several input lines, in which case the new-
107     line characters are included within it. It is possible to include the
108 nigel 73 delimiter within the pattern by escaping it, for example
109 nigel 41
110 nigel 73 /abc\/def/
111 nigel 41
112 nigel 93 If you do so, the escape and the delimiter form part of the pattern,
113     but since delimiters are always non-alphanumeric, this does not affect
114     its interpretation. If the terminating delimiter is immediately fol-
115 nigel 73 lowed by a backslash, for example,
116 nigel 41
117 nigel 73 /abc/\
118 nigel 41
119 nigel 93 then a backslash is added to the end of the pattern. This is done to
120     provide a way of testing the error condition that arises if a pattern
121 nigel 73 finishes with a backslash, because
122 nigel 49
123 nigel 73 /abc\/
124 nigel 49
125 nigel 93 is interpreted as the first line of a pattern that starts with "abc/",
126 nigel 73 causing pcretest to read the next line as a continuation of the regular
127     expression.
128 nigel 49
129 nigel 41
130 nigel 63 PATTERN MODIFIERS
131 nigel 41
132 nigel 93 A pattern may be followed by any number of modifiers, which are mostly
133     single characters. Following Perl usage, these are referred to below
134     as, for example, "the /i modifier", even though the delimiter of the
135     pattern need not always be a slash, and no slash is used when writing
136     modifiers. Whitespace may appear between the final pattern delimiter
137 nigel 75 and the first modifier, and between the modifiers themselves.
138 nigel 41
139 nigel 75 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
140 nigel 93 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com-
141     pile() is called. These four modifier letters have the same effect as
142 nigel 75 they do in Perl. For example:
143    
144 nigel 73 /caseless/i
145 nigel 41
146 nigel 75 The following table shows additional modifiers for setting PCRE options
147     that do not correspond to anything in Perl:
148 nigel 41
149 ph10 150 /A PCRE_ANCHORED
150     /C PCRE_AUTO_CALLOUT
151     /E PCRE_DOLLAR_ENDONLY
152     /f PCRE_FIRSTLINE
153     /J PCRE_DUPNAMES
154     /N PCRE_NO_AUTO_CAPTURE
155     /U PCRE_UNGREEDY
156     /X PCRE_EXTRA
157     /<cr> PCRE_NEWLINE_CR
158     /<lf> PCRE_NEWLINE_LF
159     /<crlf> PCRE_NEWLINE_CRLF
160 ph10 152 /<anycrlf> PCRE_NEWLINE_ANYCRLF
161 ph10 150 /<any> PCRE_NEWLINE_ANY
162 nigel 75
163 nigel 93 Those specifying line ending sequencess are literal strings as shown.
164     This example sets multiline matching with CRLF as the line ending
165     sequence:
166 nigel 91
167 nigel 93 /^abc/m<crlf>
168    
169     Details of the meanings of these PCRE options are given in the pcreapi
170     documentation.
171    
172 nigel 91 Finding all matches in a string
173    
174 nigel 87 Searching for all possible matches within each subject string can be
175     requested by the /g or /G modifier. After finding a match, PCRE is
176 nigel 73 called again to search the remainder of the subject string. The differ-
177     ence between /g and /G is that the former uses the startoffset argument
178 nigel 87 to pcre_exec() to start searching at a new point within the entire
179     string (which is in effect what Perl does), whereas the latter passes
180     over a shortened substring. This makes a difference to the matching
181 nigel 73 process if the pattern begins with a lookbehind assertion (including \b
182     or \B).
183 nigel 49
184 nigel 87 If any call to pcre_exec() in a /g or /G sequence matches an empty
185     string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
186     flags set in order to search for another, non-empty, match at the same
187     point. If this second match fails, the start offset is advanced by
188     one, and the normal match is retried. This imitates the way Perl han-
189 nigel 73 dles such cases when using the /g modifier or the split() function.
190 nigel 49
191 nigel 91 Other modifiers
192    
193 nigel 75 There are yet more modifiers for controlling the way pcretest operates.
194 nigel 49
195 nigel 87 The /+ modifier requests that as well as outputting the substring that
196     matched the entire pattern, pcretest should in addition output the
197     remainder of the subject string. This is useful for tests where the
198 nigel 73 subject contains multiple copies of the same substring.
199 nigel 41
200 nigel 93 The /B modifier is a debugging feature. It requests that pcretest out-
201 ph10 123 put a representation of the compiled byte code after compilation. Nor-
202     mally this information contains length and offset values; however, if
203     /Z is also present, this data is replaced by spaces. This is a special
204     feature for use in the automatic test scripts; it ensures that the same
205     output is generated for different internal link sizes.
206 nigel 93
207     The /L modifier must be followed directly by the name of a locale, for
208 nigel 73 example,
209 nigel 41
210 nigel 75 /pattern/Lfr_FR
211 nigel 41
212 nigel 75 For this reason, it must be the last modifier. The given locale is set,
213 nigel 93 pcre_maketables() is called to build a set of character tables for the
214     locale, and this is then passed to pcre_compile() when compiling the
215     regular expression. Without an /L modifier, NULL is passed as the
216     tables pointer; that is, /L applies only to the expression on which it
217 nigel 75 appears.
218 nigel 41
219 nigel 93 The /I modifier requests that pcretest output information about the
220     compiled pattern (whether it is anchored, has a fixed first character,
221     and so on). It does this by calling pcre_fullinfo() after compiling a
222     pattern. If the pattern is studied, the results of that are also out-
223 nigel 75 put.
224 nigel 63
225 nigel 93 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
226     that is, both the /B and the /I modifiers.
227 nigel 41
228 nigel 75 The /F modifier causes pcretest to flip the byte order of the fields in
229 nigel 93 the compiled pattern that contain 2-byte and 4-byte numbers. This
230     facility is for testing the feature in PCRE that allows it to execute
231 nigel 75 patterns that were compiled on a host with a different endianness. This
232 nigel 93 feature is not available when the POSIX interface to PCRE is being
233     used, that is, when the /P pattern modifier is specified. See also the
234 nigel 75 section about saving and reloading compiled patterns below.
235    
236 nigel 93 The /S modifier causes pcre_study() to be called after the expression
237 nigel 73 has been compiled, and the results used when the expression is matched.
238 nigel 41
239 nigel 93 The /M modifier causes the size of memory block used to hold the com-
240 nigel 73 piled pattern to be output.
241 nigel 41
242 nigel 93 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
243     rather than its native API. When this is done, all other modifiers
244     except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
245     and REG_NEWLINE is set if /m is present. The wrapper functions force
246     PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
247 nigel 41
248 nigel 93 The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
249     set. This turns on support for UTF-8 character handling in PCRE, pro-
250     vided that it was compiled with this support enabled. This modifier
251 nigel 73 also causes any non-printing characters in output strings to be printed
252     using the \x{hh...} notation if they are valid UTF-8 sequences.
253 nigel 41
254 nigel 93 If the /? modifier is used with /8, it causes pcretest to call
255     pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
256 nigel 73 checking of the string for UTF-8 validity.
257 nigel 41
258 nigel 71
259 nigel 53 DATA LINES
260 nigel 63
261 nigel 93 Before each data line is passed to pcre_exec(), leading and trailing
262     whitespace is removed, and it is then scanned for \ escapes. Some of
263     these are pretty esoteric features, intended for checking out some of
264     the more complicated features of PCRE. If you are just testing "ordi-
265     nary" regular expressions, you probably don't need any of these. The
266 nigel 73 following escapes are recognized:
267 nigel 49
268 nigel 93 \a alarm (BEL, \x07)
269     \b backspace (\x08)
270     \e escape (\x27)
271     \f formfeed (\x0c)
272     \n newline (\x0a)
273 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd
274     (any number of digits)
275 nigel 93 \r carriage return (\x0d)
276     \t tab (\x09)
277     \v vertical tab (\x0b)
278 nigel 73 \nnn octal character (up to 3 octal digits)
279     \xhh hexadecimal character (up to 2 hex digits)
280     \x{hh...} hexadecimal character, any number of digits
281     in UTF-8 mode
282     \A pass the PCRE_ANCHORED option to pcre_exec()
283 nigel 91 or pcre_dfa_exec()
284 nigel 73 \B pass the PCRE_NOTBOL option to pcre_exec()
285 nigel 91 or pcre_dfa_exec()
286 nigel 73 \Cdd call pcre_copy_substring() for substring dd
287 nigel 75 after a successful match (number less than 32)
288 nigel 73 \Cname call pcre_copy_named_substring() for substring
289     "name" after a successful match (name termin-
290     ated by next non alphanumeric character)
291     \C+ show the current captured substrings at callout
292     time
293     \C- do not supply a callout function
294     \C!n return 1 instead of 0 when callout number n is
295     reached
296     \C!n!m return 1 instead of 0 when callout number n is
297     reached for the nth time
298     \C*n pass the number n (may be negative) as callout
299 nigel 75 data; this is used as the callout return value
300 nigel 77 \D use the pcre_dfa_exec() match function
301     \F only shortest match for pcre_dfa_exec()
302 nigel 73 \Gdd call pcre_get_substring() for substring dd
303 nigel 75 after a successful match (number less than 32)
304 nigel 73 \Gname call pcre_get_named_substring() for substring
305     "name" after a successful match (name termin-
306     ated by next non-alphanumeric character)
307     \L call pcre_get_substringlist() after a
308     successful match
309 nigel 87 \M discover the minimum MATCH_LIMIT and
310     MATCH_LIMIT_RECURSION settings
311 nigel 73 \N pass the PCRE_NOTEMPTY option to pcre_exec()
312 nigel 91 or pcre_dfa_exec()
313 nigel 73 \Odd set the size of the output vector passed to
314 nigel 75 pcre_exec() to dd (any number of digits)
315     \P pass the PCRE_PARTIAL option to pcre_exec()
316 nigel 77 or pcre_dfa_exec()
317 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
318     (any number of digits)
319 nigel 77 \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
320 nigel 73 \S output details of memory get/free calls during matching
321     \Z pass the PCRE_NOTEOL option to pcre_exec()
322 nigel 91 or pcre_dfa_exec()
323 nigel 73 \? pass the PCRE_NO_UTF8_CHECK option to
324 nigel 91 pcre_exec() or pcre_dfa_exec()
325 nigel 75 \>dd start the match at offset dd (any number of digits);
326     this sets the startoffset argument for pcre_exec()
327 nigel 91 or pcre_dfa_exec()
328     \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec()
329     or pcre_dfa_exec()
330     \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec()
331     or pcre_dfa_exec()
332     \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec()
333     or pcre_dfa_exec()
334 ph10 150 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
335     or pcre_dfa_exec()
336 nigel 93 \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec()
337     or pcre_dfa_exec()
338 nigel 71
339 nigel 93 The escapes that specify line ending sequences are literal strings,
340     exactly as shown. No more than one newline setting should be present in
341     any data line.
342 nigel 75
343 nigel 93 A backslash followed by anything else just escapes the anything else.
344     If the very last character is a backslash, it is ignored. This gives a
345     way of passing an empty line as data, since a real empty line termi-
346     nates the data input.
347    
348 nigel 91 If \M is present, pcretest calls pcre_exec() several times, with dif-
349     ferent values in the match_limit and match_limit_recursion fields of
350     the pcre_extra data structure, until it finds the minimum numbers for
351 nigel 87 each parameter that allow pcre_exec() to complete. The match_limit num-
352 nigel 91 ber is a measure of the amount of backtracking that takes place, and
353 nigel 87 checking it out can be instructive. For most simple matches, the number
354 nigel 91 is quite small, but for patterns with very large numbers of matching
355     possibilities, it can become large very quickly with increasing length
356 nigel 87 of subject string. The match_limit_recursion number is a measure of how
357 nigel 91 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap)
358 nigel 87 memory is needed to complete the match attempt.
359 nigel 41
360 nigel 91 When \O is used, the value specified may be higher or lower than the
361 nigel 75 size set by the -O command line option (or defaulted to 45); \O applies
362     only to the call of pcre_exec() for the line in which it appears.
363 nigel 63
364 nigel 91 If the /P modifier was present on the pattern, causing the POSIX wrap-
365     per API to be used, the only option-setting sequences that have any
366     effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
367 nigel 87 to be passed to regexec().
368 nigel 41
369 nigel 91 The use of \x{hh...} to represent UTF-8 characters is not dependent on
370     the use of the /8 modifier on the pattern. It is recognized always.
371     There may be any number of hexadecimal digits inside the braces. The
372 ph10 211 result is from one to six bytes, encoded according to the original
373     UTF-8 rules of RFC 2279. This allows for values in the range 0 to
374     0x7FFFFFFF. Note that not all of those are valid Unicode code points,
375     or indeed valid UTF-8 characters according to the later rules in RFC
376     3629.
377 nigel 41
378 nigel 53
379 nigel 77 THE ALTERNATIVE MATCHING FUNCTION
380 nigel 53
381 ph10 211 By default, pcretest uses the standard PCRE matching function,
382 nigel 77 pcre_exec() to match each data line. From release 6.0, PCRE supports an
383 ph10 211 alternative matching function, pcre_dfa_test(), which operates in a
384     different way, and has some restrictions. The differences between the
385 nigel 77 two functions are described in the pcrematching documentation.
386    
387 ph10 211 If a data line contains the \D escape sequence, or if the command line
388     contains the -dfa option, the alternative matching function is called.
389 nigel 77 This function finds all possible matches at a given point. If, however,
390 ph10 211 the \F escape sequence is present in the data line, it stops after the
391 nigel 77 first match is found. This is always the shortest possible match.
392    
393    
394     DEFAULT OUTPUT FROM PCRETEST
395    
396 ph10 211 This section describes the output when the normal matching function,
397 nigel 77 pcre_exec(), is being used.
398    
399 nigel 73 When a match succeeds, pcretest outputs the list of captured substrings
400 ph10 211 that pcre_exec() returns, starting with number 0 for the string that
401 nigel 75 matched the whole pattern. Otherwise, it outputs "No match" or "Partial
402 ph10 211 match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
403     TIAL, respectively, and otherwise the PCRE negative error number. Here
404 nigel 75 is an example of an interactive pcretest run.
405 nigel 53
406 nigel 73 $ pcretest
407 nigel 93 PCRE version 7.0 30-Nov-2006
408 nigel 53
409 nigel 73 re> /^abc(\d+)/
410     data> abc123
411     0: abc123
412     1: 123
413     data> xyz
414     No match
415 nigel 53
416 ph10 211 If the strings contain any non-printing characters, they are output as
417     \0x escapes, or as \x{...} escapes if the /8 modifier was present on
418     the pattern. See below for the definition of non-printing characters.
419     If the pattern has the /+ modifier, the output for substring 0 is fol-
420     lowed by the the rest of the subject string, identified by "0+" like
421 nigel 93 this:
422 nigel 53
423 nigel 73 re> /cat/+
424     data> cataract
425     0: cat
426     0+ aract
427 nigel 53
428 ph10 211 If the pattern has the /g or /G modifier, the results of successive
429 nigel 73 matching attempts are output in sequence, like this:
430 nigel 53
431 nigel 73 re> /\Bi(\w\w)/g
432     data> Mississippi
433     0: iss
434     1: ss
435     0: iss
436     1: ss
437     0: ipp
438     1: pp
439 nigel 53
440 nigel 73 "No match" is output only if the first match attempt fails.
441 nigel 53
442 ph10 211 If any of the sequences \C, \G, or \L are present in a data line that
443     is successfully matched, the substrings extracted by the convenience
444 nigel 73 functions are output with C, G, or L after the string number instead of
445     a colon. This is in addition to the normal full list. The string length
446 ph10 211 (that is, the return from the extraction function) is given in paren-
447 nigel 73 theses after each string for \C and \G.
448 nigel 53
449 nigel 93 Note that whereas patterns can be continued over several lines (a plain
450 nigel 73 ">" prompt is used for continuations), data lines may not. However new-
451 ph10 211 lines can be included in data by means of the \n escape (or \r, \r\n,
452 nigel 93 etc., depending on the newline sequence setting).
453 nigel 53
454    
455 nigel 77 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
456    
457 ph10 211 When the alternative matching function, pcre_dfa_exec(), is used (by
458     means of the \D escape sequence or the -dfa command line option), the
459     output consists of a list of all the matches that start at the first
460 nigel 77 point in the subject where there is at least one match. For example:
461    
462     re> /(tang|tangerine|tan)/
463     data> yellow tangerine\D
464     0: tangerine
465     1: tang
466     2: tan
467    
468 ph10 211 (Using the normal matching function on this data finds only "tang".)
469     The longest matching string is always given first (and numbered zero).
470 nigel 77
471 nigel 93 If /g is present on the pattern, the search for further matches resumes
472     at the end of the longest match. For example:
473 nigel 77
474     re> /(tang|tangerine|tan)/g
475     data> yellow tangerine and tangy sultana\D
476     0: tangerine
477     1: tang
478     2: tan
479     0: tang
480     1: tan
481     0: tan
482    
483 ph10 211 Since the matching function does not support substring capture, the
484     escape sequences that are concerned with captured substrings are not
485 nigel 77 relevant.
486    
487    
488     RESTARTING AFTER A PARTIAL MATCH
489    
490     When the alternative matching function has given the PCRE_ERROR_PARTIAL
491 ph10 211 return, indicating that the subject partially matched the pattern, you
492     can restart the match with additional subject data by means of the \R
493 nigel 77 escape sequence. For example:
494    
495 ph10 155 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
496 nigel 77 data> 23ja\P\D
497     Partial match: 23ja
498     data> n05\R\D
499     0: n05
500    
501 ph10 211 For further information about partial matching, see the pcrepartial
502 nigel 77 documentation.
503    
504    
505 nigel 75 CALLOUTS
506    
507 ph10 211 If the pattern contains any callout requests, pcretest's callout func-
508     tion is called during matching. This works with both matching func-
509 nigel 77 tions. By default, the called function displays the callout number, the
510 ph10 211 start and current positions in the text at the callout time, and the
511 nigel 77 next pattern item to be tested. For example, the output
512 nigel 75
513     --->pqrabcdef
514     0 ^ ^ \d
515    
516 ph10 211 indicates that callout number 0 occurred for a match attempt starting
517     at the fourth character of the subject string, when the pointer was at
518     the seventh character of the data, and when the next pattern item was
519     \d. Just one circumflex is output if the start and current positions
520 nigel 75 are the same.
521    
522     Callouts numbered 255 are assumed to be automatic callouts, inserted as
523 ph10 211 a result of the /C pattern modifier. In this case, instead of showing
524     the callout number, the offset in the pattern, preceded by a plus, is
525 nigel 75 output. For example:
526    
527     re> /\d?[A-E]\*/C
528     data> E*
529     --->E*
530     +0 ^ \d?
531     +3 ^ [A-E]
532     +8 ^^ \*
533     +10 ^ ^
534     0: E*
535    
536 ph10 211 The callout function in pcretest returns zero (carry on matching) by
537     default, but you can use a \C item in a data line (as described above)
538 nigel 75 to change this.
539    
540 ph10 211 Inserting callouts can be helpful when using pcretest to check compli-
541     cated regular expressions. For further information about callouts, see
542 nigel 75 the pcrecallout documentation.
543    
544    
545 nigel 93 NON-PRINTING CHARACTERS
546    
547 ph10 211 When pcretest is outputting text in the compiled version of a pattern,
548     bytes other than 32-126 are always treated as non-printing characters
549 nigel 93 are are therefore shown as hex escapes.
550    
551 ph10 211 When pcretest is outputting text that is a matched part of a subject
552     string, it behaves in the same way, unless a different locale has been
553     set for the pattern (using the /L modifier). In this case, the
554 nigel 93 isprint() function to distinguish printing and non-printing characters.
555    
556    
557 nigel 75 SAVING AND RELOADING COMPILED PATTERNS
558    
559 ph10 211 The facilities described in this section are not available when the
560 nigel 75 POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
561     ifier is specified.
562    
563     When the POSIX interface is not in use, you can cause pcretest to write
564 ph10 211 a compiled pattern to a file, by following the modifiers with > and a
565 nigel 75 file name. For example:
566    
567     /pattern/im >/some/file
568    
569 ph10 211 See the pcreprecompile documentation for a discussion about saving and
570 nigel 75 re-using compiled patterns.
571    
572 ph10 211 The data that is written is binary. The first eight bytes are the
573     length of the compiled pattern data followed by the length of the
574     optional study data, each written as four bytes in big-endian order
575     (most significant byte first). If there is no study data (either the
576 nigel 75 pattern was not studied, or studying did not return any data), the sec-
577 ph10 211 ond length is zero. The lengths are followed by an exact copy of the
578 nigel 75 compiled pattern. If there is additional study data, this follows imme-
579 ph10 211 diately after the compiled pattern. After writing the file, pcretest
580 nigel 75 expects to read a new pattern.
581    
582     A saved pattern can be reloaded into pcretest by specifing < and a file
583 ph10 211 name instead of a pattern. The name of the file must not contain a <
584     character, as otherwise pcretest will interpret the line as a pattern
585 nigel 75 delimited by < characters. For example:
586    
587     re> </some/file
588     Compiled regex loaded from /some/file
589     No study data
590    
591 ph10 211 When the pattern has been loaded, pcretest proceeds to read data lines
592 nigel 75 in the usual way.
593    
594 ph10 211 You can copy a file written by pcretest to a different host and reload
595     it there, even if the new host has opposite endianness to the one on
596     which the pattern was compiled. For example, you can compile on an i86
597 nigel 75 machine and run on a SPARC machine.
598    
599 ph10 211 File names for saving and reloading can be absolute or relative, but
600     note that the shell facility of expanding a file name that starts with
601 nigel 75 a tilde (~) is not available.
602    
603 ph10 211 The ability to save and reload files in pcretest is intended for test-
604     ing and experimentation. It is not intended for production use because
605     only a single pattern can be written to a file. Furthermore, there is
606     no facility for supplying custom character tables for use with a
607     reloaded pattern. If the original pattern was compiled with custom
608     tables, an attempt to match a subject string using a reloaded pattern
609     is likely to cause pcretest to crash. Finally, if you attempt to load
610 nigel 75 a file that is not in the correct format, the result is undefined.
611    
612    
613 nigel 93 SEE ALSO
614    
615 ph10 211 pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d),
616 nigel 93 pcrepattern(3), pcreprecompile(3).
617    
618    
619 nigel 63 AUTHOR
620 nigel 53
621 nigel 77 Philip Hazel
622 ph10 99 University Computing Service
623 nigel 93 Cambridge CB2 3QH, England.
624 nigel 53
625 ph10 99
626     REVISION
627    
628 ph10 211 Last updated: 09 August 2007
629 ph10 99 Copyright (c) 1997-2007 University of Cambridge.

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