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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     /<cr> PCRE_NEWLINE_CR
164     /<lf> PCRE_NEWLINE_LF
165     /<crlf> PCRE_NEWLINE_CRLF
166     /<anycrlf> PCRE_NEWLINE_ANYCRLF
167     /<any> PCRE_NEWLINE_ANY
168     /<bsr_anycrlf> PCRE_BSR_ANYCRLF
169     /<bsr_unicode> PCRE_BSR_UNICODE
170 nigel 75
171 ph10 227 Those specifying line ending sequences are literal strings as shown,
172     but the letters can be in either case. This example sets multiline
173     matching with CRLF as the line ending sequence:
174 nigel 91
175 nigel 93 /^abc/m<crlf>
176    
177     Details of the meanings of these PCRE options are given in the pcreapi
178     documentation.
179    
180 nigel 91 Finding all matches in a string
181    
182 nigel 87 Searching for all possible matches within each subject string can be
183     requested by the /g or /G modifier. After finding a match, PCRE is
184 nigel 73 called again to search the remainder of the subject string. The differ-
185     ence between /g and /G is that the former uses the startoffset argument
186 nigel 87 to pcre_exec() to start searching at a new point within the entire
187     string (which is in effect what Perl does), whereas the latter passes
188     over a shortened substring. This makes a difference to the matching
189 nigel 73 process if the pattern begins with a lookbehind assertion (including \b
190     or \B).
191 nigel 49
192 nigel 87 If any call to pcre_exec() in a /g or /G sequence matches an empty
193     string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
194     flags set in order to search for another, non-empty, match at the same
195     point. If this second match fails, the start offset is advanced by
196     one, and the normal match is retried. This imitates the way Perl han-
197 nigel 73 dles such cases when using the /g modifier or the split() function.
198 nigel 49
199 nigel 91 Other modifiers
200    
201 nigel 75 There are yet more modifiers for controlling the way pcretest operates.
202 nigel 49
203 nigel 87 The /+ modifier requests that as well as outputting the substring that
204     matched the entire pattern, pcretest should in addition output the
205     remainder of the subject string. This is useful for tests where the
206 nigel 73 subject contains multiple copies of the same substring.
207 nigel 41
208 nigel 93 The /B modifier is a debugging feature. It requests that pcretest out-
209 ph10 123 put a representation of the compiled byte code after compilation. Nor-
210     mally this information contains length and offset values; however, if
211     /Z is also present, this data is replaced by spaces. This is a special
212     feature for use in the automatic test scripts; it ensures that the same
213     output is generated for different internal link sizes.
214 nigel 93
215     The /L modifier must be followed directly by the name of a locale, for
216 nigel 73 example,
217 nigel 41
218 nigel 75 /pattern/Lfr_FR
219 nigel 41
220 nigel 75 For this reason, it must be the last modifier. The given locale is set,
221 nigel 93 pcre_maketables() is called to build a set of character tables for the
222     locale, and this is then passed to pcre_compile() when compiling the
223     regular expression. Without an /L modifier, NULL is passed as the
224     tables pointer; that is, /L applies only to the expression on which it
225 nigel 75 appears.
226 nigel 41
227 nigel 93 The /I modifier requests that pcretest output information about the
228     compiled pattern (whether it is anchored, has a fixed first character,
229     and so on). It does this by calling pcre_fullinfo() after compiling a
230     pattern. If the pattern is studied, the results of that are also out-
231 nigel 75 put.
232 nigel 63
233 nigel 93 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
234     that is, both the /B and the /I modifiers.
235 nigel 41
236 nigel 75 The /F modifier causes pcretest to flip the byte order of the fields in
237 nigel 93 the compiled pattern that contain 2-byte and 4-byte numbers. This
238     facility is for testing the feature in PCRE that allows it to execute
239 nigel 75 patterns that were compiled on a host with a different endianness. This
240 nigel 93 feature is not available when the POSIX interface to PCRE is being
241     used, that is, when the /P pattern modifier is specified. See also the
242 nigel 75 section about saving and reloading compiled patterns below.
243    
244 nigel 93 The /S modifier causes pcre_study() to be called after the expression
245 nigel 73 has been compiled, and the results used when the expression is matched.
246 nigel 41
247 nigel 93 The /M modifier causes the size of memory block used to hold the com-
248 nigel 73 piled pattern to be output.
249 nigel 41
250 nigel 93 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
251     rather than its native API. When this is done, all other modifiers
252     except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present,
253     and REG_NEWLINE is set if /m is present. The wrapper functions force
254     PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
255 nigel 41
256 nigel 93 The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
257     set. This turns on support for UTF-8 character handling in PCRE, pro-
258     vided that it was compiled with this support enabled. This modifier
259 nigel 73 also causes any non-printing characters in output strings to be printed
260     using the \x{hh...} notation if they are valid UTF-8 sequences.
261 nigel 41
262 nigel 93 If the /? modifier is used with /8, it causes pcretest to call
263     pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the
264 nigel 73 checking of the string for UTF-8 validity.
265 nigel 41
266 nigel 71
267 nigel 53 DATA LINES
268 nigel 63
269 nigel 93 Before each data line is passed to pcre_exec(), leading and trailing
270     whitespace is removed, and it is then scanned for \ escapes. Some of
271     these are pretty esoteric features, intended for checking out some of
272     the more complicated features of PCRE. If you are just testing "ordi-
273     nary" regular expressions, you probably don't need any of these. The
274 nigel 73 following escapes are recognized:
275 nigel 49
276 nigel 93 \a alarm (BEL, \x07)
277     \b backspace (\x08)
278     \e escape (\x27)
279     \f formfeed (\x0c)
280     \n newline (\x0a)
281 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd
282     (any number of digits)
283 nigel 93 \r carriage return (\x0d)
284     \t tab (\x09)
285     \v vertical tab (\x0b)
286 nigel 73 \nnn octal character (up to 3 octal digits)
287     \xhh hexadecimal character (up to 2 hex digits)
288     \x{hh...} hexadecimal character, any number of digits
289     in UTF-8 mode
290     \A pass the PCRE_ANCHORED option to pcre_exec()
291 nigel 91 or pcre_dfa_exec()
292 nigel 73 \B pass the PCRE_NOTBOL option to pcre_exec()
293 nigel 91 or pcre_dfa_exec()
294 nigel 73 \Cdd call pcre_copy_substring() for substring dd
295 nigel 75 after a successful match (number less than 32)
296 nigel 73 \Cname call pcre_copy_named_substring() for substring
297     "name" after a successful match (name termin-
298     ated by next non alphanumeric character)
299     \C+ show the current captured substrings at callout
300     time
301     \C- do not supply a callout function
302     \C!n return 1 instead of 0 when callout number n is
303     reached
304     \C!n!m return 1 instead of 0 when callout number n is
305     reached for the nth time
306     \C*n pass the number n (may be negative) as callout
307 nigel 75 data; this is used as the callout return value
308 nigel 77 \D use the pcre_dfa_exec() match function
309     \F only shortest match for pcre_dfa_exec()
310 nigel 73 \Gdd call pcre_get_substring() for substring dd
311 nigel 75 after a successful match (number less than 32)
312 nigel 73 \Gname call pcre_get_named_substring() for substring
313     "name" after a successful match (name termin-
314     ated by next non-alphanumeric character)
315     \L call pcre_get_substringlist() after a
316     successful match
317 nigel 87 \M discover the minimum MATCH_LIMIT and
318     MATCH_LIMIT_RECURSION settings
319 nigel 73 \N pass the PCRE_NOTEMPTY option to pcre_exec()
320 nigel 91 or pcre_dfa_exec()
321 nigel 73 \Odd set the size of the output vector passed to
322 nigel 75 pcre_exec() to dd (any number of digits)
323     \P pass the PCRE_PARTIAL option to pcre_exec()
324 nigel 77 or pcre_dfa_exec()
325 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
326     (any number of digits)
327 nigel 77 \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
328 nigel 73 \S output details of memory get/free calls during matching
329     \Z pass the PCRE_NOTEOL option to pcre_exec()
330 nigel 91 or pcre_dfa_exec()
331 nigel 73 \? pass the PCRE_NO_UTF8_CHECK option to
332 nigel 91 pcre_exec() or pcre_dfa_exec()
333 nigel 75 \>dd start the match at offset dd (any number of digits);
334     this sets the startoffset argument for pcre_exec()
335 nigel 91 or pcre_dfa_exec()
336     \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec()
337     or pcre_dfa_exec()
338     \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec()
339     or pcre_dfa_exec()
340     \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec()
341     or pcre_dfa_exec()
342 ph10 150 \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
343     or pcre_dfa_exec()
344 nigel 93 \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec()
345     or pcre_dfa_exec()
346 nigel 71
347 nigel 93 The escapes that specify line ending sequences are literal strings,
348     exactly as shown. No more than one newline setting should be present in
349     any data line.
350 nigel 75
351 nigel 93 A backslash followed by anything else just escapes the anything else.
352     If the very last character is a backslash, it is ignored. This gives a
353     way of passing an empty line as data, since a real empty line termi-
354     nates the data input.
355    
356 nigel 91 If \M is present, pcretest calls pcre_exec() several times, with dif-
357     ferent values in the match_limit and match_limit_recursion fields of
358     the pcre_extra data structure, until it finds the minimum numbers for
359 nigel 87 each parameter that allow pcre_exec() to complete. The match_limit num-
360 nigel 91 ber is a measure of the amount of backtracking that takes place, and
361 nigel 87 checking it out can be instructive. For most simple matches, the number
362 nigel 91 is quite small, but for patterns with very large numbers of matching
363     possibilities, it can become large very quickly with increasing length
364 nigel 87 of subject string. The match_limit_recursion number is a measure of how
365 nigel 91 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap)
366 nigel 87 memory is needed to complete the match attempt.
367 nigel 41
368 nigel 91 When \O is used, the value specified may be higher or lower than the
369 nigel 75 size set by the -O command line option (or defaulted to 45); \O applies
370     only to the call of pcre_exec() for the line in which it appears.
371 nigel 63
372 nigel 91 If the /P modifier was present on the pattern, causing the POSIX wrap-
373     per API to be used, the only option-setting sequences that have any
374     effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
375 nigel 87 to be passed to regexec().
376 nigel 41
377 nigel 91 The use of \x{hh...} to represent UTF-8 characters is not dependent on
378     the use of the /8 modifier on the pattern. It is recognized always.
379     There may be any number of hexadecimal digits inside the braces. The
380 ph10 211 result is from one to six bytes, encoded according to the original
381     UTF-8 rules of RFC 2279. This allows for values in the range 0 to
382     0x7FFFFFFF. Note that not all of those are valid Unicode code points,
383     or indeed valid UTF-8 characters according to the later rules in RFC
384     3629.
385 nigel 41
386 nigel 53
387 nigel 77 THE ALTERNATIVE MATCHING FUNCTION
388 nigel 53
389 ph10 211 By default, pcretest uses the standard PCRE matching function,
390 nigel 77 pcre_exec() to match each data line. From release 6.0, PCRE supports an
391 ph10 211 alternative matching function, pcre_dfa_test(), which operates in a
392     different way, and has some restrictions. The differences between the
393 nigel 77 two functions are described in the pcrematching documentation.
394    
395 ph10 211 If a data line contains the \D escape sequence, or if the command line
396     contains the -dfa option, the alternative matching function is called.
397 nigel 77 This function finds all possible matches at a given point. If, however,
398 ph10 211 the \F escape sequence is present in the data line, it stops after the
399 nigel 77 first match is found. This is always the shortest possible match.
400    
401    
402     DEFAULT OUTPUT FROM PCRETEST
403    
404 ph10 211 This section describes the output when the normal matching function,
405 nigel 77 pcre_exec(), is being used.
406    
407 nigel 73 When a match succeeds, pcretest outputs the list of captured substrings
408 ph10 211 that pcre_exec() returns, starting with number 0 for the string that
409 nigel 75 matched the whole pattern. Otherwise, it outputs "No match" or "Partial
410 ph10 211 match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
411     TIAL, respectively, and otherwise the PCRE negative error number. Here
412 nigel 75 is an example of an interactive pcretest run.
413 nigel 53
414 nigel 73 $ pcretest
415 nigel 93 PCRE version 7.0 30-Nov-2006
416 nigel 53
417 nigel 73 re> /^abc(\d+)/
418     data> abc123
419     0: abc123
420     1: 123
421     data> xyz
422     No match
423 nigel 53
424 ph10 286 Note that unset capturing substrings that are not followed by one that
425     is set are not returned by pcre_exec(), and are not shown by pcretest.
426     In the following example, there are two capturing substrings, but when
427     the first data line is matched, the second, unset substring is not
428     shown. An "internal" unset substring is shown as "<unset>", as for the
429     second data line.
430    
431     re> /(a)|(b)/
432     data> a
433     0: a
434     1: a
435     data> b
436     0: b
437     1: <unset>
438     2: b
439    
440     If the strings contain any non-printing characters, they are output as
441     \0x escapes, or as \x{...} escapes if the /8 modifier was present on
442     the pattern. See below for the definition of non-printing characters.
443     If the pattern has the /+ modifier, the output for substring 0 is fol-
444     lowed by the the rest of the subject string, identified by "0+" like
445 nigel 93 this:
446 nigel 53
447 nigel 73 re> /cat/+
448     data> cataract
449     0: cat
450     0+ aract
451 nigel 53
452 ph10 286 If the pattern has the /g or /G modifier, the results of successive
453 nigel 73 matching attempts are output in sequence, like this:
454 nigel 53
455 nigel 73 re> /\Bi(\w\w)/g
456     data> Mississippi
457     0: iss
458     1: ss
459     0: iss
460     1: ss
461     0: ipp
462     1: pp
463 nigel 53
464 nigel 73 "No match" is output only if the first match attempt fails.
465 nigel 53
466 ph10 286 If any of the sequences \C, \G, or \L are present in a data line that
467     is successfully matched, the substrings extracted by the convenience
468 nigel 73 functions are output with C, G, or L after the string number instead of
469     a colon. This is in addition to the normal full list. The string length
470 ph10 286 (that is, the return from the extraction function) is given in paren-
471 nigel 73 theses after each string for \C and \G.
472 nigel 53
473 nigel 93 Note that whereas patterns can be continued over several lines (a plain
474 nigel 73 ">" prompt is used for continuations), data lines may not. However new-
475 ph10 286 lines can be included in data by means of the \n escape (or \r, \r\n,
476 nigel 93 etc., depending on the newline sequence setting).
477 nigel 53
478    
479 nigel 77 OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
480    
481 ph10 286 When the alternative matching function, pcre_dfa_exec(), is used (by
482     means of the \D escape sequence or the -dfa command line option), the
483     output consists of a list of all the matches that start at the first
484 nigel 77 point in the subject where there is at least one match. For example:
485    
486     re> /(tang|tangerine|tan)/
487     data> yellow tangerine\D
488     0: tangerine
489     1: tang
490     2: tan
491    
492 ph10 286 (Using the normal matching function on this data finds only "tang".)
493     The longest matching string is always given first (and numbered zero).
494 nigel 77
495 nigel 93 If /g is present on the pattern, the search for further matches resumes
496     at the end of the longest match. For example:
497 nigel 77
498     re> /(tang|tangerine|tan)/g
499     data> yellow tangerine and tangy sultana\D
500     0: tangerine
501     1: tang
502     2: tan
503     0: tang
504     1: tan
505     0: tan
506    
507 ph10 286 Since the matching function does not support substring capture, the
508     escape sequences that are concerned with captured substrings are not
509 nigel 77 relevant.
510    
511    
512     RESTARTING AFTER A PARTIAL MATCH
513    
514     When the alternative matching function has given the PCRE_ERROR_PARTIAL
515 ph10 286 return, indicating that the subject partially matched the pattern, you
516     can restart the match with additional subject data by means of the \R
517 nigel 77 escape sequence. For example:
518    
519 ph10 155 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
520 nigel 77 data> 23ja\P\D
521     Partial match: 23ja
522     data> n05\R\D
523     0: n05
524    
525 ph10 286 For further information about partial matching, see the pcrepartial
526 nigel 77 documentation.
527    
528    
529 nigel 75 CALLOUTS
530    
531 ph10 286 If the pattern contains any callout requests, pcretest's callout func-
532     tion is called during matching. This works with both matching func-
533 nigel 77 tions. By default, the called function displays the callout number, the
534 ph10 286 start and current positions in the text at the callout time, and the
535 nigel 77 next pattern item to be tested. For example, the output
536 nigel 75
537     --->pqrabcdef
538     0 ^ ^ \d
539    
540 ph10 286 indicates that callout number 0 occurred for a match attempt starting
541     at the fourth character of the subject string, when the pointer was at
542     the seventh character of the data, and when the next pattern item was
543     \d. Just one circumflex is output if the start and current positions
544 nigel 75 are the same.
545    
546     Callouts numbered 255 are assumed to be automatic callouts, inserted as
547 ph10 286 a result of the /C pattern modifier. In this case, instead of showing
548     the callout number, the offset in the pattern, preceded by a plus, is
549 nigel 75 output. For example:
550    
551     re> /\d?[A-E]\*/C
552     data> E*
553     --->E*
554     +0 ^ \d?
555     +3 ^ [A-E]
556     +8 ^^ \*
557     +10 ^ ^
558     0: E*
559    
560 ph10 286 The callout function in pcretest returns zero (carry on matching) by
561     default, but you can use a \C item in a data line (as described above)
562 nigel 75 to change this.
563    
564 ph10 286 Inserting callouts can be helpful when using pcretest to check compli-
565     cated regular expressions. For further information about callouts, see
566 nigel 75 the pcrecallout documentation.
567    
568    
569 nigel 93 NON-PRINTING CHARACTERS
570    
571 ph10 286 When pcretest is outputting text in the compiled version of a pattern,
572     bytes other than 32-126 are always treated as non-printing characters
573 nigel 93 are are therefore shown as hex escapes.
574    
575 ph10 286 When pcretest is outputting text that is a matched part of a subject
576     string, it behaves in the same way, unless a different locale has been
577     set for the pattern (using the /L modifier). In this case, the
578 nigel 93 isprint() function to distinguish printing and non-printing characters.
579    
580    
581 nigel 75 SAVING AND RELOADING COMPILED PATTERNS
582    
583 ph10 286 The facilities described in this section are not available when the
584 nigel 75 POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
585     ifier is specified.
586    
587     When the POSIX interface is not in use, you can cause pcretest to write
588 ph10 286 a compiled pattern to a file, by following the modifiers with > and a
589 nigel 75 file name. For example:
590    
591     /pattern/im >/some/file
592    
593 ph10 286 See the pcreprecompile documentation for a discussion about saving and
594 nigel 75 re-using compiled patterns.
595    
596 ph10 286 The data that is written is binary. The first eight bytes are the
597     length of the compiled pattern data followed by the length of the
598     optional study data, each written as four bytes in big-endian order
599     (most significant byte first). If there is no study data (either the
600 nigel 75 pattern was not studied, or studying did not return any data), the sec-
601 ph10 286 ond length is zero. The lengths are followed by an exact copy of the
602 nigel 75 compiled pattern. If there is additional study data, this follows imme-
603 ph10 286 diately after the compiled pattern. After writing the file, pcretest
604 nigel 75 expects to read a new pattern.
605    
606     A saved pattern can be reloaded into pcretest by specifing < and a file
607 ph10 286 name instead of a pattern. The name of the file must not contain a <
608     character, as otherwise pcretest will interpret the line as a pattern
609 nigel 75 delimited by < characters. For example:
610    
611     re> </some/file
612     Compiled regex loaded from /some/file
613     No study data
614    
615 ph10 286 When the pattern has been loaded, pcretest proceeds to read data lines
616 nigel 75 in the usual way.
617    
618 ph10 286 You can copy a file written by pcretest to a different host and reload
619     it there, even if the new host has opposite endianness to the one on
620     which the pattern was compiled. For example, you can compile on an i86
621 nigel 75 machine and run on a SPARC machine.
622    
623 ph10 286 File names for saving and reloading can be absolute or relative, but
624     note that the shell facility of expanding a file name that starts with
625 nigel 75 a tilde (~) is not available.
626    
627 ph10 286 The ability to save and reload files in pcretest is intended for test-
628     ing and experimentation. It is not intended for production use because
629     only a single pattern can be written to a file. Furthermore, there is
630     no facility for supplying custom character tables for use with a
631     reloaded pattern. If the original pattern was compiled with custom
632     tables, an attempt to match a subject string using a reloaded pattern
633     is likely to cause pcretest to crash. Finally, if you attempt to load
634 nigel 75 a file that is not in the correct format, the result is undefined.
635    
636    
637 nigel 93 SEE ALSO
638    
639 ph10 286 pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d),
640 nigel 93 pcrepattern(3), pcreprecompile(3).
641    
642    
643 nigel 63 AUTHOR
644 nigel 53
645 nigel 77 Philip Hazel
646 ph10 99 University Computing Service
647 nigel 93 Cambridge CB2 3QH, England.
648 nigel 53
649 ph10 99
650     REVISION
651    
652 ph10 289 Last updated: 18 December 2007
653 ph10 99 Copyright (c) 1997-2007 University of Cambridge.

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