/[pcre]/code/trunk/doc/pcretest.txt
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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 231 by ph10, Tue Sep 11 11:15:33 2007 UTC
# Line 1  Line 1 
1  PCRETEST(1)                                                        PCRETEST(1)  PCRETEST(1)                                                        PCRETEST(1)
2    
3    
   
4  NAME  NAME
5         pcretest - a program for testing Perl-compatible regular expressions.         pcretest - a program for testing Perl-compatible regular expressions.
6    
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [options] [source] [destination]
             [destination]  
11    
12         pcretest  was written as a test program for the PCRE regular expression         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         library itself, but it can also be used for experimenting with  regular
# Line 20  SYNOPSIS Line 19  SYNOPSIS
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
26                   able   information  about  the  optional  features  that  are                   able  information  about  the  optional  features  that   are
27                   included, and then exit.                   included, and then exit.
28    
29         -d        Behave as if each regex has  the  /D  (debug)  modifier;  the         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                   internal form is output after compilation.                   internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33         -dfa      Behave  as if each data line contains the \D escape sequence;         -dfa      Behave  as if each data line contains the \D escape sequence;
34                   this    causes    the    alternative    matching    function,                   this    causes    the    alternative    matching    function,
35                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                   pcre_exec() function (more detail is given below).                   pcre_exec() function (more detail is given below).
37    
38           -help     Output a brief summary these options and then exit.
39    
40         -i        Behave as if each regex  has  the  /I  modifier;  information         -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
# Line 41  OPTIONS Line 46  OPTIONS
46                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
47    
48         -o osize  Set the number of elements in the output vector that is  used         -o osize  Set the number of elements in the output vector that is  used
49                   when  calling  pcre_exec()  to be osize. The default value is                   when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
50                   45, which is enough for 14 capturing subexpressions. The vec-                   default value is 45, which is enough for 14 capturing  subex-
51                   tor  size  can  be  changed  for individual matching calls by                   pressions   for  pcre_exec()  or  22  different  matches  for
52                   including \O in the data line (see below).                   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    
56         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-         -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                   per  API  is used to call PCRE. None of the other options has
58                   any effect when -p is set.                   any effect when -p is set.
59    
60           -q        Do not output the version number of pcretest at the start  of
61                     execution.
62    
63           -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,         -t        Run each compile, study, and match many times with  a  timer,
67                   and  output resulting time per compile or match (in millisec-                   and  output resulting time per compile or match (in millisec-
68                   onds). Do not set -m with -t, because you will then  get  the                   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-                   size  output  a  zillion  times,  and the timing will be dis-
70                   torted.                   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    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
# Line 71  DESCRIPTION Line 90  DESCRIPTION
90         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
91    
92         Each  data line is matched separately and independently. If you want to         Each  data line is matched separately and independently. If you want to
93         do multiple-line matches, you have to use the \n escape sequence  in  a         do multi-line matches, you have to use the \n escape sequence (or \r or
94         single  line  of  input  to  encode the newline characters. The maximum         \r\n, etc., depending on the newline setting) in a single line of input
95         length of data line is 30,000 characters.         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    
99         An empty line signals the end of the data lines, at which point  a  new         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         regular  expression is read. The regular expressions are given enclosed
101         in any non-alphanumeric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example:
102    
103           /(a|bc)x+yz/           /(a|bc)x+yz/
104    
# Line 125  PATTERN MODIFIERS Line 146  PATTERN MODIFIERS
146         The following table shows additional modifiers for setting PCRE options         The following table shows additional modifiers for setting PCRE options
147         that do not correspond to anything in Perl:         that do not correspond to anything in Perl:
148    
149           /A    PCRE_ANCHORED           /A              PCRE_ANCHORED
150           /C    PCRE_AUTO_CALLOUT           /C              PCRE_AUTO_CALLOUT
151           /E    PCRE_DOLLAR_ENDONLY           /E              PCRE_DOLLAR_ENDONLY
152           /f    PCRE_FIRSTLINE           /f              PCRE_FIRSTLINE
153           /N    PCRE_NO_AUTO_CAPTURE           /J              PCRE_DUPNAMES
154           /U    PCRE_UNGREEDY           /N              PCRE_NO_AUTO_CAPTURE
155           /X    PCRE_EXTRA           /U              PCRE_UNGREEDY
156             /X              PCRE_EXTRA
157             /<cr>           PCRE_NEWLINE_CR
158             /<lf>           PCRE_NEWLINE_LF
159             /<crlf>         PCRE_NEWLINE_CRLF
160             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
161             /<any>          PCRE_NEWLINE_ANY
162             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
163             /<bsr_unicode>  PCRE_BSR_UNICODE
164    
165           Those  specifying  line  ending sequences are literal strings as shown,
166           but the letters can be in either  case.  This  example  sets  multiline
167           matching with CRLF as the line ending sequence:
168    
169             /^abc/m<crlf>
170    
171         Searching  for  all  possible matches within each subject string can be         Details  of the meanings of these PCRE options are given in the pcreapi
172         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is         documentation.
173    
174       Finding all matches in a string
175    
176           Searching for all possible matches within each subject  string  can  be
177           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
178         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
179         ence between /g and /G is that the former uses the startoffset argument         ence between /g and /G is that the former uses the startoffset argument
180         to  pcre_exec()  to  start  searching  at a new point within the entire         to pcre_exec() to start searching at a  new  point  within  the  entire
181         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
182         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
183         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
184         or \B).         or \B).
185    
186         If  any  call  to  pcre_exec()  in a /g or /G sequence matches an empty         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
187         string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED         string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
188         flags  set in order to search for another, non-empty, match at the same         flags set in order to search for another, non-empty, match at the  same
189         point.  If this second match fails, the start  offset  is  advanced  by         point.   If  this  second  match fails, the start offset is advanced by
190         one,  and  the normal match is retried. This imitates the way Perl han-         one, and the normal match is retried. This imitates the way  Perl  han-
191         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
192    
193       Other modifiers
194    
195         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
196    
197         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
198         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
199         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
200         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
201    
202           The  /B modifier is a debugging feature. It requests that pcretest out-
203           put a representation of the compiled byte code after compilation.  Nor-
204           mally  this  information contains length and offset values; however, if
205           /Z is also present, this data is replaced by spaces. This is a  special
206           feature for use in the automatic test scripts; it ensures that the same
207           output is generated for different internal link sizes.
208    
209         The /L modifier must be followed directly by the name of a locale,  for         The /L modifier must be followed directly by the name of a locale,  for
210         example,         example,
211    
# Line 175  PATTERN MODIFIERS Line 224  PATTERN MODIFIERS
224         pattern.  If  the pattern is studied, the results of that are also out-         pattern.  If  the pattern is studied, the results of that are also out-
225         put.         put.
226    
227         The /D modifier is a PCRE debugging feature, which also assumes /I.  It         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
228         causes  the  internal form of compiled regular expressions to be output         that is, both the /B and the /I modifiers.
        after compilation. If the pattern was studied, the information returned  
        is also output.  
229    
230         The /F modifier causes pcretest to flip the byte order of the fields in         The /F modifier causes pcretest to flip the byte order of the fields in
231         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
# Line 220  DATA LINES Line 267  DATA LINES
267         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
268         following escapes are recognized:         following escapes are recognized:
269    
270           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
271           \b         backspace           \b         backspace (\x08)
272           \e         escape           \e         escape (\x27)
273           \f         formfeed           \f         formfeed (\x0c)
274           \n         newline           \n         newline (\x0a)
275           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
276           \t         tab                        (any number of digits)
277           \v         vertical tab           \r         carriage return (\x0d)
278             \t         tab (\x09)
279             \v         vertical tab (\x0b)
280           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
281           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
282           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
283                        in UTF-8 mode                        in UTF-8 mode
284           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
285                          or pcre_dfa_exec()
286           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
287                          or pcre_dfa_exec()
288           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
289                        after a successful match (number less than 32)                        after a successful match (number less than 32)
290           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 257  DATA LINES Line 308  DATA LINES
308                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
309           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
310                        successful match                        successful match
311           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
312                          MATCH_LIMIT_RECURSION settings
313           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
314                          or pcre_dfa_exec()
315           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
316                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
317           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
318                        or pcre_dfa_exec()                        or pcre_dfa_exec()
319             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
320                          (any number of digits)
321           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
322           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
323           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
324                          or pcre_dfa_exec()
325           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
326                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
327           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
328                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
329                          or pcre_dfa_exec()
330             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
331                          or pcre_dfa_exec()
332             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
333                          or pcre_dfa_exec()
334             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
335                          or pcre_dfa_exec()
336             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
337                          or pcre_dfa_exec()
338             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
339                          or pcre_dfa_exec()
340    
341           The escapes that specify line ending  sequences  are  literal  strings,
342           exactly as shown. No more than one newline setting should be present in
343           any data line.
344    
345         A backslash followed by anything else just escapes the  anything  else.         A backslash followed by anything else just escapes the  anything  else.
346         If  the very last character is a backslash, it is ignored. This gives a         If  the very last character is a backslash, it is ignored. This gives a
# Line 277  DATA LINES Line 348  DATA LINES
348         nates the data input.         nates the data input.
349    
350         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
351         ferent values in the match_limit field of the  pcre_extra  data  struc-         ferent values in the match_limit and  match_limit_recursion  fields  of
352         ture,  until it finds the minimum number that is needed for pcre_exec()         the  pcre_extra  data structure, until it finds the minimum numbers for
353         to complete. This number is a measure of the amount  of  recursion  and         each parameter that allow pcre_exec() to complete. The match_limit num-
354         backtracking  that takes place, and checking it out can be instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
355         For most simple matches, the number is quite small,  but  for  patterns         checking it out can be instructive. For most simple matches, the number
356         with  very large numbers of matching possibilities, it can become large         is  quite  small,  but for patterns with very large numbers of matching
357         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
358           of subject string. The match_limit_recursion number is a measure of how
359           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
360           memory is needed to complete the match attempt.
361    
362         When \O is used, the value specified may be higher or  lower  than  the         When  \O  is  used, the value specified may be higher or lower than the
363         size set by the -O command line option (or defaulted to 45); \O applies         size set by the -O command line option (or defaulted to 45); \O applies
364         only to the call of pcre_exec() for the line in which it appears.         only to the call of pcre_exec() for the line in which it appears.
365    
366         If the /P modifier was present on the pattern, causing the POSIX  wrap-         If  the /P modifier was present on the pattern, causing the POSIX wrap-
367         per  API to be used, only \B and \Z have any effect, causing REG_NOTBOL         per API to be used, the only option-setting  sequences  that  have  any
368         and REG_NOTEOL to be passed to regexec() respectively.         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
369           to be passed to regexec().
370    
371         The use of \x{hh...} to represent UTF-8 characters is not dependent  on         The use of \x{hh...} to represent UTF-8 characters is not dependent  on
372         the  use  of  the  /8 modifier on the pattern. It is recognized always.         the  use  of  the  /8 modifier on the pattern. It is recognized always.
373         There may be any number of hexadecimal digits inside  the  braces.  The         There may be any number of hexadecimal digits inside  the  braces.  The
374         result  is from one to six bytes, encoded according to the UTF-8 rules.         result  is  from  one  to  six bytes, encoded according to the original
375           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
376           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
377           or indeed valid UTF-8 characters according to the later  rules  in  RFC
378           3629.
379    
380    
381  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
382    
383         By  default,  pcretest  uses  the  standard  PCRE  matching   function,         By   default,  pcretest  uses  the  standard  PCRE  matching  function,
384         pcre_exec() to match each data line. From release 6.0, PCRE supports an         pcre_exec() to match each data line. From release 6.0, PCRE supports an
385         alternative matching function, pcre_dfa_test(),  which  operates  in  a         alternative  matching  function,  pcre_dfa_test(),  which operates in a
386         different  way,  and has some restrictions. The differences between the         different way, and has some restrictions. The differences  between  the
387         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
388    
389         If a data line contains the \D escape sequence, or if the command  line         If  a data line contains the \D escape sequence, or if the command line
390         contains  the -dfa option, the alternative matching function is called.         contains the -dfa option, the alternative matching function is  called.
391         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
392         the  \F escape sequence is present in the data line, it stops after the         the \F escape sequence is present in the data line, it stops after  the
393         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
394    
395    
396  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
397    
398         This section describes the output when the  normal  matching  function,         This  section  describes  the output when the normal matching function,
399         pcre_exec(), is being used.         pcre_exec(), is being used.
400    
401         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
402         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
403         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
404         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
405         TIAL,  respectively, and otherwise the PCRE negative error number. Here         TIAL, respectively, and otherwise the PCRE negative error number.  Here
406         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
407    
408           $ pcretest           $ pcretest
409           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
410    
411             re> /^abc(\d+)/             re> /^abc(\d+)/
412           data> abc123           data> abc123
# Line 336  DEFAULT OUTPUT FROM PCRETEST Line 415  DEFAULT OUTPUT FROM PCRETEST
415           data> xyz           data> xyz
416           No match           No match
417    
418         If the strings contain any non-printing characters, they are output  as         If  the strings contain any non-printing characters, they are output as
419         \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on         \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
420         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the  pattern.  See below for the definition of non-printing characters.
421         string  0 is followed by the the rest of the subject string, identified         If the pattern has the /+ modifier, the output for substring 0 is  fol-
422         by "0+" like this:         lowed  by  the  the rest of the subject string, identified by "0+" like
423           this:
424    
425             re> /cat/+             re> /cat/+
426           data> cataract           data> cataract
# Line 368  DEFAULT OUTPUT FROM PCRETEST Line 448  DEFAULT OUTPUT FROM PCRETEST
448         (that  is,  the return from the extraction function) is given in paren-         (that  is,  the return from the extraction function) is given in paren-
449         theses after each string for \C and \G.         theses after each string for \C and \G.
450    
451         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
452         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
453         lines can be included in data by means of the \n escape.         lines can be included in data by means of the \n escape (or  \r,  \r\n,
454           etc., depending on the newline sequence setting).
455    
456    
457  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
458    
459         When the alternative matching function, pcre_dfa_exec(),  is  used  (by         When  the  alternative  matching function, pcre_dfa_exec(), is used (by
460         means  of  the \D escape sequence or the -dfa command line option), the         means of the \D escape sequence or the -dfa command line  option),  the
461         output consists of a list of all the matches that start  at  the  first         output  consists  of  a list of all the matches that start at the first
462         point in the subject where there is at least one match. For example:         point in the subject where there is at least one match. For example:
463    
464             re> /(tang|tangerine|tan)/             re> /(tang|tangerine|tan)/
# Line 386  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 467  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
467            1: tang            1: tang
468            2: tan            2: tan
469    
470         (Using  the  normal  matching function on this data finds only "tang".)         (Using the normal matching function on this data  finds  only  "tang".)
471         The longest matching string is always given first (and numbered  zero).         The  longest matching string is always given first (and numbered zero).
472    
473         If  /gP  is  present  on  the  pattern,  the search for further matches         If /g is present on the pattern, the search for further matches resumes
474         resumes at the end of the longest match. For example:         at the end of the longest match. For example:
475    
476             re> /(tang|tangerine|tan)/g             re> /(tang|tangerine|tan)/g
477           data> yellow tangerine and tangy sultana\D           data> yellow tangerine and tangy sultana\D
# Line 401  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 482  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
482            1: tan            1: tan
483            0: tan            0: tan
484    
485         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
486         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
487         relevant.         relevant.
488    
489    
490  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
491    
492         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
493         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
494         can restart the match with additional subject data by means of  the  \R         can  restart  the match with additional subject data by means of the \R
495         escape sequence. For example:         escape sequence. For example:
496    
497             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
498           data> 23ja\P\D           data> 23ja\P\D
499           Partial match: 23ja           Partial match: 23ja
500           data> n05\R\D           data> n05\R\D
501            0: n05            0: n05
502    
503         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
504         documentation.         documentation.
505    
506    
507  CALLOUTS  CALLOUTS
508    
509         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
510         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
511         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
512         start  and  current  positions in the text at the callout time, and the         start and current positions in the text at the callout  time,  and  the
513         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
514    
515           --->pqrabcdef           --->pqrabcdef
516             0    ^  ^     \d             0    ^  ^     \d
517    
518         indicates that callout number 0 occurred for a match  attempt  starting         indicates  that  callout number 0 occurred for a match attempt starting
519         at  the fourth character of the subject string, when the pointer was at         at the fourth character of the subject string, when the pointer was  at
520         the seventh character of the data, and when the next pattern  item  was         the  seventh  character of the data, and when the next pattern item was
521         \d.  Just  one  circumflex is output if the start and current positions         \d. Just one circumflex is output if the start  and  current  positions
522         are the same.         are the same.
523    
524         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
525         a  result  of the /C pattern modifier. In this case, instead of showing         a result of the /C pattern modifier. In this case, instead  of  showing
526         the callout number, the offset in the pattern, preceded by a  plus,  is         the  callout  number, the offset in the pattern, preceded by a plus, is
527         output. For example:         output. For example:
528    
529             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 454  CALLOUTS Line 535  CALLOUTS
535           +10 ^ ^           +10 ^ ^
536            0: E*            0: E*
537    
538         The  callout  function  in pcretest returns zero (carry on matching) by         The callout function in pcretest returns zero (carry  on  matching)  by
539         default, but you can use a \C item in a data line (as described  above)         default,  but you can use a \C item in a data line (as described above)
540         to change this.         to change this.
541    
542         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting callouts can be helpful when using pcretest to check  compli-
543         cated regular expressions. For further information about callouts,  see         cated  regular expressions. For further information about callouts, see
544         the pcrecallout documentation.         the pcrecallout documentation.
545    
546    
547    NON-PRINTING CHARACTERS
548    
549           When pcretest is outputting text in the compiled version of a  pattern,
550           bytes  other  than 32-126 are always treated as non-printing characters
551           are are therefore shown as hex escapes.
552    
553           When pcretest is outputting text that is a matched part  of  a  subject
554           string,  it behaves in the same way, unless a different locale has been
555           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
556           isprint() function to distinguish printing and non-printing characters.
557    
558    
559  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
560    
561         The  facilities  described  in  this section are not available when the         The facilities described in this section are  not  available  when  the
562         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
563         ifier is specified.         ifier is specified.
564    
565         When the POSIX interface is not in use, you can cause pcretest to write         When the POSIX interface is not in use, you can cause pcretest to write
566         a compiled pattern to a file, by following the modifiers with >  and  a         a  compiled  pattern to a file, by following the modifiers with > and a
567         file name.  For example:         file name.  For example:
568    
569           /pattern/im >/some/file           /pattern/im >/some/file
570    
571         See  the pcreprecompile documentation for a discussion about saving and         See the pcreprecompile documentation for a discussion about saving  and
572         re-using compiled patterns.         re-using compiled patterns.
573    
574         The data that is written is binary.  The  first  eight  bytes  are  the         The  data  that  is  written  is  binary. The first eight bytes are the
575         length  of  the  compiled  pattern  data  followed by the length of the         length of the compiled pattern data  followed  by  the  length  of  the
576         optional study data, each written as four  bytes  in  big-endian  order         optional  study  data,  each  written as four bytes in big-endian order
577         (most  significant  byte  first). If there is no study data (either the         (most significant byte first). If there is no study  data  (either  the
578         pattern was not studied, or studying did not return any data), the sec-         pattern was not studied, or studying did not return any data), the sec-
579         ond  length  is  zero. The lengths are followed by an exact copy of the         ond length is zero. The lengths are followed by an exact  copy  of  the
580         compiled pattern. If there is additional study data, this follows imme-         compiled pattern. If there is additional study data, this follows imme-
581         diately  after  the  compiled pattern. After writing the file, pcretest         diately after the compiled pattern. After writing  the  file,  pcretest
582         expects to read a new pattern.         expects to read a new pattern.
583    
584         A saved pattern can be reloaded into pcretest by specifing < and a file         A saved pattern can be reloaded into pcretest by specifing < and a file
585         name  instead  of  a pattern. The name of the file must not contain a <         name instead of a pattern. The name of the file must not  contain  a  <
586         character, as otherwise pcretest will interpret the line as  a  pattern         character,  as  otherwise pcretest will interpret the line as a pattern
587         delimited by < characters.  For example:         delimited by < characters.  For example:
588    
589            re> </some/file            re> </some/file
590           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
591           No study data           No study data
592    
593         When  the pattern has been loaded, pcretest proceeds to read data lines         When the pattern has been loaded, pcretest proceeds to read data  lines
594         in the usual way.         in the usual way.
595    
596         You can copy a file written by pcretest to a different host and  reload         You  can copy a file written by pcretest to a different host and reload
597         it  there,  even  if the new host has opposite endianness to the one on         it there, even if the new host has opposite endianness to  the  one  on
598         which the pattern was compiled. For example, you can compile on an  i86         which  the pattern was compiled. For example, you can compile on an i86
599         machine and run on a SPARC machine.         machine and run on a SPARC machine.
600    
601         File  names  for  saving and reloading can be absolute or relative, but         File names for saving and reloading can be absolute  or  relative,  but
602         note that the shell facility of expanding a file name that starts  with         note  that the shell facility of expanding a file name that starts with
603         a tilde (~) is not available.         a tilde (~) is not available.
604    
605         The  ability to save and reload files in pcretest is intended for test-         The ability to save and reload files in pcretest is intended for  test-
606         ing and experimentation. It is not intended for production use  because         ing  and experimentation. It is not intended for production use because
607         only  a  single pattern can be written to a file. Furthermore, there is         only a single pattern can be written to a file. Furthermore,  there  is
608         no facility for supplying  custom  character  tables  for  use  with  a         no  facility  for  supplying  custom  character  tables  for use with a
609         reloaded  pattern.  If  the  original  pattern was compiled with custom         reloaded pattern. If the original  pattern  was  compiled  with  custom
610         tables, an attempt to match a subject string using a  reloaded  pattern         tables,  an  attempt to match a subject string using a reloaded pattern
611         is  likely to cause pcretest to crash.  Finally, if you attempt to load         is likely to cause pcretest to crash.  Finally, if you attempt to  load
612         a file that is not in the correct format, the result is undefined.         a file that is not in the correct format, the result is undefined.
613    
614    
615    SEE ALSO
616    
617           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
618           pcrepattern(3), pcreprecompile(3).
619    
620    
621  AUTHOR  AUTHOR
622    
623         Philip Hazel         Philip Hazel
624         University Computing Service,         University Computing Service
625         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
626    
627    
628    REVISION
629    
630  Last updated: 28 February 2005         Last updated: 11 September 2007
631  Copyright (c) 1997-2005 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

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