/[pcre]/code/trunk/doc/pcretest.txt
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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 227 by ph10, Tue Aug 21 15:00:15 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    
163           Those  specifying  line  ending sequences are literal strings as shown,
164           but the letters can be in either  case.  This  example  sets  multiline
165           matching with CRLF as the line ending sequence:
166    
167             /^abc/m<crlf>
168    
169         Searching  for  all  possible matches within each subject string can be         Details  of the meanings of these PCRE options are given in the pcreapi
170         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is         documentation.
171    
172       Finding all matches in a string
173    
174           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         called again to search the remainder of the subject string. The differ-         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         ence between /g and /G is that the former uses the startoffset argument
178         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
179         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
180         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
181         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
182         or \B).         or \B).
183    
184         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
185         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
186         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
187         point.  If this second match fails, the start  offset  is  advanced  by         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-         one, and the normal match is retried. This imitates the way  Perl  han-
189         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
190    
191       Other modifiers
192    
193         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
194    
195         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
196         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
197         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
198         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
199    
200           The  /B modifier is a debugging feature. It requests that pcretest out-
201           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    
207         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
208         example,         example,
209    
# Line 175  PATTERN MODIFIERS Line 222  PATTERN MODIFIERS
222         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-
223         put.         put.
224    
225         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,
226         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.  
227    
228         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
229         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 265  DATA LINES
265         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
266         following escapes are recognized:         following escapes are recognized:
267    
268           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
269           \b         backspace           \b         backspace (\x08)
270           \e         escape           \e         escape (\x27)
271           \f         formfeed           \f         formfeed (\x0c)
272           \n         newline           \n         newline (\x0a)
273           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
274           \t         tab                        (any number of digits)
275           \v         vertical tab           \r         carriage return (\x0d)
276             \t         tab (\x09)
277             \v         vertical tab (\x0b)
278           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
279           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
280           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
281                        in UTF-8 mode                        in UTF-8 mode
282           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
283                          or pcre_dfa_exec()
284           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
285                          or pcre_dfa_exec()
286           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
287                        after a successful match (number less than 32)                        after a successful match (number less than 32)
288           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 257  DATA LINES Line 306  DATA LINES
306                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
307           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
308                        successful match                        successful match
309           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
310                          MATCH_LIMIT_RECURSION settings
311           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
312                          or pcre_dfa_exec()
313           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
314                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
315           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
316                        or pcre_dfa_exec()                        or pcre_dfa_exec()
317             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
318                          (any number of digits)
319           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
320           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
321           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
322                          or pcre_dfa_exec()
323           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
324                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
325           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
326                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
327                          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             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
335                          or pcre_dfa_exec()
336             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
337                          or pcre_dfa_exec()
338    
339           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    
343         A backslash followed by anything else just escapes the  anything  else.         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         If  the very last character is a backslash, it is ignored. This gives a
# Line 277  DATA LINES Line 346  DATA LINES
346         nates the data input.         nates the data input.
347    
348         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
349         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
350         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
351         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-
352         backtracking  that takes place, and checking it out can be instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
353         For most simple matches, the number is quite small,  but  for  patterns         checking it out can be instructive. For most simple matches, the number
354         with  very large numbers of matching possibilities, it can become large         is  quite  small,  but for patterns with very large numbers of matching
355         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
356           of subject string. The match_limit_recursion number is a measure of how
357           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
358           memory is needed to complete the match attempt.
359    
360         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
361         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
362         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.
363    
364         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-
365         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
366         and REG_NOTEOL to be passed to regexec() respectively.         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
367           to be passed to regexec().
368    
369         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
370         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.
371         There may be any number of hexadecimal digits inside  the  braces.  The         There may be any number of hexadecimal digits inside  the  braces.  The
372         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
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    
378    
379  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
380    
381         By  default,  pcretest  uses  the  standard  PCRE  matching   function,         By   default,  pcretest  uses  the  standard  PCRE  matching  function,
382         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
383         alternative matching function, pcre_dfa_test(),  which  operates  in  a         alternative  matching  function,  pcre_dfa_test(),  which operates in a
384         different  way,  and has some restrictions. The differences between the         different way, and has some restrictions. The differences  between  the
385         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
386    
387         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
388         contains  the -dfa option, the alternative matching function is called.         contains the -dfa option, the alternative matching function is  called.
389         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
390         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
391         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
392    
393    
394  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
395    
396         This section describes the output when the  normal  matching  function,         This  section  describes  the output when the normal matching function,
397         pcre_exec(), is being used.         pcre_exec(), is being used.
398    
399         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
400         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
401         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
402         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
403         TIAL,  respectively, and otherwise the PCRE negative error number. Here         TIAL, respectively, and otherwise the PCRE negative error number.  Here
404         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
405    
406           $ pcretest           $ pcretest
407           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
408    
409             re> /^abc(\d+)/             re> /^abc(\d+)/
410           data> abc123           data> abc123
# Line 336  DEFAULT OUTPUT FROM PCRETEST Line 413  DEFAULT OUTPUT FROM PCRETEST
413           data> xyz           data> xyz
414           No match           No match
415    
416         If the strings contain any non-printing characters, they are output  as         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         \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
418         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the  pattern.  See below for the definition of non-printing characters.
419         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-
420         by "0+" like this:         lowed  by  the  the rest of the subject string, identified by "0+" like
421           this:
422    
423             re> /cat/+             re> /cat/+
424           data> cataract           data> cataract
# Line 368  DEFAULT OUTPUT FROM PCRETEST Line 446  DEFAULT OUTPUT FROM PCRETEST
446         (that  is,  the return from the extraction function) is given in paren-         (that  is,  the return from the extraction function) is given in paren-
447         theses after each string for \C and \G.         theses after each string for \C and \G.
448    
449         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
450         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
451         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,
452           etc., depending on the newline sequence setting).
453    
454    
455  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
456    
457         When the alternative matching function, pcre_dfa_exec(),  is  used  (by         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         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         output  consists  of  a list of all the matches that start at the first
460         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:
461    
462             re> /(tang|tangerine|tan)/             re> /(tang|tangerine|tan)/
# Line 386  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 465  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
465            1: tang            1: tang
466            2: tan            2: tan
467    
468         (Using  the  normal  matching function on this data finds only "tang".)         (Using the normal matching function on this data  finds  only  "tang".)
469         The longest matching string is always given first (and numbered  zero).         The  longest matching string is always given first (and numbered zero).
470    
471         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
472         resumes at the end of the longest match. For example:         at the end of the longest match. For example:
473    
474             re> /(tang|tangerine|tan)/g             re> /(tang|tangerine|tan)/g
475           data> yellow tangerine and tangy sultana\D           data> yellow tangerine and tangy sultana\D
# Line 401  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 480  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
480            1: tan            1: tan
481            0: tan            0: tan
482    
483         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
484         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
485         relevant.         relevant.
486    
487    
488  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
489    
490         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
491         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
492         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
493         escape sequence. For example:         escape sequence. For example:
494    
495             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
496           data> 23ja\P\D           data> 23ja\P\D
497           Partial match: 23ja           Partial match: 23ja
498           data> n05\R\D           data> n05\R\D
499            0: n05            0: n05
500    
501         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
502         documentation.         documentation.
503    
504    
505  CALLOUTS  CALLOUTS
506    
507         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
508         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
509         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
510         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
511         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
512    
513           --->pqrabcdef           --->pqrabcdef
514             0    ^  ^     \d             0    ^  ^     \d
515    
516         indicates that callout number 0 occurred for a match  attempt  starting         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         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         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         \d. Just one circumflex is output if the start  and  current  positions
520         are the same.         are the same.
521    
522         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
523         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
524         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
525         output. For example:         output. For example:
526    
527             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 454  CALLOUTS Line 533  CALLOUTS
533           +10 ^ ^           +10 ^ ^
534            0: E*            0: E*
535    
536         The  callout  function  in pcretest returns zero (carry on matching) by         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)         default,  but you can use a \C item in a data line (as described above)
538         to change this.         to change this.
539    
540         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting callouts can be helpful when using pcretest to check  compli-
541         cated regular expressions. For further information about callouts,  see         cated  regular expressions. For further information about callouts, see
542         the pcrecallout documentation.         the pcrecallout documentation.
543    
544    
545    NON-PRINTING CHARACTERS
546    
547           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           are are therefore shown as hex escapes.
550    
551           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           isprint() function to distinguish printing and non-printing characters.
555    
556    
557  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
558    
559         The  facilities  described  in  this section are not available when the         The facilities described in this section are  not  available  when  the
560         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-
561         ifier is specified.         ifier is specified.
562    
563         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
564         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
565         file name.  For example:         file name.  For example:
566    
567           /pattern/im >/some/file           /pattern/im >/some/file
568    
569         See  the pcreprecompile documentation for a discussion about saving and         See the pcreprecompile documentation for a discussion about saving  and
570         re-using compiled patterns.         re-using compiled patterns.
571    
572         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
573         length  of  the  compiled  pattern  data  followed by the length of the         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         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         (most significant byte first). If there is no study  data  (either  the
576         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-
577         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
578         compiled pattern. If there is additional study data, this follows imme-         compiled pattern. If there is additional study data, this follows imme-
579         diately  after  the  compiled pattern. After writing the file, pcretest         diately after the compiled pattern. After writing  the  file,  pcretest
580         expects to read a new pattern.         expects to read a new pattern.
581    
582         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
583         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  <
584         character, as otherwise pcretest will interpret the line as  a  pattern         character,  as  otherwise pcretest will interpret the line as a pattern
585         delimited by < characters.  For example:         delimited by < characters.  For example:
586    
587            re> </some/file            re> </some/file
588           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
589           No study data           No study data
590    
591         When  the pattern has been loaded, pcretest proceeds to read data lines         When the pattern has been loaded, pcretest proceeds to read data  lines
592         in the usual way.         in the usual way.
593    
594         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
595         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
596         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
597         machine and run on a SPARC machine.         machine and run on a SPARC machine.
598    
599         File  names  for  saving and reloading can be absolute or relative, but         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         note  that the shell facility of expanding a file name that starts with
601         a tilde (~) is not available.         a tilde (~) is not available.
602    
603         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-
604         ing and experimentation. It is not intended for production use  because         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         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         no  facility  for  supplying  custom  character  tables  for use with a
607         reloaded  pattern.  If  the  original  pattern was compiled with custom         reloaded pattern. If the original  pattern  was  compiled  with  custom
608         tables, an attempt to match a subject string using a  reloaded  pattern         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         is likely to cause pcretest to crash.  Finally, if you attempt to  load
610         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.
611    
612    
613    SEE ALSO
614    
615           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
616           pcrepattern(3), pcreprecompile(3).
617    
618    
619  AUTHOR  AUTHOR
620    
621         Philip Hazel         Philip Hazel
622         University Computing Service,         University Computing Service
623         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
624    
625    
626    REVISION
627    
628  Last updated: 28 February 2005         Last updated: 21 August 2007
629  Copyright (c) 1997-2005 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

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