/[pcre]/code/trunk/doc/pcretest.txt
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revision 392 by ph10, Tue Mar 17 21:30:30 2009 UTC revision 535 by ph10, Thu Jun 3 19:18:24 2010 UTC
# Line 154  PATTERN MODIFIERS Line 154  PATTERN MODIFIERS
154    
155           /caseless/i           /caseless/i
156    
157         The following table shows additional modifiers for setting PCRE options         The  following  table  shows additional modifiers for setting PCRE com-
158         that do not correspond to anything in Perl:         pile-time options that do not correspond to anything in Perl:
159    
160             /8              PCRE_UTF8
161             /?              PCRE_NO_UTF8_CHECK
162           /A              PCRE_ANCHORED           /A              PCRE_ANCHORED
163           /C              PCRE_AUTO_CALLOUT           /C              PCRE_AUTO_CALLOUT
164           /E              PCRE_DOLLAR_ENDONLY           /E              PCRE_DOLLAR_ENDONLY
# Line 164  PATTERN MODIFIERS Line 166  PATTERN MODIFIERS
166           /J              PCRE_DUPNAMES           /J              PCRE_DUPNAMES
167           /N              PCRE_NO_AUTO_CAPTURE           /N              PCRE_NO_AUTO_CAPTURE
168           /U              PCRE_UNGREEDY           /U              PCRE_UNGREEDY
169             /W              PCRE_UCP
170           /X              PCRE_EXTRA           /X              PCRE_EXTRA
171           /<JS>           PCRE_JAVASCRIPT_COMPAT           /<JS>           PCRE_JAVASCRIPT_COMPAT
172           /<cr>           PCRE_NEWLINE_CR           /<cr>           PCRE_NEWLINE_CR
# Line 174  PATTERN MODIFIERS Line 177  PATTERN MODIFIERS
177           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
178           /<bsr_unicode>  PCRE_BSR_UNICODE           /<bsr_unicode>  PCRE_BSR_UNICODE
179    
180         Those specifying line ending sequences are literal  strings  as  shown,         The modifiers that are enclosed in angle brackets are  literal  strings
181         but  the  letters  can  be  in either case. This example sets multiline         as  shown,  including  the  angle  brackets,  but the letters can be in
182         matching with CRLF as the line ending sequence:         either case. This example sets multiline matching with CRLF as the line
183           ending sequence:
184    
185           /^abc/m<crlf>           /^abc/m<crlf>
186    
187         Details of the meanings of these PCRE options are given in the  pcreapi         As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
188         documentation.         any non-printing characters in output strings to be printed  using  the
189           \x{hh...}  notation  if they are valid UTF-8 sequences. Full details of
190           the PCRE options are given in the pcreapi documentation.
191    
192     Finding all matches in a string     Finding all matches in a string
193    
194         Searching  for  all  possible matches within each subject string can be         Searching for all possible matches within each subject  string  can  be
195         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
196         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
197         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
198         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
199         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
200         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
201         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
202         or \B).         or \B).
203    
204         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
205         string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
206         flags  set in order to search for another, non-empty, match at the same         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
207         point.  If this second match fails, the start  offset  is  advanced  by         match  at  the same point. If this second match fails, the start offset
208         one,  and  the normal match is retried. This imitates the way Perl han-         is advanced by one character, and the normal  match  is  retried.  This
209         dles such cases when using the /g modifier or the split() function.         imitates  the way Perl handles such cases when using the /g modifier or
210           the split() function.
211    
212     Other modifiers     Other modifiers
213    
# Line 218  PATTERN MODIFIERS Line 225  PATTERN MODIFIERS
225         feature for use in the automatic test scripts; it ensures that the same         feature for use in the automatic test scripts; it ensures that the same
226         output is generated for different internal link sizes.         output is generated for different internal link sizes.
227    
        The /L modifier must be followed directly by the name of a locale,  for  
        example,  
   
          /pattern/Lfr_FR  
   
        For this reason, it must be the last modifier. The given locale is set,  
        pcre_maketables() is called to build a set of character tables for  the  
        locale,  and  this  is then passed to pcre_compile() when compiling the  
        regular expression. Without an /L  modifier,  NULL  is  passed  as  the  
        tables  pointer; that is, /L applies only to the expression on which it  
        appears.  
   
        The /I modifier requests that pcretest  output  information  about  the  
        compiled  pattern (whether it is anchored, has a fixed first character,  
        and so on). It does this by calling pcre_fullinfo() after  compiling  a  
        pattern.  If  the pattern is studied, the results of that are also out-  
        put.  
   
228         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
229         that is, both the /B and the /I modifiers.         that is, both the /B and the /I modifiers.
230    
# Line 247  PATTERN MODIFIERS Line 236  PATTERN MODIFIERS
236         used, that is, when the /P pattern modifier is specified. See also  the         used, that is, when the /P pattern modifier is specified. See also  the
237         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
238    
239         The  /S  modifier causes pcre_study() to be called after the expression         The  /I  modifier  requests  that pcretest output information about the
240         has been compiled, and the results used when the expression is matched.         compiled pattern (whether it is anchored, has a fixed first  character,
241           and  so  on). It does this by calling pcre_fullinfo() after compiling a
242           pattern. If the pattern is studied, the results of that are  also  out-
243           put.
244    
245           The  /K modifier requests pcretest to show names from backtracking con-
246           trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
247           pcretest  to create a pcre_extra block if one has not already been cre-
248           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
249           the mark field within it, every time that pcre_exec() is called. If the
250           variable that the mark field points to is non-NULL for  a  match,  non-
251           match, or partial match, pcretest prints the string to which it points.
252           For a match, this is shown on a line by itself, tagged with "MK:".  For
253           a non-match it is added to the message.
254    
255           The  /L modifier must be followed directly by the name of a locale, for
256           example,
257    
258             /pattern/Lfr_FR
259    
260         The /M modifier causes the size of memory block used to hold  the  com-         For this reason, it must be the last modifier. The given locale is set,
261           pcre_maketables()  is called to build a set of character tables for the
262           locale, and this is then passed to pcre_compile()  when  compiling  the
263           regular  expression.  Without  an  /L  modifier,  NULL is passed as the
264           tables pointer; that is, /L applies only to the expression on which  it
265           appears.
266    
267           The  /M  modifier causes the size of memory block used to hold the com-
268         piled pattern to be output.         piled pattern to be output.
269    
270           The /S modifier causes pcre_study() to be called after  the  expression
271           has been compiled, and the results used when the expression is matched.
272    
273       Using the POSIX wrapper API
274    
275         The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API         The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
276         rather than its native API. When this  is  done,  all  other  modifiers         rather than its native API. When /P is set, the following modifiers set
277         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,         options for the regcomp() function:
278         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force  
279         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.           /i    REG_ICASE
280             /m    REG_NEWLINE
281         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option           /N    REG_NOSUB
282         set. This turns on support for UTF-8 character handling in  PCRE,  pro-           /s    REG_DOTALL     )
283         vided  that  it  was  compiled with this support enabled. This modifier           /U    REG_UNGREEDY   ) These options are not part of
284         also causes any non-printing characters in output strings to be printed           /W    REG_UCP        )   the POSIX standard
285         using the \x{hh...} notation if they are valid UTF-8 sequences.           /8    REG_UTF8       )
286    
287         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call         The  /+  modifier  works  as  described  above. All other modifiers are
288         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the         ignored.
        checking of the string for UTF-8 validity.  
289    
290    
291  DATA LINES  DATA LINES
292    
293         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
294         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
295         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
296         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
297         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
298         following escapes are recognized:         following escapes are recognized:
299    
300           \a         alarm (BEL, \x07)           \a         alarm (BEL, \x07)
# Line 323  DATA LINES Line 341  DATA LINES
341           \M         discover the minimum MATCH_LIMIT and           \M         discover the minimum MATCH_LIMIT and
342                        MATCH_LIMIT_RECURSION settings                        MATCH_LIMIT_RECURSION settings
343           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
344                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
345                          PCRE_NOTEMPTY_ATSTART option
346           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
347                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
348           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
349                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
350                          PCRE_PARTIAL_HARD option
351           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
352                        (any number of digits)                        (any number of digits)
353           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
354           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
355             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
356                          or pcre_dfa_exec()
357           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
358                        or pcre_dfa_exec()                        or pcre_dfa_exec()
359           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
# Line 350  DATA LINES Line 372  DATA LINES
372           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
373                        or pcre_dfa_exec()                        or pcre_dfa_exec()
374    
375         The escapes that specify line ending  sequences  are  literal  strings,         The  escapes  that  specify  line ending sequences are literal strings,
376         exactly as shown. No more than one newline setting should be present in         exactly as shown. No more than one newline setting should be present in
377         any data line.         any data line.
378    
379         A backslash followed by anything else just escapes the  anything  else.         A  backslash  followed by anything else just escapes the anything else.
380         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
381         way of passing an empty line as data, since a real  empty  line  termi-         way  of  passing  an empty line as data, since a real empty line termi-
382         nates the data input.         nates the data input.
383    
384         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If \M is present, pcretest calls pcre_exec() several times,  with  dif-
385         ferent values in the match_limit and  match_limit_recursion  fields  of         ferent  values  in  the match_limit and match_limit_recursion fields of
386         the  pcre_extra  data structure, until it finds the minimum numbers for         the pcre_extra data structure, until it finds the minimum  numbers  for
387         each parameter that allow pcre_exec() to complete. The match_limit num-         each parameter that allow pcre_exec() to complete. The match_limit num-
388         ber  is  a  measure of the amount of backtracking that takes place, and         ber is a measure of the amount of backtracking that  takes  place,  and
389         checking it out can be instructive. For most simple matches, the number         checking it out can be instructive. For most simple matches, the number
390         is  quite  small,  but for patterns with very large numbers of matching         is quite small, but for patterns with very large  numbers  of  matching
391         possibilities, it can become large very quickly with increasing  length         possibilities,  it can become large very quickly with increasing length
392         of subject string. The match_limit_recursion number is a measure of how         of subject string. The match_limit_recursion number is a measure of how
393         much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)         much  stack  (or,  if  PCRE is compiled with NO_RECURSE, how much heap)
394         memory is needed to complete the match attempt.         memory is needed to complete the match attempt.
395    
396         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
397         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
398         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.
399    
400         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-
401         per API to be used, the only option-setting  sequences  that  have  any         per  API  to  be  used, the only option-setting sequences that have any
402         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,         effect are \B,  \N,  and  \Z,  causing  REG_NOTBOL,  REG_NOTEMPTY,  and
403         to be passed to regexec().         REG_NOTEOL, respectively, to be passed to regexec().
404    
405         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
406         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.
407         There may be any number of hexadecimal digits inside  the  braces.  The         There  may  be  any number of hexadecimal digits inside the braces. The
408         result  is  from  one  to  six bytes, encoded according to the original         result is from one to six bytes,  encoded  according  to  the  original
409         UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to         UTF-8  rules  of  RFC  2279.  This  allows for values in the range 0 to
410         0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,         0x7FFFFFFF. Note that not all of those are valid Unicode  code  points,
411         or indeed valid UTF-8 characters according to the later  rules  in  RFC         or  indeed  valid  UTF-8 characters according to the later rules in RFC
412         3629.         3629.
413    
414    
415  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
416    
417         By   default,  pcretest  uses  the  standard  PCRE  matching  function,         By  default,  pcretest  uses  the  standard  PCRE  matching   function,
418         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
419         alternative  matching  function,  pcre_dfa_test(),  which operates in a         alternative matching function, pcre_dfa_test(),  which  operates  in  a
420         different way, and has some restrictions. The differences  between  the         different  way,  and has some restrictions. The differences between the
421         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
422    
423         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
424         contains the -dfa option, the alternative matching function is  called.         contains  the -dfa option, the alternative matching function is called.
425         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
426         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
427         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
428    
429    
430  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
431    
432         This  section  describes  the output when the normal matching function,         This section describes the output when the  normal  matching  function,
433         pcre_exec(), is being used.         pcre_exec(), is being used.
434    
435         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
436         that  pcre_exec()  returns,  starting with number 0 for the string that         that pcre_exec() returns, starting with number 0 for  the  string  that
437         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched  the  whole  pattern. Otherwise, it outputs "No match" when the
438         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
439         TIAL, respectively, and otherwise the PCRE negative error number.  Here         tially  matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL.
440           For any other returns, it outputs the PCRE negative error number.  Here
441         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
442    
443           $ pcretest           $ pcretest
# Line 496  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 519  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
519            2: tan            2: tan
520    
521         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
522         The longest matching string is always given first (and numbered zero).         The longest matching string is always given first (and numbered  zero).
523           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
524           lowed by the partially matching substring.
525    
526         If /g is present on the pattern, the search for further matches resumes         If /g is present on the pattern, the search for further matches resumes
527         at the end of the longest match. For example:         at the end of the longest match. For example:
# Line 655  AUTHOR Line 680  AUTHOR
680    
681  REVISION  REVISION
682    
683         Last updated: 10 March 2009         Last updated: 16 May 2010
684         Copyright (c) 1997-2009 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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