/[pcre]/code/trunk/doc/pcretest.txt
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revision 545 by ph10, Wed Jun 16 10:51:15 2010 UTC revision 579 by ph10, Wed Nov 24 17:39:25 2010 UTC
# Line 168  PATTERN MODIFIERS Line 168  PATTERN MODIFIERS
168           /U              PCRE_UNGREEDY           /U              PCRE_UNGREEDY
169           /W              PCRE_UCP           /W              PCRE_UCP
170           /X              PCRE_EXTRA           /X              PCRE_EXTRA
171             /Y              PCRE_NO_START_OPTIMIZE
172           /<JS>           PCRE_JAVASCRIPT_COMPAT           /<JS>           PCRE_JAVASCRIPT_COMPAT
173           /<cr>           PCRE_NEWLINE_CR           /<cr>           PCRE_NEWLINE_CR
174           /<lf>           PCRE_NEWLINE_LF           /<lf>           PCRE_NEWLINE_LF
# Line 205  PATTERN MODIFIERS Line 206  PATTERN MODIFIERS
206         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
207         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
208         match  at  the same point. If this second match fails, the start offset         match  at  the same point. If this second match fails, the start offset
209         is advanced by one character, and the normal  match  is  retried.  This         is advanced, and the normal match is retried.  This  imitates  the  way
210         imitates  the way Perl handles such cases when using the /g modifier or         Perl handles such cases when using the /g modifier or the split() func-
211         the split() function.         tion. Normally, the start offset is advanced by one character,  but  if
212           the  newline  convention  recognizes CRLF as a newline, and the current
213           character is CR followed by LF, an advance of two is used.
214    
215     Other modifiers     Other modifiers
216    
# Line 320  DATA LINES Line 323  DATA LINES
323           \t         tab (\x09)           \t         tab (\x09)
324           \v         vertical tab (\x0b)           \v         vertical tab (\x0b)
325           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
326           \xhh       hexadecimal character (up to 2 hex digits)                        always a byte unless > 255 in UTF-8 mode
327             \xhh       hexadecimal byte (up to 2 hex digits)
328           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
329                        in UTF-8 mode                        in UTF-8 mode
330           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
# Line 370  DATA LINES Line 374  DATA LINES
374                        or pcre_dfa_exec()                        or pcre_dfa_exec()
375           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
376                        pcre_exec() or pcre_dfa_exec()                        pcre_exec() or pcre_dfa_exec()
377           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (optional "-"; then
378                        this sets the startoffset argument for pcre_exec()                        any number of digits); this sets the startoffset
379                        or pcre_dfa_exec()                        argument for pcre_exec() or pcre_dfa_exec()
380           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
381                        or pcre_dfa_exec()                        or pcre_dfa_exec()
382           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
# Line 384  DATA LINES Line 388  DATA LINES
388           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
389                        or pcre_dfa_exec()                        or pcre_dfa_exec()
390    
391         The  escapes  that  specify  line ending sequences are literal strings,         Note  that  \xhh  always  specifies  one byte, even in UTF-8 mode; this
392           makes it possible to construct invalid UTF-8 sequences for testing pur-
393           poses. On the other hand, \x{hh} is interpreted as a UTF-8 character in
394           UTF-8 mode, generating more than one byte if the value is greater  than
395           127. When not in UTF-8 mode, it generates one byte for values less than
396           256, and causes an error for greater values.
397    
398           The escapes that specify line ending  sequences  are  literal  strings,
399         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
400         any data line.         any data line.
401    
402         A  backslash  followed by anything else just escapes the anything else.         A backslash followed by anything else just escapes the  anything  else.
403         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
404         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-
405         nates the data input.         nates the data input.
406    
407         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
408         ferent  values  in  the match_limit and match_limit_recursion fields of         ferent values in the match_limit and  match_limit_recursion  fields  of
409         the pcre_extra data structure, until it finds the minimum  numbers  for         the  pcre_extra  data structure, until it finds the minimum numbers for
410         each parameter that allow pcre_exec() to complete. The match_limit num-         each parameter that allow pcre_exec() to complete. The match_limit num-
411         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
412         checking it out can be instructive. For most simple matches, the number         checking it out can be instructive. For most simple matches, the number
413         is quite small, but for patterns with very large  numbers  of  matching         is  quite  small,  but for patterns with very large numbers of matching
414         possibilities,  it can become large very quickly with increasing length         possibilities, it can become large very quickly with increasing  length
415         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
416         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)
417         memory is needed to complete the match attempt.         memory is needed to complete the match attempt.
418    
419         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
420         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
421         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.
422    
423         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-
424         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
425         effect are \B,  \N,  and  \Z,  causing  REG_NOTBOL,  REG_NOTEMPTY,  and         effect  are  \B,  \N,  and  \Z,  causing  REG_NOTBOL, REG_NOTEMPTY, and
426         REG_NOTEOL, respectively, to be passed to regexec().         REG_NOTEOL, respectively, to be passed to regexec().
427    
428         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
429         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.
430         There  may  be  any number of hexadecimal digits inside the braces. The         There may be any number of hexadecimal digits inside  the  braces.  The
431         result is from one to six bytes,  encoded  according  to  the  original         result  is  from  one  to  six bytes, encoded according to the original
432         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
433         0x7FFFFFFF. Note that not all of those are valid Unicode  code  points,         0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
434         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
435         3629.         3629.
436    
437    
438  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
439    
440         By  default,  pcretest  uses  the  standard  PCRE  matching   function,         By   default,  pcretest  uses  the  standard  PCRE  matching  function,
441         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
442         alternative matching function, pcre_dfa_test(),  which  operates  in  a         alternative  matching  function,  pcre_dfa_test(),  which operates in a
443         different  way,  and has some restrictions. The differences between the         different way, and has some restrictions. The differences  between  the
444         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
445    
446         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
447         contains  the -dfa option, the alternative matching function is called.         contains the -dfa option, the alternative matching function is  called.
448         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
449         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
450         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
451    
452    
453  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
454    
455         This section describes the output when the  normal  matching  function,         This  section  describes  the output when the normal matching function,
456         pcre_exec(), is being used.         pcre_exec(), is being used.
457    
458         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
459         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
460         matched  the  whole  pattern. Otherwise, it outputs "No match" when the         matched the whole pattern. Otherwise, it outputs "No  match"  when  the
461         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
462         tially  matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL.         tially matching substring when pcre_exec() returns  PCRE_ERROR_PARTIAL.
463         For any other returns, it outputs the PCRE negative error number.  Here         (Note  that  this is the entire substring that was inspected during the
464         is an example of an interactive pcretest run.         partial match; it may include characters before the actual match  start
465           if  a  lookbehind assertion, \K, \b, or \B was involved.) For any other
466           returns, it outputs the PCRE negative error number. Here is an  example
467           of an interactive pcretest run.
468    
469           $ pcretest           $ pcretest
470           PCRE version 7.0 30-Nov-2006           PCRE version 7.0 30-Nov-2006
# Line 533  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 547  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
547         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
548         The longest matching string is always given first (and numbered  zero).         The longest matching string is always given first (and numbered  zero).
549         After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-         After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
550         lowed by the partially matching substring.         lowed by the partially matching  substring.  (Note  that  this  is  the
551           entire  substring  that  was inspected during the partial match; it may
552           include characters before the actual match start if a lookbehind asser-
553           tion, \K, \b, or \B was involved.)
554    
555         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
556         at the end of the longest match. For example:         at the end of the longest match. For example:
# Line 547  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 564  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
564            1: tan            1: tan
565            0: tan            0: tan
566    
567         Since  the  matching  function  does not support substring capture, the         Since the matching function does not  support  substring  capture,  the
568         escape sequences that are concerned with captured  substrings  are  not         escape  sequences  that  are concerned with captured substrings are not
569         relevant.         relevant.
570    
571    
572  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
573    
574         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
575         return, indicating that the subject partially matched the pattern,  you         return,  indicating that the subject partially matched the pattern, you
576         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
577         escape sequence. For example:         escape sequence. For example:
578    
579             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
# Line 565  RESTARTING AFTER A PARTIAL MATCH Line 582  RESTARTING AFTER A PARTIAL MATCH
582           data> n05\R\D           data> n05\R\D
583            0: n05            0: n05
584    
585         For further information about partial  matching,  see  the  pcrepartial         For  further  information  about  partial matching, see the pcrepartial
586         documentation.         documentation.
587    
588    
589  CALLOUTS  CALLOUTS
590    
591         If  the pattern contains any callout requests, pcretest's callout func-         If the pattern contains any callout requests, pcretest's callout  func-
592         tion is called during matching. This works  with  both  matching  func-         tion  is  called  during  matching. This works with both matching func-
593         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
594         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
595         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
596    
597           --->pqrabcdef           --->pqrabcdef
598             0    ^  ^     \d             0    ^  ^     \d
599    
600         indicates  that  callout number 0 occurred for a match attempt starting         indicates that callout number 0 occurred for a match  attempt  starting
601         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
602         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
603         \d. Just one circumflex is output if the start  and  current  positions         \d.  Just  one  circumflex is output if the start and current positions
604         are the same.         are the same.
605    
606         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
607         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
608         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
609         output. For example:         output. For example:
610    
611             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 600  CALLOUTS Line 617  CALLOUTS
617           +10 ^ ^           +10 ^ ^
618            0: E*            0: E*
619    
620         The callout function in pcretest returns zero (carry  on  matching)  by         The  callout  function  in pcretest returns zero (carry on matching) by
621         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)
622         to change this.         to change this.
623    
624         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting  callouts can be helpful when using pcretest to check compli-
625         cated  regular expressions. For further information about callouts, see         cated regular expressions. For further information about callouts,  see
626         the pcrecallout documentation.         the pcrecallout documentation.
627    
628    
629  NON-PRINTING CHARACTERS  NON-PRINTING CHARACTERS
630    
631         When pcretest is outputting text in the compiled version of a  pattern,         When  pcretest is outputting text in the compiled version of a pattern,
632         bytes  other  than 32-126 are always treated as non-printing characters         bytes other than 32-126 are always treated as  non-printing  characters
633         are are therefore shown as hex escapes.         are are therefore shown as hex escapes.
634    
635         When pcretest is outputting text that is a matched part  of  a  subject         When  pcretest  is  outputting text that is a matched part of a subject
636         string,  it behaves in the same way, unless a different locale has been         string, it behaves in the same way, unless a different locale has  been
637         set for the  pattern  (using  the  /L  modifier).  In  this  case,  the         set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
638         isprint() function to distinguish printing and non-printing characters.         isprint() function to distinguish printing and non-printing characters.
639    
640    
641  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
642    
643         The  facilities  described  in  this section are not available when the         The facilities described in this section are  not  available  when  the
644         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-
645         ifier is specified.         ifier is specified.
646    
647         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
648         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
649         file name.  For example:         file name.  For example:
650    
651           /pattern/im >/some/file           /pattern/im >/some/file
652    
653         See  the pcreprecompile documentation for a discussion about saving and         See the pcreprecompile documentation for a discussion about saving  and
654         re-using compiled patterns.         re-using compiled patterns.
655    
656         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
657         length  of  the  compiled  pattern  data  followed by the length of the         length of the compiled pattern data  followed  by  the  length  of  the
658         optional study data, each written as four  bytes  in  big-endian  order         optional  study  data,  each  written as four bytes in big-endian order
659         (most  significant  byte  first). If there is no study data (either the         (most significant byte first). If there is no study  data  (either  the
660         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-
661         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
662         compiled pattern. If there is additional study data, this follows imme-         compiled pattern. If there is additional study data, this follows imme-
663         diately  after  the  compiled pattern. After writing the file, pcretest         diately after the compiled pattern. After writing  the  file,  pcretest
664         expects to read a new pattern.         expects to read a new pattern.
665    
666         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
667         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  <
668         character, as otherwise pcretest will interpret the line as  a  pattern         character,  as  otherwise pcretest will interpret the line as a pattern
669         delimited by < characters.  For example:         delimited by < characters.  For example:
670    
671            re> </some/file            re> </some/file
672           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
673           No study data           No study data
674    
675         When  the pattern has been loaded, pcretest proceeds to read data lines         When the pattern has been loaded, pcretest proceeds to read data  lines
676         in the usual way.         in the usual way.
677    
678         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
679         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
680         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
681         machine and run on a SPARC machine.         machine and run on a SPARC machine.
682    
683         File  names  for  saving and reloading can be absolute or relative, but         File names for saving and reloading can be absolute  or  relative,  but
684         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
685         a tilde (~) is not available.         a tilde (~) is not available.
686    
687         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-
688         ing and experimentation. It is not intended for production use  because         ing  and experimentation. It is not intended for production use because
689         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
690         no facility for supplying  custom  character  tables  for  use  with  a         no  facility  for  supplying  custom  character  tables  for use with a
691         reloaded  pattern.  If  the  original  pattern was compiled with custom         reloaded pattern. If the original  pattern  was  compiled  with  custom
692         tables, an attempt to match a subject string using a  reloaded  pattern         tables,  an  attempt to match a subject string using a reloaded pattern
693         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
694         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.
695    
696    
697  SEE ALSO  SEE ALSO
698    
699         pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),         pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
700         pcrepattern(3), pcreprecompile(3).         pcrepattern(3), pcreprecompile(3).
701    
702    
# Line 692  AUTHOR Line 709  AUTHOR
709    
710  REVISION  REVISION
711    
712         Last updated: 14 June 2010         Last updated: 21 November 2010
713         Copyright (c) 1997-2010 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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