/[pcre]/code/trunk/doc/pcretest.txt
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revision 429 by ph10, Tue Sep 1 16:10:16 2009 UTC revision 579 by ph10, Wed Nov 24 17:39:25 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             /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 174  PATTERN MODIFIERS Line 178  PATTERN MODIFIERS
178           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
179           /<bsr_unicode>  PCRE_BSR_UNICODE           /<bsr_unicode>  PCRE_BSR_UNICODE
180    
181         Those specifying line ending sequences are literal  strings  as  shown,         The modifiers that are enclosed in angle brackets are  literal  strings
182         but  the  letters  can  be  in either case. This example sets multiline         as  shown,  including  the  angle  brackets,  but the letters can be in
183         matching with CRLF as the line ending sequence:         either case. This example sets multiline matching with CRLF as the line
184           ending sequence:
185    
186           /^abc/m<crlf>           /^abc/m<crlf>
187    
188         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
189         documentation.         any non-printing characters in output strings to be printed  using  the
190           \x{hh...}  notation  if they are valid UTF-8 sequences. Full details of
191           the PCRE options are given in the pcreapi documentation.
192    
193     Finding all matches in a string     Finding all matches in a string
194    
195         Searching  for  all  possible matches within each subject string can be         Searching for all possible matches within each subject  string  can  be
196         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
197         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
198         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
199         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
200         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
201         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
202         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
203         or \B).         or \B).
204    
205         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
206         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
207         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,
208         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
209         one,  and  the normal match is retried. This imitates the way Perl han-         is advanced, and the normal match is retried.  This  imitates  the  way
210         dles such cases when using the /g modifier or the split() function.         Perl handles such cases when using the /g modifier or the split() func-
211           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 218  PATTERN MODIFIERS Line 228  PATTERN MODIFIERS
228         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
229         output is generated for different internal link sizes.         output is generated for different internal link sizes.
230    
        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.  
   
231         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,
232         that is, both the /B and the /I modifiers.         that is, both the /B and the /I modifiers.
233    
# Line 247  PATTERN MODIFIERS Line 239  PATTERN MODIFIERS
239         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
240         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
241    
242         The  /S  modifier causes pcre_study() to be called after the expression         The  /I  modifier  requests  that pcretest output information about the
243         has been compiled, and the results used when the expression is matched.         compiled pattern (whether it is anchored, has a fixed first  character,
244           and  so  on). It does this by calling pcre_fullinfo() after compiling a
245           pattern. If the pattern is studied, the results of that are  also  out-
246           put.
247    
248           The  /K modifier requests pcretest to show names from backtracking con-
249           trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
250           pcretest  to create a pcre_extra block if one has not already been cre-
251           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
252           the mark field within it, every time that pcre_exec() is called. If the
253           variable that the mark field points to is non-NULL for  a  match,  non-
254           match, or partial match, pcretest prints the string to which it points.
255           For a match, this is shown on a line by itself, tagged with "MK:".  For
256           a non-match it is added to the message.
257    
258           The  /L modifier must be followed directly by the name of a locale, for
259           example,
260    
261             /pattern/Lfr_FR
262    
263         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,
264           pcre_maketables()  is called to build a set of character tables for the
265           locale, and this is then passed to pcre_compile()  when  compiling  the
266           regular  expression.  Without an /L (or /T) modifier, NULL is passed as
267           the tables pointer; that is, /L applies only to the expression on which
268           it appears.
269    
270           The  /M  modifier causes the size of memory block used to hold the com-
271         piled pattern to be output.         piled pattern to be output.
272    
273           The /S modifier causes pcre_study() to be called after  the  expression
274           has been compiled, and the results used when the expression is matched.
275    
276           The  /T  modifier  must be followed by a single digit. It causes a spe-
277           cific set of built-in character tables to be passed to  pcre_compile().
278           It is used in the standard PCRE tests to check behaviour with different
279           character tables. The digit specifies the tables as follows:
280    
281             0   the default ASCII tables, as distributed in
282                   pcre_chartables.c.dist
283             1   a set of tables defining ISO 8859 characters
284    
285           In table 1, some characters whose codes are greater than 128 are  iden-
286           tified as letters, digits, spaces, etc.
287    
288       Using the POSIX wrapper API
289    
290         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
291         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
292         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,         options for the regcomp() function:
293         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force  
294         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.           /i    REG_ICASE
295             /m    REG_NEWLINE
296         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option           /N    REG_NOSUB
297         set. This turns on support for UTF-8 character handling in  PCRE,  pro-           /s    REG_DOTALL     )
298         vided  that  it  was  compiled with this support enabled. This modifier           /U    REG_UNGREEDY   ) These options are not part of
299         also causes any non-printing characters in output strings to be printed           /W    REG_UCP        )   the POSIX standard
300         using the \x{hh...} notation if they are valid UTF-8 sequences.           /8    REG_UTF8       )
301    
302         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call         The  /+  modifier  works  as  described  above. All other modifiers are
303         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the         ignored.
        checking of the string for UTF-8 validity.  
304    
305    
306  DATA LINES  DATA LINES
307    
308         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
309         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
310         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
311         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
312         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
313         following escapes are recognized:         following escapes are recognized:
314    
315           \a         alarm (BEL, \x07)           \a         alarm (BEL, \x07)
# Line 290  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 323  DATA LINES Line 357  DATA LINES
357           \M         discover the minimum MATCH_LIMIT and           \M         discover the minimum MATCH_LIMIT and
358                        MATCH_LIMIT_RECURSION settings                        MATCH_LIMIT_RECURSION settings
359           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
360                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
361                          PCRE_NOTEMPTY_ATSTART option
362           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
363                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
364           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
# Line 333  DATA LINES Line 368  DATA LINES
368                        (any number of digits)                        (any number of digits)
369           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
370           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
371             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
372                          or pcre_dfa_exec()
373           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
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 351  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           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,         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.
# Line 378  DATA LINES Line 422  DATA LINES
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 and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,         effect  are  \B,  \N,  and  \Z,  causing  REG_NOTBOL, REG_NOTEMPTY, and
426         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.
# Line 413  DEFAULT OUTPUT FROM PCRETEST Line 457  DEFAULT OUTPUT FROM PCRETEST
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" or "Partial         matched the whole pattern. Otherwise, it outputs "No  match"  when  the
461         match:"  followed  by the partially matching substring when pcre_exec()         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
462         returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PARTIAL,  respectively,  and         tially matching substring when pcre_exec() returns  PCRE_ERROR_PARTIAL.
463         otherwise  the  PCRE  negative  error  number. Here is an example of an         (Note  that  this is the entire substring that was inspected during the
464         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 429  DEFAULT OUTPUT FROM PCRETEST Line 476  DEFAULT OUTPUT FROM PCRETEST
476           data> xyz           data> xyz
477           No match           No match
478    
479         Note that unset capturing substrings that are not followed by one  that         Note  that unset capturing substrings that are not followed by one that
480         is  set are not returned by pcre_exec(), and are not shown by pcretest.         is set are not returned by pcre_exec(), and are not shown by  pcretest.
481         In the following example, there are two capturing substrings, but  when         In  the following example, there are two capturing substrings, but when
482         the  first  data  line  is  matched, the second, unset substring is not         the first data line is matched, the  second,  unset  substring  is  not
483         shown. An "internal" unset substring is shown as "<unset>", as for  the         shown.  An "internal" unset substring is shown as "<unset>", as for the
484         second data line.         second data line.
485    
486             re> /(a)|(b)/             re> /(a)|(b)/
# Line 445  DEFAULT OUTPUT FROM PCRETEST Line 492  DEFAULT OUTPUT FROM PCRETEST
492            1: <unset>            1: <unset>
493            2: b            2: b
494    
495         If  the strings contain any non-printing characters, they are output as         If the strings contain any non-printing characters, they are output  as
496         \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
497         the  pattern.  See below for the definition of non-printing characters.         the pattern. See below for the definition of  non-printing  characters.
498         If the pattern has the /+ modifier, the output for substring 0 is  fol-         If  the pattern has the /+ modifier, the output for substring 0 is fol-
499         lowed  by  the  the rest of the subject string, identified by "0+" like         lowed by the the rest of the subject string, identified  by  "0+"  like
500         this:         this:
501    
502             re> /cat/+             re> /cat/+
# Line 457  DEFAULT OUTPUT FROM PCRETEST Line 504  DEFAULT OUTPUT FROM PCRETEST
504            0: cat            0: cat
505            0+ aract            0+ aract
506    
507         If the pattern has the /g or /G modifier,  the  results  of  successive         If  the  pattern  has  the /g or /G modifier, the results of successive
508         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
509    
510             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 471  DEFAULT OUTPUT FROM PCRETEST Line 518  DEFAULT OUTPUT FROM PCRETEST
518    
519         "No match" is output only if the first match attempt fails.         "No match" is output only if the first match attempt fails.
520    
521         If  any  of the sequences \C, \G, or \L are present in a data line that         If any of the sequences \C, \G, or \L are present in a data  line  that
522         is successfully matched, the substrings extracted  by  the  convenience         is  successfully  matched,  the substrings extracted by the convenience
523         functions are output with C, G, or L after the string number instead of         functions are output with C, G, or L after the string number instead of
524         a colon. This is in addition to the normal full list. The string length         a colon. This is in addition to the normal full list. The string length
525         (that  is,  the return from the extraction function) is given in paren-         (that is, the return from the extraction function) is given  in  paren-
526         theses after each string for \C and \G.         theses after each string for \C and \G.
527    
528         Note that whereas patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
529         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
530         lines can be included in data by means of the \n escape (or  \r,  \r\n,         lines  can  be included in data by means of the \n escape (or \r, \r\n,
531         etc., depending on the newline sequence setting).         etc., depending on the newline sequence setting).
532    
533    
534  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
535    
536         When  the  alternative  matching function, pcre_dfa_exec(), is used (by         When the alternative matching function, pcre_dfa_exec(),  is  used  (by
537         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
538         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
539         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:
540    
541             re> /(tang|tangerine|tan)/             re> /(tang|tangerine|tan)/
# Line 497  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 544  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
544            1: tang            1: tang
545            2: tan            2: tan
546    
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 659  AUTHOR Line 709  AUTHOR
709    
710  REVISION  REVISION
711    
712         Last updated: 29 August 2009         Last updated: 21 November 2010
713         Copyright (c) 1997-2009 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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