/[pcre]/code/trunk/doc/pcretest.txt
ViewVC logotype

Diff of /code/trunk/doc/pcretest.txt

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 392 by ph10, Tue Mar 17 21:30:30 2009 UTC revision 453 by ph10, Fri Sep 18 19:12:35 2009 UTC
# Line 196  PATTERN MODIFIERS Line 196  PATTERN MODIFIERS
196         or \B).         or \B).
197    
198         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
199         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
200         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,
201         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
202         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
203         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
204           the split() function.
205    
206     Other modifiers     Other modifiers
207    
208         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
209    
210         The /+ modifier requests that as well as outputting the substring  that         The  /+ modifier requests that as well as outputting the substring that
211         matched  the  entire  pattern,  pcretest  should in addition output the         matched the entire pattern, pcretest  should  in  addition  output  the
212         remainder of the subject string. This is useful  for  tests  where  the         remainder  of  the  subject  string. This is useful for tests where the
213         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
214    
215         The  /B modifier is a debugging feature. It requests that pcretest out-         The /B modifier is a debugging feature. It requests that pcretest  out-
216         put a representation of the compiled byte code after compilation.  Nor-         put  a representation of the compiled byte code after compilation. Nor-
217         mally  this  information contains length and offset values; however, if         mally this information contains length and offset values;  however,  if
218         /Z is also present, this data is replaced by spaces. This is a  special         /Z  is also present, this data is replaced by spaces. This is a special
219         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
220         output is generated for different internal link sizes.         output is generated for different internal link sizes.
221    
222         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
223         example,         example,
224    
225           /pattern/Lfr_FR           /pattern/Lfr_FR
226    
227         For this reason, it must be the last modifier. The given locale is set,         For this reason, it must be the last modifier. The given locale is set,
228         pcre_maketables() is called to build a set of character tables for  the         pcre_maketables()  is called to build a set of character tables for the
229         locale,  and  this  is then passed to pcre_compile() when compiling the         locale, and this is then passed to pcre_compile()  when  compiling  the
230         regular expression. Without an /L  modifier,  NULL  is  passed  as  the         regular  expression.  Without  an  /L  modifier,  NULL is passed as the
231         tables  pointer; that is, /L applies only to the expression on which it         tables pointer; that is, /L applies only to the expression on which  it
232         appears.         appears.
233    
234         The /I modifier requests that pcretest  output  information  about  the         The  /I  modifier  requests  that pcretest output information about the
235         compiled  pattern (whether it is anchored, has a fixed first character,         compiled pattern (whether it is anchored, has a fixed first  character,
236         and so on). It does this by calling pcre_fullinfo() after  compiling  a         and  so  on). It does this by calling pcre_fullinfo() after compiling a
237         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-
238         put.         put.
239    
240         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,
241         that is, both the /B and the /I modifiers.         that is, both the /B and the /I modifiers.
242    
243         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
244         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This
245         facility  is  for testing the feature in PCRE that allows it to execute         facility is for testing the feature in PCRE that allows it  to  execute
246         patterns that were compiled on a host with a different endianness. This         patterns that were compiled on a host with a different endianness. This
247         feature  is  not  available  when  the POSIX interface to PCRE is being         feature is not available when the POSIX  interface  to  PCRE  is  being
248         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
249         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
250    
251         The  /S  modifier causes pcre_study() to be called after the expression         The /S modifier causes pcre_study() to be called after  the  expression
252         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
253    
254         The /M modifier causes the size of memory block used to hold  the  com-         The  /M  modifier causes the size of memory block used to hold the com-
255         piled pattern to be output.         piled pattern to be output.
256    
257         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
258         rather than its native API. When this  is  done,  all  other  modifiers         rather  than  its  native  API.  When this is done, all other modifiers
259         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,         except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,
260         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force         and  REG_NEWLINE  is  set if /m is present. The wrapper functions force
261         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
262    
263         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option         The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8  option
264         set. This turns on support for UTF-8 character handling in  PCRE,  pro-         set.  This  turns on support for UTF-8 character handling in PCRE, pro-
265         vided  that  it  was  compiled with this support enabled. This modifier         vided that it was compiled with this  support  enabled.  This  modifier
266         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
267         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
268    
269         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call
270         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the
271         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
272    
273    
274  DATA LINES  DATA LINES
275    
276         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
277         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
278         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
279         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
280         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
281         following escapes are recognized:         following escapes are recognized:
282    
283           \a         alarm (BEL, \x07)           \a         alarm (BEL, \x07)
# Line 323  DATA LINES Line 324  DATA LINES
324           \M         discover the minimum MATCH_LIMIT and           \M         discover the minimum MATCH_LIMIT and
325                        MATCH_LIMIT_RECURSION settings                        MATCH_LIMIT_RECURSION settings
326           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
327                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
328                          PCRE_NOTEMPTY_ATSTART option
329           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
330                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
331           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
332                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
333                          PCRE_PARTIAL_HARD option
334           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd           \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
335                        (any number of digits)                        (any number of digits)
336           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
# Line 350  DATA LINES Line 353  DATA LINES
353           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
354                        or pcre_dfa_exec()                        or pcre_dfa_exec()
355    
356         The escapes that specify line ending  sequences  are  literal  strings,         The  escapes  that  specify  line ending sequences are literal strings,
357         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
358         any data line.         any data line.
359    
360         A backslash followed by anything else just escapes the  anything  else.         A  backslash  followed by anything else just escapes the anything else.
361         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
362         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-
363         nates the data input.         nates the data input.
364    
365         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If \M is present, pcretest calls pcre_exec() several times,  with  dif-
366         ferent values in the match_limit and  match_limit_recursion  fields  of         ferent  values  in  the match_limit and match_limit_recursion fields of
367         the  pcre_extra  data structure, until it finds the minimum numbers for         the pcre_extra data structure, until it finds the minimum  numbers  for
368         each parameter that allow pcre_exec() to complete. The match_limit num-         each parameter that allow pcre_exec() to complete. The match_limit num-
369         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
370         checking it out can be instructive. For most simple matches, the number         checking it out can be instructive. For most simple matches, the number
371         is  quite  small,  but for patterns with very large numbers of matching         is quite small, but for patterns with very large  numbers  of  matching
372         possibilities, it can become large very quickly with increasing  length         possibilities,  it can become large very quickly with increasing length
373         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
374         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)
375         memory is needed to complete the match attempt.         memory is needed to complete the match attempt.
376    
377         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
378         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
379         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.
380    
381         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-
382         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
383         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,         effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL,  respectively,
384         to be passed to regexec().         to be passed to regexec().
385    
386         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
387         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.
388         There may be any number of hexadecimal digits inside  the  braces.  The         There  may  be  any number of hexadecimal digits inside the braces. The
389         result  is  from  one  to  six bytes, encoded according to the original         result is from one to six bytes,  encoded  according  to  the  original
390         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
391         0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,         0x7FFFFFFF. Note that not all of those are valid Unicode  code  points,
392         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
393         3629.         3629.
394    
395    
396  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
397    
398         By   default,  pcretest  uses  the  standard  PCRE  matching  function,         By  default,  pcretest  uses  the  standard  PCRE  matching   function,
399         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
400         alternative  matching  function,  pcre_dfa_test(),  which operates in a         alternative matching function, pcre_dfa_test(),  which  operates  in  a
401         different way, and has some restrictions. The differences  between  the         different  way,  and has some restrictions. The differences between the
402         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
403    
404         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
405         contains the -dfa option, the alternative matching function is  called.         contains  the -dfa option, the alternative matching function is called.
406         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
407         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
408         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
409    
410    
411  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
412    
413         This  section  describes  the output when the normal matching function,         This section describes the output when the  normal  matching  function,
414         pcre_exec(), is being used.         pcre_exec(), is being used.
415    
416         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
417         that  pcre_exec()  returns,  starting with number 0 for the string that         that pcre_exec() returns, starting with number 0 for  the  string  that
418         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched  the  whole  pattern. Otherwise, it outputs "No match" when the
419         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
420         TIAL, respectively, and otherwise the PCRE negative error number.  Here         tially  matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL.
421           For any other returns, it outputs the PCRE negative error number.  Here
422         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
423    
424           $ pcretest           $ pcretest
# Line 496  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 500  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
500            2: tan            2: tan
501    
502         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
503         The longest matching string is always given first (and numbered zero).         The longest matching string is always given first (and numbered  zero).
504           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
505           lowed by the partially matching substring.
506    
507         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
508         at the end of the longest match. For example:         at the end of the longest match. For example:
# Line 655  AUTHOR Line 661  AUTHOR
661    
662  REVISION  REVISION
663    
664         Last updated: 10 March 2009         Last updated: 11 September 2009
665         Copyright (c) 1997-2009 University of Cambridge.         Copyright (c) 1997-2009 University of Cambridge.

Legend:
Removed from v.392  
changed lines
  Added in v.453

  ViewVC Help
Powered by ViewVC 1.1.5