/[pcre]/code/trunk/doc/pcretest.txt
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revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 579 by ph10, Wed Nov 24 17:39:25 2010 UTC
# Line 1  Line 1 
1  PCRETEST(1)                                                        PCRETEST(1)  PCRETEST(1)                                                        PCRETEST(1)
2    
3    
   
4  NAME  NAME
5         pcretest - a program for testing Perl-compatible regular expressions.         pcretest - a program for testing Perl-compatible regular expressions.
6    
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [options] [source] [destination]
             [destination]  
11    
12         pcretest  was written as a test program for the PCRE regular expression         pcretest  was written as a test program for the PCRE regular expression
13         library itself, but it can also be used for experimenting with  regular         library itself, but it can also be used for experimenting with  regular
# Line 20  SYNOPSIS Line 19  SYNOPSIS
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
26                   able   information  about  the  optional  features  that  are                   able  information  about  the  optional  features  that   are
27                   included, and then exit.                   included, and then exit.
28    
29         -d        Behave as if each regex had  the  /D  (debug)  modifier;  the         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                   internal form is output after compilation.                   internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33           -dfa      Behave  as if each data line contains the \D escape sequence;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38           -help     Output a brief summary these options and then exit.
39    
40         -i        Behave  as  if  each  regex  had the /I modifier; information         -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
43           -M        Behave  as if each data line contains the \M escape sequence;
44                     this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                     MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
46                     edly with different limits.
47    
48         -m        Output the size of each compiled pattern after  it  has  been         -m        Output the size of each compiled pattern after  it  has  been
49                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled.  This  is  equivalent  to adding /M to each regular
50                   expression.  For  compatibility  with  earlier  versions   of                   expression.  For  compatibility  with  earlier  versions   of
51                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
52    
53         -o osize  Set  the number of elements in the output vector that is used         -o osize  Set  the number of elements in the output vector that is used
54                   when calling pcre_exec() to be osize. The  default  value  is                   when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                   45, which is enough for 14 capturing subexpressions. The vec-                   default  value is 45, which is enough for 14 capturing subex-
56                   tor size can be changed  for  individual  matching  calls  by                   pressions  for  pcre_exec()  or  22  different  matches   for
57                   including \O in the data line (see below).                   pcre_dfa_exec().  The vector size can be changed for individ-
58                     ual matching calls by including \O  in  the  data  line  (see
59         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper                   below).
60                   API is used to call PCRE. None of the other options  has  any  
61                   effect when -p is set.         -p        Behave  as if each regex has the /P modifier; the POSIX wrap-
62                     per API is used to call PCRE. None of the other  options  has
63                     any effect when -p is set.
64    
65           -q        Do  not output the version number of pcretest at the start of
66                     execution.
67    
68           -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                     size megabytes.
70    
71         -t        Run  each  compile, study, and match many times with a timer,         -t        Run  each  compile, study, and match many times with a timer,
72                   and output resulting time per compile or match (in  millisec-                   and output resulting time per compile or match (in  millisec-
73                   onds).  Do  not set -m with -t, because you will then get the                   onds).  Do  not set -m with -t, because you will then get the
74                   size output a zillion times, and  the  timing  will  be  dis-                   size output a zillion times, and  the  timing  will  be  dis-
75                   torted.                   torted.  You  can  control  the number of iterations that are
76                     used for timing by following -t with a number (as a  separate
77                     item on the command line). For example, "-t 1000" would iter-
78                     ate 1000 times. The default is to iterate 500000 times.
79    
80           -tm       This is like -t except that it times only the matching phase,
81                     not the compile or study phases.
82    
83    
84  DESCRIPTION  DESCRIPTION
# Line 61  DESCRIPTION Line 90  DESCRIPTION
90         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
91         lines.         lines.
92    
93           When pcretest is built, a configuration  option  can  specify  that  it
94           should  be  linked  with the libreadline library. When this is done, if
95           the input is from a terminal, it is read using the readline() function.
96           This  provides line-editing and history facilities. The output from the
97           -help option states whether or not readline() will be used.
98    
99         The program handles any number of sets of input on a single input file.         The program handles any number of sets of input on a single input file.
100         Each  set starts with a regular expression, and continues with any num-         Each  set starts with a regular expression, and continues with any num-
101         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
102    
103         Each data line is matched separately and independently. If you want  to         Each data line is matched separately and independently. If you want  to
104         do  multiple-line  matches, you have to use the \n escape sequence in a         do multi-line matches, you have to use the \n escape sequence (or \r or
105         single line of input to encode  the  newline  characters.  The  maximum         \r\n, etc., depending on the newline setting) in a single line of input
106         length of data line is 30,000 characters.         to  encode  the  newline  sequences. There is no limit on the length of
107           data lines; the input buffer is automatically extended  if  it  is  too
108           small.
109    
110         An  empty  line signals the end of the data lines, at which point a new         An  empty  line signals the end of the data lines, at which point a new
111         regular expression is read. The regular expressions are given  enclosed         regular expression is read. The regular expressions are given  enclosed
112         in any non-alphanumeric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example:
113    
114           /(a|bc)x+yz/           /(a|bc)x+yz/
115    
# Line 117  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
163             /C              PCRE_AUTO_CALLOUT
164             /E              PCRE_DOLLAR_ENDONLY
165             /f              PCRE_FIRSTLINE
166             /J              PCRE_DUPNAMES
167             /N              PCRE_NO_AUTO_CAPTURE
168             /U              PCRE_UNGREEDY
169             /W              PCRE_UCP
170             /X              PCRE_EXTRA
171             /Y              PCRE_NO_START_OPTIMIZE
172             /<JS>           PCRE_JAVASCRIPT_COMPAT
173             /<cr>           PCRE_NEWLINE_CR
174             /<lf>           PCRE_NEWLINE_LF
175             /<crlf>         PCRE_NEWLINE_CRLF
176             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
177             /<any>          PCRE_NEWLINE_ANY
178             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
179             /<bsr_unicode>  PCRE_BSR_UNICODE
180    
181           The modifiers that are enclosed in angle brackets are  literal  strings
182           as  shown,  including  the  angle  brackets,  but the letters can be in
183           either case. This example sets multiline matching with CRLF as the line
184           ending sequence:
185    
186             /^abc/m<crlf>
187    
188           As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
189           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           /A    PCRE_ANCHORED     Finding all matches in a string
          /C    PCRE_AUTO_CALLOUT  
          /E    PCRE_DOLLAR_ENDONLY  
          /N    PCRE_NO_AUTO_CAPTURE  
          /U    PCRE_UNGREEDY  
          /X    PCRE_EXTRA  
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
# Line 138  PATTERN MODIFIERS Line 203  PATTERN MODIFIERS
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
216    
217         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
218    
# Line 151  PATTERN MODIFIERS Line 221  PATTERN MODIFIERS
221         remainder of the subject string. This is useful  for  tests  where  the         remainder of the subject string. This is useful  for  tests  where  the
222         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
223    
224         The  /L modifier must be followed directly by the name of a locale, for         The  /B modifier is a debugging feature. It requests that pcretest out-
225         example,         put a representation of the compiled byte code after compilation.  Nor-
226           mally  this  information contains length and offset values; however, if
227           /Z is also present, this data is replaced by spaces. This is a  special
228           feature for use in the automatic test scripts; it ensures that the same
229           output is generated for different internal link sizes.
230    
231           /pattern/Lfr_FR         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
232           that is, both the /B and the /I modifiers.
233    
234         For this reason, it must be the last modifier. The given locale is set,         The /F modifier causes pcretest to flip the byte order of the fields in
235         pcre_maketables()  is called to build a set of character tables for the         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
236         locale, and this is then passed to pcre_compile()  when  compiling  the         facility  is  for testing the feature in PCRE that allows it to execute
237         regular  expression.  Without  an  /L  modifier,  NULL is passed as the         patterns that were compiled on a host with a different endianness. This
238         tables pointer; that is, /L applies only to the expression on which  it         feature  is  not  available  when  the POSIX interface to PCRE is being
239         appears.         used, that is, when the /P pattern modifier is specified. See also  the
240           section about saving and reloading compiled patterns below.
241    
242         The  /I  modifier  requests  that pcretest output information about the         The  /I  modifier  requests  that pcretest output information about the
243         compiled pattern (whether it is anchored, has a fixed first  character,         compiled pattern (whether it is anchored, has a fixed first  character,
# Line 169  PATTERN MODIFIERS Line 245  PATTERN MODIFIERS
245         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-
246         put.         put.
247    
248         The /D modifier is a PCRE debugging feature, which also assumes /I.  It         The  /K modifier requests pcretest to show names from backtracking con-
249         causes the internal form of compiled regular expressions to  be  output         trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
250         after compilation. If the pattern was studied, the information returned         pcretest  to create a pcre_extra block if one has not already been cre-
251         is also output.         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 /F modifier causes pcretest to flip the byte order of the fields in         The  /L modifier must be followed directly by the name of a locale, for
259         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This         example,
260         facility is for testing the feature in PCRE that allows it  to  execute  
261         patterns that were compiled on a host with a different endianness. This           /pattern/Lfr_FR
262         feature is not available when the POSIX  interface  to  PCRE  is  being  
263         used,  that is, when the /P pattern modifier is specified. See also the         For this reason, it must be the last modifier. The given locale is set,
264         section about saving and reloading compiled patterns below.         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.
272    
273         The /S modifier causes pcre_study() to be called after  the  expression         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.         has been compiled, and the results used when the expression is matched.
275    
276         The /M modifier causes the size of memory block used to hold  the  com-         The  /T  modifier  must be followed by a single digit. It causes a spe-
277         piled pattern to be output.         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
# Line 214  DATA LINES Line 312  DATA LINES
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)           \a         alarm (BEL, \x07)
316           \b         backspace           \b         backspace (\x08)
317           \e         escape           \e         escape (\x27)
318           \f         formfeed           \f         formfeed (\x0c)
319           \n         newline           \n         newline (\x0a)
320           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
321           \t         tab                        (any number of digits)
322           \v         vertical tab           \r         carriage return (\x0d)
323             \t         tab (\x09)
324             \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()
331                          or pcre_dfa_exec()
332           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
333                          or pcre_dfa_exec()
334           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
335                        after a successful match (number less than 32)                        after a successful match (number less than 32)
336           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 242  DATA LINES Line 345  DATA LINES
345                        reached for the nth time                        reached for the nth time
346           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
347                        data; this is used as the callout return value                        data; this is used as the callout return value
348             \D         use the pcre_dfa_exec() match function
349             \F         only shortest match for pcre_dfa_exec()
350           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
351                        after a successful match (number less than 32)                        after a successful match (number less than 32)
352           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
# Line 249  DATA LINES Line 354  DATA LINES
354                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
355           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
356                        successful match                        successful match
357           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
358                          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(); 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 option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
365                          or pcre_dfa_exec(); if used twice, pass the
366                          PCRE_PARTIAL_HARD option
367             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
368                          (any number of digits)
369             \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()
375           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
376                        pcre_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                          argument for pcre_exec() or pcre_dfa_exec()
380         A  backslash  followed by anything else just escapes the anything else.           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
381         If the very last character is a backslash, it is ignored. This gives  a                        or pcre_dfa_exec()
382         way  of  passing  an empty line as data, since a real empty line termi-           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
383                          or pcre_dfa_exec()
384             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
385                          or pcre_dfa_exec()
386             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
387                          or pcre_dfa_exec()
388             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
389                          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,
399           exactly as shown. No more than one newline setting should be present in
400           any data line.
401    
402           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
404           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 field of the pcre_extra data struc-         ferent values in the match_limit and  match_limit_recursion  fields  of
409         ture, until it finds the minimum number that is needed for  pcre_exec()         the  pcre_extra  data structure, until it finds the minimum numbers for
410         to  complete.  This  number is a measure of the amount of recursion and         each parameter that allow pcre_exec() to complete. The match_limit num-
411         backtracking that takes place, and checking it out can be  instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
412         For  most  simple  matches, the number is quite small, but for patterns         checking it out can be instructive. For most simple matches, the number
413         with very large numbers of matching possibilities, it can become  large         is  quite  small,  but for patterns with very large numbers of matching
414         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
415           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)
417           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, only \B and \Z have any effect, causing  REG_NOTBOL         per API to be used, the only option-setting  sequences  that  have  any
425         and REG_NOTEOL to be passed to regexec() respectively.         effect  are  \B,  \N,  and  \Z,  causing  REG_NOTBOL, REG_NOTEMPTY, and
426           REG_NOTEOL, respectively, to be passed to regexec().
427    
428           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.
430           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
432           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,
434           or indeed valid UTF-8 characters according to the later  rules  in  RFC
435           3629.
436    
437    
438    THE ALTERNATIVE MATCHING FUNCTION
439    
440           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
441           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
443           different way, and has some restrictions. The differences  between  the
444           two functions are described in the pcrematching documentation.
445    
446           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.
448           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
450           first match is found. This is always the shortest possible match.
451    
        The  use of \x{hh...} to represent UTF-8 characters is not dependent on  
        the use of the /8 modifier on the pattern.  It  is  recognized  always.  
        There  may  be  any number of hexadecimal digits inside the braces. The  
        result is from one to six bytes, encoded according to the UTF-8  rules.  
452    
453    DEFAULT OUTPUT FROM PCRETEST
454    
455  OUTPUT FROM PCRETEST         This  section  describes  the output when the normal matching function,
456           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" or "Partial         matched the whole pattern. Otherwise, it outputs "No  match"  when  the
461         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
462         TIAL,  respectively, and otherwise the PCRE negative error number. Here         tially matching substring when pcre_exec() returns  PCRE_ERROR_PARTIAL.
463         is an example of an interactive pcretest run.         (Note  that  this is the entire substring that was inspected during the
464           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 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
471    
472             re> /^abc(\d+)/             re> /^abc(\d+)/
473           data> abc123           data> abc123
# Line 308  OUTPUT FROM PCRETEST Line 476  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
480           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
482           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
484           second data line.
485    
486               re> /(a)|(b)/
487             data> a
488              0: a
489              1: a
490             data> b
491              0: b
492              1: <unset>
493              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. If the pattern has the /+ modifier, the  output  for  sub-         the pattern. See below for the definition of  non-printing  characters.
498         string  0 is followed by the the rest of the subject string, identified         If  the pattern has the /+ modifier, the output for substring 0 is fol-
499         by "0+" like this:         lowed by the the rest of the subject string, identified  by  "0+"  like
500           this:
501    
502             re> /cat/+             re> /cat/+
503           data> cataract           data> cataract
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 333  OUTPUT FROM PCRETEST Line 518  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 while 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.         lines  can  be included in data by means of the \n escape (or \r, \r\n,
531           etc., depending on the newline sequence setting).
532    
533    
534    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
535    
536           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
538           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:
540    
541               re> /(tang|tangerine|tan)/
542             data> yellow tangerine\D
543              0: tangerine
544              1: tang
545              2: tan
546    
547           (Using  the  normal  matching function on this data finds only "tang".)
548           The longest matching string is always given first (and numbered  zero).
549           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
550           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
556           at the end of the longest match. For example:
557    
558               re> /(tang|tangerine|tan)/g
559             data> yellow tangerine and tangy sultana\D
560              0: tangerine
561              1: tang
562              2: tan
563              0: tang
564              1: tan
565              0: tan
566    
567           Since the matching function does not  support  substring  capture,  the
568           escape  sequences  that  are concerned with captured substrings are not
569           relevant.
570    
571    
572    RESTARTING AFTER A PARTIAL MATCH
573    
574           When the alternative matching function has given the PCRE_ERROR_PARTIAL
575           return,  indicating that the subject partially matched the pattern, you
576           can restart the match with additional subject data by means of  the  \R
577           escape sequence. For example:
578    
579               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
580             data> 23ja\P\D
581             Partial match: 23ja
582             data> n05\R\D
583              0: n05
584    
585           For  further  information  about  partial matching, see the pcrepartial
586           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. By default, it displays the callout         tion  is  called  during  matching. This works with both matching func-
593         number, the start and current positions in  the  text  at  the  callout         tions. By default, the called function displays the callout number, the
594         time, and the next pattern item to be tested. For example, the output         start  and  current  positions in the text at the callout time, and the
595           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 375  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 an \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
630    
631           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
633           are are therefore shown as hex escapes.
634    
635           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
637           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
638           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
# Line 440  SAVING AND RELOADING COMPILED PATTERNS Line 694  SAVING AND RELOADING COMPILED PATTERNS
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
698    
699           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
700           pcrepattern(3), pcreprecompile(3).
701    
702    
703  AUTHOR  AUTHOR
704    
705         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
706         University Computing Service,         University Computing Service
707         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
708    
709    
710    REVISION
711    
712  Last updated: 10 September 2004         Last updated: 21 November 2010
713  Copyright (c) 1997-2004 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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