/[pcre]/code/trunk/doc/pcretest.txt
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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 392 by ph10, Tue Mar 17 21:30:30 2009 UTC
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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] [-dfa] [-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 has  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;         -dfa      Behave  as if each data line contains the \D escape sequence;
34                   this    causes    the    alternative    matching    function,                   this    causes    the    alternative    matching    function,
35                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                   pcre_exec() function (more detail is given below).                   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  has  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        Output  the  size  of each compiled pattern after it has been         -M        Behave  as if each data line contains the \M escape sequence;
44                   compiled. This is equivalent to adding  /M  to  each  regular                   this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                   expression.   For  compatibility  with  earlier  versions  of                   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
49                     compiled.  This  is  equivalent  to adding /M to each regular
50                     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                     below).
60    
61         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-         -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                   per API is used to call PCRE. None of the other  options  has
63                   any effect when -p is set.                   any effect when -p is set.
64    
65         -t        Run each compile, study, and match many times with  a  timer,         -q        Do  not output the version number of pcretest at the start of
66                   and  output resulting time per compile or match (in millisec-                   execution.
67                   onds). Do not set -m with -t, because you will then  get  the  
68                   size  output  a  zillion  times,  and the timing will be dis-         -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                   torted.                   size megabytes.
70    
71           -t        Run  each  compile, study, and match many times with a timer,
72                     and output resulting time per compile or match (in  millisec-
73                     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-
75                     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
85    
86         If pcretest is given two filename arguments, it reads  from  the  first         If  pcretest  is  given two filename arguments, it reads from the first
87         and writes to the second. If it is given only one filename argument, it         and writes to the second. If it is given only one filename argument, it
88         reads from that file and writes to stdout.  Otherwise,  it  reads  from         reads  from  that  file  and writes to stdout. Otherwise, it reads from
89         stdin  and  writes to stdout, and prompts for each line of input, using         stdin and writes to stdout, and prompts for each line of  input,  using
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         An empty line signals the end of the data lines, at which point  a  new         small.
109         regular  expression is read. The regular expressions are given enclosed  
110         in any non-alphanumeric delimiters other than backslash, for example         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
112           in any non-alphanumeric delimiters other than backslash, for example:
113    
114           /(a|bc)x+yz/           /(a|bc)x+yz/
115    
116         White space before the initial delimiter is ignored. A regular  expres-         White  space before the initial delimiter is ignored. A regular expres-
117         sion  may be continued over several input lines, in which case the new-         sion may be continued over several input lines, in which case the  new-
118         line characters are included within it. It is possible to  include  the         line  characters  are included within it. It is possible to include the
119         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
120    
121           /abc\/def/           /abc\/def/
122    
123         If  you  do  so, the escape and the delimiter form part of the pattern,         If you do so, the escape and the delimiter form part  of  the  pattern,
124         but since delimiters are always non-alphanumeric, this does not  affect         but  since delimiters are always non-alphanumeric, this does not affect
125         its  interpretation.   If the terminating delimiter is immediately fol-         its interpretation.  If the terminating delimiter is  immediately  fol-
126         lowed by a backslash, for example,         lowed by a backslash, for example,
127    
128           /abc/\           /abc/\
129    
130         then a backslash is added to the end of the pattern. This  is  done  to         then  a  backslash  is added to the end of the pattern. This is done to
131         provide  a  way of testing the error condition that arises if a pattern         provide a way of testing the error condition that arises if  a  pattern
132         finishes with a backslash, because         finishes with a backslash, because
133    
134           /abc\/           /abc\/
135    
136         is interpreted as the first line of a pattern that starts with  "abc/",         is  interpreted as the first line of a pattern that starts with "abc/",
137         causing pcretest to read the next line as a continuation of the regular         causing pcretest to read the next line as a continuation of the regular
138         expression.         expression.
139    
140    
141  PATTERN MODIFIERS  PATTERN MODIFIERS
142    
143         A pattern may be followed by any number of modifiers, which are  mostly         A  pattern may be followed by any number of modifiers, which are mostly
144         single  characters.  Following  Perl usage, these are referred to below         single characters. Following Perl usage, these are  referred  to  below
145         as, for example, "the /i modifier", even though the  delimiter  of  the         as,  for  example,  "the /i modifier", even though the delimiter of the
146         pattern  need  not always be a slash, and no slash is used when writing         pattern need not always be a slash, and no slash is used  when  writing
147         modifiers. Whitespace may appear between the  final  pattern  delimiter         modifiers.  Whitespace  may  appear between the final pattern delimiter
148         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
149    
150         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
151         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152         pile()  is  called. These four modifier letters have the same effect as         pile() is called. These four modifier letters have the same  effect  as
153         they do in Perl. For example:         they do in Perl. For example:
154    
155           /caseless/i           /caseless/i
# Line 125  PATTERN MODIFIERS Line 157  PATTERN MODIFIERS
157         The following table shows additional modifiers for setting PCRE options         The following table shows additional modifiers for setting PCRE options
158         that do not correspond to anything in Perl:         that do not correspond to anything in Perl:
159    
160           /A    PCRE_ANCHORED           /A              PCRE_ANCHORED
161           /C    PCRE_AUTO_CALLOUT           /C              PCRE_AUTO_CALLOUT
162           /E    PCRE_DOLLAR_ENDONLY           /E              PCRE_DOLLAR_ENDONLY
163           /f    PCRE_FIRSTLINE           /f              PCRE_FIRSTLINE
164           /N    PCRE_NO_AUTO_CAPTURE           /J              PCRE_DUPNAMES
165           /U    PCRE_UNGREEDY           /N              PCRE_NO_AUTO_CAPTURE
166           /X    PCRE_EXTRA           /U              PCRE_UNGREEDY
167             /X              PCRE_EXTRA
168             /<JS>           PCRE_JAVASCRIPT_COMPAT
169             /<cr>           PCRE_NEWLINE_CR
170             /<lf>           PCRE_NEWLINE_LF
171             /<crlf>         PCRE_NEWLINE_CRLF
172             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
173             /<any>          PCRE_NEWLINE_ANY
174             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
175             /<bsr_unicode>  PCRE_BSR_UNICODE
176    
177           Those specifying line ending sequences are literal  strings  as  shown,
178           but  the  letters  can  be  in either case. This example sets multiline
179           matching with CRLF as the line ending sequence:
180    
181             /^abc/m<crlf>
182    
183           Details of the meanings of these PCRE options are given in the  pcreapi
184           documentation.
185    
186       Finding all matches in a string
187    
188         Searching  for  all  possible matches within each subject string can be         Searching  for  all  possible matches within each subject string can be
189         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 150  PATTERN MODIFIERS Line 202  PATTERN MODIFIERS
202         one,  and  the normal match is retried. This imitates the way Perl han-         one,  and  the normal match is retried. This imitates the way Perl han-
203         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
204    
205       Other modifiers
206    
207         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
208    
209         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
210         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
211         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
212         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
213    
214           The  /B modifier is a debugging feature. It requests that pcretest out-
215           put a representation of the compiled byte code after compilation.  Nor-
216           mally  this  information contains length and offset values; however, if
217           /Z is also present, this data is replaced by spaces. This is a  special
218           feature for use in the automatic test scripts; it ensures that the same
219           output is generated for different internal link sizes.
220    
221         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
222         example,         example,
223    
# Line 175  PATTERN MODIFIERS Line 236  PATTERN MODIFIERS
236         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-
237         put.         put.
238    
239         The /D modifier is a PCRE debugging feature, which also assumes /I.  It         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
240         causes  the  internal form of compiled regular expressions to be output         that is, both the /B and the /I modifiers.
        after compilation. If the pattern was studied, the information returned  
        is also output.  
241    
242         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
243         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
# Line 191  PATTERN MODIFIERS Line 250  PATTERN MODIFIERS
250         The  /S  modifier causes pcre_study() to be called after the expression         The  /S  modifier causes pcre_study() to be called after the expression
251         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
252    
253         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-
254         piled pattern to be output.         piled pattern to be output.
255    
256         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
257         rather  than  its  native  API.  When this is done, all other modifiers         rather than its native API. When this  is  done,  all  other  modifiers
258         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,
259         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
260         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
261    
262         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
263         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-
# Line 220  DATA LINES Line 279  DATA LINES
279         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
280         following escapes are recognized:         following escapes are recognized:
281    
282           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
283           \b         backspace           \b         backspace (\x08)
284           \e         escape           \e         escape (\x27)
285           \f         formfeed           \f         formfeed (\x0c)
286           \n         newline           \n         newline (\x0a)
287           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
288           \t         tab                        (any number of digits)
289           \v         vertical tab           \r         carriage return (\x0d)
290             \t         tab (\x09)
291             \v         vertical tab (\x0b)
292           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
293           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
294           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
295                        in UTF-8 mode                        in UTF-8 mode
296           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
297                          or pcre_dfa_exec()
298           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
299                          or pcre_dfa_exec()
300           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
301                        after a successful match (number less than 32)                        after a successful match (number less than 32)
302           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 257  DATA LINES Line 320  DATA LINES
320                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
321           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
322                        successful match                        successful match
323           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
324                          MATCH_LIMIT_RECURSION settings
325           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
326                          or pcre_dfa_exec()
327           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
328                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
329           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
330                        or pcre_dfa_exec()                        or pcre_dfa_exec()
331             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
332                          (any number of digits)
333           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
334           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
335           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
336                          or pcre_dfa_exec()
337           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
338                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
339           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
340                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
341                          or pcre_dfa_exec()
342             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
343                          or pcre_dfa_exec()
344             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
345                          or pcre_dfa_exec()
346             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
347                          or pcre_dfa_exec()
348             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
349                          or pcre_dfa_exec()
350             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
351                          or pcre_dfa_exec()
352    
353           The escapes that specify line ending  sequences  are  literal  strings,
354           exactly as shown. No more than one newline setting should be present in
355           any data line.
356    
357         A backslash followed by anything else just escapes the  anything  else.         A backslash followed by anything else just escapes the  anything  else.
358         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
# Line 277  DATA LINES Line 360  DATA LINES
360         nates the data input.         nates the data input.
361    
362         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
363         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
364         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
365         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-
366         backtracking  that takes place, and checking it out can be instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
367         For most simple matches, the number is quite small,  but  for  patterns         checking it out can be instructive. For most simple matches, the number
368         with  very large numbers of matching possibilities, it can become large         is  quite  small,  but for patterns with very large numbers of matching
369         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
370           of subject string. The match_limit_recursion number is a measure of how
371           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
372           memory is needed to complete the match attempt.
373    
374         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
375         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
376         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.
377    
378         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-
379         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
380         and REG_NOTEOL to be passed to regexec() respectively.         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
381           to be passed to regexec().
382    
383         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
384         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.
385         There may be any number of hexadecimal digits inside  the  braces.  The         There may be any number of hexadecimal digits inside  the  braces.  The
386         result  is from one to six bytes, encoded according to the UTF-8 rules.         result  is  from  one  to  six bytes, encoded according to the original
387           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
388           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
389           or indeed valid UTF-8 characters according to the later  rules  in  RFC
390           3629.
391    
392    
393  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
394    
395         By  default,  pcretest  uses  the  standard  PCRE  matching   function,         By   default,  pcretest  uses  the  standard  PCRE  matching  function,
396         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
397         alternative matching function, pcre_dfa_test(),  which  operates  in  a         alternative  matching  function,  pcre_dfa_test(),  which operates in a
398         different  way,  and has some restrictions. The differences between the         different way, and has some restrictions. The differences  between  the
399         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
400    
401         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
402         contains  the -dfa option, the alternative matching function is called.         contains the -dfa option, the alternative matching function is  called.
403         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
404         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
405         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
406    
407    
408  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
409    
410         This section describes the output when the  normal  matching  function,         This  section  describes  the output when the normal matching function,
411         pcre_exec(), is being used.         pcre_exec(), is being used.
412    
413         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
414         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
415         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
416         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
417         TIAL,  respectively, and otherwise the PCRE negative error number. Here         TIAL, respectively, and otherwise the PCRE negative error number.  Here
418         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
419    
420           $ pcretest           $ pcretest
421           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
422    
423             re> /^abc(\d+)/             re> /^abc(\d+)/
424           data> abc123           data> abc123
# Line 336  DEFAULT OUTPUT FROM PCRETEST Line 427  DEFAULT OUTPUT FROM PCRETEST
427           data> xyz           data> xyz
428           No match           No match
429    
430           Note  that unset capturing substrings that are not followed by one that
431           is set are not returned by pcre_exec(), and are not shown by  pcretest.
432           In  the following example, there are two capturing substrings, but when
433           the first data line is matched, the  second,  unset  substring  is  not
434           shown.  An "internal" unset substring is shown as "<unset>", as for the
435           second data line.
436    
437               re> /(a)|(b)/
438             data> a
439              0: a
440              1: a
441             data> b
442              0: b
443              1: <unset>
444              2: b
445    
446         If the strings contain any non-printing characters, they are output  as         If the strings contain any non-printing characters, they are output  as
447         \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
448         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the pattern. See below for the definition of  non-printing  characters.
449         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-
450         by "0+" like this:         lowed by the the rest of the subject string, identified  by  "0+"  like
451           this:
452    
453             re> /cat/+             re> /cat/+
454           data> cataract           data> cataract
455            0: cat            0: cat
456            0+ aract            0+ aract
457    
458         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
459         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
460    
461             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 361  DEFAULT OUTPUT FROM PCRETEST Line 469  DEFAULT OUTPUT FROM PCRETEST
469    
470         "No match" is output only if the first match attempt fails.         "No match" is output only if the first match attempt fails.
471    
472         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
473         is successfully matched, the substrings extracted  by  the  convenience         is  successfully  matched,  the substrings extracted by the convenience
474         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
475         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
476         (that  is,  the return from the extraction function) is given in paren-         (that is, the return from the extraction function) is given  in  paren-
477         theses after each string for \C and \G.         theses after each string for \C and \G.
478    
479         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
480         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
481         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,
482           etc., depending on the newline sequence setting).
483    
484    
485  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
# Line 387  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 496  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
496            2: tan            2: tan
497    
498         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
499         The longest matching string is always given first (and numbered  zero).         The longest matching string is always given first (and numbered zero).
500    
501         If  /gP  is  present  on  the  pattern,  the search for further matches         If /g is present on the pattern, the search for further matches resumes
502         resumes at the end of the longest match. For example:         at the end of the longest match. For example:
503    
504             re> /(tang|tangerine|tan)/g             re> /(tang|tangerine|tan)/g
505           data> yellow tangerine and tangy sultana\D           data> yellow tangerine and tangy sultana\D
# Line 401  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 510  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
510            1: tan            1: tan
511            0: tan            0: tan
512    
513         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
514         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
515         relevant.         relevant.
516    
517    
518  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
519    
520         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
521         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
522         can restart the match with additional subject data by means of  the  \R         can  restart  the match with additional subject data by means of the \R
523         escape sequence. For example:         escape sequence. For example:
524    
525             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
526           data> 23ja\P\D           data> 23ja\P\D
527           Partial match: 23ja           Partial match: 23ja
528           data> n05\R\D           data> n05\R\D
529            0: n05            0: n05
530    
531         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
532         documentation.         documentation.
533    
534    
535  CALLOUTS  CALLOUTS
536    
537         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
538         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
539         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
540         start  and  current  positions in the text at the callout time, and the         start and current positions in the text at the callout  time,  and  the
541         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
542    
543           --->pqrabcdef           --->pqrabcdef
544             0    ^  ^     \d             0    ^  ^     \d
545    
546         indicates that callout number 0 occurred for a match  attempt  starting         indicates  that  callout number 0 occurred for a match attempt starting
547         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
548         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
549         \d.  Just  one  circumflex is output if the start and current positions         \d. Just one circumflex is output if the start  and  current  positions
550         are the same.         are the same.
551    
552         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
553         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
554         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
555         output. For example:         output. For example:
556    
557             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 454  CALLOUTS Line 563  CALLOUTS
563           +10 ^ ^           +10 ^ ^
564            0: E*            0: E*
565    
566         The  callout  function  in pcretest returns zero (carry on matching) by         The callout function in pcretest returns zero (carry  on  matching)  by
567         default, but you can use a \C item in a data line (as described  above)         default,  but you can use a \C item in a data line (as described above)
568         to change this.         to change this.
569    
570         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting callouts can be helpful when using pcretest to check  compli-
571         cated regular expressions. For further information about callouts,  see         cated  regular expressions. For further information about callouts, see
572         the pcrecallout documentation.         the pcrecallout documentation.
573    
574    
575    NON-PRINTING CHARACTERS
576    
577           When pcretest is outputting text in the compiled version of a  pattern,
578           bytes  other  than 32-126 are always treated as non-printing characters
579           are are therefore shown as hex escapes.
580    
581           When pcretest is outputting text that is a matched part  of  a  subject
582           string,  it behaves in the same way, unless a different locale has been
583           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
584           isprint() function to distinguish printing and non-printing characters.
585    
586    
587  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
588    
589         The  facilities  described  in  this section are not available when the         The  facilities  described  in  this section are not available when the
# Line 519  SAVING AND RELOADING COMPILED PATTERNS Line 640  SAVING AND RELOADING COMPILED PATTERNS
640         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.
641    
642    
643    SEE ALSO
644    
645           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
646           pcrepattern(3), pcreprecompile(3).
647    
648    
649  AUTHOR  AUTHOR
650    
651         Philip Hazel         Philip Hazel
652         University Computing Service,         University Computing Service
653         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
654    
655    
656    REVISION
657    
658  Last updated: 28 February 2005         Last updated: 10 March 2009
659  Copyright (c) 1997-2005 University of Cambridge.         Copyright (c) 1997-2009 University of Cambridge.

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