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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 96 by nigel, Fri Mar 2 13:10:43 2007 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         pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]  
10           pcretest [options] [source] [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
14         expressions.  This document describes the features of the test program;         expressions.  This document describes the features of the test program;
15         for details of the regular expressions themselves, see the  pcrepattern         for details of the regular expressions themselves, see the  pcrepattern
16         documentation.  For  details  of  PCRE and its options, see the pcreapi         documentation. For details of the PCRE library function calls and their
17         documentation.         options, see the pcreapi documentation.
18    
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 modifier (see below);  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         -i        Behave  as  if  each  regex  had the /I modifier; information         -help     Output a brief summary these options and then exit.
39    
40           -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        Output  the  size  of each compiled pattern after it has been
44                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled. This is equivalent to adding  /M  to  each  regular
45                   expression.  For  compatibility  with  earlier  versions   of                   expression.   For  compatibility  with  earlier  versions  of
46                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
47    
48         -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
49                   when calling PCRE to be osize. The default value is 45, which                   when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
50                   is  enough  for  14 capturing subexpressions. The vector size                   default value is 45, which is enough for 14 capturing  subex-
51                   can be changed for individual matching calls by including  \O                   pressions   for  pcre_exec()  or  22  different  matches  for
52                   in the data line (see below).                   pcre_dfa_exec(). The vector size can be changed for  individ-
53                     ual  matching  calls  by  including  \O in the data line (see
54         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper                   below).
55                   API is used to call PCRE. None of the other options  has  any  
56                   effect when -p is set.         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
57                     per  API  is used to call PCRE. None of the other options has
58         -t        Run  each  compile, study, and match many times with a timer,                   any effect when -p is set.
59                   and output resulting time per compile or match (in  millisec-  
60                   onds).  Do  not set -t with -m, because you will then get the         -q        Do not output the version number of pcretest at the start  of
61                   size output 20000 times and the timing will be distorted.                   execution.
62    
63           -S size   On  Unix-like  systems,  set the size of the runtime stack to
64                     size megabytes.
65    
66           -t        Run each compile, study, and match many times with  a  timer,
67                     and  output resulting time per compile or match (in millisec-
68                     onds). Do not set -m with -t, because you will then  get  the
69                     size  output  a  zillion  times,  and the timing will be dis-
70                     torted. You can control the number  of  iterations  that  are
71                     used  for timing by following -t with a number (as a separate
72                     item on the command line). For example, "-t 1000" would iter-
73                     ate 1000 times. The default is to iterate 500000 times.
74    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
# Line 63  DESCRIPTION Line 89  DESCRIPTION
89         Each set starts with a regular expression, and continues with any  num-         Each set starts with a regular expression, and continues with any  num-
90         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
91    
92         Each  line  is  matched separately and independently. If you want to do         Each  data line is matched separately and independently. If you want to
93         multiple-line matches, you have to use the \n escape sequence in a sin-         do multi-line matches, you have to use the \n escape sequence (or \r or
94         gle  line of input to encode the newline characters. The maximum length         \r\n, etc., depending on the newline setting) in a single line of input
95         of data line is 30,000 characters.         to encode the newline sequences. There is no limit  on  the  length  of
96           data  lines;  the  input  buffer is automatically extended if it is too
97           small.
98    
99         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
100         regular  expression is read. The regular expressions are given enclosed         regular  expression is read. The regular expressions are given enclosed
101         in any non-alphameric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example:
102    
103           /(a|bc)x+yz/           /(a|bc)x+yz/
104    
# Line 82  DESCRIPTION Line 110  DESCRIPTION
110           /abc\/def/           /abc\/def/
111    
112         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,
113         but since delimiters are always non-alphameric, this  does  not  affect         but since delimiters are always non-alphanumeric, this does not  affect
114         its  interpretation.   If the terminating delimiter is immediately fol-         its  interpretation.   If the terminating delimiter is immediately fol-
115         lowed by a backslash, for example,         lowed by a backslash, for example,
116    
# Line 101  DESCRIPTION Line 129  DESCRIPTION
129    
130  PATTERN MODIFIERS  PATTERN MODIFIERS
131    
132         The pattern may be followed by i, m, s, or x to set the  PCRE_CASELESS,         A pattern may be followed by any number of modifiers, which are  mostly
133         PCRE_MULTILINE,  PCRE_DOTALL,  or  PCRE_EXTENDED options, respectively.         single  characters.  Following  Perl usage, these are referred to below
134         For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
135           pattern  need  not always be a slash, and no slash is used when writing
136           modifiers. Whitespace may appear between the  final  pattern  delimiter
137           and the first modifier, and between the modifiers themselves.
138    
139           The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
140           PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
141           pile()  is  called. These four modifier letters have the same effect as
142           they do in Perl. For example:
143    
144           /caseless/i           /caseless/i
145    
146         These modifier letters have the same effect as they do in  Perl.  There         The following table shows additional modifiers for setting PCRE options
147         are  others that set PCRE options that do not correspond to anything in         that do not correspond to anything in Perl:
148         Perl: /A, /E, /N, /U, and /X  set  PCRE_ANCHORED,  PCRE_DOLLAR_ENDONLY,  
149         PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA respectively.           /A       PCRE_ANCHORED
150             /C       PCRE_AUTO_CALLOUT
151             /E       PCRE_DOLLAR_ENDONLY
152             /f       PCRE_FIRSTLINE
153             /J       PCRE_DUPNAMES
154             /N       PCRE_NO_AUTO_CAPTURE
155             /U       PCRE_UNGREEDY
156             /X       PCRE_EXTRA
157             /<cr>    PCRE_NEWLINE_CR
158             /<lf>    PCRE_NEWLINE_LF
159             /<crlf>  PCRE_NEWLINE_CRLF
160             /<any>   PCRE_NEWLINE_ANY
161    
162           Those  specifying  line ending sequencess are literal strings as shown.
163           This example sets multiline matching  with  CRLF  as  the  line  ending
164           sequence:
165    
166             /^abc/m<crlf>
167    
168         Searching  for  all  possible matches within each subject string can be         Details  of the meanings of these PCRE options are given in the pcreapi
169         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is         documentation.
170    
171       Finding all matches in a string
172    
173           Searching for all possible matches within each subject  string  can  be
174           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
175         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
176         ence between /g and /G is that the former uses the startoffset argument         ence between /g and /G is that the former uses the startoffset argument
177         to  pcre_exec()  to  start  searching  at a new point within the entire         to pcre_exec() to start searching at a  new  point  within  the  entire
178         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
179         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
180         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
181         or \B).         or \B).
182    
183         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
184         string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED         string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
185         flags  set in order to search for another, non-empty, match at the same         flags set in order to search for another, non-empty, match at the  same
186         point.  If this second match fails, the start  offset  is  advanced  by         point.   If  this  second  match fails, the start offset is advanced by
187         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-
188         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
189    
190         There are a number of other modifiers for controlling the way  pcretest     Other modifiers
191         operates.  
192           There are yet more modifiers for controlling the way pcretest operates.
193    
194         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
195         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
196         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
197         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
198    
199           The  /B modifier is a debugging feature. It requests that pcretest out-
200           put a representation of the compiled byte code after compilation.
201    
202         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
203         example,         example,
204    
205           /pattern/Lfr           /pattern/Lfr_FR
206    
207         For  this reason, it must be the last modifier letter. The given locale         For this reason, it must be the last modifier. The given locale is set,
208         is set, pcre_maketables() is called to build a set of character  tables         pcre_maketables() is called to build a set of character tables for  the
209         for  the locale, and this is then passed to pcre_compile() when compil-         locale,  and  this  is then passed to pcre_compile() when compiling the
210         ing the regular expression. Without an /L modifier, NULL is  passed  as         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
211         the tables pointer; that is, /L applies only to the expression on which         tables  pointer; that is, /L applies only to the expression on which it
212         it appears.         appears.
213    
214         The /I modifier requests that pcretest  output  information  about  the         The /I modifier requests that pcretest  output  information  about  the
215         compiled  expression (whether it is anchored, has a fixed first charac-         compiled  pattern (whether it is anchored, has a fixed first character,
216         ter, and so on). It does this by calling pcre_fullinfo() after  compil-         and so on). It does this by calling pcre_fullinfo() after  compiling  a
217         ing  an expression, and outputting the information it gets back. If the         pattern.  If  the pattern is studied, the results of that are also out-
218         pattern is studied, the results of that are also output.         put.
219    
220         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,
221         causes  the  internal form of compiled regular expressions to be output         that is, both the /B and the /I modifiers.
222         after compilation. If the pattern was studied, the information returned  
223         is also output.         The /F modifier causes pcretest to flip the byte order of the fields in
224           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
225           facility  is  for testing the feature in PCRE that allows it to execute
226           patterns that were compiled on a host with a different endianness. This
227           feature  is  not  available  when  the POSIX interface to PCRE is being
228           used, that is, when the /P pattern modifier is specified. See also  the
229           section about saving and reloading compiled patterns below.
230    
231         The  /S  modifier causes pcre_study() to be called after the expression         The  /S  modifier causes pcre_study() to be called after the expression
232         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
# Line 183  PATTERN MODIFIERS Line 251  PATTERN MODIFIERS
251         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
252    
253    
 CALLOUTS  
   
        If  the pattern contains any callout requests, pcretest's callout func-  
        tion will be called. By default, it displays the  callout  number,  and  
        the  start  and  current positions in the text at the callout time. For  
        example, the output  
   
          --->pqrabcdef  
            0    ^  ^  
   
        indicates that callout number 0 occurred for a match  attempt  starting  
        at  the fourth character of the subject string, when the pointer was at  
        the seventh character. The callout  function  returns  zero  (carry  on  
        matching) by default.  
   
        Inserting  callouts may be helpful when using pcretest to check compli-  
        cated regular expressions. For further information about callouts,  see  
        the pcrecallout documentation.  
   
        For  testing  the PCRE library, additional control of callout behaviour  
        is available via escape sequences in the data, as described in the fol-  
        lowing  section.  In  particular, it is possible to pass in a number as  
        callout data (the default is zero). If the callout function receives  a  
        non-zero number, it returns that value instead of zero.  
   
   
254  DATA LINES  DATA LINES
255    
256         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before  each  data  line is passed to pcre_exec(), leading and trailing
# Line 218  DATA LINES Line 260  DATA LINES
260         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
261         following escapes are recognized:         following escapes are recognized:
262    
263           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
264           \b         backspace           \b         backspace (\x08)
265           \e         escape           \e         escape (\x27)
266           \f         formfeed           \f         formfeed (\x0c)
267           \n         newline           \n         newline (\x0a)
268           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
269           \t         tab                        (any number of digits)
270           \v         vertical tab           \r         carriage return (\x0d)
271             \t         tab (\x09)
272             \v         vertical tab (\x0b)
273           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
274           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
275           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
276                        in UTF-8 mode                        in UTF-8 mode
277           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
278                          or pcre_dfa_exec()
279           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
280                          or pcre_dfa_exec()
281           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
282                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
283           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
284                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
285                        ated by next non alphanumeric character)                        ated by next non alphanumeric character)
# Line 246  DATA LINES Line 291  DATA LINES
291           \C!n!m     return 1 instead of 0 when callout number n is           \C!n!m     return 1 instead of 0 when callout number n is
292                        reached for the nth time                        reached for the nth time
293           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
294                        data                        data; this is used as the callout return value
295             \D         use the pcre_dfa_exec() match function
296             \F         only shortest match for pcre_dfa_exec()
297           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
298                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
299           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
300                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
301                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
302           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
303                        successful match                        successful match
304           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
305                          MATCH_LIMIT_RECURSION settings
306           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
307                          or pcre_dfa_exec()
308           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
309                        pcre_exec() to dd (any number of decimal                        pcre_exec() to dd (any number of digits)
310                        digits)           \P         pass the PCRE_PARTIAL option to pcre_exec()
311                          or pcre_dfa_exec()
312             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
313                          (any number of digits)
314             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
315           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
316           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
317                          or pcre_dfa_exec()
318           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
319                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
320             \>dd       start the match at offset dd (any number of digits);
321         If \M is present, pcretest calls pcre_exec() several times,  with  dif-                        this sets the startoffset argument for pcre_exec()
322         ferent  values  in  the match_limit field of the pcre_extra data struc-                        or pcre_dfa_exec()
323         ture, until it finds the minimum number that is needed for  pcre_exec()           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
324         to  complete.  This  number is a measure of the amount of recursion and                        or pcre_dfa_exec()
325         backtracking that takes place, and checking it out can be  instructive.           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
326         For  most  simple  matches, the number is quite small, but for patterns                        or pcre_dfa_exec()
327         with very large numbers of matching possibilities, it can become  large           \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
328         very quickly with increasing length of subject string.                        or pcre_dfa_exec()
329             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
330         When  \O is used, it may be higher or lower than the size set by the -O                        or pcre_dfa_exec()
331         option (or defaulted to 45); \O applies only to the call of pcre_exec()  
332         for the line in which it appears.         The escapes that specify line ending  sequences  are  literal  strings,
333           exactly as shown. No more than one newline setting should be present in
334         A  backslash  followed by anything else just escapes the anything else.         any data line.
335         If the very last character is a backslash, it is ignored. This gives  a  
336         way  of  passing  an empty line as data, since a real empty line termi-         A backslash followed by anything else just escapes the  anything  else.
337           If  the very last character is a backslash, it is ignored. This gives a
338           way of passing an empty line as data, since a real  empty  line  termi-
339         nates the data input.         nates the data input.
340    
341         If /P was present on the regex, causing the POSIX  wrapper  API  to  be         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
342         used,  only  0  causing  REG_NOTBOL  and  REG_NOTEOL  to  be  passed to         ferent values in the match_limit and  match_limit_recursion  fields  of
343         regexec() respectively.         the  pcre_extra  data structure, until it finds the minimum numbers for
344           each parameter that allow pcre_exec() to complete. The match_limit num-
345           ber  is  a  measure of the amount of backtracking that takes place, and
346           checking it out can be instructive. For most simple matches, the number
347           is  quite  small,  but for patterns with very large numbers of matching
348           possibilities, it can become large very quickly with increasing  length
349           of subject string. The match_limit_recursion number is a measure of how
350           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
351           memory is needed to complete the match attempt.
352    
353           When  \O  is  used, the value specified may be higher or lower than the
354           size set by the -O command line option (or defaulted to 45); \O applies
355           only to the call of pcre_exec() for the line in which it appears.
356    
357           If  the /P modifier was present on the pattern, causing the POSIX wrap-
358           per API to be used, the only option-setting  sequences  that  have  any
359           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
360           to be passed to regexec().
361    
362         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
363         the  use  of  the  /8 modifier on the pattern. It is recognized always.         the  use  of  the  /8 modifier on the pattern. It is recognized always.
# Line 293  DATA LINES Line 365  DATA LINES
365         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 UTF-8 rules.
366    
367    
368  OUTPUT FROM PCRETEST  THE ALTERNATIVE MATCHING FUNCTION
369    
370           By  default,  pcretest  uses  the  standard  PCRE  matching   function,
371           pcre_exec() to match each data line. From release 6.0, PCRE supports an
372           alternative matching function, pcre_dfa_test(),  which  operates  in  a
373           different  way,  and has some restrictions. The differences between the
374           two functions are described in the pcrematching documentation.
375    
376           If a data line contains the \D escape sequence, or if the command  line
377           contains  the -dfa option, the alternative matching function is called.
378           This function finds all possible matches at a given point. If, however,
379           the  \F escape sequence is present in the data line, it stops after the
380           first match is found. This is always the shortest possible match.
381    
382    
383    DEFAULT OUTPUT FROM PCRETEST
384    
385           This section describes the output when the  normal  matching  function,
386           pcre_exec(), is being used.
387    
388         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
389         that  pcre_exec()  returns,  starting with number 0 for the string that         that pcre_exec() returns, starting with number 0 for  the  string  that
390         matched the whole  pattern.  Here  is  an  example  of  an  interactive         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
391         pcretest run.         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-
392           TIAL,  respectively, and otherwise the PCRE negative error number. Here
393           is an example of an interactive pcretest run.
394    
395           $ pcretest           $ pcretest
396           PCRE version 4.00 08-Jan-2003           PCRE version 7.0 30-Nov-2006
397    
398             re> /^abc(\d+)/             re> /^abc(\d+)/
399           data> abc123           data> abc123
# Line 310  OUTPUT FROM PCRETEST Line 402  OUTPUT FROM PCRETEST
402           data> xyz           data> xyz
403           No match           No match
404    
405         If  the strings contain any non-printing characters, they are output as         If the strings contain any non-printing characters, they are output  as
406         \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
407         the  pattern.  If  the pattern has the /+ modifier, then the output for         the pattern. See below for the definition of  non-printing  characters.
408         substring 0 is followed by the the rest of the subject string,  identi-         If  the pattern has the /+ modifier, the output for substring 0 is fol-
409         fied by "0+" like this:         lowed by the the rest of the subject string, identified  by  "0+"  like
410           this:
411    
412             re> /cat/+             re> /cat/+
413           data> cataract           data> cataract
# Line 342  OUTPUT FROM PCRETEST Line 435  OUTPUT FROM PCRETEST
435         (that is, the return from the extraction function) is given  in  paren-         (that is, the return from the extraction function) is given  in  paren-
436         theses after each string for \C and \G.         theses after each string for \C and \G.
437    
438         Note  that  while patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
439         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
440         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,
441           etc., depending on the newline sequence setting).
442    
443    
444    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
445    
446           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
447           means  of  the \D escape sequence or the -dfa command line option), the
448           output consists of a list of all the matches that start  at  the  first
449           point in the subject where there is at least one match. For example:
450    
451               re> /(tang|tangerine|tan)/
452             data> yellow tangerine\D
453              0: tangerine
454              1: tang
455              2: tan
456    
457           (Using  the  normal  matching function on this data finds only "tang".)
458           The longest matching string is always given first (and numbered  zero).
459    
460           If /g is present on the pattern, the search for further matches resumes
461           at the end of the longest match. For example:
462    
463               re> /(tang|tangerine|tan)/g
464             data> yellow tangerine and tangy sultana\D
465              0: tangerine
466              1: tang
467              2: tan
468              0: tang
469              1: tan
470              0: tan
471    
472           Since the matching function does not  support  substring  capture,  the
473           escape  sequences  that  are concerned with captured substrings are not
474           relevant.
475    
476    
477    RESTARTING AFTER A PARTIAL MATCH
478    
479           When the alternative matching function has given the PCRE_ERROR_PARTIAL
480           return,  indicating that the subject partially matched the pattern, you
481           can restart the match with additional subject data by means of  the  \R
482           escape sequence. For example:
483    
484               re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
485             data> 23ja\P\D
486             Partial match: 23ja
487             data> n05\R\D
488              0: n05
489    
490           For  further  information  about  partial matching, see the pcrepartial
491           documentation.
492    
493    
494    CALLOUTS
495    
496           If the pattern contains any callout requests, pcretest's callout  func-
497           tion  is  called  during  matching. This works with both matching func-
498           tions. By default, the called function displays the callout number, the
499           start  and  current  positions in the text at the callout time, and the
500           next pattern item to be tested. For example, the output
501    
502             --->pqrabcdef
503               0    ^  ^     \d
504    
505           indicates that callout number 0 occurred for a match  attempt  starting
506           at  the fourth character of the subject string, when the pointer was at
507           the seventh character of the data, and when the next pattern  item  was
508           \d.  Just  one  circumflex is output if the start and current positions
509           are the same.
510    
511           Callouts numbered 255 are assumed to be automatic callouts, inserted as
512           a  result  of the /C pattern modifier. In this case, instead of showing
513           the callout number, the offset in the pattern, preceded by a  plus,  is
514           output. For example:
515    
516               re> /\d?[A-E]\*/C
517             data> E*
518             --->E*
519              +0 ^      \d?
520              +3 ^      [A-E]
521              +8 ^^     \*
522             +10 ^ ^
523              0: E*
524    
525           The  callout  function  in pcretest returns zero (carry on matching) by
526           default, but you can use a \C item in a data line (as described  above)
527           to change this.
528    
529           Inserting  callouts can be helpful when using pcretest to check compli-
530           cated regular expressions. For further information about callouts,  see
531           the pcrecallout documentation.
532    
533    
534    NON-PRINTING CHARACTERS
535    
536           When  pcretest is outputting text in the compiled version of a pattern,
537           bytes other than 32-126 are always treated as  non-printing  characters
538           are are therefore shown as hex escapes.
539    
540           When  pcretest  is  outputting text that is a matched part of a subject
541           string, it behaves in the same way, unless a different locale has  been
542           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
543           isprint() function to distinguish printing and non-printing characters.
544    
545    
546    SAVING AND RELOADING COMPILED PATTERNS
547    
548           The  facilities  described  in  this section are not available when the
549           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
550           ifier is specified.
551    
552           When the POSIX interface is not in use, you can cause pcretest to write
553           a compiled pattern to a file, by following the modifiers with >  and  a
554           file name.  For example:
555    
556             /pattern/im >/some/file
557    
558           See  the pcreprecompile documentation for a discussion about saving and
559           re-using compiled patterns.
560    
561           The data that is written is binary.  The  first  eight  bytes  are  the
562           length  of  the  compiled  pattern  data  followed by the length of the
563           optional study data, each written as four  bytes  in  big-endian  order
564           (most  significant  byte  first). If there is no study data (either the
565           pattern was not studied, or studying did not return any data), the sec-
566           ond  length  is  zero. The lengths are followed by an exact copy of the
567           compiled pattern. If there is additional study data, this follows imme-
568           diately  after  the  compiled pattern. After writing the file, pcretest
569           expects to read a new pattern.
570    
571           A saved pattern can be reloaded into pcretest by specifing < and a file
572           name  instead  of  a pattern. The name of the file must not contain a <
573           character, as otherwise pcretest will interpret the line as  a  pattern
574           delimited by < characters.  For example:
575    
576              re> </some/file
577             Compiled regex loaded from /some/file
578             No study data
579    
580           When  the pattern has been loaded, pcretest proceeds to read data lines
581           in the usual way.
582    
583           You can copy a file written by pcretest to a different host and  reload
584           it  there,  even  if the new host has opposite endianness to the one on
585           which the pattern was compiled. For example, you can compile on an  i86
586           machine and run on a SPARC machine.
587    
588           File  names  for  saving and reloading can be absolute or relative, but
589           note that the shell facility of expanding a file name that starts  with
590           a tilde (~) is not available.
591    
592           The  ability to save and reload files in pcretest is intended for test-
593           ing and experimentation. It is not intended for production use  because
594           only  a  single pattern can be written to a file. Furthermore, there is
595           no facility for supplying  custom  character  tables  for  use  with  a
596           reloaded  pattern.  If  the  original  pattern was compiled with custom
597           tables, an attempt to match a subject string using a  reloaded  pattern
598           is  likely to cause pcretest to crash.  Finally, if you attempt to load
599           a file that is not in the correct format, the result is undefined.
600    
601    
602    SEE ALSO
603    
604           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
605           pcrepattern(3), pcreprecompile(3).
606    
607    
608  AUTHOR  AUTHOR
609    
610         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
611         University Computing Service,         University Computing Service,
612         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
613    
614  Last updated: 09 December 2003  Last updated: 30 November 2006
615  Copyright (c) 1997-2003 University of Cambridge.  Copyright (c) 1997-2006 University of Cambridge.

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