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1    PCRETEST(1)                                                        PCRETEST(1)
2    
3    
4  NAME  NAME
5       pcretest - a program  for  testing  Perl-compatible  regular         pcretest - a program for testing Perl-compatible regular expressions.
      expressions.  
6    
7    
8  SYNOPSIS  SYNOPSIS
      pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source]  [des-  
      tination]  
9    
10       pcretest was written as a test program for the PCRE  regular         pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]
11       expression  library  itself,  but  it  can  also be used for              [destination]
      experimenting  with  regular  expressions.   This   document  
      describes  the  features of the test program; for details of  
      the regular  expressions  themselves,  see  the  pcrepattern  
      documentation.  For details of PCRE and its options, see the  
      pcreapi documentation.  
12    
13           pcretest  was written as a test program for the PCRE regular expression
14           library itself, but it can also be used for experimenting with  regular
15           expressions.  This document describes the features of the test program;
16           for details of the regular expressions themselves, see the  pcrepattern
17           documentation. For details of the PCRE library function calls and their
18           options, see the pcreapi documentation.
19    
 OPTIONS  
20    
21    OPTIONS
22    
23       -C        Output the version number of the PCRE library, and         -C        Output the version number of the PCRE library, and all avail-
24                 all   available  information  about  the  optional                   able   information  about  the  optional  features  that  are
25                 features that are included, and then exit.                   included, and then exit.
26    
27       -d        Behave as if each regex had the /D  modifier  (see         -d        Behave as if each regex has  the  /D  (debug)  modifier;  the
28                 below); the internal form is output after compila-                   internal form is output after compilation.
29                 tion.  
30           -dfa      Behave  as if each data line contains the \D escape sequence;
31       -i        Behave as if  each  regex  had  the  /I  modifier;                   this    causes    the    alternative    matching    function,
32                 information  about  the  compiled pattern is given                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
33                 after compilation.                   pcre_exec() function (more detail is given below).
34    
35       -m        Output the size of each compiled pattern after  it         -i        Behave as if each regex  has  the  /I  modifier;  information
36                 has been compiled. This is equivalent to adding /M                   about the compiled pattern is given after compilation.
37                 to each regular expression. For compatibility with  
38                 earlier  versions of pcretest, -s is a synonym for         -m        Output  the  size  of each compiled pattern after it has been
39                 -m.                   compiled. This is equivalent to adding  /M  to  each  regular
40                     expression.   For  compatibility  with  earlier  versions  of
41       -o osize  Set the number of elements in  the  output  vector                   pcretest, -s is a synonym for -m.
42                 that  is  used  when calling PCRE to be osize. The  
43                 default value is 45, which is enough for  14  cap-         -o osize  Set the number of elements in the output vector that is  used
44                 turing  subexpressions.  The  vector  size  can be                   when  calling  pcre_exec()  to be osize. The default value is
45                 changed for individual matching calls by including                   45, which is enough for 14 capturing subexpressions. The vec-
46                 \O in the data line (see below).                   tor  size  can  be  changed  for individual matching calls by
47                     including \O in the data line (see below).
48       -p        Behave as if each regex has /P modifier; the POSIX  
49                 wrapper  API  is  used  to  call PCRE. None of the         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
50                 other options has any effect when -p is set.                   per  API  is used to call PCRE. None of the other options has
51                     any effect when -p is set.
52       -t        Run each compile, study, and match many times with  
53                 a  timer, and output resulting time per compile or         -q        Do not output the version number of pcretest at the start  of
54                 match (in milliseconds). Do not set  -t  with  -m,                   execution.
55                 because  you  will  then get the size output 20000  
56                 times and the timing will be distorted.         -t        Run  each  compile, study, and match many times with a timer,
57                     and output resulting time per compile or match (in  millisec-
58                     onds).  Do  not set -m with -t, because you will then get the
59                     size output a zillion times, and  the  timing  will  be  dis-
60                     torted.
61    
62    
63  DESCRIPTION  DESCRIPTION
64    
65       If pcretest is given two filename arguments, it  reads  from         If  pcretest  is  given two filename arguments, it reads from the first
66       the  first and writes to the second. If it is given only one         and writes to the second. If it is given only one filename argument, it
67       filename argument, it reads from that  file  and  writes  to         reads  from  that  file  and writes to stdout. Otherwise, it reads from
68       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin and writes to stdout, and prompts for each line of  input,  using
69       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
70       for  regular  expressions,  and  "data>"  to prompt for data         lines.
71       lines.  
72           The program handles any number of sets of input on a single input file.
73       The program handles any number of sets of input on a  single         Each  set starts with a regular expression, and continues with any num-
74       input  file.  Each set starts with a regular expression, and         ber of data lines to be matched against the pattern.
75       continues with any  number  of  data  lines  to  be  matched  
76       against the pattern.         Each data line is matched separately and independently. If you want  to
77           do  multiple-line  matches, you have to use the \n escape sequence in a
78       Each line is matched separately and  independently.  If  you         single line of input to encode  the  newline  characters.  The  maximum
79       want  to  do  multiple-line  matches, you have to use the \n         length of data line is 30,000 characters.
80       escape sequence in a single line of input to encode the new-  
81       line  characters.  The maximum length of data line is 30,000         An  empty  line signals the end of the data lines, at which point a new
82       characters.         regular expression is read. The regular expressions are given  enclosed
83           in any non-alphanumeric delimiters other than backslash, for example
84       An empty line signals the end of the data  lines,  at  which  
85       point  a new regular expression is read. The regular expres-           /(a|bc)x+yz/
86       sions are given enclosed in  any  non-alphameric  delimiters  
87       other than backslash, for example         White  space before the initial delimiter is ignored. A regular expres-
88           sion may be continued over several input lines, in which case the  new-
89         /(a|bc)x+yz/         line  characters  are included within it. It is possible to include the
90           delimiter within the pattern by escaping it, for example
91       White space before the initial delimiter is ignored. A regu-  
92       lar expression may be continued over several input lines, in           /abc\/def/
93       which case the newline characters are included within it. It  
94       is  possible  to include the delimiter within the pattern by         If you do so, the escape and the delimiter form part  of  the  pattern,
95       escaping it, for example         but  since delimiters are always non-alphanumeric, this does not affect
96           its interpretation.  If the terminating delimiter is  immediately  fol-
97         /abc\/def/         lowed by a backslash, for example,
98    
99       If you do so, the escape and the delimiter form part of  the           /abc/\
100       pattern,  but  since  delimiters  are always non-alphameric,  
101       this does not affect its interpretation.  If the terminating         then  a  backslash  is added to the end of the pattern. This is done to
102       delimiter  is immediately followed by a backslash, for exam-         provide a way of testing the error condition that arises if  a  pattern
103       ple,         finishes with a backslash, because
104    
105         /abc/\           /abc\/
106    
107       then a backslash is added to the end of the pattern. This is         is  interpreted as the first line of a pattern that starts with "abc/",
108       done  to  provide  a way of testing the error condition that         causing pcretest to read the next line as a continuation of the regular
109       arises if a pattern finishes with a backslash, because         expression.
   
        /abc\/  
   
      is interpreted as the first line of a  pattern  that  starts  
      with  "abc/",  causing  pcretest  to read the next line as a  
      continuation of the regular expression.  
110    
111    
112  PATTERN MODIFIERS  PATTERN MODIFIERS
113    
114       The pattern may be followed by i, m, s,  or  x  to  set  the         A  pattern may be followed by any number of modifiers, which are mostly
115       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single characters. Following Perl usage, these are  referred  to  below
116       options, respectively. For example:         as,  for  example,  "the /i modifier", even though the delimiter of the
117           pattern need not always be a slash, and no slash is used  when  writing
118         /caseless/i         modifiers.  Whitespace  may  appear between the final pattern delimiter
119           and the first modifier, and between the modifiers themselves.
120       These modifier letters have the same effect as  they  do  in  
121       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
122       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
123       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile() is called. These four modifier letters have the same  effect  as
124       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
125    
126       Searching for  all  possible  matches  within  each  subject           /caseless/i
127       string  can  be  requested  by  the /g or /G modifier. After  
128       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for setting PCRE options
129       remainder  of  the subject string. The difference between /g         that do not correspond to anything in Perl:
130       and /G is that the former uses the startoffset  argument  to  
131       pcre_exec()  to  start  searching  at a new point within the           /A    PCRE_ANCHORED
132       entire string (which is in effect what Perl  does),  whereas           /C    PCRE_AUTO_CALLOUT
133       the  latter  passes over a shortened substring. This makes a           /E    PCRE_DOLLAR_ENDONLY
134       difference to the matching process  if  the  pattern  begins           /f    PCRE_FIRSTLINE
135       with a lookbehind assertion (including \b or \B).           /N    PCRE_NO_AUTO_CAPTURE
136             /U    PCRE_UNGREEDY
137       If any call to pcre_exec() in a /g or /G sequence matches an           /X    PCRE_EXTRA
138       empty  string,  the next call is done with the PCRE_NOTEMPTY  
139       and PCRE_ANCHORED flags set in order to search for  another,         Searching for all possible matches within each subject  string  can  be
140       non-empty,  match  at  the same point.  If this second match         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
141       fails, the start offset is advanced by one, and  the  normal         called again to search the remainder of the subject string. The differ-
142       match  is  retried.  This imitates the way Perl handles such         ence between /g and /G is that the former uses the startoffset argument
143       cases when using the /g modifier or the split() function.         to pcre_exec() to start searching at a  new  point  within  the  entire
144           string  (which  is in effect what Perl does), whereas the latter passes
145       There are a number of other modifiers  for  controlling  the         over a shortened substring. This makes a  difference  to  the  matching
146       way pcretest operates.         process if the pattern begins with a lookbehind assertion (including \b
147           or \B).
148       The /+ modifier requests that as well as outputting the sub-  
149       string  that  matched the entire pattern, pcretest should in         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
150       addition output the remainder of the subject string. This is         string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
151       useful  for tests where the subject contains multiple copies         flags set in order to search for another, non-empty, match at the  same
152       of the same substring.         point.   If  this  second  match fails, the start offset is advanced by
153           one, and the normal match is retried. This imitates the way  Perl  han-
154       The /L modifier must be followed directly by the name  of  a         dles such cases when using the /g modifier or the split() function.
155       locale, for example,  
156           There are yet more modifiers for controlling the way pcretest operates.
157         /pattern/Lfr  
158           The /+ modifier requests that as well as outputting the substring  that
159       For this reason, it must be the last  modifier  letter.  The         matched  the  entire  pattern,  pcretest  should in addition output the
160       given  locale is set, pcre_maketables() is called to build a         remainder of the subject string. This is useful  for  tests  where  the
161       set of character tables for the locale,  and  this  is  then         subject contains multiple copies of the same substring.
162       passed  to pcre_compile() when compiling the regular expres-  
163       sion. Without an /L modifier, NULL is passed as  the  tables         The  /L modifier must be followed directly by the name of a locale, for
164       pointer; that is, /L applies only to the expression on which         example,
165       it appears.  
166             /pattern/Lfr_FR
167       The /I modifier requests that  pcretest  output  information  
168       about the compiled expression (whether it is anchored, has a         For this reason, it must be the last modifier. The given locale is set,
169       fixed first character, and so on). It does this  by  calling         pcre_maketables()  is called to build a set of character tables for the
170       pcre_fullinfo()  after  compiling an expression, and output-         locale, and this is then passed to pcre_compile()  when  compiling  the
171       ting the information it gets back. If the  pattern  is  stu-         regular  expression.  Without  an  /L  modifier,  NULL is passed as the
172       died, the results of that are also output.         tables pointer; that is, /L applies only to the expression on which  it
173           appears.
174       The /D modifier is a  PCRE  debugging  feature,  which  also  
175       assumes /I.  It causes the internal form of compiled regular         The  /I  modifier  requests  that pcretest output information about the
176       expressions to be output after compilation. If  the  pattern         compiled pattern (whether it is anchored, has a fixed first  character,
177       was studied, the information returned is also output.         and  so  on). It does this by calling pcre_fullinfo() after compiling a
178           pattern. If the pattern is studied, the results of that are  also  out-
179       The /S modifier causes pcre_study() to be called  after  the         put.
180       expression  has been compiled, and the results used when the  
181       expression is matched.         The /D modifier is a PCRE debugging feature, which also assumes /I.  It
182           causes the internal form of compiled regular expressions to  be  output
183       The /M modifier causes the size of memory block used to hold         after compilation. If the pattern was studied, the information returned
184       the compiled pattern to be output.         is also output.
185    
186       The /P modifier causes pcretest to call PCRE via  the  POSIX         The /F modifier causes pcretest to flip the byte order of the fields in
187       wrapper  API  rather than its native API. When this is done,         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This
188       all other modifiers except  /i,  /m,  and  /+  are  ignored.         facility is for testing the feature in PCRE that allows it  to  execute
189       REG_ICASE is set if /i is present, and REG_NEWLINE is set if         patterns that were compiled on a host with a different endianness. This
190       /m    is    present.    The    wrapper    functions    force         feature is not available when the POSIX  interface  to  PCRE  is  being
191       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless         used,  that is, when the /P pattern modifier is specified. See also the
192       REG_NEWLINE is set.         section about saving and reloading compiled patterns below.
193    
194       The /8 modifier  causes  pcretest  to  call  PCRE  with  the         The /S modifier causes pcre_study() to be called after  the  expression
195       PCRE_UTF8  option set. This turns on support for UTF-8 char-         has been compiled, and the results used when the expression is matched.
196       acter handling in PCRE, provided that it was  compiled  with  
197       this  support  enabled.  This  modifier also causes any non-         The /M modifier causes the size of memory block used to hold  the  com-
198       printing characters in output strings to  be  printed  using         piled pattern to be output.
199       the \x{hh...} notation if they are valid UTF-8 sequences.  
200           The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
201       If the /? modifier is used with /8, it  causes  pcretest  to         rather than its native API. When this  is  done,  all  other  modifiers
202       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,
203       suppress the checking of the string for UTF-8 validity.         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force
204           PCRE_DOLLAR_ENDONLY  always, and PCRE_DOTALL unless REG_NEWLINE is set.
205    
206           The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8  option
207           set.  This  turns on support for UTF-8 character handling in PCRE, pro-
208           vided that it was compiled with this  support  enabled.  This  modifier
209           also causes any non-printing characters in output strings to be printed
210           using the \x{hh...} notation if they are valid UTF-8 sequences.
211    
212           If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call
213           pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the
214           checking of the string for UTF-8 validity.
215    
216    
217  CALLOUTS  DATA LINES
218    
219       If the pattern contains  any  callout  requests,  pcretest's         Before each data line is passed to pcre_exec(),  leading  and  trailing
220       callout function will be called. By default, it displays the         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
221       callout number, and the start and current positions  in  the         these are pretty esoteric features, intended for checking out  some  of
222       text at the callout time. For example, the output         the  more  complicated features of PCRE. If you are just testing "ordi-
223           nary" regular expressions, you probably don't need any  of  these.  The
224         --->pqrabcdef         following escapes are recognized:
225           0    ^  ^  
226             \a         alarm (= BEL)
227       indicates that callout number 0 occurred for a match attempt           \b         backspace
228       starting at the fourth character of the subject string, when           \e         escape
229       the pointer was at the seventh character. The callout  func-           \f         formfeed
230       tion returns zero (carry on matching) by default.           \n         newline
231             \r         carriage return
232       Inserting callouts may be helpful  when  using  pcretest  to           \t         tab
233       check  complicated regular expressions. For further informa-           \v         vertical tab
234       tion about callouts, see the pcrecallout documentation.           \nnn       octal character (up to 3 octal digits)
235             \xhh       hexadecimal character (up to 2 hex digits)
236       For testing the PCRE library, additional control of  callout           \x{hh...}  hexadecimal character, any number of digits
237       behaviour  is available via escape sequences in the data, as                        in UTF-8 mode
238       described in the following section.  In  particular,  it  is           \A         pass the PCRE_ANCHORED option to pcre_exec()
239       possible to pass in a number as callout data (the default is           \B         pass the PCRE_NOTBOL option to pcre_exec()
240       zero). If the callout function receives a  non-zero  number,           \Cdd       call pcre_copy_substring() for substring dd
241       it returns that value instead of zero.                        after a successful match (number less than 32)
242             \Cname     call pcre_copy_named_substring() for substring
243                          "name" after a successful match (name termin-
244                          ated by next non alphanumeric character)
245             \C+        show the current captured substrings at callout
246                          time
247             \C-        do not supply a callout function
248             \C!n       return 1 instead of 0 when callout number n is
249                          reached
250             \C!n!m     return 1 instead of 0 when callout number n is
251                          reached for the nth time
252             \C*n       pass the number n (may be negative) as callout
253                          data; this is used as the callout return value
254             \D         use the pcre_dfa_exec() match function
255             \F         only shortest match for pcre_dfa_exec()
256             \Gdd       call pcre_get_substring() for substring dd
257                          after a successful match (number less than 32)
258             \Gname     call pcre_get_named_substring() for substring
259                          "name" after a successful match (name termin-
260                          ated by next non-alphanumeric character)
261             \L         call pcre_get_substringlist() after a
262                          successful match
263             \M         discover the minimum MATCH_LIMIT and
264                          MATCH_LIMIT_RECURSION settings
265             \N         pass the PCRE_NOTEMPTY option to pcre_exec()
266             \Odd       set the size of the output vector passed to
267                          pcre_exec() to dd (any number of digits)
268             \P         pass the PCRE_PARTIAL option to pcre_exec()
269                          or pcre_dfa_exec()
270             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
271             \S         output details of memory get/free calls during matching
272             \Z         pass the PCRE_NOTEOL option to pcre_exec()
273             \?         pass the PCRE_NO_UTF8_CHECK option to
274                          pcre_exec()
275             \>dd       start the match at offset dd (any number of digits);
276                          this sets the startoffset argument for pcre_exec()
277    
278           A  backslash  followed by anything else just escapes the anything else.
279           If the very last character is a backslash, it is ignored. This gives  a
280           way  of  passing  an empty line as data, since a real empty line termi-
281           nates the data input.
282    
283           If \M is present, pcretest calls pcre_exec() several times,  with  dif-
284           ferent  values  in  the match_limit and match_limit_recursion fields of
285           the pcre_extra data structure, until it finds the minimum  numbers  for
286           each parameter that allow pcre_exec() to complete. The match_limit num-
287           ber is a measure of the amount of backtracking that  takes  place,  and
288           checking it out can be instructive. For most simple matches, the number
289           is quite small, but for patterns with very large  numbers  of  matching
290           possibilities,  it can become large very quickly with increasing length
291           of subject string. The match_limit_recursion number is a measure of how
292           much  stack  (or,  if  PCRE is compiled with NO_RECURSE, how much heap)
293           memory is needed to complete the match attempt.
294    
295           When \O is used, the value specified may be higher or  lower  than  the
296           size set by the -O command line option (or defaulted to 45); \O applies
297           only to the call of pcre_exec() for the line in which it appears.
298    
299           If the /P modifier was present on the pattern, causing the POSIX  wrap-
300           per  API  to  be  used, the only option-setting sequences that have any
301           effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL,  respectively,
302           to be passed to regexec().
303    
304           The  use of \x{hh...} to represent UTF-8 characters is not dependent on
305           the use of the /8 modifier on the pattern.  It  is  recognized  always.
306           There  may  be  any number of hexadecimal digits inside the braces. The
307           result is from one to six bytes, encoded according to the UTF-8  rules.
308    
309    
310    THE ALTERNATIVE MATCHING FUNCTION
311    
312           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
313           pcre_exec() to match each data line. From release 6.0, PCRE supports an
314           alternative  matching  function,  pcre_dfa_test(),  which operates in a
315           different way, and has some restrictions. The differences  between  the
316           two functions are described in the pcrematching documentation.
317    
318           If  a data line contains the \D escape sequence, or if the command line
319           contains the -dfa option, the alternative matching function is  called.
320           This function finds all possible matches at a given point. If, however,
321           the \F escape sequence is present in the data line, it stops after  the
322           first match is found. This is always the shortest possible match.
323    
324    
325    DEFAULT OUTPUT FROM PCRETEST
326    
327           This  section  describes  the output when the normal matching function,
328           pcre_exec(), is being used.
329    
330           When a match succeeds, pcretest outputs the list of captured substrings
331           that  pcre_exec()  returns,  starting with number 0 for the string that
332           matched the whole pattern. Otherwise, it outputs "No match" or "Partial
333           match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
334           TIAL, respectively, and otherwise the PCRE negative error number.  Here
335           is an example of an interactive pcretest run.
336    
337             $ pcretest
338             PCRE version 5.00 07-Sep-2004
339    
340               re> /^abc(\d+)/
341             data> abc123
342              0: abc123
343              1: 123
344             data> xyz
345             No match
346    
347           If  the strings contain any non-printing characters, they are output as
348           \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
349           the  pattern.  If  the pattern has the /+ modifier, the output for sub-
350           string 0 is followed by the the rest of the subject string,  identified
351           by "0+" like this:
352    
353               re> /cat/+
354             data> cataract
355              0: cat
356              0+ aract
357    
358           If  the  pattern  has  the /g or /G modifier, the results of successive
359           matching attempts are output in sequence, like this:
360    
361               re> /\Bi(\w\w)/g
362             data> Mississippi
363              0: iss
364              1: ss
365              0: iss
366              1: ss
367              0: ipp
368              1: pp
369    
370           "No match" is output only if the first match attempt fails.
371    
372           If any of the sequences \C, \G, or \L are present in a data  line  that
373           is  successfully  matched,  the substrings extracted by the convenience
374           functions are output with C, G, or L after the string number instead of
375           a colon. This is in addition to the normal full list. The string length
376           (that is, the return from the extraction function) is given  in  paren-
377           theses after each string for \C and \G.
378    
379           Note  that  while patterns can be continued over several lines (a plain
380           ">" prompt is used for continuations), data lines may not. However new-
381           lines can be included in data by means of the \n escape.
382    
383    
384    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
385    
386           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
387           means of the \D escape sequence or the -dfa command line  option),  the
388           output  consists  of  a list of all the matches that start at the first
389           point in the subject where there is at least one match. For example:
390    
391               re> /(tang|tangerine|tan)/
392             data> yellow tangerine\D
393              0: tangerine
394              1: tang
395              2: tan
396    
397           (Using the normal matching function on this data  finds  only  "tang".)
398           The  longest matching string is always given first (and numbered zero).
399    
400           If /gP is present on  the  pattern,  the  search  for  further  matches
401           resumes at the end of the longest match. For example:
402    
403               re> /(tang|tangerine|tan)/g
404             data> yellow tangerine and tangy sultana\D
405              0: tangerine
406              1: tang
407              2: tan
408              0: tang
409              1: tan
410              0: tan
411    
412           Since  the  matching  function  does not support substring capture, the
413           escape sequences that are concerned with captured  substrings  are  not
414           relevant.
415    
416    
417    RESTARTING AFTER A PARTIAL MATCH
418    
419           When the alternative matching function has given the PCRE_ERROR_PARTIAL
420           return, indicating that the subject partially matched the pattern,  you
421           can  restart  the match with additional subject data by means of the \R
422           escape sequence. For example:
423    
424               re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
425             data> 23ja\P\D
426             Partial match: 23ja
427             data> n05\R\D
428              0: n05
429    
430           For further information about partial  matching,  see  the  pcrepartial
431           documentation.
432    
 DATA LINES  
433    
434       Before each data line is passed to pcre_exec(), leading  and  CALLOUTS
435       trailing whitespace is removed, and it is then scanned for \  
436       escapes.  Some  of  these  are  pretty  esoteric   features,         If  the pattern contains any callout requests, pcretest's callout func-
437       intended  for  checking  out  some  of  the more complicated         tion is called during matching. This works  with  both  matching  func-
438       features of PCRE. If you are just testing "ordinary" regular         tions. By default, the called function displays the callout number, the
439       expressions,  you probably don't need any of these. The fol-         start and current positions in the text at the callout  time,  and  the
440       lowing escapes are recognized:         next pattern item to be tested. For example, the output
441    
442         \a         alarm (= BEL)           --->pqrabcdef
443         \b         backspace             0    ^  ^     \d
444         \e         escape  
445         \f         formfeed         indicates  that  callout number 0 occurred for a match attempt starting
446         \n         newline         at the fourth character of the subject string, when the pointer was  at
447         \r         carriage return         the  seventh  character of the data, and when the next pattern item was
448         \t         tab         \d. Just one circumflex is output if the start  and  current  positions
449         \v         vertical tab         are the same.
450         \nnn       octal character (up to 3 octal digits)  
451         \xhh       hexadecimal character (up to 2 hex digits)         Callouts numbered 255 are assumed to be automatic callouts, inserted as
452         \x{hh...}  hexadecimal character, any number of digits         a result of the /C pattern modifier. In this case, instead  of  showing
453                      in UTF-8 mode         the  callout  number, the offset in the pattern, preceded by a plus, is
454         \A         pass the PCRE_ANCHORED option to pcre_exec()         output. For example:
455         \B         pass the PCRE_NOTBOL option to pcre_exec()  
456         \Cdd       call pcre_copy_substring() for substring dd             re> /\d?[A-E]\*/C
457                      after a successful match (any decimal number           data> E*
458                      less than 32)           --->E*
459         \Cname     call pcre_copy_named_substring() for substring            +0 ^      \d?
460              +3 ^      [A-E]
461                      "name" after a successful match (name termin-            +8 ^^     \*
462                      ated by next non alphanumeric character)           +10 ^ ^
463         \C+        show the current captured substrings at callout            0: E*
464                      time  
465         \C-        do not supply a callout function         The callout function in pcretest returns zero (carry  on  matching)  by
466         \C!n       return 1 instead of 0 when callout number n is         default,  but you can use a \C item in a data line (as described above)
467                      reached         to change this.
468         \C!n!m     return 1 instead of 0 when callout number n is  
469                      reached for the nth time         Inserting callouts can be helpful when using pcretest to check  compli-
470         \C*n       pass the number n (may be negative) as callout         cated  regular expressions. For further information about callouts, see
471                      data         the pcrecallout documentation.
472         \Gdd       call pcre_get_substring() for substring dd  
473                      after a successful match (any decimal number  
474                      less than 32)  SAVING AND RELOADING COMPILED PATTERNS
475         \Gname     call pcre_get_named_substring() for substring  
476                      "name" after a successful match (name termin-         The facilities described in this section are  not  available  when  the
477                      ated by next non-alphanumeric character)         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
478         \L         call pcre_get_substringlist() after a         ifier is specified.
479                      successful match  
480         \M         discover the minimum MATCH_LIMIT setting         When the POSIX interface is not in use, you can cause pcretest to write
481         \N         pass the PCRE_NOTEMPTY option to pcre_exec()         a  compiled  pattern to a file, by following the modifiers with > and a
482         \Odd       set the size of the output vector passed to         file name.  For example:
483                      pcre_exec() to dd (any number of decimal  
484                      digits)           /pattern/im >/some/file
485         \Z         pass the PCRE_NOTEOL option to pcre_exec()  
486         \?         pass the PCRE_NO_UTF8_CHECK option to         See the pcreprecompile documentation for a discussion about saving  and
487                      pcre_exec()         re-using compiled patterns.
488    
489       If \M is present, pcretest calls pcre_exec() several  times,         The  data  that  is  written  is  binary. The first eight bytes are the
490       with  different  values  in  the  match_limit  field  of the         length of the compiled pattern data  followed  by  the  length  of  the
491       pcre_extra data structure, until it finds the minimum number         optional  study  data,  each  written as four bytes in big-endian order
492       that is needed for pcre_exec() to complete. This number is a         (most significant byte first). If there is no study  data  (either  the
493       measure of the amount of  recursion  and  backtracking  that         pattern was not studied, or studying did not return any data), the sec-
494       takes  place,  and  checking  it out can be instructive. For         ond length is zero. The lengths are followed by an exact  copy  of  the
495       most simple matches, the number is quite small, but for pat-         compiled pattern. If there is additional study data, this follows imme-
496       terns  with very large numbers of matching possibilities, it         diately after the compiled pattern. After writing  the  file,  pcretest
497       can become large very quickly with increasing length of sub-         expects to read a new pattern.
498       ject string.  
499           A saved pattern can be reloaded into pcretest by specifing < and a file
500       When \O is used, it may be higher or lower than the size set         name instead of a pattern. The name of the file must not  contain  a  <
501       by  the  -O  option (or defaulted to 45); \O applies only to         character,  as  otherwise pcretest will interpret the line as a pattern
502       the call of pcre_exec() for the line in which it appears.         delimited by < characters.  For example:
503    
504       A backslash followed by anything else just escapes the  any-            re> </some/file
505       thing else. If the very last character is a backslash, it is           Compiled regex loaded from /some/file
506       ignored. This gives a way of passing an empty line as  data,           No study data
507       since a real empty line terminates the data input.  
508           When the pattern has been loaded, pcretest proceeds to read data  lines
509       If /P was present on the regex, causing  the  POSIX  wrapper         in the usual way.
510       API  to  be  used,  only  B,  and Z have any effect, causing  
511       REG_NOTBOL and REG_NOTEOL to be passed to regexec()  respec-         You  can copy a file written by pcretest to a different host and reload
512       tively.         it there, even if the new host has opposite endianness to  the  one  on
513       The use of \x{hh...} to represent UTF-8  characters  is  not         which  the pattern was compiled. For example, you can compile on an i86
514       dependent  on  the use of the /8 modifier on the pattern. It         machine and run on a SPARC machine.
515       is recognized always. There may be any number of hexadecimal  
516       digits  inside  the  braces.  The  result is from one to six         File names for saving and reloading can be absolute  or  relative,  but
517       bytes, encoded according to the UTF-8 rules.         note  that the shell facility of expanding a file name that starts with
518           a tilde (~) is not available.
519    
520  OUTPUT FROM PCRETEST         The ability to save and reload files in pcretest is intended for  test-
521           ing  and experimentation. It is not intended for production use because
522       When a match succeeds, pcretest outputs the list of captured         only a single pattern can be written to a file. Furthermore,  there  is
523       substrings  that pcre_exec() returns, starting with number 0         no  facility  for  supplying  custom  character  tables  for use with a
524       for the string that matched the whole pattern.  Here  is  an         reloaded pattern. If the original  pattern  was  compiled  with  custom
525       example of an interactive pcretest run.         tables,  an  attempt to match a subject string using a reloaded pattern
526           is likely to cause pcretest to crash.  Finally, if you attempt to  load
527         $ pcretest         a file that is not in the correct format, the result is undefined.
        PCRE version 4.00 08-Jan-2003  
   
          re> /^abc(\d+)/  
        data> abc123  
         0: abc123  
         1: 123  
        data> xyz  
        No match  
   
      If the strings contain any non-printing characters, they are  
      output  as  \0x  escapes,  or  as  \x{...} escapes if the /8  
      modifier was present on the pattern. If the pattern has  the  
      /+  modifier, then the output for substring 0 is followed by  
      the the rest of the subject string, identified by "0+"  like  
      this:  
   
          re> /cat/+  
        data> cataract  
         0: cat  
         0+ aract  
   
      If the pattern has the /g or /G  modifier,  the  results  of  
      successive  matching  attempts  are output in sequence, like  
      this:  
   
          re> /\Bi(\w\w)/g  
        data> Mississippi  
         0: iss  
         1: ss  
         0: iss  
         1: ss  
         0: ipp  
         1: pp  
   
      "No match" is output only if the first match attempt fails.  
   
      If any of the sequences \C, \G, or \L are present in a  data  
      line  that is successfully matched, the substrings extracted  
      by the convenience functions are output  with  C,  G,  or  L  
      after the string number instead of a colon. This is in addi-  
      tion to the normal full list. The string  length  (that  is,  
      the  return  from  the  extraction  function)  is  given  in  
      parentheses after each string for \C and \G.  
   
      Note that while patterns can be continued over several lines  
      (a  plain  ">" prompt is used for continuations), data lines  
      may not. However newlines can be included in data  by  means  
      of the \n escape.  
528    
529    
530  AUTHOR  AUTHOR
531    
532       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
533       University Computing Service,         University Computing Service,
534       Cambridge CB2 3QG, England.         Cambridge CB2 3QG, England.
535    
536  Last updated: 20 August 2003  Last updated: 18 January 2006
537  Copyright (c) 1997-2003 University of Cambridge.  Copyright (c) 1997-2006 University of Cambridge.

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