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

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

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

revision 49 by nigel, Sat Feb 24 21:39:33 2007 UTC revision 429 by ph10, Tue Sep 1 16:10:16 2009 UTC
# Line 1  Line 1 
1  The pcretest program  PCRETEST(1)                                                        PCRETEST(1)
 --------------------  
2    
 This program is intended for testing PCRE, but it can also be used for  
 experimenting with regular expressions.  
3    
4  If it is given two filename arguments, it reads from the first and writes to  NAME
5  the second. If it is given only one filename argument, it reads from that file         pcretest - a program for testing Perl-compatible regular expressions.
 and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and  
 prompts for each line of input, using "re>" to prompt for regular expressions,  
 and "data>" to prompt for data lines.  
   
 The program handles any number of sets of input on a single input file. Each  
 set starts with a regular expression, and continues with any number of data  
 lines to be matched against the pattern. An empty line signals the end of the  
 data lines, at which point a new regular expression is read. The regular  
 expressions are given enclosed in any non-alphameric delimiters other than  
 backslash, for example  
   
   /(a|bc)x+yz/  
   
 White space before the initial delimiter is ignored. A regular expression may  
 be continued over several input lines, in which case the newline characters are  
 included within it. See the test input files in the testdata directory for many  
 examples. It is possible to include the delimiter within the pattern by  
 escaping it, for example  
   
   /abc\/def/  
   
 If you do so, the escape and the delimiter form part of the pattern, but since  
 delimiters are always non-alphameric, this does not affect its interpretation.  
 If the terminating delimiter is immediately followed by a backslash, for  
 example,  
   
   /abc/\  
   
 then a backslash is added to the end of the pattern. This is done to provide a  
 way of testing the error condition that arises if a pattern finishes with a  
 backslash, because  
6    
   /abc\/  
7    
8  is interpreted as the first line of a pattern that starts with "abc/", causing  SYNOPSIS
9  pcretest to read the next line as a continuation of the regular expression.  
10           pcretest [options] [source] [destination]
11    
12           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
14           expressions.  This document describes the features of the test program;
15           for details of the regular expressions themselves, see the  pcrepattern
16           documentation. For details of the PCRE library function calls and their
17           options, see the pcreapi documentation.
18    
19    
20    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-
26                     able  information  about  the  optional  features  that   are
27                     included, and then exit.
28    
29           -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                     internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33           -dfa      Behave  as if each data line contains the \D escape sequence;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38           -help     Output a brief summary these options and then exit.
39    
40           -i        Behave as if each regex  has  the  /I  modifier;  information
41                     about the compiled pattern is given after compilation.
42    
43           -M        Behave  as if each data line contains the \M escape sequence;
44                     this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                     MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
46                     edly with different limits.
47    
48           -m        Output the size of each compiled pattern after  it  has  been
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.
52    
53           -o osize  Set  the number of elements in the output vector that is used
54                     when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                     default  value is 45, which is enough for 14 capturing subex-
56                     pressions  for  pcre_exec()  or  22  different  matches   for
57                     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-
62                     per API is used to call PCRE. None of the other  options  has
63                     any effect when -p is set.
64    
65           -q        Do  not output the version number of pcretest at the start of
66                     execution.
67    
68           -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                     size megabytes.
70    
71           -t        Run  each  compile, study, and match many times with a timer,
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
85    
86           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
88           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
90           "re>" to prompt for regular expressions, and "data>" to prompt for data
91           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.
100           Each  set starts with a regular expression, and continues with any num-
101           ber of data lines to be matched against the pattern.
102    
103           Each data line is matched separately and independently. If you want  to
104           do multi-line matches, you have to use the \n escape sequence (or \r or
105           \r\n, etc., depending on the newline setting) in a single line of input
106           to  encode  the  newline  sequences. There is no limit on the length of
107           data lines; the input buffer is automatically extended  if  it  is  too
108           small.
109    
110           An  empty  line signals the end of the data lines, at which point a new
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/
115    
116           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-
118           line  characters  are included within it. It is possible to include the
119           delimiter within the pattern by escaping it, for example
120    
121             /abc\/def/
122    
123           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
125           its interpretation.  If the terminating delimiter is  immediately  fol-
126           lowed by a backslash, for example,
127    
128             /abc/\
129    
130           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
132           finishes with a backslash, because
133    
134             /abc\/
135    
136           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
138           expression.
139    
140    
141  PATTERN MODIFIERS  PATTERN MODIFIERS
 -----------------  
142    
143  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
144  PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For         single characters. Following Perl usage, these are  referred  to  below
145  example:         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
147    /caseless/i         modifiers.  Whitespace  may  appear between the final pattern delimiter
148           and the first modifier, and between the modifiers themselves.
149  These modifier letters have the same effect as they do in Perl. There are  
150  others which set PCRE options that do not correspond to anything in Perl: /A,         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
151  /E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152           pile() is called. These four modifier letters have the same  effect  as
153  Searching for all possible matches within each subject string can be requested         they do in Perl. For example:
154  by the /g or /G modifier. After finding a match, PCRE is called again to search  
155  the remainder of the subject string. The difference between /g and /G is that           /caseless/i
156  the former uses the startoffset argument to pcre_exec() to start searching at  
157  a new point within the entire string (which is in effect what Perl does),         The following table shows additional modifiers for setting PCRE options
158  whereas the latter passes over a shortened substring. This makes a difference         that do not correspond to anything in Perl:
159  to the matching process if the pattern begins with a lookbehind assertion  
160  (including \b or \B).           /A              PCRE_ANCHORED
161             /C              PCRE_AUTO_CALLOUT
162  If any call to pcre_exec() in a /g or /G sequence matches an empty string, the           /E              PCRE_DOLLAR_ENDONLY
163  next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED flags set in order           /f              PCRE_FIRSTLINE
164  to search for another, non-empty, match at the same point. If this second match           /J              PCRE_DUPNAMES
165  fails, the start offset is advanced by one, and the normal match is retried.           /N              PCRE_NO_AUTO_CAPTURE
166  This imitates the way Perl handles such cases when using the /g modifier or the           /U              PCRE_UNGREEDY
167  split() function.           /X              PCRE_EXTRA
168             /<JS>           PCRE_JAVASCRIPT_COMPAT
169  There are a number of other modifiers for controlling the way pcretest           /<cr>           PCRE_NEWLINE_CR
170  operates.           /<lf>           PCRE_NEWLINE_LF
171             /<crlf>         PCRE_NEWLINE_CRLF
172  The /+ modifier requests that as well as outputting the substring that matched           /<anycrlf>      PCRE_NEWLINE_ANYCRLF
173  the entire pattern, pcretest should in addition output the remainder of the           /<any>          PCRE_NEWLINE_ANY
174  subject string. This is useful for tests where the subject contains multiple           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
175  copies of the same substring.           /<bsr_unicode>  PCRE_BSR_UNICODE
176    
177  The /L modifier must be followed directly by the name of a locale, for example,         Those specifying line ending sequences are literal  strings  as  shown,
178           but  the  letters  can  be  in either case. This example sets multiline
179    /pattern/Lfr         matching with CRLF as the line ending sequence:
180    
181  For this reason, it must be the last modifier letter. The given locale is set,           /^abc/m<crlf>
182  pcre_maketables() is called to build a set of character tables for the locale,  
183  and this is then passed to pcre_compile() when compiling the regular         Details of the meanings of these PCRE options are given in the  pcreapi
184  expression. Without an /L modifier, NULL is passed as the tables pointer; that         documentation.
185  is, /L applies only to the expression on which it appears.  
186       Finding all matches in a string
187  The /I modifier requests that pcretest output information about the compiled  
188  expression (whether it is anchored, has a fixed first character, and so on). It         Searching  for  all  possible matches within each subject string can be
189  does this by calling pcre_fullinfo() after compiling an expression, and         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is
190  outputting the information it gets back. If the pattern is studied, the results         called again to search the remainder of the subject string. The differ-
191  of that are also output.         ence between /g and /G is that the former uses the startoffset argument
192           to  pcre_exec()  to  start  searching  at a new point within the entire
193  The /D modifier is a PCRE debugging feature, which also assumes /I. It causes         string (which is in effect what Perl does), whereas the  latter  passes
194  the internal form of compiled regular expressions to be output after         over  a  shortened  substring.  This makes a difference to the matching
195  compilation.         process if the pattern begins with a lookbehind assertion (including \b
196           or \B).
197  The /S modifier causes pcre_study() to be called after the expression has been  
198  compiled, and the results used when the expression is matched.         If  any  call  to  pcre_exec()  in a /g or /G sequence matches an empty
199           string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED
200  The /M modifier causes the size of memory block used to hold the compiled         flags  set in order to search for another, non-empty, match at the same
201  pattern to be output.         point.  If this second match fails, the start  offset  is  advanced  by
202           one,  and  the normal match is retried. This imitates the way Perl han-
203  The /P modifier causes pcretest to call PCRE via the POSIX wrapper API rather         dles such cases when using the /g modifier or the split() function.
204  than its native API. When this is done, all other modifiers except /i, /m, and  
205  /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is set if /m     Other modifiers
206  is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, and  
207  PCRE_DOTALL unless REG_NEWLINE is set.         There are yet more modifiers for controlling the way pcretest operates.
208    
209  The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option set.         The /+ modifier requests that as well as outputting the substring  that
210  This turns on the (currently incomplete) support for UTF-8 character handling         matched  the  entire  pattern,  pcretest  should in addition output the
211  in PCRE, provided that it was compiled with this support enabled. This modifier         remainder of the subject string. This is useful  for  tests  where  the
212  also causes any non-printing characters in output strings to be printed using         subject contains multiple copies of the same substring.
213  the \x{hh...} notation if they are valid UTF-8 sequences.  
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
222           example,
223    
224             /pattern/Lfr_FR
225    
226           For this reason, it must be the last modifier. The given locale is set,
227           pcre_maketables() is called to build a set of character tables for  the
228           locale,  and  this  is then passed to pcre_compile() when compiling the
229           regular expression. Without an /L  modifier,  NULL  is  passed  as  the
230           tables  pointer; that is, /L applies only to the expression on which it
231           appears.
232    
233           The /I modifier requests that pcretest  output  information  about  the
234           compiled  pattern (whether it is anchored, has a fixed first character,
235           and so on). It does this by calling pcre_fullinfo() after  compiling  a
236           pattern.  If  the pattern is studied, the results of that are also out-
237           put.
238    
239           The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
240           that is, both the /B and the /I modifiers.
241    
242           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
244           facility  is  for testing the feature in PCRE that allows it to execute
245           patterns that were compiled on a host with a different endianness. This
246           feature  is  not  available  when  the POSIX interface to PCRE is being
247           used, that is, when the /P pattern modifier is specified. See also  the
248           section about saving and reloading compiled patterns below.
249    
250           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.
252    
253           The /M modifier causes the size of memory block used to hold  the  com-
254           piled pattern to be output.
255    
256           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
258           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
260           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
263           set. This turns on support for UTF-8 character handling in  PCRE,  pro-
264           vided  that  it  was  compiled with this support enabled. This modifier
265           also causes any non-printing characters in output strings to be printed
266           using the \x{hh...} notation if they are valid UTF-8 sequences.
267    
268           If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
269           pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
270           checking of the string for UTF-8 validity.
271    
272    
273  DATA LINES  DATA LINES
 ----------  
274    
275  Before each data line is passed to pcre_exec(), leading and trailing whitespace         Before  each  data  line is passed to pcre_exec(), leading and trailing
276  is removed, and it is then scanned for \ escapes. The following are recognized:         whitespace is removed, and it is then scanned for \  escapes.  Some  of
277           these  are  pretty esoteric features, intended for checking out some of
278           the more complicated features of PCRE. If you are just  testing  "ordi-
279           nary"  regular  expressions,  you probably don't need any of these. The
280           following escapes are recognized:
281    
282             \a         alarm (BEL, \x07)
283             \b         backspace (\x08)
284             \e         escape (\x27)
285             \f         formfeed (\x0c)
286             \n         newline (\x0a)
287             \qdd       set the PCRE_MATCH_LIMIT limit to dd
288                          (any number of digits)
289             \r         carriage return (\x0d)
290             \t         tab (\x09)
291             \v         vertical tab (\x0b)
292             \nnn       octal character (up to 3 octal digits)
293             \xhh       hexadecimal character (up to 2 hex digits)
294             \x{hh...}  hexadecimal character, any number of digits
295                          in UTF-8 mode
296             \A         pass the PCRE_ANCHORED option to pcre_exec()
297                          or pcre_dfa_exec()
298             \B         pass the PCRE_NOTBOL option to pcre_exec()
299                          or pcre_dfa_exec()
300             \Cdd       call pcre_copy_substring() for substring dd
301                          after a successful match (number less than 32)
302             \Cname     call pcre_copy_named_substring() for substring
303                          "name" after a successful match (name termin-
304                          ated by next non alphanumeric character)
305             \C+        show the current captured substrings at callout
306                          time
307             \C-        do not supply a callout function
308             \C!n       return 1 instead of 0 when callout number n is
309                          reached
310             \C!n!m     return 1 instead of 0 when callout number n is
311                          reached for the nth time
312             \C*n       pass the number n (may be negative) as callout
313                          data; this is used as the callout return value
314             \D         use the pcre_dfa_exec() match function
315             \F         only shortest match for pcre_dfa_exec()
316             \Gdd       call pcre_get_substring() for substring dd
317                          after a successful match (number less than 32)
318             \Gname     call pcre_get_named_substring() for substring
319                          "name" after a successful match (name termin-
320                          ated by next non-alphanumeric character)
321             \L         call pcre_get_substringlist() after a
322                          successful match
323             \M         discover the minimum MATCH_LIMIT and
324                          MATCH_LIMIT_RECURSION settings
325             \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
328                          pcre_exec() to dd (any number of digits)
329             \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
330                          or pcre_dfa_exec(); if used twice, pass the
331                          PCRE_PARTIAL_HARD option
332             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
333                          (any number of digits)
334             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
335             \S         output details of memory get/free calls during matching
336             \Z         pass the PCRE_NOTEOL option to pcre_exec()
337                          or pcre_dfa_exec()
338             \?         pass the PCRE_NO_UTF8_CHECK option to
339                          pcre_exec() or pcre_dfa_exec()
340             \>dd       start the match at offset dd (any number of digits);
341                          this sets the startoffset argument for pcre_exec()
342                          or pcre_dfa_exec()
343             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
344                          or pcre_dfa_exec()
345             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
346                          or pcre_dfa_exec()
347             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
348                          or pcre_dfa_exec()
349             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
350                          or pcre_dfa_exec()
351             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
352                          or pcre_dfa_exec()
353    
354           The escapes that specify line ending  sequences  are  literal  strings,
355           exactly as shown. No more than one newline setting should be present in
356           any data line.
357    
358           A backslash followed by anything else just escapes the  anything  else.
359           If  the very last character is a backslash, it is ignored. This gives a
360           way of passing an empty line as data, since a real  empty  line  termi-
361           nates the data input.
362    
363           If  \M  is present, pcretest calls pcre_exec() several times, with dif-
364           ferent values in the match_limit and  match_limit_recursion  fields  of
365           the  pcre_extra  data structure, until it finds the minimum numbers for
366           each parameter that allow pcre_exec() to complete. The match_limit num-
367           ber  is  a  measure of the amount of backtracking that takes place, and
368           checking it out can be instructive. For most simple matches, the number
369           is  quite  small,  but for patterns with very large numbers of matching
370           possibilities, it can become large very quickly with increasing  length
371           of subject string. The match_limit_recursion number is a measure of how
372           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
373           memory is needed to complete the match attempt.
374    
375           When  \O  is  used, the value specified may be higher or lower than the
376           size set by the -O command line option (or defaulted to 45); \O applies
377           only to the call of pcre_exec() for the line in which it appears.
378    
379           If  the /P modifier was present on the pattern, causing the POSIX wrap-
380           per API to be used, the only option-setting  sequences  that  have  any
381           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
382           to be passed to regexec().
383    
384           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
385           the  use  of  the  /8 modifier on the pattern. It is recognized always.
386           There may be any number of hexadecimal digits inside  the  braces.  The
387           result  is  from  one  to  six bytes, encoded according to the original
388           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
389           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
390           or indeed valid UTF-8 characters according to the later  rules  in  RFC
391           3629.
392    
393    
394    THE ALTERNATIVE MATCHING FUNCTION
395    
396           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
397           pcre_exec() to match each data line. From release 6.0, PCRE supports an
398           alternative  matching  function,  pcre_dfa_test(),  which operates in a
399           different way, and has some restrictions. The differences  between  the
400           two functions are described in the pcrematching documentation.
401    
402           If  a data line contains the \D escape sequence, or if the command line
403           contains the -dfa option, the alternative matching function is  called.
404           This function finds all possible matches at a given point. If, however,
405           the \F escape sequence is present in the data line, it stops after  the
406           first match is found. This is always the shortest possible match.
407    
408    
409    DEFAULT OUTPUT FROM PCRETEST
410    
411           This  section  describes  the output when the normal matching function,
412           pcre_exec(), is being used.
413    
414           When a match succeeds, pcretest outputs the list of captured substrings
415           that  pcre_exec()  returns,  starting with number 0 for the string that
416           matched the whole pattern. Otherwise, it outputs "No match" or "Partial
417           match:"  followed  by the partially matching substring when pcre_exec()
418           returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PARTIAL,  respectively,  and
419           otherwise  the  PCRE  negative  error  number. Here is an example of an
420           interactive pcretest run.
421    
422             $ pcretest
423             PCRE version 7.0 30-Nov-2006
424    
425               re> /^abc(\d+)/
426             data> abc123
427              0: abc123
428              1: 123
429             data> xyz
430             No match
431    
432           Note that unset capturing substrings that are not followed by one  that
433           is  set are not returned by pcre_exec(), and are not shown by pcretest.
434           In the following example, there are two capturing substrings, but  when
435           the  first  data  line  is  matched, the second, unset substring is not
436           shown. An "internal" unset substring is shown as "<unset>", as for  the
437           second data line.
438    
439               re> /(a)|(b)/
440             data> a
441              0: a
442              1: a
443             data> b
444              0: b
445              1: <unset>
446              2: b
447    
448           If  the strings contain any non-printing characters, they are output as
449           \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
450           the  pattern.  See below for the definition of non-printing characters.
451           If the pattern has the /+ modifier, the output for substring 0 is  fol-
452           lowed  by  the  the rest of the subject string, identified by "0+" like
453           this:
454    
455               re> /cat/+
456             data> cataract
457              0: cat
458              0+ aract
459    
460           If the pattern has the /g or /G modifier,  the  results  of  successive
461           matching attempts are output in sequence, like this:
462    
463               re> /\Bi(\w\w)/g
464             data> Mississippi
465              0: iss
466              1: ss
467              0: iss
468              1: ss
469              0: ipp
470              1: pp
471    
472           "No match" is output only if the first match attempt fails.
473    
474           If  any  of the sequences \C, \G, or \L are present in a data line that
475           is successfully matched, the substrings extracted  by  the  convenience
476           functions are output with C, G, or L after the string number instead of
477           a colon. This is in addition to the normal full list. The string length
478           (that  is,  the return from the extraction function) is given in paren-
479           theses after each string for \C and \G.
480    
481           Note that whereas patterns can be continued over several lines (a plain
482           ">" prompt is used for continuations), data lines may not. However new-
483           lines can be included in data by means of the \n escape (or  \r,  \r\n,
484           etc., depending on the newline sequence setting).
485    
486    
487    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
488    
489           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
490           means of the \D escape sequence or the -dfa command line  option),  the
491           output  consists  of  a list of all the matches that start at the first
492           point in the subject where there is at least one match. For example:
493    
494               re> /(tang|tangerine|tan)/
495             data> yellow tangerine\D
496              0: tangerine
497              1: tang
498              2: tan
499    
500           (Using the normal matching function on this data  finds  only  "tang".)
501           The  longest matching string is always given first (and numbered zero).
502           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
503           lowed by the partially matching substring.
504    
505           If /g is present on the pattern, the search for further matches resumes
506           at the end of the longest match. For example:
507    
508               re> /(tang|tangerine|tan)/g
509             data> yellow tangerine and tangy sultana\D
510              0: tangerine
511              1: tang
512              2: tan
513              0: tang
514              1: tan
515              0: tan
516    
517           Since the matching function does not  support  substring  capture,  the
518           escape  sequences  that  are concerned with captured substrings are not
519           relevant.
520    
521    
522    RESTARTING AFTER A PARTIAL MATCH
523    
524           When the alternative matching function has given the PCRE_ERROR_PARTIAL
525           return,  indicating that the subject partially matched the pattern, you
526           can restart the match with additional subject data by means of  the  \R
527           escape sequence. For example:
528    
529               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
530             data> 23ja\P\D
531             Partial match: 23ja
532             data> n05\R\D
533              0: n05
534    
535           For  further  information  about  partial matching, see the pcrepartial
536           documentation.
537    
538    
539    CALLOUTS
540    
541           If the pattern contains any callout requests, pcretest's callout  func-
542           tion  is  called  during  matching. This works with both matching func-
543           tions. By default, the called function displays the callout number, the
544           start  and  current  positions in the text at the callout time, and the
545           next pattern item to be tested. For example, the output
546    
547             --->pqrabcdef
548               0    ^  ^     \d
549    
550           indicates that callout number 0 occurred for a match  attempt  starting
551           at  the fourth character of the subject string, when the pointer was at
552           the seventh character of the data, and when the next pattern  item  was
553           \d.  Just  one  circumflex is output if the start and current positions
554           are the same.
555    
556           Callouts numbered 255 are assumed to be automatic callouts, inserted as
557           a  result  of the /C pattern modifier. In this case, instead of showing
558           the callout number, the offset in the pattern, preceded by a  plus,  is
559           output. For example:
560    
561               re> /\d?[A-E]\*/C
562             data> E*
563             --->E*
564              +0 ^      \d?
565              +3 ^      [A-E]
566              +8 ^^     \*
567             +10 ^ ^
568              0: E*
569    
570           The  callout  function  in pcretest returns zero (carry on matching) by
571           default, but you can use a \C item in a data line (as described  above)
572           to change this.
573    
574           Inserting  callouts can be helpful when using pcretest to check compli-
575           cated regular expressions. For further information about callouts,  see
576           the pcrecallout documentation.
577    
578    
579    NON-PRINTING CHARACTERS
580    
581           When  pcretest is outputting text in the compiled version of a pattern,
582           bytes other than 32-126 are always treated as  non-printing  characters
583           are are therefore shown as hex escapes.
584    
585           When  pcretest  is  outputting text that is a matched part of a subject
586           string, it behaves in the same way, unless a different locale has  been
587           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
588           isprint() function to distinguish printing and non-printing characters.
589    
590    
591    SAVING AND RELOADING COMPILED PATTERNS
592    
593           The facilities described in this section are  not  available  when  the
594           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
595           ifier is specified.
596    
597           When the POSIX interface is not in use, you can cause pcretest to write
598           a  compiled  pattern to a file, by following the modifiers with > and a
599           file name.  For example:
600    
601             /pattern/im >/some/file
602    
603           See the pcreprecompile documentation for a discussion about saving  and
604           re-using compiled patterns.
605    
606           The  data  that  is  written  is  binary. The first eight bytes are the
607           length of the compiled pattern data  followed  by  the  length  of  the
608           optional  study  data,  each  written as four bytes in big-endian order
609           (most significant byte first). If there is no study  data  (either  the
610           pattern was not studied, or studying did not return any data), the sec-
611           ond length is zero. The lengths are followed by an exact  copy  of  the
612           compiled pattern. If there is additional study data, this follows imme-
613           diately after the compiled pattern. After writing  the  file,  pcretest
614           expects to read a new pattern.
615    
616           A saved pattern can be reloaded into pcretest by specifing < and a file
617           name instead of a pattern. The name of the file must not  contain  a  <
618           character,  as  otherwise pcretest will interpret the line as a pattern
619           delimited by < characters.  For example:
620    
621              re> </some/file
622             Compiled regex loaded from /some/file
623             No study data
624    
625           When the pattern has been loaded, pcretest proceeds to read data  lines
626           in the usual way.
627    
628           You  can copy a file written by pcretest to a different host and reload
629           it there, even if the new host has opposite endianness to  the  one  on
630           which  the pattern was compiled. For example, you can compile on an i86
631           machine and run on a SPARC machine.
632    
633           File names for saving and reloading can be absolute  or  relative,  but
634           note  that the shell facility of expanding a file name that starts with
635           a tilde (~) is not available.
636    
637           The ability to save and reload files in pcretest is intended for  test-
638           ing  and experimentation. It is not intended for production use because
639           only a single pattern can be written to a file. Furthermore,  there  is
640           no  facility  for  supplying  custom  character  tables  for use with a
641           reloaded pattern. If the original  pattern  was  compiled  with  custom
642           tables,  an  attempt to match a subject string using a reloaded pattern
643           is likely to cause pcretest to crash.  Finally, if you attempt to  load
644           a file that is not in the correct format, the result is undefined.
645    
646    
647    SEE ALSO
648    
649           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
650           pcrepattern(3), pcreprecompile(3).
651    
652    
653    AUTHOR
654    
655           Philip Hazel
656           University Computing Service
657           Cambridge CB2 3QH, England.
658    
659    
660    \a         alarm (= BEL)  REVISION
   \b         backspace  
   \e         escape  
   \f         formfeed  
   \n         newline  
   \r         carriage return  
   \t         tab  
   \v         vertical tab  
   \nnn       octal character (up to 3 octal digits)  
   \xhh       hexadecimal character (up to 2 hex digits)  
   \x{hh...}  hexadecimal UTF-8 character  
   
   \A         pass the PCRE_ANCHORED option to pcre_exec()  
   \B         pass the PCRE_NOTBOL option to pcre_exec()  
   \Cdd       call pcre_copy_substring() for substring dd after a successful  
                match (any decimal number less than 32)  
   \Gdd       call pcre_get_substring() for substring dd after a successful  
                match (any decimal number less than 32)  
   \L         call pcre_get_substringlist() after a successful match  
   \N         pass the PCRE_NOTEMPTY option to pcre_exec()  
   \Odd       set the size of the output vector passed to pcre_exec() to dd  
                (any number of decimal digits)  
   \Z         pass the PCRE_NOTEOL option to pcre_exec()  
   
 A backslash followed by anything else just escapes the anything else. If the  
 very last character is a backslash, it is ignored. This gives a way of passing  
 an empty line as data, since a real empty line terminates the data input.  
   
 If /P was present on the regex, causing the POSIX wrapper API to be used, only  
 \B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to  
 regexec() respectively.  
   
 The use of \x{hh...} to represent UTF-8 characters is not dependent on the use  
 of the /8 modifier on the pattern. It is recognized always. There may be any  
 number of hexadecimal digits inside the braces. The result is from one to six  
 bytes, encoded according to the UTF-8 rules.  
   
   
 OUTPUT FROM PCRETEST  
 --------------------  
   
 When a match succeeds, pcretest outputs the list of captured substrings that  
 pcre_exec() returns, starting with number 0 for the string that matched the  
 whole pattern. Here is an example of an interactive pcretest run.  
   
   $ pcretest  
   PCRE version 2.06 08-Jun-1999  
   
     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 \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 addition 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.  
   
   
 COMMAND LINE OPTIONS  
 --------------------  
   
 If the -p option is given to pcretest, it is equivalent to adding /P to each  
 regular expression: the POSIX wrapper API is used to call PCRE. None of the  
 following flags has any effect in this case.  
   
 If the option -d is given to pcretest, it is equivalent to adding /D to each  
 regular expression: the internal form is output after compilation.  
   
 If the option -i is given to pcretest, it is equivalent to adding /I to each  
 regular expression: information about the compiled pattern is given after  
 compilation.  
   
 If the option -m is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled. It is equivalent to adding /M to each  
 regular expression. For compatibility with earlier versions of pcretest, -s is  
 a synonym for -m.  
   
 If the -t option is given, each compile, study, and match is run 20000 times  
 while being timed, and the resulting time per compile or match is output in  
 milliseconds. Do not set -t with -m, because you will then get the size output  
 20000 times and the timing will be distorted. If you want to change the number  
 of repetitions used for timing, edit the definition of LOOPREPEAT at the top of  
 pcretest.c  
661    
662  Philip Hazel <ph10@cam.ac.uk>         Last updated: 29 August 2009
663  August 2000         Copyright (c) 1997-2009 University of Cambridge.

Legend:
Removed from v.49  
changed lines
  Added in v.429

  ViewVC Help
Powered by ViewVC 1.1.5