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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 289 by ph10, Sun Dec 23 12:17:20 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           -help     Output a brief summary these options and then exit.
39    
40         -i        Behave  as  if  each  regex  had the /I modifier; information         -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
43         -m        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 59  DESCRIPTION Line 85  DESCRIPTION
85         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
86         lines.         lines.
87    
88           When  pcretest  is  built,  a  configuration option can specify that it
89           should be linked with the libreadline library. When this  is  done,  if
90           the input is from a terminal, it is read using the readline() function.
91           This provides line-editing and history facilities. The output from  the
92           -help option states whether or not readline() will be used.
93    
94         The program handles any number of sets of input on a single input file.         The program handles any number of sets of input on a single input file.
95         Each set starts with a regular expression, and continues with any  num-         Each set starts with a regular expression, and continues with any  num-
96         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
97    
98         Each  line  is  matched separately and independently. If you want to do         Each  data line is matched separately and independently. If you want to
99         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
100         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
101         of data line is 30,000 characters.         to encode the newline sequences. There is no limit  on  the  length  of
102           data  lines;  the  input  buffer is automatically extended if it is too
103           small.
104    
105         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
106         regular  expression is read. The regular expressions are given enclosed         regular  expression is read. The regular expressions are given enclosed
107         in any non-alphameric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example:
108    
109           /(a|bc)x+yz/           /(a|bc)x+yz/
110    
# Line 82  DESCRIPTION Line 116  DESCRIPTION
116           /abc\/def/           /abc\/def/
117    
118         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,
119         but since delimiters are always non-alphameric, this  does  not  affect         but since delimiters are always non-alphanumeric, this does not  affect
120         its  interpretation.   If the terminating delimiter is immediately fol-         its  interpretation.   If the terminating delimiter is immediately fol-
121         lowed by a backslash, for example,         lowed by a backslash, for example,
122    
# Line 101  DESCRIPTION Line 135  DESCRIPTION
135    
136  PATTERN MODIFIERS  PATTERN MODIFIERS
137    
138         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
139         PCRE_MULTILINE,  PCRE_DOTALL,  or  PCRE_EXTENDED options, respectively.         single  characters.  Following  Perl usage, these are referred to below
140         For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
141           pattern  need  not always be a slash, and no slash is used when writing
142           modifiers. Whitespace may appear between the  final  pattern  delimiter
143           and the first modifier, and between the modifiers themselves.
144    
145           The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
146           PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
147           pile()  is  called. These four modifier letters have the same effect as
148           they do in Perl. For example:
149    
150           /caseless/i           /caseless/i
151    
152         These modifier letters have the same effect as they do in  Perl.  There         The following table shows additional modifiers for setting PCRE options
153         are  others that set PCRE options that do not correspond to anything in         that do not correspond to anything in Perl:
154         Perl: /A, /E, /N, /U, and /X  set  PCRE_ANCHORED,  PCRE_DOLLAR_ENDONLY,  
155         PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA respectively.           /A              PCRE_ANCHORED
156             /C              PCRE_AUTO_CALLOUT
157             /E              PCRE_DOLLAR_ENDONLY
158             /f              PCRE_FIRSTLINE
159             /J              PCRE_DUPNAMES
160             /N              PCRE_NO_AUTO_CAPTURE
161             /U              PCRE_UNGREEDY
162             /X              PCRE_EXTRA
163             /<cr>           PCRE_NEWLINE_CR
164             /<lf>           PCRE_NEWLINE_LF
165             /<crlf>         PCRE_NEWLINE_CRLF
166             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
167             /<any>          PCRE_NEWLINE_ANY
168             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
169             /<bsr_unicode>  PCRE_BSR_UNICODE
170    
171           Those  specifying  line  ending sequences are literal strings as shown,
172           but the letters can be in either  case.  This  example  sets  multiline
173           matching with CRLF as the line ending sequence:
174    
175             /^abc/m<crlf>
176    
177         Searching  for  all  possible matches within each subject string can be         Details  of the meanings of these PCRE options are given in the pcreapi
178         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is         documentation.
179    
180       Finding all matches in a string
181    
182           Searching for all possible matches within each subject  string  can  be
183           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
184         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
185         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
186         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
187         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
188         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
189         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
190         or \B).         or \B).
191    
192         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
193         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
194         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
195         point.  If this second match fails, the start  offset  is  advanced  by         point.   If  this  second  match fails, the start offset is advanced by
196         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-
197         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
198    
199         There are a number of other modifiers for controlling the way  pcretest     Other modifiers
200         operates.  
201           There are yet more modifiers for controlling the way pcretest operates.
202    
203         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
204         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
205         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
206         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
207    
208           The  /B modifier is a debugging feature. It requests that pcretest out-
209           put a representation of the compiled byte code after compilation.  Nor-
210           mally  this  information contains length and offset values; however, if
211           /Z is also present, this data is replaced by spaces. This is a  special
212           feature for use in the automatic test scripts; it ensures that the same
213           output is generated for different internal link sizes.
214    
215         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
216         example,         example,
217    
218           /pattern/Lfr           /pattern/Lfr_FR
219    
220         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,
221         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
222         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
223         ing the regular expression. Without an /L modifier, NULL is  passed  as         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
224         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
225         it appears.         appears.
226    
227         The /I modifier requests that pcretest  output  information  about  the         The /I modifier requests that pcretest  output  information  about  the
228         compiled  expression (whether it is anchored, has a fixed first charac-         compiled  pattern (whether it is anchored, has a fixed first character,
229         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
230         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-
231         pattern is studied, the results of that are also output.         put.
232    
233         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,
234         causes  the  internal form of compiled regular expressions to be output         that is, both the /B and the /I modifiers.
235         after compilation. If the pattern was studied, the information returned  
236         is also output.         The /F modifier causes pcretest to flip the byte order of the fields in
237           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
238           facility  is  for testing the feature in PCRE that allows it to execute
239           patterns that were compiled on a host with a different endianness. This
240           feature  is  not  available  when  the POSIX interface to PCRE is being
241           used, that is, when the /P pattern modifier is specified. See also  the
242           section about saving and reloading compiled patterns below.
243    
244         The  /S  modifier causes pcre_study() to be called after the expression         The  /S  modifier causes pcre_study() to be called after the expression
245         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 264  PATTERN MODIFIERS
264         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
265    
266    
 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.  
   
   
267  DATA LINES  DATA LINES
268    
269         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 273  DATA LINES
273         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
274         following escapes are recognized:         following escapes are recognized:
275    
276           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
277           \b         backspace           \b         backspace (\x08)
278           \e         escape           \e         escape (\x27)
279           \f         formfeed           \f         formfeed (\x0c)
280           \n         newline           \n         newline (\x0a)
281           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
282           \t         tab                        (any number of digits)
283           \v         vertical tab           \r         carriage return (\x0d)
284             \t         tab (\x09)
285             \v         vertical tab (\x0b)
286           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
287           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
288           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
289                        in UTF-8 mode                        in UTF-8 mode
290           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
291                          or pcre_dfa_exec()
292           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
293                          or pcre_dfa_exec()
294           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
295                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
296           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
297                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
298                        ated by next non alphanumeric character)                        ated by next non alphanumeric character)
# Line 246  DATA LINES Line 304  DATA LINES
304           \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
305                        reached for the nth time                        reached for the nth time
306           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
307                        data                        data; this is used as the callout return value
308             \D         use the pcre_dfa_exec() match function
309             \F         only shortest match for pcre_dfa_exec()
310           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
311                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
312           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
313                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
314                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
315           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
316                        successful match                        successful match
317           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
318                          MATCH_LIMIT_RECURSION settings
319           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
320                          or pcre_dfa_exec()
321           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
322                        pcre_exec() to dd (any number of decimal                        pcre_exec() to dd (any number of digits)
323                        digits)           \P         pass the PCRE_PARTIAL option to pcre_exec()
324                          or pcre_dfa_exec()
325             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
326                          (any number of digits)
327             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
328           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
329           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
330                          or pcre_dfa_exec()
331           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
332                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
333             \>dd       start the match at offset dd (any number of digits);
334         If \M is present, pcretest calls pcre_exec() several times,  with  dif-                        this sets the startoffset argument for pcre_exec()
335         ferent  values  in  the match_limit field of the pcre_extra data struc-                        or pcre_dfa_exec()
336         ture, until it finds the minimum number that is needed for  pcre_exec()           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
337         to  complete.  This  number is a measure of the amount of recursion and                        or pcre_dfa_exec()
338         backtracking that takes place, and checking it out can be  instructive.           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
339         For  most  simple  matches, the number is quite small, but for patterns                        or pcre_dfa_exec()
340         with very large numbers of matching possibilities, it can become  large           \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
341         very quickly with increasing length of subject string.                        or pcre_dfa_exec()
342             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
343         When  \O is used, it may be higher or lower than the size set by the -O                        or pcre_dfa_exec()
344         option (or defaulted to 45); \O applies only to the call of pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
345         for the line in which it appears.                        or pcre_dfa_exec()
346    
347         A  backslash  followed by anything else just escapes the anything else.         The escapes that specify line ending  sequences  are  literal  strings,
348         If the very last character is a backslash, it is ignored. This gives  a         exactly as shown. No more than one newline setting should be present in
349         way  of  passing  an empty line as data, since a real empty line termi-         any data line.
350    
351           A backslash followed by anything else just escapes the  anything  else.
352           If  the very last character is a backslash, it is ignored. This gives a
353           way of passing an empty line as data, since a real  empty  line  termi-
354         nates the data input.         nates the data input.
355    
356         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-
357         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
358         regexec() respectively.         the  pcre_extra  data structure, until it finds the minimum numbers for
359           each parameter that allow pcre_exec() to complete. The match_limit num-
360           ber  is  a  measure of the amount of backtracking that takes place, and
361           checking it out can be instructive. For most simple matches, the number
362           is  quite  small,  but for patterns with very large numbers of matching
363           possibilities, it can become large very quickly with increasing  length
364           of subject string. The match_limit_recursion number is a measure of how
365           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
366           memory is needed to complete the match attempt.
367    
368           When  \O  is  used, the value specified may be higher or lower than the
369           size set by the -O command line option (or defaulted to 45); \O applies
370           only to the call of pcre_exec() for the line in which it appears.
371    
372           If  the /P modifier was present on the pattern, causing the POSIX wrap-
373           per API to be used, the only option-setting  sequences  that  have  any
374           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
375           to be passed to regexec().
376    
377         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
378         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.
379         There may be any number of hexadecimal digits inside  the  braces.  The         There may be any number of hexadecimal digits inside  the  braces.  The
380         result  is from one to six bytes, encoded according to the UTF-8 rules.         result  is  from  one  to  six bytes, encoded according to the original
381           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
382           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
383           or indeed valid UTF-8 characters according to the later  rules  in  RFC
384           3629.
385    
386    
387    THE ALTERNATIVE MATCHING FUNCTION
388    
389           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
390           pcre_exec() to match each data line. From release 6.0, PCRE supports an
391           alternative  matching  function,  pcre_dfa_test(),  which operates in a
392           different way, and has some restrictions. The differences  between  the
393           two functions are described in the pcrematching documentation.
394    
395  OUTPUT FROM PCRETEST         If  a data line contains the \D escape sequence, or if the command line
396           contains the -dfa option, the alternative matching function is  called.
397           This function finds all possible matches at a given point. If, however,
398           the \F escape sequence is present in the data line, it stops after  the
399           first match is found. This is always the shortest possible match.
400    
401    
402    DEFAULT OUTPUT FROM PCRETEST
403    
404           This  section  describes  the output when the normal matching function,
405           pcre_exec(), is being used.
406    
407         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
408         that  pcre_exec()  returns,  starting with number 0 for the string that         that  pcre_exec()  returns,  starting with number 0 for the string that
409         matched the whole  pattern.  Here  is  an  example  of  an  interactive         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
410         pcretest run.         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
411           TIAL, respectively, and otherwise the PCRE negative error number.  Here
412           is an example of an interactive pcretest run.
413    
414           $ pcretest           $ pcretest
415           PCRE version 4.00 08-Jan-2003           PCRE version 7.0 30-Nov-2006
416    
417             re> /^abc(\d+)/             re> /^abc(\d+)/
418           data> abc123           data> abc123
# Line 310  OUTPUT FROM PCRETEST Line 421  OUTPUT FROM PCRETEST
421           data> xyz           data> xyz
422           No match           No match
423    
424         If  the strings contain any non-printing characters, they are output as         Note  that unset capturing substrings that are not followed by one that
425         \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on         is set are not returned by pcre_exec(), and are not shown by  pcretest.
426         the  pattern.  If  the pattern has the /+ modifier, then the output for         In  the following example, there are two capturing substrings, but when
427         substring 0 is followed by the the rest of the subject string,  identi-         the first data line is matched, the  second,  unset  substring  is  not
428         fied by "0+" like this:         shown.  An "internal" unset substring is shown as "<unset>", as for the
429           second data line.
430    
431               re> /(a)|(b)/
432             data> a
433              0: a
434              1: a
435             data> b
436              0: b
437              1: <unset>
438              2: b
439    
440           If the strings contain any non-printing characters, they are output  as
441           \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
442           the pattern. See below for the definition of  non-printing  characters.
443           If  the pattern has the /+ modifier, the output for substring 0 is fol-
444           lowed by the the rest of the subject string, identified  by  "0+"  like
445           this:
446    
447             re> /cat/+             re> /cat/+
448           data> cataract           data> cataract
# Line 342  OUTPUT FROM PCRETEST Line 470  OUTPUT FROM PCRETEST
470         (that is, the return from the extraction function) is given  in  paren-         (that is, the return from the extraction function) is given  in  paren-
471         theses after each string for \C and \G.         theses after each string for \C and \G.
472    
473         Note  that  while patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
474         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
475         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,
476           etc., depending on the newline sequence setting).
477    
478    
479    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
480    
481           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
482           means  of  the \D escape sequence or the -dfa command line option), the
483           output consists of a list of all the matches that start  at  the  first
484           point in the subject where there is at least one match. For example:
485    
486               re> /(tang|tangerine|tan)/
487             data> yellow tangerine\D
488              0: tangerine
489              1: tang
490              2: tan
491    
492           (Using  the  normal  matching function on this data finds only "tang".)
493           The longest matching string is always given first (and numbered  zero).
494    
495           If /g is present on the pattern, the search for further matches resumes
496           at the end of the longest match. For example:
497    
498               re> /(tang|tangerine|tan)/g
499             data> yellow tangerine and tangy sultana\D
500              0: tangerine
501              1: tang
502              2: tan
503              0: tang
504              1: tan
505              0: tan
506    
507           Since the matching function does not  support  substring  capture,  the
508           escape  sequences  that  are concerned with captured substrings are not
509           relevant.
510    
511    
512    RESTARTING AFTER A PARTIAL MATCH
513    
514           When the alternative matching function has given the PCRE_ERROR_PARTIAL
515           return,  indicating that the subject partially matched the pattern, you
516           can restart the match with additional subject data by means of  the  \R
517           escape sequence. For example:
518    
519               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
520             data> 23ja\P\D
521             Partial match: 23ja
522             data> n05\R\D
523              0: n05
524    
525           For  further  information  about  partial matching, see the pcrepartial
526           documentation.
527    
528    
529    CALLOUTS
530    
531           If the pattern contains any callout requests, pcretest's callout  func-
532           tion  is  called  during  matching. This works with both matching func-
533           tions. By default, the called function displays the callout number, the
534           start  and  current  positions in the text at the callout time, and the
535           next pattern item to be tested. For example, the output
536    
537             --->pqrabcdef
538               0    ^  ^     \d
539    
540           indicates that callout number 0 occurred for a match  attempt  starting
541           at  the fourth character of the subject string, when the pointer was at
542           the seventh character of the data, and when the next pattern  item  was
543           \d.  Just  one  circumflex is output if the start and current positions
544           are the same.
545    
546           Callouts numbered 255 are assumed to be automatic callouts, inserted as
547           a  result  of the /C pattern modifier. In this case, instead of showing
548           the callout number, the offset in the pattern, preceded by a  plus,  is
549           output. For example:
550    
551               re> /\d?[A-E]\*/C
552             data> E*
553             --->E*
554              +0 ^      \d?
555              +3 ^      [A-E]
556              +8 ^^     \*
557             +10 ^ ^
558              0: E*
559    
560           The  callout  function  in pcretest returns zero (carry on matching) by
561           default, but you can use a \C item in a data line (as described  above)
562           to change this.
563    
564           Inserting  callouts can be helpful when using pcretest to check compli-
565           cated regular expressions. For further information about callouts,  see
566           the pcrecallout documentation.
567    
568    
569    NON-PRINTING CHARACTERS
570    
571           When  pcretest is outputting text in the compiled version of a pattern,
572           bytes other than 32-126 are always treated as  non-printing  characters
573           are are therefore shown as hex escapes.
574    
575           When  pcretest  is  outputting text that is a matched part of a subject
576           string, it behaves in the same way, unless a different locale has  been
577           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
578           isprint() function to distinguish printing and non-printing characters.
579    
580    
581    SAVING AND RELOADING COMPILED PATTERNS
582    
583           The  facilities  described  in  this section are not available when the
584           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
585           ifier is specified.
586    
587           When the POSIX interface is not in use, you can cause pcretest to write
588           a compiled pattern to a file, by following the modifiers with >  and  a
589           file name.  For example:
590    
591             /pattern/im >/some/file
592    
593           See  the pcreprecompile documentation for a discussion about saving and
594           re-using compiled patterns.
595    
596           The data that is written is binary.  The  first  eight  bytes  are  the
597           length  of  the  compiled  pattern  data  followed by the length of the
598           optional study data, each written as four  bytes  in  big-endian  order
599           (most  significant  byte  first). If there is no study data (either the
600           pattern was not studied, or studying did not return any data), the sec-
601           ond  length  is  zero. The lengths are followed by an exact copy of the
602           compiled pattern. If there is additional study data, this follows imme-
603           diately  after  the  compiled pattern. After writing the file, pcretest
604           expects to read a new pattern.
605    
606           A saved pattern can be reloaded into pcretest by specifing < and a file
607           name  instead  of  a pattern. The name of the file must not contain a <
608           character, as otherwise pcretest will interpret the line as  a  pattern
609           delimited by < characters.  For example:
610    
611              re> </some/file
612             Compiled regex loaded from /some/file
613             No study data
614    
615           When  the pattern has been loaded, pcretest proceeds to read data lines
616           in the usual way.
617    
618           You can copy a file written by pcretest to a different host and  reload
619           it  there,  even  if the new host has opposite endianness to the one on
620           which the pattern was compiled. For example, you can compile on an  i86
621           machine and run on a SPARC machine.
622    
623           File  names  for  saving and reloading can be absolute or relative, but
624           note that the shell facility of expanding a file name that starts  with
625           a tilde (~) is not available.
626    
627           The  ability to save and reload files in pcretest is intended for test-
628           ing and experimentation. It is not intended for production use  because
629           only  a  single pattern can be written to a file. Furthermore, there is
630           no facility for supplying  custom  character  tables  for  use  with  a
631           reloaded  pattern.  If  the  original  pattern was compiled with custom
632           tables, an attempt to match a subject string using a  reloaded  pattern
633           is  likely to cause pcretest to crash.  Finally, if you attempt to load
634           a file that is not in the correct format, the result is undefined.
635    
636    
637    SEE ALSO
638    
639           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
640           pcrepattern(3), pcreprecompile(3).
641    
642    
643  AUTHOR  AUTHOR
644    
645         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
646         University Computing Service,         University Computing Service
647         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
648    
649    
650    REVISION
651    
652  Last updated: 09 December 2003         Last updated: 18 December 2007
653  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

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