/[pcre]/code/trunk/doc/pcretest.txt
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# Line 7  NAME Line 7  NAME
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [options] [source] [destination]         pcretest [options] [input file [output file]]
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 the PCRE library function calls and their         documentation. For details of the PCRE library function calls and their
17         options, see the pcreapi documentation.         options, see the pcreapi documentation. The input  for  pcretest  is  a
18           sequence  of  regular expression patterns and strings to be matched, as
19           described below. The output shows the result of each match. Options  on
20           the command line and the patterns control PCRE options and exactly what
21           is output.
22    
23    
24  OPTIONS  COMMAND LINE OPTIONS
25    
26         -b        Behave as if each regex has the /B (show bytecode)  modifier;         -b        Behave as if each pattern has the /B (show byte  code)  modi-
27                   the internal form is output after compilation.                   fier; the internal form is output after compilation.
28    
29         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
30                   able  information  about  the  optional  features  that   are                   able  information  about  the  optional  features  that   are
31                   included, and then exit.                   included, and then exit.
32    
33         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the         -d        Behave  as  if  each pattern has the /D (debug) modifier; the
34                   internal form and information about the compiled  pattern  is                   internal form and information about the compiled  pattern  is
35                   output after compilation; -d is equivalent to -b -i.                   output after compilation; -d is equivalent to -b -i.
36    
# Line 37  OPTIONS Line 41  OPTIONS
41    
42         -help     Output a brief summary these options and then exit.         -help     Output a brief summary these options and then exit.
43    
44         -i        Behave as if each regex  has  the  /I  modifier;  information         -i        Behave as if each pattern has the  /I  modifier;  information
45                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
46    
47         -M        Behave  as if each data line contains the \M escape sequence;         -M        Behave  as if each data line contains the \M escape sequence;
# Line 47  OPTIONS Line 51  OPTIONS
51    
52         -m        Output the size of each compiled pattern after  it  has  been         -m        Output the size of each compiled pattern after  it  has  been
53                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled.  This  is  equivalent  to adding /M to each regular
54                   expression.  For  compatibility  with  earlier  versions   of                   expression.
                  pcretest, -s is a synonym for -m.  
55    
56         -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
57                   when calling pcre_exec() or pcre_dfa_exec() to be osize.  The                   when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
58                   default  value is 45, which is enough for 14 capturing subex-                   default value is 45, which is enough for 14 capturing  subex-
59                   pressions  for  pcre_exec()  or  22  different  matches   for                   pressions   for  pcre_exec()  or  22  different  matches  for
60                   pcre_dfa_exec().  The vector size can be changed for individ-                   pcre_dfa_exec(). The vector size can be changed for  individ-
61                   ual matching calls by including \O  in  the  data  line  (see                   ual  matching  calls  by  including  \O in the data line (see
62                   below).                   below).
63    
64         -p        Behave  as if each regex has the /P modifier; the POSIX wrap-         -p        Behave as if each pattern has  the  /P  modifier;  the  POSIX
65                   per API is used to call PCRE. None of the other  options  has                   wrapper  API  is used to call PCRE. None of the other options
66                   any effect when -p is set.                   has any effect when -p is set.
67    
68         -q        Do  not output the version number of pcretest at the start of         -q        Do not output the version number of pcretest at the start  of
69                   execution.                   execution.
70    
71         -S size   On Unix-like systems, set the size of the  runtime  stack  to         -S size   On  Unix-like  systems, set the size of the run-time stack to
72                   size megabytes.                   size megabytes.
73    
74         -t        Run  each  compile, study, and match many times with a timer,         -s        Behave as if each pattern  has  the  /S  modifier;  in  other
75                   and output resulting time per compile or match (in  millisec-                   words,  force  each  pattern  to  be studied. If the /I or /D
76                   onds).  Do  not set -m with -t, because you will then get the                   option is present on a pattern (requesting output  about  the
77                   size output a zillion times, and  the  timing  will  be  dis-                   compiled  pattern),  information about the result of studying
78                   torted.  You  can  control  the number of iterations that are                   is not included when studying is caused only by -s  and  nei-
79                   used for timing by following -t with a number (as a  separate                   ther -i nor -d is present on the command line. This behaviour
80                     means that the output from tests that are run with and  with-
81                     out  -s  should be identical, except when options that output
82                     information about the actual running of a match are set.  The
83                     -M,  -t,  and  -tm  options,  which  give  information  about
84                     resources used, are likely to produce different  output  with
85                     and  without  -s.  Output may also differ if the /C option is
86                     present on an individual pattern. This uses callouts to trace
87                     the  the  matching process, and this may be different between
88                     studied and non-studied patterns.  If  the  pattern  contains
89                     (*MARK)  items  there  may  also be differences, for the same
90                     reason. The -s command line option can be overridden for spe-
91                     cific  patterns  that  should  never  be  studied (see the /S
92                     option below).
93    
94           -t        Run each compile, study, and match many times with  a  timer,
95                     and  output resulting time per compile or match (in millisec-
96                     onds). Do not set -m with -t, because you will then  get  the
97                     size  output  a  zillion  times,  and the timing will be dis-
98                     torted. You can control the number  of  iterations  that  are
99                     used  for timing by following -t with a number (as a separate
100                   item on the command line). For example, "-t 1000" would iter-                   item on the command line). For example, "-t 1000" would iter-
101                   ate 1000 times. The default is to iterate 500000 times.                   ate 1000 times. The default is to iterate 500000 times.
102    
# Line 83  OPTIONS Line 106  OPTIONS
106    
107  DESCRIPTION  DESCRIPTION
108    
109         If  pcretest  is  given two filename arguments, it reads from the first         If pcretest is given two filename arguments, it reads  from  the  first
110         and writes to the second. If it is given only one filename argument, it         and writes to the second. If it is given only one filename argument, it
111         reads  from  that  file  and writes to stdout. Otherwise, it reads from         reads from that file and writes to stdout.  Otherwise,  it  reads  from
112         stdin and writes to stdout, and prompts for each line of  input,  using         stdin  and  writes to stdout, and prompts for each line of input, using
113         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
114         lines.         lines.
115    
116         When pcretest is built, a configuration  option  can  specify  that  it         When  pcretest  is  built,  a  configuration option can specify that it
117         should  be  linked  with the libreadline library. When this is done, if         should be linked with the libreadline library. When this  is  done,  if
118         the input is from a terminal, it is read using the readline() function.         the input is from a terminal, it is read using the readline() function.
119         This  provides line-editing and history facilities. The output from the         This provides line-editing and history facilities. The output from  the
120         -help option states whether or not readline() will be used.         -help option states whether or not readline() will be used.
121    
122         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.
123         Each  set starts with a regular expression, and continues with any num-         Each set starts with a regular expression, and continues with any  num-
124         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
125    
126         Each data line is matched separately and independently. If you want  to         Each  data line is matched separately and independently. If you want to
127         do multi-line matches, you have to use the \n escape sequence (or \r or         do multi-line matches, you have to use the \n escape sequence (or \r or
128         \r\n, etc., depending on the newline setting) in a single line of input         \r\n, etc., depending on the newline setting) in a single line of input
129         to  encode  the  newline  sequences. There is no limit on the length of         to encode the newline sequences. There is no limit  on  the  length  of
130         data lines; the input buffer is automatically extended  if  it  is  too         data  lines;  the  input  buffer is automatically extended if it is too
131         small.         small.
132    
133         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
134         regular expression is read. The regular expressions are given  enclosed         regular  expression is read. The regular expressions are given enclosed
135         in any non-alphanumeric delimiters other than backslash, for example:         in any non-alphanumeric delimiters other than backslash, for example:
136    
137           /(a|bc)x+yz/           /(a|bc)x+yz/
138    
139         White  space before the initial delimiter is ignored. A regular expres-         White space before the initial delimiter is ignored. A regular  expres-
140         sion may be continued over several input lines, in which case the  new-         sion  may be continued over several input lines, in which case the new-
141         line  characters  are included within it. It is possible to include the         line characters are included within it. It is possible to  include  the
142         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
143    
144           /abc\/def/           /abc\/def/
145    
146         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,
147         but  since delimiters are always non-alphanumeric, this does not affect         but since delimiters are always non-alphanumeric, this does not  affect
148         its interpretation.  If the terminating delimiter is  immediately  fol-         its  interpretation.   If the terminating delimiter is immediately fol-
149         lowed by a backslash, for example,         lowed by a backslash, for example,
150    
151           /abc/\           /abc/\
152    
153         then  a  backslash  is added to the end of the pattern. This is done to         then a backslash is added to the end of the pattern. This  is  done  to
154         provide a way of testing the error condition that arises if  a  pattern         provide  a  way of testing the error condition that arises if a pattern
155         finishes with a backslash, because         finishes with a backslash, because
156    
157           /abc\/           /abc\/
158    
159         is  interpreted as the first line of a pattern that starts with "abc/",         is interpreted as the first line of a pattern that starts with  "abc/",
160         causing pcretest to read the next line as a continuation of the regular         causing pcretest to read the next line as a continuation of the regular
161         expression.         expression.
162    
163    
164  PATTERN MODIFIERS  PATTERN MODIFIERS
165    
166         A  pattern may be followed by any number of modifiers, which are mostly         A pattern may be followed by any number of modifiers, which are  mostly
167         single characters. Following Perl usage, these are  referred  to  below         single  characters.  Following  Perl usage, these are referred to below
168         as,  for  example,  "the /i modifier", even though the delimiter of the         as, for example, "the /i modifier", even though the  delimiter  of  the
169         pattern need not always be a slash, and no slash is used  when  writing         pattern  need  not always be a slash, and no slash is used when writing
170         modifiers.  Whitespace  may  appear between the final pattern delimiter         modifiers. White space may appear between the final  pattern  delimiter
171         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
172    
173         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
174         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
175         pile() is called. These four modifier letters have the same  effect  as         pile()  is  called. These four modifier letters have the same effect as
176         they do in Perl. For example:         they do in Perl. For example:
177    
178           /caseless/i           /caseless/i
179    
180         The  following  table  shows additional modifiers for setting PCRE com-         The following table shows additional modifiers for  setting  PCRE  com-
181         pile-time options that do not correspond to anything in Perl:         pile-time options that do not correspond to anything in Perl:
182    
183           /8              PCRE_UTF8           /8              PCRE_UTF8
# Line 178  PATTERN MODIFIERS Line 201  PATTERN MODIFIERS
201           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
202           /<bsr_unicode>  PCRE_BSR_UNICODE           /<bsr_unicode>  PCRE_BSR_UNICODE
203    
204         The modifiers that are enclosed in angle brackets are  literal  strings         The  modifiers  that are enclosed in angle brackets are literal strings
205         as  shown,  including  the  angle  brackets,  but the letters can be in         as shown, including the angle brackets, but the letters within  can  be
206         either case. This example sets multiline matching with CRLF as the line         in  either case.  This example sets multiline matching with CRLF as the
207         ending sequence:         line ending sequence:
208    
209           /^abc/m<crlf>           /^abc/m<CRLF>
210    
211         As well as turning on the PCRE_UTF8 option, the /8 modifier also causes         As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
212         any non-printing characters in output strings to be printed  using  the         any  non-printing  characters in output strings to be printed using the
213         \x{hh...}  notation  if they are valid UTF-8 sequences. Full details of         \x{hh...} notation if they are valid UTF-8 sequences. Full  details  of
214         the PCRE options are given in the pcreapi documentation.         the PCRE options are given in the pcreapi documentation.
215    
216     Finding all matches in a string     Finding all matches in a string
217    
218         Searching for all possible matches within each subject  string  can  be         Searching  for  all  possible matches within each subject string can be
219         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is
220         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
221         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
222         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
223         string  (which  is in effect what Perl does), whereas the latter passes         string (which is in effect what Perl does), whereas the  latter  passes
224         over a shortened substring. This makes a  difference  to  the  matching         over  a  shortened  substring.  This makes a difference to the matching
225         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
226         or \B).         or \B).
227    
228         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
229         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and         string, the next  call  is  done  with  the  PCRE_NOTEMPTY_ATSTART  and
230         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,         PCRE_ANCHORED  flags  set  in  order  to search for another, non-empty,
231         match  at  the same point. If this second match fails, the start offset         match at the same point. If this second match fails, the  start  offset
232         is advanced, and the normal match is retried.  This  imitates  the  way         is  advanced,  and  the  normal match is retried. This imitates the way
233         Perl handles such cases when using the /g modifier or the split() func-         Perl handles such cases when using the /g modifier or the split() func-
234         tion. Normally, the start offset is advanced by one character,  but  if         tion.  Normally,  the start offset is advanced by one character, but if
235         the  newline  convention  recognizes CRLF as a newline, and the current         the newline convention recognizes CRLF as a newline,  and  the  current
236         character is CR followed by LF, an advance of two is used.         character is CR followed by LF, an advance of two is used.
237    
238     Other modifiers     Other modifiers
239    
240         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
241    
242         The /+ modifier requests that as well as outputting the substring  that         The  /+ modifier requests that as well as outputting the substring that
243         matched  the  entire  pattern,  pcretest  should in addition output the         matched the entire pattern, pcretest  should  in  addition  output  the
244         remainder of the subject string. This is useful  for  tests  where  the         remainder  of  the  subject  string. This is useful for tests where the
245         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring. If the +  modi-
246           fier  appears  twice, the same action is taken for captured substrings.
247           In each case the remainder is output on the following line with a  plus
248           character following the capture number.
249    
250           The  /=  modifier  requests  that  the values of all potential captured
251           parentheses be output after a match by pcre_exec().  By  default,  only
252           those up to the highest one actually used in the match are output (cor-
253           responding to the return code from pcre_exec()). Values in the  offsets
254           vector  corresponding  to higher numbers should be set to -1, and these
255           are output as "<unset>". This modifier gives a  way  of  checking  that
256           this is happening.
257    
258         The  /B modifier is a debugging feature. It requests that pcretest out-         The  /B modifier is a debugging feature. It requests that pcretest out-
259         put a representation of the compiled byte code after compilation.  Nor-         put a representation of the compiled byte code after compilation.  Nor-
# Line 270  PATTERN MODIFIERS Line 304  PATTERN MODIFIERS
304         The  /M  modifier causes the size of memory block used to hold the com-         The  /M  modifier causes the size of memory block used to hold the com-
305         piled pattern to be output.         piled pattern to be output.
306    
307         The /S modifier causes pcre_study() to be called after  the  expression         If the /S modifier appears once, it causes pcre_study()  to  be  called
308         has been compiled, and the results used when the expression is matched.         after  the  expression has been compiled, and the results used when the
309           expression is matched. If /S appears  twice,  it  suppresses  studying,
310           even if it was requested externally by the -s command line option. This
311           makes it possible to specify that certain patterns are always  studied,
312           and others are never studied, independently of -s. This feature is used
313           in the test files in a few cases where the output is different when the
314           pattern is studied.
315    
316         The  /T  modifier  must be followed by a single digit. It causes a spe-         The  /T  modifier  must be followed by a single digit. It causes a spe-
317         cific set of built-in character tables to be passed to  pcre_compile().         cific set of built-in character tables to be passed to  pcre_compile().
# Line 306  PATTERN MODIFIERS Line 346  PATTERN MODIFIERS
346  DATA LINES  DATA LINES
347    
348         Before each data line is passed to pcre_exec(),  leading  and  trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
349         whitespace  is  removed,  and it is then scanned for \ escapes. Some of         white  space  is removed, and it is then scanned for \ escapes. Some of
350         these are pretty esoteric features, intended for checking out  some  of         these are pretty esoteric features, intended for checking out  some  of
351         the  more  complicated features of PCRE. If you are just testing "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
352         nary" regular expressions, you probably don't need any  of  these.  The         nary" regular expressions, you probably don't need any  of  these.  The
# Line 315  DATA LINES Line 355  DATA LINES
355           \a         alarm (BEL, \x07)           \a         alarm (BEL, \x07)
356           \b         backspace (\x08)           \b         backspace (\x08)
357           \e         escape (\x27)           \e         escape (\x27)
358           \f         formfeed (\x0c)           \f         form feed (\x0c)
359           \n         newline (\x0a)           \n         newline (\x0a)
360           \qdd       set the PCRE_MATCH_LIMIT limit to dd           \qdd       set the PCRE_MATCH_LIMIT limit to dd
361                        (any number of digits)                        (any number of digits)
# Line 463  DEFAULT OUTPUT FROM PCRETEST Line 503  DEFAULT OUTPUT FROM PCRETEST
503         (Note  that  this is the entire substring that was inspected during the         (Note  that  this is the entire substring that was inspected during the
504         partial match; it may include characters before the actual match  start         partial match; it may include characters before the actual match  start
505         if  a  lookbehind assertion, \K, \b, or \B was involved.) For any other         if  a  lookbehind assertion, \K, \b, or \B was involved.) For any other
506         returns, it outputs the PCRE negative error number. Here is an  example         return, pcretest outputs the PCRE negative error  number  and  a  short
507         of an interactive pcretest run.         descriptive  phrase.  If  the error is a failed UTF-8 string check, the
508           byte offset of the start of the failing character and the  reason  code
509           are  also  output,  provided  that  the size of the output vector is at
510           least two. Here is an example of an interactive pcretest run.
511    
512           $ pcretest           $ pcretest
513           PCRE version 7.0 30-Nov-2006           PCRE version 8.13 2011-04-30
514    
515             re> /^abc(\d+)/             re> /^abc(\d+)/
516           data> abc123           data> abc123
# Line 476  DEFAULT OUTPUT FROM PCRETEST Line 519  DEFAULT OUTPUT FROM PCRETEST
519           data> xyz           data> xyz
520           No match           No match
521    
522         Note  that unset capturing substrings that are not followed by one that         Unset capturing substrings that are not followed by one that is set are
523         is set are not returned by pcre_exec(), and are not shown by  pcretest.         not returned by pcre_exec(), and are not shown by pcretest. In the fol-
524         In  the following example, there are two capturing substrings, but when         lowing example, there are two capturing substrings, but when the  first
525         the first data line is matched, the  second,  unset  substring  is  not         data  line  is  matched,  the  second, unset substring is not shown. An
526         shown.  An "internal" unset substring is shown as "<unset>", as for the         "internal" unset substring is shown as "<unset>",  as  for  the  second
527         second data line.         data line.
528    
529             re> /(a)|(b)/             re> /(a)|(b)/
530           data> a           data> a
# Line 492  DEFAULT OUTPUT FROM PCRETEST Line 535  DEFAULT OUTPUT FROM PCRETEST
535            1: <unset>            1: <unset>
536            2: b            2: b
537    
538         If the strings contain any non-printing characters, they are output  as         If  the strings contain any non-printing characters, they are output as
539         \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on         \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
540         the pattern. See below for the definition of  non-printing  characters.         the  pattern.  See below for the definition of non-printing characters.
541         If  the pattern has the /+ modifier, the output for substring 0 is fol-         If the pattern has the /+ modifier, the output for substring 0 is  fol-
542         lowed by the the rest of the subject string, identified  by  "0+"  like         lowed  by  the  the rest of the subject string, identified by "0+" like
543         this:         this:
544    
545             re> /cat/+             re> /cat/+
# Line 504  DEFAULT OUTPUT FROM PCRETEST Line 547  DEFAULT OUTPUT FROM PCRETEST
547            0: cat            0: cat
548            0+ aract            0+ aract
549    
550         If  the  pattern  has  the /g or /G modifier, the results of successive         If the pattern has the /g or /G modifier,  the  results  of  successive
551         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
552    
553             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 516  DEFAULT OUTPUT FROM PCRETEST Line 559  DEFAULT OUTPUT FROM PCRETEST
559            0: ipp            0: ipp
560            1: pp            1: pp
561    
562         "No match" is output only if the first match attempt fails.         "No  match" is output only if the first match attempt fails. Here is an
563           example of a failure message (the offset 4 that is specified by \>4  is
564           past the end of the subject string):
565    
566               re> /xyz/
567             data> xyz\>4
568             Error -24 (bad offset value)
569    
570         If any of the sequences \C, \G, or \L are present in a data  line  that         If  any  of the sequences \C, \G, or \L are present in a data line that
571         is  successfully  matched,  the substrings extracted by the convenience         is successfully matched, the substrings extracted  by  the  convenience
572         functions are output with C, G, or L after the string number instead of         functions are output with C, G, or L after the string number instead of
573         a colon. This is in addition to the normal full list. The string length         a colon. This is in addition to the normal full list. The string length
574         (that is, the return from the extraction function) is given  in  paren-         (that  is,  the return from the extraction function) is given in paren-
575         theses after each string for \C and \G.         theses after each string for \C and \G.
576    
577         Note that whereas patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
578         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
579         lines  can  be included in data by means of the \n escape (or \r, \r\n,         lines can be included in data by means of the \n escape (or  \r,  \r\n,
580         etc., depending on the newline sequence setting).         etc., depending on the newline sequence setting).
581    
582    
583  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
584    
585         When the alternative matching function, pcre_dfa_exec(),  is  used  (by         When  the  alternative  matching function, pcre_dfa_exec(), is used (by
586         means  of  the \D escape sequence or the -dfa command line option), the         means of the \D escape sequence or the -dfa command line  option),  the
587         output consists of a list of all the matches that start  at  the  first         output  consists  of  a list of all the matches that start at the first
588         point in the subject where there is at least one match. For example:         point in the subject where there is at least one match. For example:
589    
590             re> /(tang|tangerine|tan)/             re> /(tang|tangerine|tan)/
# Line 544  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 593  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
593            1: tang            1: tang
594            2: tan            2: tan
595    
596         (Using  the  normal  matching function on this data finds only "tang".)         (Using the normal matching function on this data  finds  only  "tang".)
597         The longest matching string is always given first (and numbered  zero).         The  longest matching string is always given first (and numbered zero).
598         After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-         After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
599         lowed by the partially matching  substring.  (Note  that  this  is  the         lowed  by  the  partially  matching  substring.  (Note that this is the
600         entire  substring  that  was inspected during the partial match; it may         entire substring that was inspected during the partial  match;  it  may
601         include characters before the actual match start if a lookbehind asser-         include characters before the actual match start if a lookbehind asser-
602         tion, \K, \b, or \B was involved.)         tion, \K, \b, or \B was involved.)
603    
# Line 564  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 613  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
613            1: tan            1: tan
614            0: tan            0: tan
615    
616         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
617         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
618         relevant.         relevant.
619    
620    
621  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
622    
623         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
624         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
625         can restart the match with additional subject data by means of  the  \R         can  restart  the match with additional subject data by means of the \R
626         escape sequence. For example:         escape sequence. For example:
627    
628             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
# Line 582  RESTARTING AFTER A PARTIAL MATCH Line 631  RESTARTING AFTER A PARTIAL MATCH
631           data> n05\R\D           data> n05\R\D
632            0: n05            0: n05
633    
634         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
635         documentation.         documentation.
636    
637    
638  CALLOUTS  CALLOUTS
639    
640         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
641         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
642         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
643         start  and  current  positions in the text at the callout time, and the         start and current positions in the text at the callout  time,  and  the
644         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
645    
646           --->pqrabcdef           --->pqrabcdef
647             0    ^  ^     \d             0    ^  ^     \d
648    
649         indicates that callout number 0 occurred for a match  attempt  starting         indicates  that  callout number 0 occurred for a match attempt starting
650         at  the fourth character of the subject string, when the pointer was at         at the fourth character of the subject string, when the pointer was  at
651         the seventh character of the data, and when the next pattern  item  was         the  seventh  character of the data, and when the next pattern item was
652         \d.  Just  one  circumflex is output if the start and current positions         \d. Just one circumflex is output if the start  and  current  positions
653         are the same.         are the same.
654    
655         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
656         a  result  of the /C pattern modifier. In this case, instead of showing         a result of the /C pattern modifier. In this case, instead  of  showing
657         the callout number, the offset in the pattern, preceded by a  plus,  is         the  callout  number, the offset in the pattern, preceded by a plus, is
658         output. For example:         output. For example:
659    
660             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 617  CALLOUTS Line 666  CALLOUTS
666           +10 ^ ^           +10 ^ ^
667            0: E*            0: E*
668    
669           If a pattern contains (*MARK) items, an additional line is output when-
670           ever  a  change  of  latest mark is passed to the callout function. For
671           example:
672    
673               re> /a(*MARK:X)bc/C
674             data> abc
675             --->abc
676              +0 ^       a
677              +1 ^^      (*MARK:X)
678             +10 ^^      b
679             Latest Mark: X
680             +11 ^ ^     c
681             +12 ^  ^
682              0: abc
683    
684           The mark changes between matching "a" and "b", but stays the  same  for
685           the  rest  of  the match, so nothing more is output. If, as a result of
686           backtracking, the mark reverts to being unset, the  text  "<unset>"  is
687           output.
688    
689         The  callout  function  in pcretest returns zero (carry on matching) by         The  callout  function  in pcretest returns zero (carry on matching) by
690         default, but you can use a \C item in a data line (as described  above)         default, but you can use a \C item in a data line (as described  above)
691         to change this.         to change this and other parameters of the callout.
692    
693         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting  callouts can be helpful when using pcretest to check compli-
694         cated regular expressions. For further information about callouts,  see         cated regular expressions. For further information about callouts,  see
# Line 641  NON-PRINTING CHARACTERS Line 710  NON-PRINTING CHARACTERS
710  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
711    
712         The facilities described in this section are  not  available  when  the         The facilities described in this section are  not  available  when  the
713         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-         POSIX  interface  to  PCRE  is being used, that is, when the /P pattern
714         ifier is specified.         modifier is specified.
715    
716         When the POSIX interface is not in use, you can cause pcretest to write         When the POSIX interface is not in use, you can cause pcretest to write
717         a  compiled  pattern to a file, by following the modifiers with > and a         a  compiled  pattern to a file, by following the modifiers with > and a
# Line 663  SAVING AND RELOADING COMPILED PATTERNS Line 732  SAVING AND RELOADING COMPILED PATTERNS
732         diately after the compiled pattern. After writing  the  file,  pcretest         diately after the compiled pattern. After writing  the  file,  pcretest
733         expects to read a new pattern.         expects to read a new pattern.
734    
735         A saved pattern can be reloaded into pcretest by specifing < and a file         A  saved  pattern  can  be reloaded into pcretest by specifying < and a
736         name instead of a pattern. The name of the file must not  contain  a  <         file name instead of a pattern. The name of the file must not contain a
737         character,  as  otherwise pcretest will interpret the line as a pattern         < character, as otherwise pcretest will interpret the line as a pattern
738         delimited by < characters.  For example:         delimited by < characters.  For example:
739    
740            re> </some/file            re> </some/file
741           Compiled regex loaded from /some/file           Compiled pattern loaded from /some/file
742           No study data           No study data
743    
744         When the pattern has been loaded, pcretest proceeds to read data  lines         When the pattern has been loaded, pcretest proceeds to read data  lines
# Line 709  AUTHOR Line 778  AUTHOR
778    
779  REVISION  REVISION
780    
781         Last updated: 21 November 2010         Last updated: 01 August 2011
782         Copyright (c) 1997-2010 University of Cambridge.         Copyright (c) 1997-2011 University of Cambridge.

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