/[pcre]/code/trunk/doc/pcretest.txt
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revision 74 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC
# Line 6  NAME Line 6  NAME
6         pcretest - a program for testing Perl-compatible regular expressions.         pcretest - a program for testing Perl-compatible regular expressions.
7    
8  SYNOPSIS  SYNOPSIS
9         pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]  
10           pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]
11                [destination]
12    
13         pcretest  was written as a test program for the PCRE regular expression         pcretest  was written as a test program for the PCRE regular expression
14         library itself, but it can also be used for experimenting with  regular         library itself, but it can also be used for experimenting with  regular
15         expressions.  This document describes the features of the test program;         expressions.  This document describes the features of the test program;
16         for details of the regular expressions themselves, see the  pcrepattern         for details of the regular expressions themselves, see the  pcrepattern
17         documentation.  For  details  of  PCRE and its options, see the pcreapi         documentation. For details of the PCRE library function calls and their
18         documentation.         options, see the pcreapi documentation.
19    
20    
21  OPTIONS  OPTIONS
22    
   
23         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
24                   able   information  about  the  optional  features  that  are                   able   information  about  the  optional  features  that  are
25                   included, and then exit.                   included, and then exit.
26    
27         -d        Behave as if each regex had the /D modifier (see below);  the         -d        Behave as if each regex had  the  /D  (debug)  modifier;  the
28                   internal form is output after compilation.                   internal form is output after compilation.
29    
30         -i        Behave  as  if  each  regex  had the /I modifier; information         -i        Behave  as  if  each  regex  had the /I modifier; information
# Line 35  OPTIONS Line 36  OPTIONS
36                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
37    
38         -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
39                   when calling PCRE to be osize. The default value is 45, which                   when calling pcre_exec() to be osize. The  default  value  is
40                   is  enough  for  14 capturing subexpressions. The vector size                   45, which is enough for 14 capturing subexpressions. The vec-
41                   can be changed for individual matching calls by including  \O                   tor size can be changed  for  individual  matching  calls  by
42                   in the data line (see below).                   including \O in the data line (see below).
43    
44         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper
45                   API is used to call PCRE. None of the other options  has  any                   API is used to call PCRE. None of the other options  has  any
# Line 46  OPTIONS Line 47  OPTIONS
47    
48         -t        Run  each  compile, study, and match many times with a timer,         -t        Run  each  compile, study, and match many times with a timer,
49                   and output resulting time per compile or match (in  millisec-                   and output resulting time per compile or match (in  millisec-
50                   onds).  Do  not set -t with -m, because you will then get the                   onds).  Do  not set -m with -t, because you will then get the
51                   size output 20000 times and the timing will be distorted.                   size output a zillion times, and  the  timing  will  be  dis-
52                     torted.
53    
54    
55  DESCRIPTION  DESCRIPTION
56    
57         If pcretest is given two filename arguments, it reads  from  the  first         If  pcretest  is  given two filename arguments, it reads from the first
58         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
59         reads from that file and writes to stdout.  Otherwise,  it  reads  from         reads  from  that  file  and writes to stdout. Otherwise, it reads from
60         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
61         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
62         lines.         lines.
63    
64         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.
65         Each set starts with a regular expression, and continues with any  num-         Each  set starts with a regular expression, and continues with any num-
66         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
67    
68         Each  line  is  matched separately and independently. If you want to do         Each data line is matched separately and independently. If you want  to
69         multiple-line matches, you have to use the \n escape sequence in a sin-         do  multiple-line  matches, you have to use the \n escape sequence in a
70         gle  line of input to encode the newline characters. The maximum length         single line of input to encode  the  newline  characters.  The  maximum
71         of data line is 30,000 characters.         length of data line is 30,000 characters.
72    
73         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
74         regular  expression is read. The regular expressions are given enclosed         regular expression is read. The regular expressions are given  enclosed
75         in any non-alphameric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example
76    
77           /(a|bc)x+yz/           /(a|bc)x+yz/
78    
79         White space before the initial delimiter is ignored. A regular  expres-         White  space before the initial delimiter is ignored. A regular expres-
80         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-
81         line characters are included within it. It is possible to  include  the         line  characters  are included within it. It is possible to include the
82         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
83    
84           /abc\/def/           /abc\/def/
85    
86         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,
87         but since delimiters are always non-alphameric, this  does  not  affect         but  since delimiters are always non-alphanumeric, this does not affect
88         its  interpretation.   If the terminating delimiter is immediately fol-         its interpretation.  If the terminating delimiter is  immediately  fol-
89         lowed by a backslash, for example,         lowed by a backslash, for example,
90    
91           /abc/\           /abc/\
92    
93         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
94         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
95         finishes with a backslash, because         finishes with a backslash, because
96    
97           /abc\/           /abc\/
98    
99         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/",
100         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
101         expression.         expression.
102    
103    
104  PATTERN MODIFIERS  PATTERN MODIFIERS
105    
106         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
107         PCRE_MULTILINE,  PCRE_DOTALL,  or  PCRE_EXTENDED options, respectively.         single characters. Following Perl usage, these are  referred  to  below
108         For example:         as,  for  example,  "the /i modifier", even though the delimiter of the
109           pattern need not always be a slash, and no slash is used  when  writing
110           modifiers.  Whitespace  may  appear between the final pattern delimiter
111           and the first modifier, and between the modifiers themselves.
112    
113           The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
114           PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
115           pile() is called. These four modifier letters have the same  effect  as
116           they do in Perl. For example:
117    
118           /caseless/i           /caseless/i
119    
120         These modifier letters have the same effect as they do in  Perl.  There         The following table shows additional modifiers for setting PCRE options
121         are  others that set PCRE options that do not correspond to anything in         that do not correspond to anything in Perl:
122         Perl: /A, /E, /N, /U, and /X  set  PCRE_ANCHORED,  PCRE_DOLLAR_ENDONLY,  
123         PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA respectively.           /A    PCRE_ANCHORED
124             /C    PCRE_AUTO_CALLOUT
125             /E    PCRE_DOLLAR_ENDONLY
126             /N    PCRE_NO_AUTO_CAPTURE
127             /U    PCRE_UNGREEDY
128             /X    PCRE_EXTRA
129    
130         Searching  for  all  possible matches within each subject string can be         Searching for all possible matches within each subject  string  can  be
131         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
132         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
133         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
134         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
135         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
136         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
137         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
138         or \B).         or \B).
139    
140         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
141         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
142         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
143         point.  If this second match fails, the start  offset  is  advanced  by         point.   If  this  second  match fails, the start offset is advanced by
144         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-
145         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
146    
147         There are a number of other modifiers for controlling the way  pcretest         There are yet more modifiers for controlling the way pcretest operates.
        operates.  
148    
149         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
150         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
151         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
152         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
153    
154         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
155         example,         example,
156    
157           /pattern/Lfr           /pattern/Lfr_FR
158    
159         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,
160         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
161         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
162         ing the regular expression. Without an /L modifier, NULL is  passed  as         regular  expression.  Without  an  /L  modifier,  NULL is passed as the
163         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
164         it appears.         appears.
165    
166         The /I modifier requests that pcretest  output  information  about  the         The  /I  modifier  requests  that pcretest output information about the
167         compiled  expression (whether it is anchored, has a fixed first charac-         compiled pattern (whether it is anchored, has a fixed first  character,
168         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
169         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-
170         pattern is studied, the results of that are also output.         put.
171    
172         The /D modifier is a PCRE debugging feature, which also assumes /I.  It         The /D modifier is a PCRE debugging feature, which also assumes /I.  It
173         causes  the  internal form of compiled regular expressions to be output         causes the internal form of compiled regular expressions to  be  output
174         after compilation. If the pattern was studied, the information returned         after compilation. If the pattern was studied, the information returned
175         is also output.         is also output.
176    
177         The  /S  modifier causes pcre_study() to be called after the expression         The /F modifier causes pcretest to flip the byte order of the fields in
178           the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This
179           facility is for testing the feature in PCRE that allows it  to  execute
180           patterns that were compiled on a host with a different endianness. This
181           feature is not available when the POSIX  interface  to  PCRE  is  being
182           used,  that is, when the /P pattern modifier is specified. See also the
183           section about saving and reloading compiled patterns below.
184    
185           The /S modifier causes pcre_study() to be called after  the  expression
186         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
187    
188         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-
189         piled pattern to be output.         piled pattern to be output.
190    
191         The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API         The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
192         rather  than  its  native  API.  When this is done, all other modifiers         rather than its native API. When this  is  done,  all  other  modifiers
193         except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,         except  /i,  /m, and /+ are ignored. REG_ICASE is set if /i is present,
194         and  REG_NEWLINE  is  set if /m is present. The wrapper functions force         and REG_NEWLINE is set if /m is present. The  wrapper  functions  force
195         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.         PCRE_DOLLAR_ENDONLY  always, and PCRE_DOTALL unless REG_NEWLINE is set.
196    
197         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option         The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8  option
198         set. This turns on support for UTF-8 character handling in  PCRE,  pro-         set.  This  turns on support for UTF-8 character handling in PCRE, pro-
199         vided  that  it  was  compiled with this support enabled. This modifier         vided that it was compiled with this  support  enabled.  This  modifier
200         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
201         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
202    
203         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call
204         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the
205         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
206    
207    
 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.  
   
   
208  DATA LINES  DATA LINES
209    
210         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
211         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
212         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
213         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
214         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
215         following escapes are recognized:         following escapes are recognized:
216    
217           \a         alarm (= BEL)           \a         alarm (= BEL)
# Line 233  DATA LINES Line 229  DATA LINES
229           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
230           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
231           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
232                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
233           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
234                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
235                        ated by next non alphanumeric character)                        ated by next non alphanumeric character)
# Line 246  DATA LINES Line 241  DATA LINES
241           \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
242                        reached for the nth time                        reached for the nth time
243           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
244                        data                        data; this is used as the callout return value
245           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
246                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
247           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
248                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
249                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
# Line 258  DATA LINES Line 252  DATA LINES
252           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT setting
253           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
254           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
255                        pcre_exec() to dd (any number of decimal                        pcre_exec() to dd (any number of digits)
256                        digits)           \P         pass the PCRE_PARTIAL option to pcre_exec()
257           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
258           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
259           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
260                        pcre_exec()                        pcre_exec()
261             \>dd       start the match at offset dd (any number of digits);
262                          this sets the startoffset argument for pcre_exec()
263    
264           A  backslash  followed by anything else just escapes the anything else.
265           If the very last character is a backslash, it is ignored. This gives  a
266           way  of  passing  an empty line as data, since a real empty line termi-
267           nates the data input.
268    
269         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If \M is present, pcretest calls pcre_exec() several times,  with  dif-
270         ferent  values  in  the match_limit field of the pcre_extra data struc-         ferent  values  in  the match_limit field of the pcre_extra data struc-
# Line 274  DATA LINES Line 275  DATA LINES
275         with very large numbers of matching possibilities, it can become  large         with very large numbers of matching possibilities, it can become  large
276         very quickly with increasing length of subject string.         very quickly with increasing length of subject string.
277    
278         When  \O is used, it may be higher or lower than the size set by the -O         When  \O  is  used, the value specified may be higher or lower than the
279         option (or defaulted to 45); \O applies only to the call of pcre_exec()         size set by the -O command line option (or defaulted to 45); \O applies
280         for the line in which it appears.         only to the call of pcre_exec() for the line in which it appears.
281    
282         A  backslash  followed by anything else just escapes the anything else.         If  the /P modifier was present on the pattern, causing the POSIX wrap-
283         If the very last character is a backslash, it is ignored. This gives  a         per API to be used, only \B and \Z have any effect, causing  REG_NOTBOL
284         way  of  passing  an empty line as data, since a real empty line termi-         and REG_NOTEOL to be passed to regexec() respectively.
285         nates the data input.  
286           The  use of \x{hh...} to represent UTF-8 characters is not dependent on
287         If /P was present on the regex, causing the POSIX  wrapper  API  to  be         the use of the /8 modifier on the pattern.  It  is  recognized  always.
288         used,  only  0  causing  REG_NOTBOL  and  REG_NOTEOL  to  be  passed to         There  may  be  any number of hexadecimal digits inside the braces. The
289         regexec() respectively.         result is from one to six bytes, encoded according to the UTF-8  rules.
   
        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.  
290    
291    
292  OUTPUT FROM PCRETEST  OUTPUT FROM PCRETEST
293    
294         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
295         that  pcre_exec()  returns,  starting with number 0 for the string that         that pcre_exec() returns, starting with number 0 for  the  string  that
296         matched the whole  pattern.  Here  is  an  example  of  an  interactive         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
297         pcretest run.         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-
298           TIAL,  respectively, and otherwise the PCRE negative error number. Here
299           is an example of an interactive pcretest run.
300    
301           $ pcretest           $ pcretest
302           PCRE version 4.00 08-Jan-2003           PCRE version 5.00 07-Sep-2004
303    
304             re> /^abc(\d+)/             re> /^abc(\d+)/
305           data> abc123           data> abc123
# Line 310  OUTPUT FROM PCRETEST Line 308  OUTPUT FROM PCRETEST
308           data> xyz           data> xyz
309           No match           No match
310    
311         If  the strings contain any non-printing characters, they are output as         If the strings contain any non-printing characters, they are output  as
312         \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
313         the  pattern.  If  the pattern has the /+ modifier, then the output for         the pattern. If the pattern has the /+ modifier, the  output  for  sub-
314         substring 0 is followed by the the rest of the subject string,  identi-         string  0 is followed by the the rest of the subject string, identified
315         fied by "0+" like this:         by "0+" like this:
316    
317             re> /cat/+             re> /cat/+
318           data> cataract           data> cataract
319            0: cat            0: cat
320            0+ aract            0+ aract
321    
322         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
323         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
324    
325             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 335  OUTPUT FROM PCRETEST Line 333  OUTPUT FROM PCRETEST
333    
334         "No match" is output only if the first match attempt fails.         "No match" is output only if the first match attempt fails.
335    
336         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
337         is  successfully  matched,  the substrings extracted by the convenience         is successfully matched, the substrings extracted  by  the  convenience
338         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
339         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
340         (that is, the return from the extraction function) is given  in  paren-         (that  is,  the return from the extraction function) is given in paren-
341         theses after each string for \C and \G.         theses after each string for \C and \G.
342    
343         Note  that  while patterns can be continued over several lines (a plain         Note that while patterns can be continued over several lines  (a  plain
344         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
345         lines can be included in data by means of the \n escape.         lines can be included in data by means of the \n escape.
346    
347    
348    CALLOUTS
349    
350           If the pattern contains any callout requests, pcretest's callout  func-
351           tion  is  called  during  matching. By default, it displays the callout
352           number, the start and current positions in  the  text  at  the  callout
353           time, and the next pattern item to be tested. For example, the output
354    
355             --->pqrabcdef
356               0    ^  ^     \d
357    
358           indicates  that  callout number 0 occurred for a match attempt starting
359           at the fourth character of the subject string, when the pointer was  at
360           the  seventh  character of the data, and when the next pattern item was
361           \d. Just one circumflex is output if the start  and  current  positions
362           are the same.
363    
364           Callouts numbered 255 are assumed to be automatic callouts, inserted as
365           a result of the /C pattern modifier. In this case, instead  of  showing
366           the  callout  number, the offset in the pattern, preceded by a plus, is
367           output. For example:
368    
369               re> /\d?[A-E]\*/C
370             data> E*
371             --->E*
372              +0 ^      \d?
373              +3 ^      [A-E]
374              +8 ^^     \*
375             +10 ^ ^
376              0: E*
377    
378           The callout function in pcretest returns zero (carry  on  matching)  by
379           default, but you can use an \C item in a data line (as described above)
380           to change this.
381    
382           Inserting callouts can be helpful when using pcretest to check  compli-
383           cated  regular expressions. For further information about callouts, see
384           the pcrecallout documentation.
385    
386    
387    SAVING AND RELOADING COMPILED PATTERNS
388    
389           The facilities described in this section are  not  available  when  the
390           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
391           ifier is specified.
392    
393           When the POSIX interface is not in use, you can cause pcretest to write
394           a  compiled  pattern to a file, by following the modifiers with > and a
395           file name.  For example:
396    
397             /pattern/im >/some/file
398    
399           See the pcreprecompile documentation for a discussion about saving  and
400           re-using compiled patterns.
401    
402           The  data  that  is  written  is  binary. The first eight bytes are the
403           length of the compiled pattern data  followed  by  the  length  of  the
404           optional  study  data,  each  written as four bytes in big-endian order
405           (most significant byte first). If there is no study  data  (either  the
406           pattern was not studied, or studying did not return any data), the sec-
407           ond length is zero. The lengths are followed by an exact  copy  of  the
408           compiled pattern. If there is additional study data, this follows imme-
409           diately after the compiled pattern. After writing  the  file,  pcretest
410           expects to read a new pattern.
411    
412           A saved pattern can be reloaded into pcretest by specifing < and a file
413           name instead of a pattern. The name of the file must not  contain  a  <
414           character,  as  otherwise pcretest will interpret the line as a pattern
415           delimited by < characters.  For example:
416    
417              re> </some/file
418             Compiled regex loaded from /some/file
419             No study data
420    
421           When the pattern has been loaded, pcretest proceeds to read data  lines
422           in the usual way.
423    
424           You  can copy a file written by pcretest to a different host and reload
425           it there, even if the new host has opposite endianness to  the  one  on
426           which  the pattern was compiled. For example, you can compile on an i86
427           machine and run on a SPARC machine.
428    
429           File names for saving and reloading can be absolute  or  relative,  but
430           note  that the shell facility of expanding a file name that starts with
431           a tilde (~) is not available.
432    
433           The ability to save and reload files in pcretest is intended for  test-
434           ing  and experimentation. It is not intended for production use because
435           only a single pattern can be written to a file. Furthermore,  there  is
436           no  facility  for  supplying  custom  character  tables  for use with a
437           reloaded pattern. If the original  pattern  was  compiled  with  custom
438           tables,  an  attempt to match a subject string using a reloaded pattern
439           is likely to cause pcretest to crash.  Finally, if you attempt to  load
440           a file that is not in the correct format, the result is undefined.
441    
442    
443  AUTHOR  AUTHOR
444    
445         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel <ph10@cam.ac.uk>
446         University Computing Service,         University Computing Service,
447         Cambridge CB2 3QG, England.         Cambridge CB2 3QG, England.
448    
449  Last updated: 09 December 2003  Last updated: 10 September 2004
450  Copyright (c) 1997-2003 University of Cambridge.  Copyright (c) 1997-2004 University of Cambridge.

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