/[pcre]/code/trunk/doc/pcretest.txt
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revision 76 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC
# Line 7  NAME Line 7  NAME
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]
11              [destination]              [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
# Line 24  OPTIONS Line 24  OPTIONS
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  (debug)  modifier;  the         -d        Behave as if each regex has  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         -dfa      Behave  as if each data line contains the \D escape sequence;
31                     this    causes    the    alternative    matching    function,
32                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
33                     pcre_exec() function (more detail is given below).
34    
35           -i        Behave as if each regex  has  the  /I  modifier;  information
36                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
37    
38         -m        Output the size of each compiled pattern after  it  has  been         -m        Output  the  size  of each compiled pattern after it has been
39                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled. This is equivalent to adding  /M  to  each  regular
40                   expression.  For  compatibility  with  earlier  versions   of                   expression.   For  compatibility  with  earlier  versions  of
41                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
42    
43         -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
44                   when calling pcre_exec() to be osize. The  default  value  is                   when  calling  pcre_exec()  to be osize. The default value is
45                   45, which is enough for 14 capturing subexpressions. The vec-                   45, which is enough for 14 capturing subexpressions. The vec-
46                   tor size can be changed  for  individual  matching  calls  by                   tor  size  can  be  changed  for individual matching calls by
47                   including \O in the data line (see below).                   including \O in the data line (see below).
48    
49         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
50                   API is used to call PCRE. None of the other options  has  any                   per  API  is used to call PCRE. None of the other options has
51                   effect when -p is set.                   any effect when -p is set.
52    
53         -t        Run  each  compile, study, and match many times with a timer,         -t        Run each compile, study, and match many times with  a  timer,
54                   and output resulting time per compile or match (in  millisec-                   and  output resulting time per compile or match (in millisec-
55                   onds).  Do  not set -m with -t, because you will then get the                   onds). Do not set -m with -t, because you will then  get  the
56                   size output a zillion times, and  the  timing  will  be  dis-                   size  output  a  zillion  times,  and the timing will be dis-
57                   torted.                   torted.
58    
59    
60  DESCRIPTION  DESCRIPTION
61    
62         If  pcretest  is  given two filename arguments, it reads from the first         If pcretest is given two filename arguments, it reads  from  the  first
63         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
64         reads  from  that  file  and writes to stdout. Otherwise, it reads from         reads from that file and writes to stdout.  Otherwise,  it  reads  from
65         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
66         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
67         lines.         lines.
68    
69         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.
70         Each  set starts with a regular expression, and continues with any num-         Each set starts with a regular expression, and continues with any  num-
71         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
72    
73         Each data line is matched separately and independently. If you want  to         Each  data line is matched separately and independently. If you want to
74         do  multiple-line  matches, you have to use the \n escape sequence in a         do multiple-line matches, you have to use the \n escape sequence  in  a
75         single line of input to encode  the  newline  characters.  The  maximum         single  line  of  input  to  encode the newline characters. The maximum
76         length of data line is 30,000 characters.         length of data line is 30,000 characters.
77    
78         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
79         regular expression is read. The regular expressions are given  enclosed         regular  expression is read. The regular expressions are given enclosed
80         in any non-alphanumeric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example
81    
82           /(a|bc)x+yz/           /(a|bc)x+yz/
83    
84         White  space before the initial delimiter is ignored. A regular expres-         White space before the initial delimiter is ignored. A regular  expres-
85         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-
86         line  characters  are included within it. It is possible to include the         line characters are included within it. It is possible to  include  the
87         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
88    
89           /abc\/def/           /abc\/def/
90    
91         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,
92         but  since delimiters are always non-alphanumeric, this does not affect         but since delimiters are always non-alphanumeric, this does not  affect
93         its interpretation.  If the terminating delimiter is  immediately  fol-         its  interpretation.   If the terminating delimiter is immediately fol-
94         lowed by a backslash, for example,         lowed by a backslash, for example,
95    
96           /abc/\           /abc/\
97    
98         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
99         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
100         finishes with a backslash, because         finishes with a backslash, because
101    
102           /abc\/           /abc\/
103    
104         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/",
105         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
106         expression.         expression.
107    
108    
109  PATTERN MODIFIERS  PATTERN MODIFIERS
110    
111         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
112         single characters. Following Perl usage, these are  referred  to  below         single  characters.  Following  Perl usage, these are referred to below
113         as,  for  example,  "the /i modifier", even though the delimiter of the         as, for example, "the /i modifier", even though the  delimiter  of  the
114         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
115         modifiers.  Whitespace  may  appear between the final pattern delimiter         modifiers. Whitespace may appear between the  final  pattern  delimiter
116         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
117    
118         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,
119         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
120         pile() is called. These four modifier letters have the same  effect  as         pile()  is  called. These four modifier letters have the same effect as
121         they do in Perl. For example:         they do in Perl. For example:
122    
123           /caseless/i           /caseless/i
# Line 123  PATTERN MODIFIERS Line 128  PATTERN MODIFIERS
128           /A    PCRE_ANCHORED           /A    PCRE_ANCHORED
129           /C    PCRE_AUTO_CALLOUT           /C    PCRE_AUTO_CALLOUT
130           /E    PCRE_DOLLAR_ENDONLY           /E    PCRE_DOLLAR_ENDONLY
131             /f    PCRE_FIRSTLINE
132           /N    PCRE_NO_AUTO_CAPTURE           /N    PCRE_NO_AUTO_CAPTURE
133           /U    PCRE_UNGREEDY           /U    PCRE_UNGREEDY
134           /X    PCRE_EXTRA           /X    PCRE_EXTRA
135    
136         Searching for all possible matches within each subject  string  can  be         Searching  for  all  possible matches within each subject string can be
137         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
138         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
139         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
140         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
141         string  (which  is in effect what Perl does), whereas the latter passes         string (which is in effect what Perl does), whereas the  latter  passes
142         over a shortened substring. This makes a  difference  to  the  matching         over  a  shortened  substring.  This makes a difference to the matching
143         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
144         or \B).         or \B).
145    
146         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
147         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
148         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
149         point.   If  this  second  match fails, the start offset is advanced by         point.  If this second match fails, the start  offset  is  advanced  by
150         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-
151         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
152    
153         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
154    
155         The /+ modifier requests that as well as outputting the substring  that         The  /+ modifier requests that as well as outputting the substring that
156         matched  the  entire  pattern,  pcretest  should in addition output the         matched the entire pattern, pcretest  should  in  addition  output  the
157         remainder of the subject string. This is useful  for  tests  where  the         remainder  of  the  subject  string. This is useful for tests where the
158         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
159    
160         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
161         example,         example,
162    
163           /pattern/Lfr_FR           /pattern/Lfr_FR
164    
165         For this reason, it must be the last modifier. The given locale is set,         For this reason, it must be the last modifier. The given locale is set,
166         pcre_maketables()  is called to build a set of character tables for the         pcre_maketables() is called to build a set of character tables for  the
167         locale, and this is then passed to pcre_compile()  when  compiling  the         locale,  and  this  is then passed to pcre_compile() when compiling the
168         regular  expression.  Without  an  /L  modifier,  NULL is passed as the         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
169         tables pointer; that is, /L applies only to the expression on which  it         tables  pointer; that is, /L applies only to the expression on which it
170         appears.         appears.
171    
172         The  /I  modifier  requests  that pcretest output information about the         The /I modifier requests that pcretest  output  information  about  the
173         compiled pattern (whether it is anchored, has a fixed first  character,         compiled  pattern (whether it is anchored, has a fixed first character,
174         and  so  on). It does this by calling pcre_fullinfo() after compiling a         and so on). It does this by calling pcre_fullinfo() after  compiling  a
175         pattern. If the pattern is studied, the results of that are  also  out-         pattern.  If  the pattern is studied, the results of that are also out-
176         put.         put.
177    
178         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
179         causes the internal form of compiled regular expressions to  be  output         causes  the  internal form of compiled regular expressions to be output
180         after compilation. If the pattern was studied, the information returned         after compilation. If the pattern was studied, the information returned
181         is also output.         is also output.
182    
183         The /F modifier causes pcretest to flip the byte order of the fields in         The /F modifier causes pcretest to flip the byte order of the fields in
184         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
185         facility is for testing the feature in PCRE that allows it  to  execute         facility  is  for testing the feature in PCRE that allows it to execute
186         patterns that were compiled on a host with a different endianness. This         patterns that were compiled on a host with a different endianness. This
187         feature is not available when the POSIX  interface  to  PCRE  is  being         feature  is  not  available  when  the POSIX interface to PCRE is being
188         used,  that is, when the /P pattern modifier is specified. See also the         used, that is, when the /P pattern modifier is specified. See also  the
189         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
190    
191         The /S modifier causes pcre_study() to be called after  the  expression         The  /S  modifier causes pcre_study() to be called after the expression
192         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
193    
194         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-
195         piled pattern to be output.         piled pattern to be output.
196    
197         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
198         rather than its native API. When this  is  done,  all  other  modifiers         rather  than  its  native  API.  When this is done, all other modifiers
199         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,
200         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
201         PCRE_DOLLAR_ENDONLY  always, and PCRE_DOTALL unless REG_NEWLINE is set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.
202    
203         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
204         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-
205         vided that it was compiled with this  support  enabled.  This  modifier         vided  that  it  was  compiled with this support enabled. This modifier
206         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
207         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
208    
209         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
210         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
211         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
212    
213    
214  DATA LINES  DATA LINES
215    
216         Before each data line is passed to pcre_exec(),  leading  and  trailing         Before  each  data  line is passed to pcre_exec(), leading and trailing
217         whitespace  is  removed,  and it is then scanned for \ escapes. Some of         whitespace is removed, and it is then scanned for \  escapes.  Some  of
218         these are pretty esoteric features, intended for checking out  some  of         these  are  pretty esoteric features, intended for checking out some of
219         the  more  complicated features of PCRE. If you are just testing "ordi-         the more complicated features of PCRE. If you are just  testing  "ordi-
220         nary" regular expressions, you probably don't need any  of  these.  The         nary"  regular  expressions,  you probably don't need any of these. The
221         following escapes are recognized:         following escapes are recognized:
222    
223           \a         alarm (= BEL)           \a         alarm (= BEL)
# Line 242  DATA LINES Line 248  DATA LINES
248                        reached for the nth time                        reached for the nth time
249           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
250                        data; this is used as the callout return value                        data; this is used as the callout return value
251             \D         use the pcre_dfa_exec() match function
252             \F         only shortest match for pcre_dfa_exec()
253           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
254                        after a successful match (number less than 32)                        after a successful match (number less than 32)
255           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
# Line 254  DATA LINES Line 262  DATA LINES
262           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
263                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
264           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
265                          or pcre_dfa_exec()
266             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
267           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
268           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
269           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
# Line 261  DATA LINES Line 271  DATA LINES
271           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
272                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
273    
274         A  backslash  followed by anything else just escapes the anything else.         A backslash followed by anything else just escapes the  anything  else.
275         If the very last character is a backslash, it is ignored. This gives  a         If  the very last character is a backslash, it is ignored. This gives a
276         way  of  passing  an empty line as data, since a real empty line termi-         way of passing an empty line as data, since a real  empty  line  termi-
277         nates the data input.         nates the data input.
278    
279         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
280         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-
281         ture, until it finds the minimum number that is needed for  pcre_exec()         ture,  until it finds the minimum number that is needed for pcre_exec()
282         to  complete.  This  number is a measure of the amount of recursion and         to complete. This number is a measure of the amount  of  recursion  and
283         backtracking that takes place, and checking it out can be  instructive.         backtracking  that takes place, and checking it out can be instructive.
284         For  most  simple  matches, the number is quite small, but for patterns         For most simple matches, the number is quite small,  but  for  patterns
285         with very large numbers of matching possibilities, it can become  large         with  very large numbers of matching possibilities, it can become large
286         very quickly with increasing length of subject string.         very quickly with increasing length of subject string.
287    
288         When  \O  is  used, the value specified may be higher or lower than the         When \O is used, the value specified may be higher or  lower  than  the
289         size set by the -O command line option (or defaulted to 45); \O applies         size set by the -O command line option (or defaulted to 45); \O applies
290         only to the call of pcre_exec() for the line in which it appears.         only to the call of pcre_exec() for the line in which it appears.
291    
292         If  the /P modifier was present on the pattern, causing the POSIX wrap-         If the /P modifier was present on the pattern, causing the POSIX  wrap-
293         per API to be used, only \B and \Z have any effect, causing  REG_NOTBOL         per  API to be used, only \B and \Z have any effect, causing REG_NOTBOL
294         and REG_NOTEOL to be passed to regexec() respectively.         and REG_NOTEOL to be passed to regexec() respectively.
295    
296         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
297         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.
298         There  may  be  any number of hexadecimal digits inside the braces. The         There may be any number of hexadecimal digits inside  the  braces.  The
299         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 UTF-8 rules.
300    
301    
302    THE ALTERNATIVE MATCHING FUNCTION
303    
304           By  default,  pcretest  uses  the  standard  PCRE  matching   function,
305           pcre_exec() to match each data line. From release 6.0, PCRE supports an
306           alternative matching function, pcre_dfa_test(),  which  operates  in  a
307           different  way,  and has some restrictions. The differences between the
308           two functions are described in the pcrematching documentation.
309    
310           If a data line contains the \D escape sequence, or if the command  line
311           contains  the -dfa option, the alternative matching function is called.
312           This function finds all possible matches at a given point. If, however,
313           the  \F escape sequence is present in the data line, it stops after the
314           first match is found. This is always the shortest possible match.
315    
316    
317  OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
318    
319           This section describes the output when the  normal  matching  function,
320           pcre_exec(), is being used.
321    
322         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
323         that pcre_exec() returns, starting with number 0 for  the  string  that         that pcre_exec() returns, starting with number 0 for  the  string  that
# Line 345  OUTPUT FROM PCRETEST Line 373  OUTPUT FROM PCRETEST
373         lines can be included in data by means of the \n escape.         lines can be included in data by means of the \n escape.
374    
375    
376    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
377    
378           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
379           means  of  the \D escape sequence or the -dfa command line option), the
380           output consists of a list of all the matches that start  at  the  first
381           point in the subject where there is at least one match. For example:
382    
383               re> /(tang|tangerine|tan)/
384             data> yellow tangerine\D
385              0: tangerine
386              1: tang
387              2: tan
388    
389           (Using  the  normal  matching function on this data finds only "tang".)
390           The longest matching string is always given first (and numbered  zero).
391    
392           If  /gP  is  present  on  the  pattern,  the search for further matches
393           resumes at the end of the longest match. For example:
394    
395               re> /(tang|tangerine|tan)/g
396             data> yellow tangerine and tangy sultana\D
397              0: tangerine
398              1: tang
399              2: tan
400              0: tang
401              1: tan
402              0: tan
403    
404           Since the matching function does not  support  substring  capture,  the
405           escape  sequences  that  are concerned with captured substrings are not
406           relevant.
407    
408    
409    RESTARTING AFTER A PARTIAL MATCH
410    
411           When the alternative matching function has given the PCRE_ERROR_PARTIAL
412           return,  indicating that the subject partially matched the pattern, you
413           can restart the match with additional subject data by means of  the  \R
414           escape sequence. For example:
415    
416               re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
417             data> 23ja\P\D
418             Partial match: 23ja
419             data> n05\R\D
420              0: n05
421    
422           For  further  information  about  partial matching, see the pcrepartial
423           documentation.
424    
425    
426  CALLOUTS  CALLOUTS
427    
428         If the pattern contains any callout requests, pcretest's callout  func-         If the pattern contains any callout requests, pcretest's callout  func-
429         tion  is  called  during  matching. By default, it displays the callout         tion  is  called  during  matching. This works with both matching func-
430         number, the start and current positions in  the  text  at  the  callout         tions. By default, the called function displays the callout number, the
431         time, and the next pattern item to be tested. For example, the output         start  and  current  positions in the text at the callout time, and the
432           next pattern item to be tested. For example, the output
433    
434           --->pqrabcdef           --->pqrabcdef
435             0    ^  ^     \d             0    ^  ^     \d
436    
437         indicates  that  callout number 0 occurred for a match attempt starting         indicates that callout number 0 occurred for a match  attempt  starting
438         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
439         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
440         \d. Just one circumflex is output if the start  and  current  positions         \d.  Just  one  circumflex is output if the start and current positions
441         are the same.         are the same.
442    
443         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
444         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
445         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
446         output. For example:         output. For example:
447    
448             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 375  CALLOUTS Line 454  CALLOUTS
454           +10 ^ ^           +10 ^ ^
455            0: E*            0: E*
456    
457         The callout function in pcretest returns zero (carry  on  matching)  by         The  callout  function  in pcretest returns zero (carry on matching) by
458         default, but you can use an \C item in a data line (as described above)         default, but you can use a \C item in a data line (as described  above)
459         to change this.         to change this.
460    
461         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting  callouts can be helpful when using pcretest to check compli-
462         cated  regular expressions. For further information about callouts, see         cated regular expressions. For further information about callouts,  see
463         the pcrecallout documentation.         the pcrecallout documentation.
464    
465    
466  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
467    
468         The facilities described in this section are  not  available  when  the         The  facilities  described  in  this section are not available when the
469         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
470         ifier is specified.         ifier is specified.
471    
472         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
473         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
474         file name.  For example:         file name.  For example:
475    
476           /pattern/im >/some/file           /pattern/im >/some/file
477    
478         See the pcreprecompile documentation for a discussion about saving  and         See  the pcreprecompile documentation for a discussion about saving and
479         re-using compiled patterns.         re-using compiled patterns.
480    
481         The  data  that  is  written  is  binary. The first eight bytes are the         The data that is written is binary.  The  first  eight  bytes  are  the
482         length of the compiled pattern data  followed  by  the  length  of  the         length  of  the  compiled  pattern  data  followed by the length of the
483         optional  study  data,  each  written as four bytes in big-endian order         optional study data, each written as four  bytes  in  big-endian  order
484         (most significant byte first). If there is no study  data  (either  the         (most  significant  byte  first). If there is no study data (either the
485         pattern was not studied, or studying did not return any data), the sec-         pattern was not studied, or studying did not return any data), the sec-
486         ond length is zero. The lengths are followed by an exact  copy  of  the         ond  length  is  zero. The lengths are followed by an exact copy of the
487         compiled pattern. If there is additional study data, this follows imme-         compiled pattern. If there is additional study data, this follows imme-
488         diately after the compiled pattern. After writing  the  file,  pcretest         diately  after  the  compiled pattern. After writing the file, pcretest
489         expects to read a new pattern.         expects to read a new pattern.
490    
491         A saved pattern can be reloaded into pcretest by specifing < and a file         A saved pattern can be reloaded into pcretest by specifing < and a file
492         name instead of a pattern. The name of the file must not  contain  a  <         name  instead  of  a pattern. The name of the file must not contain a <
493         character,  as  otherwise pcretest will interpret the line as a pattern         character, as otherwise pcretest will interpret the line as  a  pattern
494         delimited by < characters.  For example:         delimited by < characters.  For example:
495    
496            re> </some/file            re> </some/file
497           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
498           No study data           No study data
499    
500         When the pattern has been loaded, pcretest proceeds to read data  lines         When  the pattern has been loaded, pcretest proceeds to read data lines
501         in the usual way.         in the usual way.
502    
503         You  can copy a file written by pcretest to a different host and reload         You can copy a file written by pcretest to a different host and  reload
504         it there, even if the new host has opposite endianness to  the  one  on         it  there,  even  if the new host has opposite endianness to the one on
505         which  the pattern was compiled. For example, you can compile on an i86         which the pattern was compiled. For example, you can compile on an  i86
506         machine and run on a SPARC machine.         machine and run on a SPARC machine.
507    
508         File names for saving and reloading can be absolute  or  relative,  but         File  names  for  saving and reloading can be absolute or relative, but
509         note  that the shell facility of expanding a file name that starts with         note that the shell facility of expanding a file name that starts  with
510         a tilde (~) is not available.         a tilde (~) is not available.
511    
512         The ability to save and reload files in pcretest is intended for  test-         The  ability to save and reload files in pcretest is intended for test-
513         ing  and experimentation. It is not intended for production use because         ing and experimentation. It is not intended for production use  because
514         only a single pattern can be written to a file. Furthermore,  there  is         only  a  single pattern can be written to a file. Furthermore, there is
515         no  facility  for  supplying  custom  character  tables  for use with a         no facility for supplying  custom  character  tables  for  use  with  a
516         reloaded pattern. If the original  pattern  was  compiled  with  custom         reloaded  pattern.  If  the  original  pattern was compiled with custom
517         tables,  an  attempt to match a subject string using a reloaded pattern         tables, an attempt to match a subject string using a  reloaded  pattern
518         is likely to cause pcretest to crash.  Finally, if you attempt to  load         is  likely to cause pcretest to crash.  Finally, if you attempt to load
519         a file that is not in the correct format, the result is undefined.         a file that is not in the correct format, the result is undefined.
520    
521    
522  AUTHOR  AUTHOR
523    
524         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
525         University Computing Service,         University Computing Service,
526         Cambridge CB2 3QG, England.         Cambridge CB2 3QG, England.
527    
528  Last updated: 10 September 2004  Last updated: 28 February 2005
529  Copyright (c) 1997-2004 University of Cambridge.  Copyright (c) 1997-2005 University of Cambridge.

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