/[pcre]/code/trunk/doc/pcretest.txt
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revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC revision 96 by nigel, Fri Mar 2 13:10:43 2007 UTC
# Line 7  NAME Line 7  NAME
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [options] [source] [destination]
             [destination]  
11    
12         pcretest  was written as a test program for the PCRE regular expression         pcretest  was written as a test program for the PCRE regular expression
13         library itself, but it can also be used for experimenting with  regular         library itself, but it can also be used for experimenting with  regular
# Line 20  SYNOPSIS Line 19  SYNOPSIS
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
26                   able   information  about  the  optional  features  that  are                   able  information  about  the  optional  features  that   are
27                   included, and then exit.                   included, and then exit.
28    
29         -d        Behave as if each regex has  the  /D  (debug)  modifier;  the         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                   internal form is output after compilation.                   internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33         -dfa      Behave  as if each data line contains the \D escape sequence;         -dfa      Behave  as if each data line contains the \D escape sequence;
34                   this    causes    the    alternative    matching    function,                   this    causes    the    alternative    matching    function,
35                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                   pcre_exec() function (more detail is given below).                   pcre_exec() function (more detail is given below).
37    
38           -help     Output a brief summary these options and then exit.
39    
40         -i        Behave as if each regex  has  the  /I  modifier;  information         -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
# Line 41  OPTIONS Line 46  OPTIONS
46                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
47    
48         -o osize  Set the number of elements in the output vector that is  used         -o osize  Set the number of elements in the output vector that is  used
49                   when  calling  pcre_exec()  to be osize. The default value is                   when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
50                   45, which is enough for 14 capturing subexpressions. The vec-                   default value is 45, which is enough for 14 capturing  subex-
51                   tor  size  can  be  changed  for individual matching calls by                   pressions   for  pcre_exec()  or  22  different  matches  for
52                   including \O in the data line (see below).                   pcre_dfa_exec(). The vector size can be changed for  individ-
53                     ual  matching  calls  by  including  \O in the data line (see
54                     below).
55    
56         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
57                   per  API  is used to call PCRE. None of the other options has                   per  API  is used to call PCRE. None of the other options has
# Line 53  OPTIONS Line 60  OPTIONS
60         -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
61                   execution.                   execution.
62    
63         -t        Run  each  compile, study, and match many times with a timer,         -S size   On  Unix-like  systems,  set the size of the runtime stack to
64                   and output resulting time per compile or match (in  millisec-                   size megabytes.
65                   onds).  Do  not set -m with -t, because you will then get the  
66                   size output a zillion times, and  the  timing  will  be  dis-         -t        Run each compile, study, and match many times with  a  timer,
67                   torted.                   and  output resulting time per compile or match (in millisec-
68                     onds). Do not set -m with -t, because you will then  get  the
69                     size  output  a  zillion  times,  and the timing will be dis-
70                     torted. You can control the number  of  iterations  that  are
71                     used  for timing by following -t with a number (as a separate
72                     item on the command line). For example, "-t 1000" would iter-
73                     ate 1000 times. The default is to iterate 500000 times.
74    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
80    
81         If  pcretest  is  given two filename arguments, it reads from the first         If pcretest is given two filename arguments, it reads  from  the  first
82         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
83         reads  from  that  file  and writes to stdout. Otherwise, it reads from         reads from that file and writes to stdout.  Otherwise,  it  reads  from
84         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
85         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
86         lines.         lines.
87    
88         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.
89         Each  set starts with a regular expression, and continues with any num-         Each set starts with a regular expression, and continues with any  num-
90         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
91    
92         Each data line is matched separately and independently. If you want  to         Each  data line is matched separately and independently. If you want to
93         do  multiple-line  matches, you have to use the \n escape sequence in a         do multi-line matches, you have to use the \n escape sequence (or \r or
94         single line of input to encode  the  newline  characters.  The  maximum         \r\n, etc., depending on the newline setting) in a single line of input
95         length of data line is 30,000 characters.         to encode the newline sequences. There is no limit  on  the  length  of
96           data  lines;  the  input  buffer is automatically extended if it is too
97         An  empty  line signals the end of the data lines, at which point a new         small.
98         regular expression is read. The regular expressions are given  enclosed  
99         in any non-alphanumeric delimiters other than backslash, for example         An empty line signals the end of the data lines, at which point  a  new
100           regular  expression is read. The regular expressions are given enclosed
101           in any non-alphanumeric delimiters other than backslash, for example:
102    
103           /(a|bc)x+yz/           /(a|bc)x+yz/
104    
105         White  space before the initial delimiter is ignored. A regular expres-         White space before the initial delimiter is ignored. A regular  expres-
106         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-
107         line  characters  are included within it. It is possible to include the         line characters are included within it. It is possible to  include  the
108         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
109    
110           /abc\/def/           /abc\/def/
111    
112         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,
113         but  since delimiters are always non-alphanumeric, this does not affect         but since delimiters are always non-alphanumeric, this does not  affect
114         its interpretation.  If the terminating delimiter is  immediately  fol-         its  interpretation.   If the terminating delimiter is immediately fol-
115         lowed by a backslash, for example,         lowed by a backslash, for example,
116    
117           /abc/\           /abc/\
118    
119         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
120         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
121         finishes with a backslash, because         finishes with a backslash, because
122    
123           /abc\/           /abc\/
124    
125         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/",
126         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
127         expression.         expression.
128    
129    
130  PATTERN MODIFIERS  PATTERN MODIFIERS
131    
132         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
133         single characters. Following Perl usage, these are  referred  to  below         single  characters.  Following  Perl usage, these are referred to below
134         as,  for  example,  "the /i modifier", even though the delimiter of the         as, for example, "the /i modifier", even though the  delimiter  of  the
135         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
136         modifiers.  Whitespace  may  appear between the final pattern delimiter         modifiers. Whitespace may appear between the  final  pattern  delimiter
137         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
138    
139         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,
140         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
141         pile() is called. These four modifier letters have the same  effect  as         pile()  is  called. These four modifier letters have the same effect as
142         they do in Perl. For example:         they do in Perl. For example:
143    
144           /caseless/i           /caseless/i
# Line 128  PATTERN MODIFIERS Line 146  PATTERN MODIFIERS
146         The following table shows additional modifiers for setting PCRE options         The following table shows additional modifiers for setting PCRE options
147         that do not correspond to anything in Perl:         that do not correspond to anything in Perl:
148    
149           /A    PCRE_ANCHORED           /A       PCRE_ANCHORED
150           /C    PCRE_AUTO_CALLOUT           /C       PCRE_AUTO_CALLOUT
151           /E    PCRE_DOLLAR_ENDONLY           /E       PCRE_DOLLAR_ENDONLY
152           /f    PCRE_FIRSTLINE           /f       PCRE_FIRSTLINE
153           /N    PCRE_NO_AUTO_CAPTURE           /J       PCRE_DUPNAMES
154           /U    PCRE_UNGREEDY           /N       PCRE_NO_AUTO_CAPTURE
155           /X    PCRE_EXTRA           /U       PCRE_UNGREEDY
156             /X       PCRE_EXTRA
157             /<cr>    PCRE_NEWLINE_CR
158             /<lf>    PCRE_NEWLINE_LF
159             /<crlf>  PCRE_NEWLINE_CRLF
160             /<any>   PCRE_NEWLINE_ANY
161    
162           Those  specifying  line ending sequencess are literal strings as shown.
163           This example sets multiline matching  with  CRLF  as  the  line  ending
164           sequence:
165    
166             /^abc/m<crlf>
167    
168           Details  of the meanings of these PCRE options are given in the pcreapi
169           documentation.
170    
171       Finding all matches in a string
172    
173         Searching for all possible matches within each subject  string  can  be         Searching for all possible matches within each subject  string  can  be
174         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
# Line 153  PATTERN MODIFIERS Line 187  PATTERN MODIFIERS
187         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-
188         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
189    
190       Other modifiers
191    
192         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
193    
194         The /+ modifier requests that as well as outputting the substring  that         The /+ modifier requests that as well as outputting the substring  that
# Line 160  PATTERN MODIFIERS Line 196  PATTERN MODIFIERS
196         remainder of the subject string. This is useful  for  tests  where  the         remainder of the subject string. This is useful  for  tests  where  the
197         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
198    
199         The  /L modifier must be followed directly by the name of a locale, for         The  /B modifier is a debugging feature. It requests that pcretest out-
200           put a representation of the compiled byte code after compilation.
201    
202           The /L modifier must be followed directly by the name of a locale,  for
203         example,         example,
204    
205           /pattern/Lfr_FR           /pattern/Lfr_FR
206    
207         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,
208         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
209         locale, and this is then passed to pcre_compile()  when  compiling  the         locale,  and  this  is then passed to pcre_compile() when compiling the
210         regular  expression.  Without  an  /L  modifier,  NULL is passed as the         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
211         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
212         appears.         appears.
213    
214         The  /I  modifier  requests  that pcretest output information about the         The /I modifier requests that pcretest  output  information  about  the
215         compiled pattern (whether it is anchored, has a fixed first  character,         compiled  pattern (whether it is anchored, has a fixed first character,
216         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
217         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-
218         put.         put.
219    
220         The /D modifier is a PCRE debugging feature, which also assumes /I.  It         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
221         causes the internal form of compiled regular expressions to  be  output         that is, both the /B and the /I modifiers.
        after compilation. If the pattern was studied, the information returned  
        is also output.  
222    
223         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
224         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
225         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
226         patterns that were compiled on a host with a different endianness. This         patterns that were compiled on a host with a different endianness. This
227         feature is not available when the POSIX  interface  to  PCRE  is  being         feature  is  not  available  when  the POSIX interface to PCRE is being
228         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
229         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
230    
231         The /S modifier causes pcre_study() to be called after  the  expression         The  /S  modifier causes pcre_study() to be called after the expression
232         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
233    
234         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-
235         piled pattern to be output.         piled pattern to be output.
236    
237         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
238         rather than its native API. When this  is  done,  all  other  modifiers         rather  than  its  native  API.  When this is done, all other modifiers
239         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,
240         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
241         PCRE_DOLLAR_ENDONLY  always, and PCRE_DOTALL unless REG_NEWLINE is set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.
242    
243         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
244         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-
245         vided that it was compiled with this  support  enabled.  This  modifier         vided  that  it  was  compiled with this support enabled. This modifier
246         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
247         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
248    
249         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
250         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
251         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
252    
253    
254  DATA LINES  DATA LINES
255    
256         Before each data line is passed to pcre_exec(),  leading  and  trailing         Before  each  data  line is passed to pcre_exec(), leading and trailing
257         whitespace  is  removed,  and it is then scanned for \ escapes. Some of         whitespace is removed, and it is then scanned for \  escapes.  Some  of
258         these are pretty esoteric features, intended for checking out  some  of         these  are  pretty esoteric features, intended for checking out some of
259         the  more  complicated features of PCRE. If you are just testing "ordi-         the more complicated features of PCRE. If you are just  testing  "ordi-
260         nary" regular expressions, you probably don't need any  of  these.  The         nary"  regular  expressions,  you probably don't need any of these. The
261         following escapes are recognized:         following escapes are recognized:
262    
263           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
264           \b         backspace           \b         backspace (\x08)
265           \e         escape           \e         escape (\x27)
266           \f         formfeed           \f         formfeed (\x0c)
267           \n         newline           \n         newline (\x0a)
268           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
269           \t         tab                        (any number of digits)
270           \v         vertical tab           \r         carriage return (\x0d)
271             \t         tab (\x09)
272             \v         vertical tab (\x0b)
273           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
274           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
275           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
276                        in UTF-8 mode                        in UTF-8 mode
277           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
278                          or pcre_dfa_exec()
279           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
280                          or pcre_dfa_exec()
281           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
282                        after a successful match (number less than 32)                        after a successful match (number less than 32)
283           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 263  DATA LINES Line 304  DATA LINES
304           \M         discover the minimum MATCH_LIMIT and           \M         discover the minimum MATCH_LIMIT and
305                        MATCH_LIMIT_RECURSION settings                        MATCH_LIMIT_RECURSION settings
306           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
307                          or pcre_dfa_exec()
308           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
309                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
310           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
311                        or pcre_dfa_exec()                        or pcre_dfa_exec()
312             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
313                          (any number of digits)
314           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
315           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
316           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
317                          or pcre_dfa_exec()
318           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
319                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
320           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
321                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
322                          or pcre_dfa_exec()
323             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
324                          or pcre_dfa_exec()
325             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
326                          or pcre_dfa_exec()
327             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
328                          or pcre_dfa_exec()
329             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
330                          or pcre_dfa_exec()
331    
332         A  backslash  followed by anything else just escapes the anything else.         The escapes that specify line ending  sequences  are  literal  strings,
333         If the very last character is a backslash, it is ignored. This gives  a         exactly as shown. No more than one newline setting should be present in
334         way  of  passing  an empty line as data, since a real empty line termi-         any data line.
335    
336           A backslash followed by anything else just escapes the  anything  else.
337           If  the very last character is a backslash, it is ignored. This gives a
338           way of passing an empty line as data, since a real  empty  line  termi-
339         nates the data input.         nates the data input.
340    
341         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
342         ferent  values  in  the match_limit and match_limit_recursion fields of         ferent values in the match_limit and  match_limit_recursion  fields  of
343         the pcre_extra data structure, until it finds the minimum  numbers  for         the  pcre_extra  data structure, until it finds the minimum numbers for
344         each parameter that allow pcre_exec() to complete. The match_limit num-         each parameter that allow pcre_exec() to complete. The match_limit num-
345         ber is a measure of the amount of backtracking that  takes  place,  and         ber  is  a  measure of the amount of backtracking that takes place, and
346         checking it out can be instructive. For most simple matches, the number         checking it out can be instructive. For most simple matches, the number
347         is quite small, but for patterns with very large  numbers  of  matching         is  quite  small,  but for patterns with very large numbers of matching
348         possibilities,  it can become large very quickly with increasing length         possibilities, it can become large very quickly with increasing  length
349         of subject string. The match_limit_recursion number is a measure of how         of subject string. The match_limit_recursion number is a measure of how
350         much  stack  (or,  if  PCRE is compiled with NO_RECURSE, how much heap)         much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
351         memory is needed to complete the match attempt.         memory is needed to complete the match attempt.
352    
353         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
354         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
355         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.
356    
357         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-
358         per  API  to  be  used, the only option-setting sequences that have any         per API to be used, the only option-setting  sequences  that  have  any
359         effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL,  respectively,         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
360         to be passed to regexec().         to be passed to regexec().
361    
362         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
363         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.
364         There  may  be  any number of hexadecimal digits inside the braces. The         There may be any number of hexadecimal digits inside  the  braces.  The
365         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.
366    
367    
368  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
369    
370         By   default,  pcretest  uses  the  standard  PCRE  matching  function,         By  default,  pcretest  uses  the  standard  PCRE  matching   function,
371         pcre_exec() to match each data line. From release 6.0, PCRE supports an         pcre_exec() to match each data line. From release 6.0, PCRE supports an
372         alternative  matching  function,  pcre_dfa_test(),  which operates in a         alternative matching function, pcre_dfa_test(),  which  operates  in  a
373         different way, and has some restrictions. The differences  between  the         different  way,  and has some restrictions. The differences between the
374         two functions are described in the pcrematching documentation.         two functions are described in the pcrematching documentation.
375    
376         If  a data line contains the \D escape sequence, or if the command line         If a data line contains the \D escape sequence, or if the command  line
377         contains the -dfa option, the alternative matching function is  called.         contains  the -dfa option, the alternative matching function is called.
378         This function finds all possible matches at a given point. If, however,         This function finds all possible matches at a given point. If, however,
379         the \F escape sequence is present in the data line, it stops after  the         the  \F escape sequence is present in the data line, it stops after the
380         first match is found. This is always the shortest possible match.         first match is found. This is always the shortest possible match.
381    
382    
383  DEFAULT OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
384    
385         This  section  describes  the output when the normal matching function,         This section describes the output when the  normal  matching  function,
386         pcre_exec(), is being used.         pcre_exec(), is being used.
387    
388         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
389         that  pcre_exec()  returns,  starting with number 0 for the string that         that pcre_exec() returns, starting with number 0 for  the  string  that
390         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
391         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-
392         TIAL, respectively, and otherwise the PCRE negative error number.  Here         TIAL,  respectively, and otherwise the PCRE negative error number. Here
393         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
394    
395           $ pcretest           $ pcretest
396           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
397    
398             re> /^abc(\d+)/             re> /^abc(\d+)/
399           data> abc123           data> abc123
# Line 344  DEFAULT OUTPUT FROM PCRETEST Line 402  DEFAULT OUTPUT FROM PCRETEST
402           data> xyz           data> xyz
403           No match           No match
404    
405         If  the strings contain any non-printing characters, they are output as         If the strings contain any non-printing characters, they are output  as
406         \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
407         the  pattern.  If  the pattern has the /+ modifier, the output for sub-         the pattern. See below for the definition of  non-printing  characters.
408         string 0 is followed by the the rest of the subject string,  identified         If  the pattern has the /+ modifier, the output for substring 0 is fol-
409         by "0+" like this:         lowed by the the rest of the subject string, identified  by  "0+"  like
410           this:
411    
412             re> /cat/+             re> /cat/+
413           data> cataract           data> cataract
# Line 376  DEFAULT OUTPUT FROM PCRETEST Line 435  DEFAULT OUTPUT FROM PCRETEST
435         (that is, the return from the extraction function) is given  in  paren-         (that is, the return from the extraction function) is given  in  paren-
436         theses after each string for \C and \G.         theses after each string for \C and \G.
437    
438         Note  that  while patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
439         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
440         lines can be included in data by means of the \n escape.         lines  can  be included in data by means of the \n escape (or \r, \r\n,
441           etc., depending on the newline sequence setting).
442    
443    
444  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
445    
446         When  the  alternative  matching function, pcre_dfa_exec(), is used (by         When the alternative matching function, pcre_dfa_exec(),  is  used  (by
447         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
448         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
449         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:
450    
451             re> /(tang|tangerine|tan)/             re> /(tang|tangerine|tan)/
# Line 394  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 454  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
454            1: tang            1: tang
455            2: tan            2: tan
456    
457         (Using the normal matching function on this data  finds  only  "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
458         The  longest matching string is always given first (and numbered zero).         The longest matching string is always given first (and numbered  zero).
459    
460         If /gP is present on  the  pattern,  the  search  for  further  matches         If /g is present on the pattern, the search for further matches resumes
461         resumes at the end of the longest match. For example:         at the end of the longest match. For example:
462    
463             re> /(tang|tangerine|tan)/g             re> /(tang|tangerine|tan)/g
464           data> yellow tangerine and tangy sultana\D           data> yellow tangerine and tangy sultana\D
# Line 409  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 469  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
469            1: tan            1: tan
470            0: tan            0: tan
471    
472         Since  the  matching  function  does not support substring capture, the         Since the matching function does not  support  substring  capture,  the
473         escape sequences that are concerned with captured  substrings  are  not         escape  sequences  that  are concerned with captured substrings are not
474         relevant.         relevant.
475    
476    
477  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
478    
479         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
480         return, indicating that the subject partially matched the pattern,  you         return,  indicating that the subject partially matched the pattern, you
481         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
482         escape sequence. For example:         escape sequence. For example:
483    
484             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
# Line 427  RESTARTING AFTER A PARTIAL MATCH Line 487  RESTARTING AFTER A PARTIAL MATCH
487           data> n05\R\D           data> n05\R\D
488            0: n05            0: n05
489    
490         For further information about partial  matching,  see  the  pcrepartial         For  further  information  about  partial matching, see the pcrepartial
491         documentation.         documentation.
492    
493    
494  CALLOUTS  CALLOUTS
495    
496         If  the pattern contains any callout requests, pcretest's callout func-         If the pattern contains any callout requests, pcretest's callout  func-
497         tion is called during matching. This works  with  both  matching  func-         tion  is  called  during  matching. This works with both matching func-
498         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
499         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
500         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
501    
502           --->pqrabcdef           --->pqrabcdef
503             0    ^  ^     \d             0    ^  ^     \d
504    
505         indicates  that  callout number 0 occurred for a match attempt starting         indicates that callout number 0 occurred for a match  attempt  starting
506         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
507         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
508         \d. Just one circumflex is output if the start  and  current  positions         \d.  Just  one  circumflex is output if the start and current positions
509         are the same.         are the same.
510    
511         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
512         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
513         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
514         output. For example:         output. For example:
515    
516             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 462  CALLOUTS Line 522  CALLOUTS
522           +10 ^ ^           +10 ^ ^
523            0: E*            0: E*
524    
525         The callout function in pcretest returns zero (carry  on  matching)  by         The  callout  function  in pcretest returns zero (carry on matching) by
526         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)
527         to change this.         to change this.
528    
529         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting  callouts can be helpful when using pcretest to check compli-
530         cated  regular expressions. For further information about callouts, see         cated regular expressions. For further information about callouts,  see
531         the pcrecallout documentation.         the pcrecallout documentation.
532    
533    
534    NON-PRINTING CHARACTERS
535    
536           When  pcretest is outputting text in the compiled version of a pattern,
537           bytes other than 32-126 are always treated as  non-printing  characters
538           are are therefore shown as hex escapes.
539    
540           When  pcretest  is  outputting text that is a matched part of a subject
541           string, it behaves in the same way, unless a different locale has  been
542           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
543           isprint() function to distinguish printing and non-printing characters.
544    
545    
546  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
547    
548         The facilities described in this section are  not  available  when  the         The  facilities  described  in  this section are not available when the
549         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-
550         ifier is specified.         ifier is specified.
551    
552         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
553         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
554         file name.  For example:         file name.  For example:
555    
556           /pattern/im >/some/file           /pattern/im >/some/file
557    
558         See the pcreprecompile documentation for a discussion about saving  and         See  the pcreprecompile documentation for a discussion about saving and
559         re-using compiled patterns.         re-using compiled patterns.
560    
561         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
562         length of the compiled pattern data  followed  by  the  length  of  the         length  of  the  compiled  pattern  data  followed by the length of the
563         optional  study  data,  each  written as four bytes in big-endian order         optional study data, each written as four  bytes  in  big-endian  order
564         (most significant byte first). If there is no study  data  (either  the         (most  significant  byte  first). If there is no study data (either the
565         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-
566         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
567         compiled pattern. If there is additional study data, this follows imme-         compiled pattern. If there is additional study data, this follows imme-
568         diately after the compiled pattern. After writing  the  file,  pcretest         diately  after  the  compiled pattern. After writing the file, pcretest
569         expects to read a new pattern.         expects to read a new pattern.
570    
571         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
572         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 <
573         character,  as  otherwise pcretest will interpret the line as a pattern         character, as otherwise pcretest will interpret the line as  a  pattern
574         delimited by < characters.  For example:         delimited by < characters.  For example:
575    
576            re> </some/file            re> </some/file
577           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
578           No study data           No study data
579    
580         When the pattern has been loaded, pcretest proceeds to read data  lines         When  the pattern has been loaded, pcretest proceeds to read data lines
581         in the usual way.         in the usual way.
582    
583         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
584         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
585         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
586         machine and run on a SPARC machine.         machine and run on a SPARC machine.
587    
588         File names for saving and reloading can be absolute  or  relative,  but         File  names  for  saving and reloading can be absolute or relative, but
589         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
590         a tilde (~) is not available.         a tilde (~) is not available.
591    
592         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-
593         ing  and experimentation. It is not intended for production use because         ing and experimentation. It is not intended for production use  because
594         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
595         no  facility  for  supplying  custom  character  tables  for use with a         no facility for supplying  custom  character  tables  for  use  with  a
596         reloaded pattern. If the original  pattern  was  compiled  with  custom         reloaded  pattern.  If  the  original  pattern was compiled with custom
597         tables,  an  attempt to match a subject string using a reloaded pattern         tables, an attempt to match a subject string using a  reloaded  pattern
598         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
599         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.
600    
601    
602    SEE ALSO
603    
604           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
605           pcrepattern(3), pcreprecompile(3).
606    
607    
608  AUTHOR  AUTHOR
609    
610         Philip Hazel         Philip Hazel
611         University Computing Service,         University Computing Service,
612         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
613    
614  Last updated: 18 January 2006  Last updated: 30 November 2006
615  Copyright (c) 1997-2006 University of Cambridge.  Copyright (c) 1997-2006 University of Cambridge.

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