/[pcre]/code/trunk/doc/pcretest.txt
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revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 211 by ph10, Thu Aug 9 09:52:43 2007 UTC
# Line 1  Line 1 
1  PCRETEST(1)                                                        PCRETEST(1)  PCRETEST(1)                                                        PCRETEST(1)
2    
3    
   
4  NAME  NAME
5         pcretest - a program for testing Perl-compatible regular expressions.         pcretest - a program for testing Perl-compatible regular expressions.
6    
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-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 had  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;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38         -i        Behave  as  if  each  regex  had the /I modifier; information         -help     Output a brief summary these options and then exit.
39    
40           -i        Behave as if each regex  has  the  /I  modifier;  information
41                   about the compiled pattern is given after compilation.                   about the compiled pattern is given after compilation.
42    
43         -m        Output the size of each compiled pattern after  it  has  been         -m        Output  the  size  of each compiled pattern after it has been
44                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled. This is equivalent to adding  /M  to  each  regular
45                   expression.  For  compatibility  with  earlier  versions   of                   expression.   For  compatibility  with  earlier  versions  of
46                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
47    
48         -o osize  Set  the number of elements in the output vector that is used         -o osize  Set the number of elements in the output vector that is  used
49                   when calling pcre_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         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper                   below).
55                   API is used to call PCRE. None of the other options  has  any  
56                   effect when -p is set.         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
57                     per  API  is used to call PCRE. None of the other options has
58         -t        Run  each  compile, study, and match many times with a timer,                   any effect when -p is set.
59                   and output resulting time per compile or match (in  millisec-  
60                   onds).  Do  not set -m with -t, because you will then get the         -q        Do not output the version number of pcretest at the start  of
61                   size output a zillion times, and  the  timing  will  be  dis-                   execution.
62                   torted.  
63           -S size   On  Unix-like  systems,  set the size of the runtime stack to
64                     size megabytes.
65    
66           -t        Run each compile, study, and match many times with  a  timer,
67                     and  output resulting time per compile or match (in millisec-
68                     onds). Do not set -m with -t, because you will then  get  the
69                     size  output  a  zillion  times,  and the timing will be dis-
70                     torted. You can control the number  of  iterations  that  are
71                     used  for timing by following -t with a number (as a separate
72                     item on the command line). For example, "-t 1000" would iter-
73                     ate 1000 times. The default is to iterate 500000 times.
74    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
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 120  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           /N    PCRE_NO_AUTO_CAPTURE           /f          PCRE_FIRSTLINE
153           /U    PCRE_UNGREEDY           /J          PCRE_DUPNAMES
154           /X    PCRE_EXTRA           /N          PCRE_NO_AUTO_CAPTURE
155             /U          PCRE_UNGREEDY
156             /X          PCRE_EXTRA
157             /<cr>       PCRE_NEWLINE_CR
158             /<lf>       PCRE_NEWLINE_LF
159             /<crlf>     PCRE_NEWLINE_CRLF
160             /<anycrlf>  PCRE_NEWLINE_ANYCRLF
161             /<any>      PCRE_NEWLINE_ANY
162    
163           Those  specifying  line ending sequencess are literal strings as shown.
164           This example sets multiline matching  with  CRLF  as  the  line  ending
165           sequence:
166    
167             /^abc/m<crlf>
168    
169           Details  of the meanings of these PCRE options are given in the pcreapi
170           documentation.
171    
172       Finding all matches in a string
173    
174         Searching for all possible matches within each subject  string  can  be         Searching for all possible matches within each subject  string  can  be
175         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 144  PATTERN MODIFIERS Line 188  PATTERN MODIFIERS
188         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-
189         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
190    
191       Other modifiers
192    
193         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
194    
195         The /+ modifier requests that as well as outputting the substring  that         The /+ modifier requests that as well as outputting the substring  that
# Line 151  PATTERN MODIFIERS Line 197  PATTERN MODIFIERS
197         remainder of the subject string. This is useful  for  tests  where  the         remainder of the subject string. This is useful  for  tests  where  the
198         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
199    
200         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-
201           put a representation of the compiled byte code after compilation.  Nor-
202           mally  this  information contains length and offset values; however, if
203           /Z is also present, this data is replaced by spaces. This is a  special
204           feature for use in the automatic test scripts; it ensures that the same
205           output is generated for different internal link sizes.
206    
207           The /L modifier must be followed directly by the name of a locale,  for
208         example,         example,
209    
210           /pattern/Lfr_FR           /pattern/Lfr_FR
211    
212         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,
213         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
214         locale, and this is then passed to pcre_compile()  when  compiling  the         locale,  and  this  is then passed to pcre_compile() when compiling the
215         regular  expression.  Without  an  /L  modifier,  NULL is passed as the         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
216         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
217         appears.         appears.
218    
219         The  /I  modifier  requests  that pcretest output information about the         The /I modifier requests that pcretest  output  information  about  the
220         compiled pattern (whether it is anchored, has a fixed first  character,         compiled  pattern (whether it is anchored, has a fixed first character,
221         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
222         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-
223         put.         put.
224    
225         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,
226         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.  
227    
228         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
229         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
230         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
231         patterns that were compiled on a host with a different endianness. This         patterns that were compiled on a host with a different endianness. This
232         feature is not available when the POSIX  interface  to  PCRE  is  being         feature  is  not  available  when  the POSIX interface to PCRE is being
233         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
234         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
235    
236         The /S modifier causes pcre_study() to be called after  the  expression         The  /S  modifier causes pcre_study() to be called after the expression
237         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
238    
239         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-
240         piled pattern to be output.         piled pattern to be output.
241    
242         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
243         rather than its native API. When this  is  done,  all  other  modifiers         rather  than  its  native  API.  When this is done, all other modifiers
244         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,
245         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
246         PCRE_DOLLAR_ENDONLY  always, and PCRE_DOTALL unless REG_NEWLINE is set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.
247    
248         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
249         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-
250         vided that it was compiled with this  support  enabled.  This  modifier         vided  that  it  was  compiled with this support enabled. This modifier
251         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
252         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
253    
254         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
255         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
256         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
257    
258    
259  DATA LINES  DATA LINES
260    
261         Before each data line is passed to pcre_exec(),  leading  and  trailing         Before  each  data  line is passed to pcre_exec(), leading and trailing
262         whitespace  is  removed,  and it is then scanned for \ escapes. Some of         whitespace is removed, and it is then scanned for \  escapes.  Some  of
263         these are pretty esoteric features, intended for checking out  some  of         these  are  pretty esoteric features, intended for checking out some of
264         the  more  complicated features of PCRE. If you are just testing "ordi-         the more complicated features of PCRE. If you are just  testing  "ordi-
265         nary" regular expressions, you probably don't need any  of  these.  The         nary"  regular  expressions,  you probably don't need any of these. The
266         following escapes are recognized:         following escapes are recognized:
267    
268           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
269           \b         backspace           \b         backspace (\x08)
270           \e         escape           \e         escape (\x27)
271           \f         formfeed           \f         formfeed (\x0c)
272           \n         newline           \n         newline (\x0a)
273           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
274           \t         tab                        (any number of digits)
275           \v         vertical tab           \r         carriage return (\x0d)
276             \t         tab (\x09)
277             \v         vertical tab (\x0b)
278           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
279           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
280           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
281                        in UTF-8 mode                        in UTF-8 mode
282           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
283                          or pcre_dfa_exec()
284           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
285                          or pcre_dfa_exec()
286           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
287                        after a successful match (number less than 32)                        after a successful match (number less than 32)
288           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 242  DATA LINES Line 297  DATA LINES
297                        reached for the nth time                        reached for the nth time
298           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
299                        data; this is used as the callout return value                        data; this is used as the callout return value
300             \D         use the pcre_dfa_exec() match function
301             \F         only shortest match for pcre_dfa_exec()
302           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
303                        after a successful match (number less than 32)                        after a successful match (number less than 32)
304           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
# Line 249  DATA LINES Line 306  DATA LINES
306                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
307           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
308                        successful match                        successful match
309           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
310                          MATCH_LIMIT_RECURSION settings
311           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
312                          or pcre_dfa_exec()
313           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
314                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
315           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL option to pcre_exec()
316                          or pcre_dfa_exec()
317             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
318                          (any number of digits)
319             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
320           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
321           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
322                          or pcre_dfa_exec()
323           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
324                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
325           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
326                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
327                          or pcre_dfa_exec()
328         A  backslash  followed by anything else just escapes the anything else.           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
329         If the very last character is a backslash, it is ignored. This gives  a                        or pcre_dfa_exec()
330         way  of  passing  an empty line as data, since a real empty line termi-           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
331                          or pcre_dfa_exec()
332             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
333                          or pcre_dfa_exec()
334             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
335                          or pcre_dfa_exec()
336             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
337                          or pcre_dfa_exec()
338    
339           The escapes that specify line ending  sequences  are  literal  strings,
340           exactly as shown. No more than one newline setting should be present in
341           any data line.
342    
343           A backslash followed by anything else just escapes the  anything  else.
344           If  the very last character is a backslash, it is ignored. This gives a
345           way of passing an empty line as data, since a real  empty  line  termi-
346         nates the data input.         nates the data input.
347    
348         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
349         ferent  values  in  the match_limit field of the pcre_extra data struc-         ferent values in the match_limit and  match_limit_recursion  fields  of
350         ture, until it finds the minimum number that is needed for  pcre_exec()         the  pcre_extra  data structure, until it finds the minimum numbers for
351         to  complete.  This  number is a measure of the amount of recursion and         each parameter that allow pcre_exec() to complete. The match_limit num-
352         backtracking that takes place, and checking it out can be  instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
353         For  most  simple  matches, the number is quite small, but for patterns         checking it out can be instructive. For most simple matches, the number
354         with very large numbers of matching possibilities, it can become  large         is  quite  small,  but for patterns with very large numbers of matching
355         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
356           of subject string. The match_limit_recursion number is a measure of how
357           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
358           memory is needed to complete the match attempt.
359    
360         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
361         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
362         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.
363    
364         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-
365         per API to be used, only \B and \Z have any effect, causing  REG_NOTBOL         per API to be used, the only option-setting  sequences  that  have  any
366         and REG_NOTEOL to be passed to regexec() respectively.         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
367           to be passed to regexec().
368    
369           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
370           the  use  of  the  /8 modifier on the pattern. It is recognized always.
371           There may be any number of hexadecimal digits inside  the  braces.  The
372           result  is  from  one  to  six bytes, encoded according to the original
373           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
374           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
375           or indeed valid UTF-8 characters according to the later  rules  in  RFC
376           3629.
377    
378    
379    THE ALTERNATIVE MATCHING FUNCTION
380    
381           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
382           pcre_exec() to match each data line. From release 6.0, PCRE supports an
383           alternative  matching  function,  pcre_dfa_test(),  which operates in a
384           different way, and has some restrictions. The differences  between  the
385           two functions are described in the pcrematching documentation.
386    
387           If  a data line contains the \D escape sequence, or if the command line
388           contains the -dfa option, the alternative matching function is  called.
389           This function finds all possible matches at a given point. If, however,
390           the \F escape sequence is present in the data line, it stops after  the
391           first match is found. This is always the shortest possible match.
392    
        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.  
393    
394    DEFAULT OUTPUT FROM PCRETEST
395    
396  OUTPUT FROM PCRETEST         This  section  describes  the output when the normal matching function,
397           pcre_exec(), is being used.
398    
399         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
400         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
401         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
402         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
403         TIAL,  respectively, and otherwise the PCRE negative error number. Here         TIAL, respectively, and otherwise the PCRE negative error number.  Here
404         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
405    
406           $ pcretest           $ pcretest
407           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
408    
409             re> /^abc(\d+)/             re> /^abc(\d+)/
410           data> abc123           data> abc123
# Line 308  OUTPUT FROM PCRETEST Line 413  OUTPUT FROM PCRETEST
413           data> xyz           data> xyz
414           No match           No match
415    
416         If the strings contain any non-printing characters, they are output  as         If  the strings contain any non-printing characters, they are output as
417         \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
418         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the  pattern.  See below for the definition of non-printing characters.
419         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-
420         by "0+" like this:         lowed  by  the  the rest of the subject string, identified by "0+" like
421           this:
422    
423             re> /cat/+             re> /cat/+
424           data> cataract           data> cataract
# Line 340  OUTPUT FROM PCRETEST Line 446  OUTPUT FROM PCRETEST
446         (that  is,  the return from the extraction function) is given in paren-         (that  is,  the return from the extraction function) is given in paren-
447         theses after each string for \C and \G.         theses after each string for \C and \G.
448    
449         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
450         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
451         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,
452           etc., depending on the newline sequence setting).
453    
454    
455    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
456    
457           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
458           means of the \D escape sequence or the -dfa command line  option),  the
459           output  consists  of  a list of all the matches that start at the first
460           point in the subject where there is at least one match. For example:
461    
462               re> /(tang|tangerine|tan)/
463             data> yellow tangerine\D
464              0: tangerine
465              1: tang
466              2: tan
467    
468           (Using the normal matching function on this data  finds  only  "tang".)
469           The  longest matching string is always given first (and numbered zero).
470    
471           If /g is present on the pattern, the search for further matches resumes
472           at the end of the longest match. For example:
473    
474               re> /(tang|tangerine|tan)/g
475             data> yellow tangerine and tangy sultana\D
476              0: tangerine
477              1: tang
478              2: tan
479              0: tang
480              1: tan
481              0: tan
482    
483           Since  the  matching  function  does not support substring capture, the
484           escape sequences that are concerned with captured  substrings  are  not
485           relevant.
486    
487    
488    RESTARTING AFTER A PARTIAL MATCH
489    
490           When the alternative matching function has given the PCRE_ERROR_PARTIAL
491           return, indicating that the subject partially matched the pattern,  you
492           can  restart  the match with additional subject data by means of the \R
493           escape sequence. For example:
494    
495               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
496             data> 23ja\P\D
497             Partial match: 23ja
498             data> n05\R\D
499              0: n05
500    
501           For further information about partial  matching,  see  the  pcrepartial
502           documentation.
503    
504    
505  CALLOUTS  CALLOUTS
506    
507         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
508         tion  is  called  during  matching. By default, it displays the callout         tion is called during matching. This works  with  both  matching  func-
509         number, the start and current positions in  the  text  at  the  callout         tions. By default, the called function displays the callout number, the
510         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
511           next pattern item to be tested. For example, the output
512    
513           --->pqrabcdef           --->pqrabcdef
514             0    ^  ^     \d             0    ^  ^     \d
# Line 376  CALLOUTS Line 534  CALLOUTS
534            0: E*            0: E*
535    
536         The callout function in pcretest returns zero (carry  on  matching)  by         The callout function in pcretest returns zero (carry  on  matching)  by
537         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)
538         to change this.         to change this.
539    
540         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting callouts can be helpful when using pcretest to check  compli-
# Line 384  CALLOUTS Line 542  CALLOUTS
542         the pcrecallout documentation.         the pcrecallout documentation.
543    
544    
545    NON-PRINTING CHARACTERS
546    
547           When pcretest is outputting text in the compiled version of a  pattern,
548           bytes  other  than 32-126 are always treated as non-printing characters
549           are are therefore shown as hex escapes.
550    
551           When pcretest is outputting text that is a matched part  of  a  subject
552           string,  it behaves in the same way, unless a different locale has been
553           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
554           isprint() function to distinguish printing and non-printing characters.
555    
556    
557  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
558    
559         The facilities described in this section are  not  available  when  the         The facilities described in this section are  not  available  when  the
# Line 440  SAVING AND RELOADING COMPILED PATTERNS Line 610  SAVING AND RELOADING COMPILED PATTERNS
610         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.
611    
612    
613    SEE ALSO
614    
615           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
616           pcrepattern(3), pcreprecompile(3).
617    
618    
619  AUTHOR  AUTHOR
620    
621         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
622         University Computing Service,         University Computing Service
623         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
624    
625    
626    REVISION
627    
628  Last updated: 10 September 2004         Last updated: 09 August 2007
629  Copyright (c) 1997-2004 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

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