/[pcre]/code/trunk/doc/pcretest.txt
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revision 77 by nigel, Sat Feb 24 21:40:45 2007 UTC revision 535 by ph10, Thu Jun 3 19:18:24 2010 UTC
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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] [-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    
43         -m        Output  the  size  of each compiled pattern after it has been         -M        Behave  as if each data line contains the \M escape sequence;
44                   compiled. This is equivalent to adding  /M  to  each  regular                   this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                   expression.   For  compatibility  with  earlier  versions  of                   MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
46                     edly with different limits.
47    
48           -m        Output the size of each compiled pattern after  it  has  been
49                     compiled.  This  is  equivalent  to adding /M to each regular
50                     expression.  For  compatibility  with  earlier  versions   of
51                   pcretest, -s is a synonym for -m.                   pcretest, -s is a synonym for -m.
52    
53         -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
54                   when  calling  pcre_exec()  to be osize. The default value is                   when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                   45, which is enough for 14 capturing subexpressions. The vec-                   default  value is 45, which is enough for 14 capturing subex-
56                   tor  size  can  be  changed  for individual matching calls by                   pressions  for  pcre_exec()  or  22  different  matches   for
57                   including \O in the data line (see below).                   pcre_dfa_exec().  The vector size can be changed for individ-
58                     ual matching calls by including \O  in  the  data  line  (see
59                     below).
60    
61         -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-
62                   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
63                   any effect when -p is set.                   any effect when -p is set.
64    
65         -t        Run each compile, study, and match many times with  a  timer,         -q        Do  not output the version number of pcretest at the start of
66                   and  output resulting time per compile or match (in millisec-                   execution.
67                   onds). Do not set -m with -t, because you will then  get  the  
68                   size  output  a  zillion  times,  and the timing will be dis-         -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                   torted.                   size megabytes.
70    
71           -t        Run  each  compile, study, and match many times with a timer,
72                     and output resulting time per compile or match (in  millisec-
73                     onds).  Do  not set -m with -t, because you will then get the
74                     size output a zillion times, and  the  timing  will  be  dis-
75                     torted.  You  can  control  the number of iterations that are
76                     used for timing by following -t with a number (as a  separate
77                     item on the command line). For example, "-t 1000" would iter-
78                     ate 1000 times. The default is to iterate 500000 times.
79    
80           -tm       This is like -t except that it times only the matching phase,
81                     not the compile or study phases.
82    
83    
84  DESCRIPTION  DESCRIPTION
85    
86         If pcretest is given two filename arguments, it reads  from  the  first         If  pcretest  is  given two filename arguments, it reads from the first
87         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
88         reads from that file and writes to stdout.  Otherwise,  it  reads  from         reads  from  that  file  and writes to stdout. Otherwise, it reads from
89         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
90         "re>" to prompt for regular expressions, and "data>" to prompt for data         "re>" to prompt for regular expressions, and "data>" to prompt for data
91         lines.         lines.
92    
93           When pcretest is built, a configuration  option  can  specify  that  it
94           should  be  linked  with the libreadline library. When this is done, if
95           the input is from a terminal, it is read using the readline() function.
96           This  provides line-editing and history facilities. The output from the
97           -help option states whether or not readline() will be used.
98    
99         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.
100         Each set starts with a regular expression, and continues with any  num-         Each  set starts with a regular expression, and continues with any num-
101         ber of data lines to be matched against the pattern.         ber of data lines to be matched against the pattern.
102    
103         Each  data line is matched separately and independently. If you want to         Each data line is matched separately and independently. If you want  to
104         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
105         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
106         length of data line is 30,000 characters.         to  encode  the  newline  sequences. There is no limit on the length of
107           data lines; the input buffer is automatically extended  if  it  is  too
108         An empty line signals the end of the data lines, at which point  a  new         small.
109         regular  expression is read. The regular expressions are given enclosed  
110         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
111           regular expression is read. The regular expressions are given  enclosed
112           in any non-alphanumeric delimiters other than backslash, for example:
113    
114           /(a|bc)x+yz/           /(a|bc)x+yz/
115    
116         White space before the initial delimiter is ignored. A regular  expres-         White  space before the initial delimiter is ignored. A regular expres-
117         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-
118         line characters are included within it. It is possible to  include  the         line  characters  are included within it. It is possible to include the
119         delimiter within the pattern by escaping it, for example         delimiter within the pattern by escaping it, for example
120    
121           /abc\/def/           /abc\/def/
122    
123         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,
124         but since delimiters are always non-alphanumeric, this does not  affect         but  since delimiters are always non-alphanumeric, this does not affect
125         its  interpretation.   If the terminating delimiter is immediately fol-         its interpretation.  If the terminating delimiter is  immediately  fol-
126         lowed by a backslash, for example,         lowed by a backslash, for example,
127    
128           /abc/\           /abc/\
129    
130         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
131         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
132         finishes with a backslash, because         finishes with a backslash, because
133    
134           /abc\/           /abc\/
135    
136         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/",
137         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
138         expression.         expression.
139    
140    
141  PATTERN MODIFIERS  PATTERN MODIFIERS
142    
143         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
144         single  characters.  Following  Perl usage, these are referred to below         single characters. Following Perl usage, these are  referred  to  below
145         as, for example, "the /i modifier", even though the  delimiter  of  the         as,  for  example,  "the /i modifier", even though the delimiter of the
146         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
147         modifiers. Whitespace may appear between the  final  pattern  delimiter         modifiers.  Whitespace  may  appear between the final pattern delimiter
148         and the first modifier, and between the modifiers themselves.         and the first modifier, and between the modifiers themselves.
149    
150         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,
151         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152         pile()  is  called. These four modifier letters have the same effect as         pile() is called. These four modifier letters have the same  effect  as
153         they do in Perl. For example:         they do in Perl. For example:
154    
155           /caseless/i           /caseless/i
156    
157         The following table shows additional modifiers for setting PCRE options         The  following  table  shows additional modifiers for setting PCRE com-
158         that do not correspond to anything in Perl:         pile-time options that do not correspond to anything in Perl:
159    
160             /8              PCRE_UTF8
161             /?              PCRE_NO_UTF8_CHECK
162             /A              PCRE_ANCHORED
163             /C              PCRE_AUTO_CALLOUT
164             /E              PCRE_DOLLAR_ENDONLY
165             /f              PCRE_FIRSTLINE
166             /J              PCRE_DUPNAMES
167             /N              PCRE_NO_AUTO_CAPTURE
168             /U              PCRE_UNGREEDY
169             /W              PCRE_UCP
170             /X              PCRE_EXTRA
171             /<JS>           PCRE_JAVASCRIPT_COMPAT
172             /<cr>           PCRE_NEWLINE_CR
173             /<lf>           PCRE_NEWLINE_LF
174             /<crlf>         PCRE_NEWLINE_CRLF
175             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
176             /<any>          PCRE_NEWLINE_ANY
177             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
178             /<bsr_unicode>  PCRE_BSR_UNICODE
179    
180           The modifiers that are enclosed in angle brackets are  literal  strings
181           as  shown,  including  the  angle  brackets,  but the letters can be in
182           either case. This example sets multiline matching with CRLF as the line
183           ending sequence:
184    
185             /^abc/m<crlf>
186    
187           As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
188           any non-printing characters in output strings to be printed  using  the
189           \x{hh...}  notation  if they are valid UTF-8 sequences. Full details of
190           the PCRE options are given in the pcreapi documentation.
191    
192           /A    PCRE_ANCHORED     Finding all matches in a string
          /C    PCRE_AUTO_CALLOUT  
          /E    PCRE_DOLLAR_ENDONLY  
          /f    PCRE_FIRSTLINE  
          /N    PCRE_NO_AUTO_CAPTURE  
          /U    PCRE_UNGREEDY  
          /X    PCRE_EXTRA  
193    
194         Searching  for  all  possible matches within each subject string can be         Searching for all possible matches within each subject  string  can  be
195         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
196         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
197         ence between /g and /G is that the former uses the startoffset argument         ence between /g and /G is that the former uses the startoffset argument
198         to  pcre_exec()  to  start  searching  at a new point within the entire         to pcre_exec() to start searching at a  new  point  within  the  entire
199         string (which is in effect what Perl does), whereas the  latter  passes         string  (which  is in effect what Perl does), whereas the latter passes
200         over  a  shortened  substring.  This makes a difference to the matching         over a shortened substring. This makes a  difference  to  the  matching
201         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
202         or \B).         or \B).
203    
204         If  any  call  to  pcre_exec()  in a /g or /G sequence matches an empty         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
205         string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
206         flags  set in order to search for another, non-empty, match at the same         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
207         point.  If this second match fails, the start  offset  is  advanced  by         match  at  the same point. If this second match fails, the start offset
208         one,  and  the normal match is retried. This imitates the way Perl han-         is advanced by one character, and the normal  match  is  retried.  This
209         dles such cases when using the /g modifier or the split() function.         imitates  the way Perl handles such cases when using the /g modifier or
210           the split() function.
211    
212       Other modifiers
213    
214         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
215    
216         The  /+ modifier requests that as well as outputting the substring that         The /+ modifier requests that as well as outputting the substring  that
217         matched the entire pattern, pcretest  should  in  addition  output  the         matched  the  entire  pattern,  pcretest  should in addition output the
218         remainder  of  the  subject  string. This is useful for tests where the         remainder of the subject string. This is useful  for  tests  where  the
219         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
220    
221         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-
222         example,         put a representation of the compiled byte code after compilation.  Nor-
223           mally  this  information contains length and offset values; however, if
224           /Z is also present, this data is replaced by spaces. This is a  special
225           feature for use in the automatic test scripts; it ensures that the same
226           output is generated for different internal link sizes.
227    
228           /pattern/Lfr_FR         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
229           that is, both the /B and the /I modifiers.
        For this reason, it must be the last modifier. The given locale is set,  
        pcre_maketables() is called to build a set of character tables for  the  
        locale,  and  this  is then passed to pcre_compile() when compiling the  
        regular expression. Without an /L  modifier,  NULL  is  passed  as  the  
        tables  pointer; that is, /L applies only to the expression on which it  
        appears.  
   
        The /I modifier requests that pcretest  output  information  about  the  
        compiled  pattern (whether it is anchored, has a fixed first character,  
        and so on). It does this by calling pcre_fullinfo() after  compiling  a  
        pattern.  If  the pattern is studied, the results of that are also out-  
        put.  
   
        The /D modifier is a PCRE debugging feature, which also assumes /I.  It  
        causes  the  internal form of compiled regular expressions to be output  
        after compilation. If the pattern was studied, the information returned  
        is also output.  
230    
231         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
232         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
# Line 188  PATTERN MODIFIERS Line 236  PATTERN MODIFIERS
236         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
237         section about saving and reloading compiled patterns below.         section about saving and reloading compiled patterns below.
238    
239         The  /S  modifier causes pcre_study() to be called after the expression         The  /I  modifier  requests  that pcretest output information about the
240         has been compiled, and the results used when the expression is matched.         compiled pattern (whether it is anchored, has a fixed first  character,
241           and  so  on). It does this by calling pcre_fullinfo() after compiling a
242           pattern. If the pattern is studied, the results of that are  also  out-
243           put.
244    
245           The  /K modifier requests pcretest to show names from backtracking con-
246           trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
247           pcretest  to create a pcre_extra block if one has not already been cre-
248           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
249           the mark field within it, every time that pcre_exec() is called. If the
250           variable that the mark field points to is non-NULL for  a  match,  non-
251           match, or partial match, pcretest prints the string to which it points.
252           For a match, this is shown on a line by itself, tagged with "MK:".  For
253           a non-match it is added to the message.
254    
255           The  /L modifier must be followed directly by the name of a locale, for
256           example,
257    
258             /pattern/Lfr_FR
259    
260           For this reason, it must be the last modifier. The given locale is set,
261           pcre_maketables()  is called to build a set of character tables for the
262           locale, and this is then passed to pcre_compile()  when  compiling  the
263           regular  expression.  Without  an  /L  modifier,  NULL is passed as the
264           tables pointer; that is, /L applies only to the expression on which  it
265           appears.
266    
267         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-
268         piled pattern to be output.         piled pattern to be output.
269    
270         The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API         The /S modifier causes pcre_study() to be called after  the  expression
271         rather  than  its  native  API.  When this is done, all other modifiers         has been compiled, and the results used when the expression is matched.
272         except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,  
273         and  REG_NEWLINE  is  set if /m is present. The wrapper functions force     Using the POSIX wrapper API
274         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.  
275           The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
276         The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option         rather than its native API. When /P is set, the following modifiers set
277         set. This turns on support for UTF-8 character handling in  PCRE,  pro-         options for the regcomp() function:
278         vided  that  it  was  compiled with this support enabled. This modifier  
279         also causes any non-printing characters in output strings to be printed           /i    REG_ICASE
280         using the \x{hh...} notation if they are valid UTF-8 sequences.           /m    REG_NEWLINE
281             /N    REG_NOSUB
282         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call           /s    REG_DOTALL     )
283         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the           /U    REG_UNGREEDY   ) These options are not part of
284         checking of the string for UTF-8 validity.           /W    REG_UCP        )   the POSIX standard
285             /8    REG_UTF8       )
286    
287           The  /+  modifier  works  as  described  above. All other modifiers are
288           ignored.
289    
290    
291  DATA LINES  DATA LINES
292    
293         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before each data line is passed to pcre_exec(),  leading  and  trailing
294         whitespace is removed, and it is then scanned for \  escapes.  Some  of         whitespace  is  removed,  and it is then scanned for \ escapes. Some of
295         these  are  pretty esoteric features, intended for checking out some of         these are pretty esoteric features, intended for checking out  some  of
296         the more complicated features of PCRE. If you are just  testing  "ordi-         the  more  complicated features of PCRE. If you are just testing "ordi-
297         nary"  regular  expressions,  you probably don't need any of these. The         nary" regular expressions, you probably don't need any  of  these.  The
298         following escapes are recognized:         following escapes are recognized:
299    
300           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
301           \b         backspace           \b         backspace (\x08)
302           \e         escape           \e         escape (\x27)
303           \f         formfeed           \f         formfeed (\x0c)
304           \n         newline           \n         newline (\x0a)
305           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
306           \t         tab                        (any number of digits)
307           \v         vertical tab           \r         carriage return (\x0d)
308             \t         tab (\x09)
309             \v         vertical tab (\x0b)
310           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
311           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
312           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
313                        in UTF-8 mode                        in UTF-8 mode
314           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
315                          or pcre_dfa_exec()
316           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
317                          or pcre_dfa_exec()
318           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
319                        after a successful match (number less than 32)                        after a successful match (number less than 32)
320           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 257  DATA LINES Line 338  DATA LINES
338                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
339           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
340                        successful match                        successful match
341           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
342                          MATCH_LIMIT_RECURSION settings
343           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
344                          or pcre_dfa_exec(); if used twice, pass the
345                          PCRE_NOTEMPTY_ATSTART option
346           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
347                        pcre_exec() to dd (any number of digits)                        pcre_exec() to dd (any number of digits)
348           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
349                        or pcre_dfa_exec()                        or pcre_dfa_exec(); if used twice, pass the
350                          PCRE_PARTIAL_HARD option
351             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
352                          (any number of digits)
353           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()           \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
354           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
355             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
356                          or pcre_dfa_exec()
357           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
358                          or pcre_dfa_exec()
359           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
360                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
361           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
362                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
363                          or pcre_dfa_exec()
364             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
365                          or pcre_dfa_exec()
366             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
367                          or pcre_dfa_exec()
368             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
369                          or pcre_dfa_exec()
370             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
371                          or pcre_dfa_exec()
372             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
373                          or pcre_dfa_exec()
374    
375         A backslash followed by anything else just escapes the  anything  else.         The  escapes  that  specify  line ending sequences are literal strings,
376         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
377         way of passing an empty line as data, since a real  empty  line  termi-         any data line.
378    
379           A  backslash  followed by anything else just escapes the anything else.
380           If the very last character is a backslash, it is ignored. This gives  a
381           way  of  passing  an empty line as data, since a real empty line termi-
382         nates the data input.         nates the data input.
383    
384         If  \M  is present, pcretest calls pcre_exec() several times, with dif-         If \M is present, pcretest calls pcre_exec() several times,  with  dif-
385         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
386         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
387         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-
388         backtracking  that takes place, and checking it out can be instructive.         ber is a measure of the amount of backtracking that  takes  place,  and
389         For most simple matches, the number is quite small,  but  for  patterns         checking it out can be instructive. For most simple matches, the number
390         with  very large numbers of matching possibilities, it can become large         is quite small, but for patterns with very large  numbers  of  matching
391         very quickly with increasing length of subject string.         possibilities,  it can become large very quickly with increasing length
392           of subject string. The match_limit_recursion number is a measure of how
393           much  stack  (or,  if  PCRE is compiled with NO_RECURSE, how much heap)
394           memory is needed to complete the match attempt.
395    
396         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
397         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
398         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.
399    
400         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-
401         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
402         and REG_NOTEOL to be passed to regexec() respectively.         effect are \B,  \N,  and  \Z,  causing  REG_NOTBOL,  REG_NOTEMPTY,  and
403           REG_NOTEOL, respectively, to be passed to regexec().
404         The use of \x{hh...} to represent UTF-8 characters is not dependent  on  
405         the  use  of  the  /8 modifier on the pattern. It is recognized always.         The  use of \x{hh...} to represent UTF-8 characters is not dependent on
406         There may be any number of hexadecimal digits inside  the  braces.  The         the use of the /8 modifier on the pattern.  It  is  recognized  always.
407         result  is from one to six bytes, encoded according to the UTF-8 rules.         There  may  be  any number of hexadecimal digits inside the braces. The
408           result is from one to six bytes,  encoded  according  to  the  original
409           UTF-8  rules  of  RFC  2279.  This  allows for values in the range 0 to
410           0x7FFFFFFF. Note that not all of those are valid Unicode  code  points,
411           or  indeed  valid  UTF-8 characters according to the later rules in RFC
412           3629.
413    
414    
415  THE ALTERNATIVE MATCHING FUNCTION  THE ALTERNATIVE MATCHING FUNCTION
# Line 321  DEFAULT OUTPUT FROM PCRETEST Line 434  DEFAULT OUTPUT FROM PCRETEST
434    
435         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
436         that pcre_exec() returns, starting with number 0 for  the  string  that         that pcre_exec() returns, starting with number 0 for  the  string  that
437         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched  the  whole  pattern. Otherwise, it outputs "No match" when the
438         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
439         TIAL,  respectively, and otherwise the PCRE negative error number. Here         tially  matching substring when pcre_exec() returns PCRE_ERROR_PARTIAL.
440           For any other returns, it outputs the PCRE negative error number.  Here
441         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
442    
443           $ pcretest           $ pcretest
444           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
445    
446             re> /^abc(\d+)/             re> /^abc(\d+)/
447           data> abc123           data> abc123
# Line 336  DEFAULT OUTPUT FROM PCRETEST Line 450  DEFAULT OUTPUT FROM PCRETEST
450           data> xyz           data> xyz
451           No match           No match
452    
453           Note  that unset capturing substrings that are not followed by one that
454           is set are not returned by pcre_exec(), and are not shown by  pcretest.
455           In  the following example, there are two capturing substrings, but when
456           the first data line is matched, the  second,  unset  substring  is  not
457           shown.  An "internal" unset substring is shown as "<unset>", as for the
458           second data line.
459    
460               re> /(a)|(b)/
461             data> a
462              0: a
463              1: a
464             data> b
465              0: b
466              1: <unset>
467              2: b
468    
469         If the strings contain any non-printing characters, they are output  as         If the strings contain any non-printing characters, they are output  as
470         \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
471         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the pattern. See below for the definition of  non-printing  characters.
472         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-
473         by "0+" like this:         lowed by the the rest of the subject string, identified  by  "0+"  like
474           this:
475    
476             re> /cat/+             re> /cat/+
477           data> cataract           data> cataract
478            0: cat            0: cat
479            0+ aract            0+ aract
480    
481         If the pattern has the /g or /G modifier,  the  results  of  successive         If  the  pattern  has  the /g or /G modifier, the results of successive
482         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
483    
484             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 361  DEFAULT OUTPUT FROM PCRETEST Line 492  DEFAULT OUTPUT FROM PCRETEST
492    
493         "No match" is output only if the first match attempt fails.         "No match" is output only if the first match attempt fails.
494    
495         If  any  of the sequences \C, \G, or \L are present in a data line that         If any of the sequences \C, \G, or \L are present in a data  line  that
496         is successfully matched, the substrings extracted  by  the  convenience         is  successfully  matched,  the substrings extracted by the convenience
497         functions are output with C, G, or L after the string number instead of         functions are output with C, G, or L after the string number instead of
498         a colon. This is in addition to the normal full list. The string length         a colon. This is in addition to the normal full list. The string length
499         (that  is,  the return from the extraction function) is given in paren-         (that is, the return from the extraction function) is given  in  paren-
500         theses after each string for \C and \G.         theses after each string for \C and \G.
501    
502         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
503         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
504         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,
505           etc., depending on the newline sequence setting).
506    
507    
508  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION  OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
# Line 388  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 520  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
520    
521         (Using  the  normal  matching function on this data finds only "tang".)         (Using  the  normal  matching function on this data finds only "tang".)
522         The longest matching string is always given first (and numbered  zero).         The longest matching string is always given first (and numbered  zero).
523           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
524           lowed by the partially matching substring.
525    
526         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
527         resumes at the end of the longest match. For example:         at the end of the longest match. For example:
528    
529             re> /(tang|tangerine|tan)/g             re> /(tang|tangerine|tan)/g
530           data> yellow tangerine and tangy sultana\D           data> yellow tangerine and tangy sultana\D
# Line 401  OUTPUT FROM THE ALTERNATIVE MATCHING FUN Line 535  OUTPUT FROM THE ALTERNATIVE MATCHING FUN
535            1: tan            1: tan
536            0: tan            0: tan
537    
538         Since the matching function does not  support  substring  capture,  the         Since  the  matching  function  does not support substring capture, the
539         escape  sequences  that  are concerned with captured substrings are not         escape sequences that are concerned with captured  substrings  are  not
540         relevant.         relevant.
541    
542    
543  RESTARTING AFTER A PARTIAL MATCH  RESTARTING AFTER A PARTIAL MATCH
544    
545         When the alternative matching function has given the PCRE_ERROR_PARTIAL         When the alternative matching function has given the PCRE_ERROR_PARTIAL
546         return,  indicating that the subject partially matched the pattern, you         return, indicating that the subject partially matched the pattern,  you
547         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
548         escape sequence. For example:         escape sequence. For example:
549    
550             re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/             re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
551           data> 23ja\P\D           data> 23ja\P\D
552           Partial match: 23ja           Partial match: 23ja
553           data> n05\R\D           data> n05\R\D
554            0: n05            0: n05
555    
556         For  further  information  about  partial matching, see the pcrepartial         For further information about partial  matching,  see  the  pcrepartial
557         documentation.         documentation.
558    
559    
560  CALLOUTS  CALLOUTS
561    
562         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
563         tion  is  called  during  matching. This works with both matching func-         tion is called during matching. This works  with  both  matching  func-
564         tions. By default, the called function displays the callout number, the         tions. By default, the called function displays the callout number, the
565         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
566         next pattern item to be tested. For example, the output         next pattern item to be tested. For example, the output
567    
568           --->pqrabcdef           --->pqrabcdef
569             0    ^  ^     \d             0    ^  ^     \d
570    
571         indicates that callout number 0 occurred for a match  attempt  starting         indicates  that  callout number 0 occurred for a match attempt starting
572         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
573         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
574         \d.  Just  one  circumflex is output if the start and current positions         \d. Just one circumflex is output if the start  and  current  positions
575         are the same.         are the same.
576    
577         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
578         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
579         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
580         output. For example:         output. For example:
581    
582             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 454  CALLOUTS Line 588  CALLOUTS
588           +10 ^ ^           +10 ^ ^
589            0: E*            0: E*
590    
591         The  callout  function  in pcretest returns zero (carry on matching) by         The callout function in pcretest returns zero (carry  on  matching)  by
592         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)
593         to change this.         to change this.
594    
595         Inserting  callouts can be helpful when using pcretest to check compli-         Inserting callouts can be helpful when using pcretest to check  compli-
596         cated regular expressions. For further information about callouts,  see         cated  regular expressions. For further information about callouts, see
597         the pcrecallout documentation.         the pcrecallout documentation.
598    
599    
600    NON-PRINTING CHARACTERS
601    
602           When pcretest is outputting text in the compiled version of a  pattern,
603           bytes  other  than 32-126 are always treated as non-printing characters
604           are are therefore shown as hex escapes.
605    
606           When pcretest is outputting text that is a matched part  of  a  subject
607           string,  it behaves in the same way, unless a different locale has been
608           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
609           isprint() function to distinguish printing and non-printing characters.
610    
611    
612  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
613    
614         The  facilities  described  in  this section are not available when the         The  facilities  described  in  this section are not available when the
# Line 519  SAVING AND RELOADING COMPILED PATTERNS Line 665  SAVING AND RELOADING COMPILED PATTERNS
665         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.
666    
667    
668    SEE ALSO
669    
670           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
671           pcrepattern(3), pcreprecompile(3).
672    
673    
674  AUTHOR  AUTHOR
675    
676         Philip Hazel         Philip Hazel
677         University Computing Service,         University Computing Service
678         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
679    
680    
681    REVISION
682    
683  Last updated: 28 February 2005         Last updated: 16 May 2010
684  Copyright (c) 1997-2005 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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