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revision 73 by nigel, Sat Feb 24 21:40:30 2007 UTC revision 392 by ph10, Tue Mar 17 21:30:30 2009 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         pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]  
10           pcretest [options] [source] [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
14         expressions.  This document describes the features of the test program;         expressions.  This document describes the features of the test program;
15         for details of the regular expressions themselves, see the  pcrepattern         for details of the regular expressions themselves, see the  pcrepattern
16         documentation.  For  details  of  PCRE and its options, see the pcreapi         documentation. For details of the PCRE library function calls and their
17         documentation.         options, see the pcreapi documentation.
18    
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 modifier (see below);  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           -help     Output a brief summary these options and then exit.
39    
40         -i        Behave  as  if  each  regex  had 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        Behave  as if each data line contains the \M escape sequence;
44                     this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                     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         -m        Output the size of each compiled pattern after  it  has  been
49                   compiled.  This  is  equivalent  to adding /M to each regular                   compiled.  This  is  equivalent  to adding /M to each regular
50                   expression.  For  compatibility  with  earlier  versions   of                   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 to be osize. The default value is 45, which                   when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                   is  enough  for  14 capturing subexpressions. The vector size                   default  value is 45, which is enough for 14 capturing subex-
56                   can be changed for individual matching calls by including  \O                   pressions  for  pcre_exec()  or  22  different  matches   for
57                   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         -p        Behave  as  if  each regex has /P modifier; the POSIX wrapper                   below).
60                   API is used to call PCRE. None of the other options  has  any  
61                   effect when -p is set.         -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
63                     any effect when -p is set.
64    
65           -q        Do  not output the version number of pcretest at the start of
66                     execution.
67    
68           -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                     size megabytes.
70    
71         -t        Run  each  compile, study, and match many times with a timer,         -t        Run  each  compile, study, and match many times with a timer,
72                   and output resulting time per compile or match (in  millisec-                   and output resulting time per compile or match (in  millisec-
73                   onds).  Do  not set -t with -m, because you will then get the                   onds).  Do  not set -m with -t, because you will then get the
74                   size output 20000 times and the timing will be distorted.                   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  line  is  matched separately and independently. If you want to do         Each data line is matched separately and independently. If you want  to
104         multiple-line matches, you have to use the \n escape sequence in a sin-         do multi-line matches, you have to use the \n escape sequence (or \r or
105         gle  line of input to encode the newline characters. The maximum length         \r\n, etc., depending on the newline setting) in a single line of input
106         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-alphameric 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-alphameric, 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         The pattern may be followed by i, m, s, or x to set the  PCRE_CASELESS,         A  pattern may be followed by any number of modifiers, which are mostly
144         PCRE_MULTILINE,  PCRE_DOTALL,  or  PCRE_EXTENDED options, respectively.         single characters. Following Perl usage, these are  referred  to  below
145         For example:         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
147           modifiers.  Whitespace  may  appear between the final pattern delimiter
148           and the first modifier, and between the modifiers themselves.
149    
150           The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
151           PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152           pile() is called. These four modifier letters have the same  effect  as
153           they do in Perl. For example:
154    
155           /caseless/i           /caseless/i
156    
157         These modifier letters have the same effect as they do in  Perl.  There         The following table shows additional modifiers for setting PCRE options
158         are  others that set PCRE options that do not correspond to anything in         that do not correspond to anything in Perl:
159         Perl: /A, /E, /N, /U, and /X  set  PCRE_ANCHORED,  PCRE_DOLLAR_ENDONLY,  
160         PCRE_NO_AUTO_CAPTURE, PCRE_UNGREEDY, and PCRE_EXTRA respectively.           /A              PCRE_ANCHORED
161             /C              PCRE_AUTO_CALLOUT
162             /E              PCRE_DOLLAR_ENDONLY
163             /f              PCRE_FIRSTLINE
164             /J              PCRE_DUPNAMES
165             /N              PCRE_NO_AUTO_CAPTURE
166             /U              PCRE_UNGREEDY
167             /X              PCRE_EXTRA
168             /<JS>           PCRE_JAVASCRIPT_COMPAT
169             /<cr>           PCRE_NEWLINE_CR
170             /<lf>           PCRE_NEWLINE_LF
171             /<crlf>         PCRE_NEWLINE_CRLF
172             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
173             /<any>          PCRE_NEWLINE_ANY
174             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
175             /<bsr_unicode>  PCRE_BSR_UNICODE
176    
177           Those specifying line ending sequences are literal  strings  as  shown,
178           but  the  letters  can  be  in either case. This example sets multiline
179           matching with CRLF as the line ending sequence:
180    
181             /^abc/m<crlf>
182    
183           Details of the meanings of these PCRE options are given in the  pcreapi
184           documentation.
185    
186       Finding all matches in a string
187    
188         Searching  for  all  possible matches within each subject string can be         Searching  for  all  possible matches within each subject string can be
189         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 129  PATTERN MODIFIERS Line 202  PATTERN MODIFIERS
202         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-
203         dles such cases when using the /g modifier or the split() function.         dles such cases when using the /g modifier or the split() function.
204    
205         There are a number of other modifiers for controlling the way  pcretest     Other modifiers
        operates.  
206    
207         The  /+ modifier requests that as well as outputting the substring that         There are yet more modifiers for controlling the way pcretest operates.
208         matched the entire pattern, pcretest  should  in  addition  output  the  
209         remainder  of  the  subject  string. This is useful for tests where the         The /+ modifier requests that as well as outputting the substring  that
210           matched  the  entire  pattern,  pcretest  should in addition output the
211           remainder of the subject string. This is useful  for  tests  where  the
212         subject contains multiple copies of the same substring.         subject contains multiple copies of the same substring.
213    
214           The  /B modifier is a debugging feature. It requests that pcretest out-
215           put a representation of the compiled byte code after compilation.  Nor-
216           mally  this  information contains length and offset values; however, if
217           /Z is also present, this data is replaced by spaces. This is a  special
218           feature for use in the automatic test scripts; it ensures that the same
219           output is generated for different internal link sizes.
220    
221         The /L modifier must be followed directly by the name of a locale,  for         The /L modifier must be followed directly by the name of a locale,  for
222         example,         example,
223    
224           /pattern/Lfr           /pattern/Lfr_FR
225    
226         For  this reason, it must be the last modifier letter. The given locale         For this reason, it must be the last modifier. The given locale is set,
227         is set, pcre_maketables() is called to build a set of character  tables         pcre_maketables() is called to build a set of character tables for  the
228         for  the locale, and this is then passed to pcre_compile() when compil-         locale,  and  this  is then passed to pcre_compile() when compiling the
229         ing the regular expression. Without an /L modifier, NULL is  passed  as         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
230         the tables pointer; that is, /L applies only to the expression on which         tables  pointer; that is, /L applies only to the expression on which it
231         it appears.         appears.
232    
233         The /I modifier requests that pcretest  output  information  about  the         The /I modifier requests that pcretest  output  information  about  the
234         compiled  expression (whether it is anchored, has a fixed first charac-         compiled  pattern (whether it is anchored, has a fixed first character,
235         ter, and so on). It does this by calling pcre_fullinfo() after  compil-         and so on). It does this by calling pcre_fullinfo() after  compiling  a
236         ing  an expression, and outputting the information it gets back. If the         pattern.  If  the pattern is studied, the results of that are also out-
237         pattern is studied, the results of that are also output.         put.
238    
239         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,
240         causes  the  internal form of compiled regular expressions to be output         that is, both the /B and the /I modifiers.
241         after compilation. If the pattern was studied, the information returned  
242         is also output.         The /F modifier causes pcretest to flip the byte order of the fields in
243           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
244           facility  is  for testing the feature in PCRE that allows it to execute
245           patterns that were compiled on a host with a different endianness. This
246           feature  is  not  available  when  the POSIX interface to PCRE is being
247           used, that is, when the /P pattern modifier is specified. See also  the
248           section about saving and reloading compiled patterns below.
249    
250         The  /S  modifier causes pcre_study() to be called after the expression         The  /S  modifier causes pcre_study() to be called after the expression
251         has been compiled, and the results used when the expression is matched.         has been compiled, and the results used when the expression is matched.
252    
253         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-
254         piled pattern to be output.         piled pattern to be output.
255    
256         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
257         rather  than  its  native  API.  When this is done, all other modifiers         rather than its native API. When this  is  done,  all  other  modifiers
258         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,
259         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
260         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.         PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
261    
262         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
263         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-
# Line 183  PATTERN MODIFIERS Line 270  PATTERN MODIFIERS
270         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
271    
272    
 CALLOUTS  
   
        If  the pattern contains any callout requests, pcretest's callout func-  
        tion will be called. By default, it displays the  callout  number,  and  
        the  start  and  current positions in the text at the callout time. For  
        example, the output  
   
          --->pqrabcdef  
            0    ^  ^  
   
        indicates that callout number 0 occurred for a match  attempt  starting  
        at  the fourth character of the subject string, when the pointer was at  
        the seventh character. The callout  function  returns  zero  (carry  on  
        matching) by default.  
   
        Inserting  callouts may be helpful when using pcretest to check compli-  
        cated regular expressions. For further information about callouts,  see  
        the pcrecallout documentation.  
   
        For  testing  the PCRE library, additional control of callout behaviour  
        is available via escape sequences in the data, as described in the fol-  
        lowing  section.  In  particular, it is possible to pass in a number as  
        callout data (the default is zero). If the callout function receives  a  
        non-zero number, it returns that value instead of zero.  
   
   
273  DATA LINES  DATA LINES
274    
275         Before  each  data  line is passed to pcre_exec(), leading and trailing         Before  each  data  line is passed to pcre_exec(), leading and trailing
# Line 218  DATA LINES Line 279  DATA LINES
279         nary"  regular  expressions,  you probably don't need any of these. The         nary"  regular  expressions,  you probably don't need any of these. The
280         following escapes are recognized:         following escapes are recognized:
281    
282           \a         alarm (= BEL)           \a         alarm (BEL, \x07)
283           \b         backspace           \b         backspace (\x08)
284           \e         escape           \e         escape (\x27)
285           \f         formfeed           \f         formfeed (\x0c)
286           \n         newline           \n         newline (\x0a)
287           \r         carriage return           \qdd       set the PCRE_MATCH_LIMIT limit to dd
288           \t         tab                        (any number of digits)
289           \v         vertical tab           \r         carriage return (\x0d)
290             \t         tab (\x09)
291             \v         vertical tab (\x0b)
292           \nnn       octal character (up to 3 octal digits)           \nnn       octal character (up to 3 octal digits)
293           \xhh       hexadecimal character (up to 2 hex digits)           \xhh       hexadecimal character (up to 2 hex digits)
294           \x{hh...}  hexadecimal character, any number of digits           \x{hh...}  hexadecimal character, any number of digits
295                        in UTF-8 mode                        in UTF-8 mode
296           \A         pass the PCRE_ANCHORED option to pcre_exec()           \A         pass the PCRE_ANCHORED option to pcre_exec()
297                          or pcre_dfa_exec()
298           \B         pass the PCRE_NOTBOL option to pcre_exec()           \B         pass the PCRE_NOTBOL option to pcre_exec()
299                          or pcre_dfa_exec()
300           \Cdd       call pcre_copy_substring() for substring dd           \Cdd       call pcre_copy_substring() for substring dd
301                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
302           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
303                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
304                        ated by next non alphanumeric character)                        ated by next non alphanumeric character)
# Line 246  DATA LINES Line 310  DATA LINES
310           \C!n!m     return 1 instead of 0 when callout number n is           \C!n!m     return 1 instead of 0 when callout number n is
311                        reached for the nth time                        reached for the nth time
312           \C*n       pass the number n (may be negative) as callout           \C*n       pass the number n (may be negative) as callout
313                        data                        data; this is used as the callout return value
314             \D         use the pcre_dfa_exec() match function
315             \F         only shortest match for pcre_dfa_exec()
316           \Gdd       call pcre_get_substring() for substring dd           \Gdd       call pcre_get_substring() for substring dd
317                        after a successful match (any decimal number                        after a successful match (number less than 32)
                       less than 32)  
318           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
319                        "name" after a successful match (name termin-                        "name" after a successful match (name termin-
320                        ated by next non-alphanumeric character)                        ated by next non-alphanumeric character)
321           \L         call pcre_get_substringlist() after a           \L         call pcre_get_substringlist() after a
322                        successful match                        successful match
323           \M         discover the minimum MATCH_LIMIT setting           \M         discover the minimum MATCH_LIMIT and
324                          MATCH_LIMIT_RECURSION settings
325           \N         pass the PCRE_NOTEMPTY option to pcre_exec()           \N         pass the PCRE_NOTEMPTY option to pcre_exec()
326                          or pcre_dfa_exec()
327           \Odd       set the size of the output vector passed to           \Odd       set the size of the output vector passed to
328                        pcre_exec() to dd (any number of decimal                        pcre_exec() to dd (any number of digits)
329                        digits)           \P         pass the PCRE_PARTIAL option to pcre_exec()
330                          or pcre_dfa_exec()
331             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
332                          (any number of digits)
333             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
334           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
335           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
336                          or pcre_dfa_exec()
337           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
338                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
339             \>dd       start the match at offset dd (any number of digits);
340         If \M is present, pcretest calls pcre_exec() several times,  with  dif-                        this sets the startoffset argument for pcre_exec()
341         ferent  values  in  the match_limit field of the pcre_extra data struc-                        or pcre_dfa_exec()
342         ture, until it finds the minimum number that is needed for  pcre_exec()           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
343         to  complete.  This  number is a measure of the amount of recursion and                        or pcre_dfa_exec()
344         backtracking that takes place, and checking it out can be  instructive.           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
345         For  most  simple  matches, the number is quite small, but for patterns                        or pcre_dfa_exec()
346         with very large numbers of matching possibilities, it can become  large           \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
347         very quickly with increasing length of subject string.                        or pcre_dfa_exec()
348             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
349         When  \O is used, it may be higher or lower than the size set by the -O                        or pcre_dfa_exec()
350         option (or defaulted to 45); \O applies only to the call of pcre_exec()           \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
351         for the line in which it appears.                        or pcre_dfa_exec()
352    
353         A  backslash  followed by anything else just escapes the anything else.         The escapes that specify line ending  sequences  are  literal  strings,
354         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
355         way  of  passing  an empty line as data, since a real empty line termi-         any data line.
356    
357           A backslash followed by anything else just escapes the  anything  else.
358           If  the very last character is a backslash, it is ignored. This gives a
359           way of passing an empty line as data, since a real  empty  line  termi-
360         nates the data input.         nates the data input.
361    
362         If /P was present on the regex, causing the POSIX  wrapper  API  to  be         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
363         used,  only  0  causing  REG_NOTBOL  and  REG_NOTEOL  to  be  passed to         ferent values in the match_limit and  match_limit_recursion  fields  of
364         regexec() respectively.         the  pcre_extra  data structure, until it finds the minimum numbers for
365           each parameter that allow pcre_exec() to complete. The match_limit num-
366           ber  is  a  measure of the amount of backtracking that takes place, and
367           checking it out can be instructive. For most simple matches, the number
368           is  quite  small,  but for patterns with very large numbers of matching
369           possibilities, it can become large very quickly with increasing  length
370           of subject string. The match_limit_recursion number is a measure of how
371           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
372           memory is needed to complete the match attempt.
373    
374           When  \O  is  used, the value specified may be higher or lower than the
375           size set by the -O command line option (or defaulted to 45); \O applies
376           only to the call of pcre_exec() for the line in which it appears.
377    
378           If  the /P modifier was present on the pattern, causing the POSIX wrap-
379           per API to be used, the only option-setting  sequences  that  have  any
380           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
381           to be passed to regexec().
382    
383         The use of \x{hh...} to represent UTF-8 characters is not dependent  on         The use of \x{hh...} to represent UTF-8 characters is not dependent  on
384         the  use  of  the  /8 modifier on the pattern. It is recognized always.         the  use  of  the  /8 modifier on the pattern. It is recognized always.
385         There may be any number of hexadecimal digits inside  the  braces.  The         There may be any number of hexadecimal digits inside  the  braces.  The
386         result  is from one to six bytes, encoded according to the UTF-8 rules.         result  is  from  one  to  six bytes, encoded according to the original
387           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
388           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
389           or indeed valid UTF-8 characters according to the later  rules  in  RFC
390           3629.
391    
392    
393    THE ALTERNATIVE MATCHING FUNCTION
394    
395           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
396           pcre_exec() to match each data line. From release 6.0, PCRE supports an
397           alternative  matching  function,  pcre_dfa_test(),  which operates in a
398           different way, and has some restrictions. The differences  between  the
399           two functions are described in the pcrematching documentation.
400    
401           If  a data line contains the \D escape sequence, or if the command line
402           contains the -dfa option, the alternative matching function is  called.
403           This function finds all possible matches at a given point. If, however,
404           the \F escape sequence is present in the data line, it stops after  the
405           first match is found. This is always the shortest possible match.
406    
407    
408  OUTPUT FROM PCRETEST  DEFAULT OUTPUT FROM PCRETEST
409    
410           This  section  describes  the output when the normal matching function,
411           pcre_exec(), is being used.
412    
413         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
414         that  pcre_exec()  returns,  starting with number 0 for the string that         that  pcre_exec()  returns,  starting with number 0 for the string that
415         matched the whole  pattern.  Here  is  an  example  of  an  interactive         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
416         pcretest run.         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
417           TIAL, respectively, and otherwise the PCRE negative error number.  Here
418           is an example of an interactive pcretest run.
419    
420           $ pcretest           $ pcretest
421           PCRE version 4.00 08-Jan-2003           PCRE version 7.0 30-Nov-2006
422    
423             re> /^abc(\d+)/             re> /^abc(\d+)/
424           data> abc123           data> abc123
# Line 310  OUTPUT FROM PCRETEST Line 427  OUTPUT FROM PCRETEST
427           data> xyz           data> xyz
428           No match           No match
429    
430         If  the strings contain any non-printing characters, they are output as         Note  that unset capturing substrings that are not followed by one that
431         \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on         is set are not returned by pcre_exec(), and are not shown by  pcretest.
432         the  pattern.  If  the pattern has the /+ modifier, then the output for         In  the following example, there are two capturing substrings, but when
433         substring 0 is followed by the the rest of the subject string,  identi-         the first data line is matched, the  second,  unset  substring  is  not
434         fied by "0+" like this:         shown.  An "internal" unset substring is shown as "<unset>", as for the
435           second data line.
436    
437               re> /(a)|(b)/
438             data> a
439              0: a
440              1: a
441             data> b
442              0: b
443              1: <unset>
444              2: b
445    
446           If the strings contain any non-printing characters, they are output  as
447           \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
448           the pattern. See below for the definition of  non-printing  characters.
449           If  the pattern has the /+ modifier, the output for substring 0 is fol-
450           lowed by the the rest of the subject string, identified  by  "0+"  like
451           this:
452    
453             re> /cat/+             re> /cat/+
454           data> cataract           data> cataract
# Line 342  OUTPUT FROM PCRETEST Line 476  OUTPUT FROM PCRETEST
476         (that is, the return from the extraction function) is given  in  paren-         (that is, the return from the extraction function) is given  in  paren-
477         theses after each string for \C and \G.         theses after each string for \C and \G.
478    
479         Note  that  while patterns can be continued over several lines (a plain         Note that whereas patterns can be continued over several lines (a plain
480         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
481         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,
482           etc., depending on the newline sequence setting).
483    
484    
485    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
486    
487           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
488           means  of  the \D escape sequence or the -dfa command line option), the
489           output consists of a list of all the matches that start  at  the  first
490           point in the subject where there is at least one match. For example:
491    
492               re> /(tang|tangerine|tan)/
493             data> yellow tangerine\D
494              0: tangerine
495              1: tang
496              2: tan
497    
498           (Using  the  normal  matching function on this data finds only "tang".)
499           The longest matching string is always given first (and numbered zero).
500    
501           If /g is present on the pattern, the search for further matches resumes
502           at the end of the longest match. For example:
503    
504               re> /(tang|tangerine|tan)/g
505             data> yellow tangerine and tangy sultana\D
506              0: tangerine
507              1: tang
508              2: tan
509              0: tang
510              1: tan
511              0: tan
512    
513           Since  the  matching  function  does not support substring capture, the
514           escape sequences that are concerned with captured  substrings  are  not
515           relevant.
516    
517    
518    RESTARTING AFTER A PARTIAL MATCH
519    
520           When the alternative matching function has given the PCRE_ERROR_PARTIAL
521           return, indicating that the subject partially matched the pattern,  you
522           can  restart  the match with additional subject data by means of the \R
523           escape sequence. For example:
524    
525               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
526             data> 23ja\P\D
527             Partial match: 23ja
528             data> n05\R\D
529              0: n05
530    
531           For further information about partial  matching,  see  the  pcrepartial
532           documentation.
533    
534    
535    CALLOUTS
536    
537           If  the pattern contains any callout requests, pcretest's callout func-
538           tion is called during matching. This works  with  both  matching  func-
539           tions. By default, the called function displays the callout number, the
540           start and current positions in the text at the callout  time,  and  the
541           next pattern item to be tested. For example, the output
542    
543             --->pqrabcdef
544               0    ^  ^     \d
545    
546           indicates  that  callout number 0 occurred for a match attempt starting
547           at the fourth character of the subject string, when the pointer was  at
548           the  seventh  character of the data, and when the next pattern item was
549           \d. Just one circumflex is output if the start  and  current  positions
550           are the same.
551    
552           Callouts numbered 255 are assumed to be automatic callouts, inserted as
553           a result of the /C pattern modifier. In this case, instead  of  showing
554           the  callout  number, the offset in the pattern, preceded by a plus, is
555           output. For example:
556    
557               re> /\d?[A-E]\*/C
558             data> E*
559             --->E*
560              +0 ^      \d?
561              +3 ^      [A-E]
562              +8 ^^     \*
563             +10 ^ ^
564              0: E*
565    
566           The callout function in pcretest returns zero (carry  on  matching)  by
567           default,  but you can use a \C item in a data line (as described above)
568           to change this.
569    
570           Inserting callouts can be helpful when using pcretest to check  compli-
571           cated  regular expressions. For further information about callouts, see
572           the pcrecallout documentation.
573    
574    
575    NON-PRINTING CHARACTERS
576    
577           When pcretest is outputting text in the compiled version of a  pattern,
578           bytes  other  than 32-126 are always treated as non-printing characters
579           are are therefore shown as hex escapes.
580    
581           When pcretest is outputting text that is a matched part  of  a  subject
582           string,  it behaves in the same way, unless a different locale has been
583           set for the  pattern  (using  the  /L  modifier).  In  this  case,  the
584           isprint() function to distinguish printing and non-printing characters.
585    
586    
587    SAVING AND RELOADING COMPILED PATTERNS
588    
589           The  facilities  described  in  this section are not available when the
590           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
591           ifier is specified.
592    
593           When the POSIX interface is not in use, you can cause pcretest to write
594           a compiled pattern to a file, by following the modifiers with >  and  a
595           file name.  For example:
596    
597             /pattern/im >/some/file
598    
599           See  the pcreprecompile documentation for a discussion about saving and
600           re-using compiled patterns.
601    
602           The data that is written is binary.  The  first  eight  bytes  are  the
603           length  of  the  compiled  pattern  data  followed by the length of the
604           optional study data, each written as four  bytes  in  big-endian  order
605           (most  significant  byte  first). If there is no study data (either the
606           pattern was not studied, or studying did not return any data), the sec-
607           ond  length  is  zero. The lengths are followed by an exact copy of the
608           compiled pattern. If there is additional study data, this follows imme-
609           diately  after  the  compiled pattern. After writing the file, pcretest
610           expects to read a new pattern.
611    
612           A saved pattern can be reloaded into pcretest by specifing < and a file
613           name  instead  of  a pattern. The name of the file must not contain a <
614           character, as otherwise pcretest will interpret the line as  a  pattern
615           delimited by < characters.  For example:
616    
617              re> </some/file
618             Compiled regex loaded from /some/file
619             No study data
620    
621           When  the pattern has been loaded, pcretest proceeds to read data lines
622           in the usual way.
623    
624           You can copy a file written by pcretest to a different host and  reload
625           it  there,  even  if the new host has opposite endianness to the one on
626           which the pattern was compiled. For example, you can compile on an  i86
627           machine and run on a SPARC machine.
628    
629           File  names  for  saving and reloading can be absolute or relative, but
630           note that the shell facility of expanding a file name that starts  with
631           a tilde (~) is not available.
632    
633           The  ability to save and reload files in pcretest is intended for test-
634           ing and experimentation. It is not intended for production use  because
635           only  a  single pattern can be written to a file. Furthermore, there is
636           no facility for supplying  custom  character  tables  for  use  with  a
637           reloaded  pattern.  If  the  original  pattern was compiled with custom
638           tables, an attempt to match a subject string using a  reloaded  pattern
639           is  likely to cause pcretest to crash.  Finally, if you attempt to load
640           a file that is not in the correct format, the result is undefined.
641    
642    
643    SEE ALSO
644    
645           pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
646           pcrepattern(3), pcreprecompile(3).
647    
648    
649  AUTHOR  AUTHOR
650    
651         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
652         University Computing Service,         University Computing Service
653         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
654    
655    
656    REVISION
657    
658  Last updated: 09 December 2003         Last updated: 10 March 2009
659  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2009 University of Cambridge.

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