/[pcre]/code/trunk/doc/pcretest.txt
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revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 429 by ph10, Tue Sep 1 16:10:16 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    
10         pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [options] [source] [destination]
             [destination]  
11    
12         pcretest  was written as a test program for the PCRE regular expression         pcretest  was written as a test program for the PCRE regular expression
13         library itself, but it can also be used for experimenting with  regular         library itself, but it can also be used for experimenting with  regular
# Line 20  SYNOPSIS Line 19  SYNOPSIS
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
26                   able   information  about  the  optional  features  that  are                   able  information  about  the  optional  features  that   are
27                   included, and then exit.                   included, and then exit.
28    
29         -d        Behave as if each regex had  the  /D  (debug)  modifier;  the         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                   internal form is output after compilation.                   internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33           -dfa      Behave  as if each data line contains the \D escape sequence;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38           -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_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         -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 -m with -t, because you will then get the                   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-                   size output a zillion times, and  the  timing  will  be  dis-
75                   torted.                   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
# Line 61  DESCRIPTION Line 90  DESCRIPTION
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           small.
109    
110         An  empty  line signals the end of the data lines, at which point a new         An  empty  line signals the end of the data lines, at which point a new
111         regular expression is read. The regular expressions are given  enclosed         regular expression is read. The regular expressions are given  enclosed
112         in any non-alphanumeric delimiters other than backslash, for example         in any non-alphanumeric delimiters other than backslash, for example:
113    
114           /(a|bc)x+yz/           /(a|bc)x+yz/
115    
# Line 120  PATTERN MODIFIERS Line 157  PATTERN MODIFIERS
157         The following table shows additional modifiers for setting PCRE options         The following table shows additional modifiers for setting PCRE options
158         that do not correspond to anything in Perl:         that do not correspond to anything in Perl:
159    
160           /A    PCRE_ANCHORED           /A              PCRE_ANCHORED
161           /C    PCRE_AUTO_CALLOUT           /C              PCRE_AUTO_CALLOUT
162           /E    PCRE_DOLLAR_ENDONLY           /E              PCRE_DOLLAR_ENDONLY
163           /N    PCRE_NO_AUTO_CAPTURE           /f              PCRE_FIRSTLINE
164           /U    PCRE_UNGREEDY           /J              PCRE_DUPNAMES
165           /X    PCRE_EXTRA           /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         Searching for all possible matches within each subject  string  can  be     Finding all matches in a string
187         requested  by  the  /g  or  /G modifier. After finding a match, PCRE is  
188           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
190         called again to search the remainder of the subject string. The differ-         called again to search the remainder of the subject string. The differ-
191         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
192         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
193         string  (which  is in effect what Perl does), whereas the latter passes         string (which is in effect what Perl does), whereas the  latter  passes
194         over a shortened substring. This makes a  difference  to  the  matching         over  a  shortened  substring.  This makes a difference to the matching
195         process if the pattern begins with a lookbehind assertion (including \b         process if the pattern begins with a lookbehind assertion (including \b
196         or \B).         or \B).
197    
198         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
199         string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED         string, the next call is done with the PCRE_NOTEMPTY and  PCRE_ANCHORED
200         flags set in order to search for another, non-empty, match at the  same         flags  set in order to search for another, non-empty, match at the same
201         point.   If  this  second  match fails, the start offset is advanced by         point.  If this second match fails, the start  offset  is  advanced  by
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       Other modifiers
206    
207         There are yet more modifiers for controlling the way pcretest operates.         There are yet more modifiers for controlling the way pcretest operates.
208    
209         The /+ modifier requests that as well as outputting the substring  that         The /+ modifier requests that as well as outputting the substring  that
# Line 151  PATTERN MODIFIERS Line 211  PATTERN MODIFIERS
211         remainder of the subject string. This is useful  for  tests  where  the         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  /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-
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
222         example,         example,
223    
224           /pattern/Lfr_FR           /pattern/Lfr_FR
225    
226         For this reason, it must be the last modifier. The given locale is set,         For this reason, it must be the last modifier. The given locale is set,
227         pcre_maketables()  is called to build a set of character tables for the         pcre_maketables() is called to build a set of character tables for  the
228         locale, and this is then passed to pcre_compile()  when  compiling  the         locale,  and  this  is then passed to pcre_compile() when compiling the
229         regular  expression.  Without  an  /L  modifier,  NULL is passed as the         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
230         tables pointer; that is, /L applies only to the expression on which  it         tables  pointer; that is, /L applies only to the expression on which it
231         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 pattern (whether it is anchored, has a fixed first  character,         compiled  pattern (whether it is anchored, has a fixed first character,
235         and  so  on). It does this by calling pcre_fullinfo() after compiling a         and so on). It does this by calling pcre_fullinfo() after  compiling  a
236         pattern. If the pattern is studied, the results of that are  also  out-         pattern.  If  the pattern is studied, the results of that are also out-
237         put.         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.
        after compilation. If the pattern was studied, the information returned  
        is also output.  
241    
242         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
243         the  compiled  pattern  that  contain  2-byte  and 4-byte numbers. This         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         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         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         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         used, that is, when the /P pattern modifier is specified. See also  the
248         section about saving and reloading compiled patterns below.         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-
# Line 192  PATTERN MODIFIERS Line 257  PATTERN MODIFIERS
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-
264         vided that it was compiled with this  support  enabled.  This  modifier         vided  that  it  was  compiled with this support enabled. This modifier
265         also causes any non-printing characters in output strings to be printed         also causes any non-printing characters in output strings to be printed
266         using the \x{hh...} notation if they are valid UTF-8 sequences.         using the \x{hh...} notation if they are valid UTF-8 sequences.
267    
268         If the /? modifier  is  used  with  /8,  it  causes  pcretest  to  call         If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
269         pcre_compile()  with  the  PCRE_NO_UTF8_CHECK  option,  to suppress the         pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
270         checking of the string for UTF-8 validity.         checking of the string for UTF-8 validity.
271    
272    
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
276         whitespace  is  removed,  and it is then scanned for \ escapes. Some of         whitespace is removed, and it is then scanned for \  escapes.  Some  of
277         these are pretty esoteric features, intended for checking out  some  of         these  are  pretty esoteric features, intended for checking out some of
278         the  more  complicated features of PCRE. If you are just testing "ordi-         the more complicated features of PCRE. If you are just  testing  "ordi-
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 (number less than 32)                        after a successful match (number less than 32)
302           \Cname     call pcre_copy_named_substring() for substring           \Cname     call pcre_copy_named_substring() for substring
# Line 242  DATA LINES Line 311  DATA LINES
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; this is used as the callout return value                        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 (number less than 32)                        after a successful match (number less than 32)
318           \Gname     call pcre_get_named_substring() for substring           \Gname     call pcre_get_named_substring() for substring
# Line 249  DATA LINES Line 320  DATA LINES
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 digits)                        pcre_exec() to dd (any number of digits)
329           \P         pass the PCRE_PARTIAL option to pcre_exec()           \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
330                          or pcre_dfa_exec(); if used twice, pass the
331                          PCRE_PARTIAL_HARD option
332             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
333                          (any number of digits)
334             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
335           \S         output details of memory get/free calls during matching           \S         output details of memory get/free calls during matching
336           \Z         pass the PCRE_NOTEOL option to pcre_exec()           \Z         pass the PCRE_NOTEOL option to pcre_exec()
337                          or pcre_dfa_exec()
338           \?         pass the PCRE_NO_UTF8_CHECK option to           \?         pass the PCRE_NO_UTF8_CHECK option to
339                        pcre_exec()                        pcre_exec() or pcre_dfa_exec()
340           \>dd       start the match at offset dd (any number of digits);           \>dd       start the match at offset dd (any number of digits);
341                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
342                          or pcre_dfa_exec()
343         A  backslash  followed by anything else just escapes the anything else.           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
344         If the very last character is a backslash, it is ignored. This gives  a                        or pcre_dfa_exec()
345         way  of  passing  an empty line as data, since a real empty line termi-           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
346                          or pcre_dfa_exec()
347             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
348                          or pcre_dfa_exec()
349             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
350                          or pcre_dfa_exec()
351             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
352                          or pcre_dfa_exec()
353    
354           The escapes that specify line ending  sequences  are  literal  strings,
355           exactly as shown. No more than one newline setting should be present in
356           any data line.
357    
358           A backslash followed by anything else just escapes the  anything  else.
359           If  the very last character is a backslash, it is ignored. This gives a
360           way of passing an empty line as data, since a real  empty  line  termi-
361         nates the data input.         nates the data input.
362    
363         If \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
364         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
365         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
366         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-
367         backtracking that takes place, and checking it out can be  instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
368         For  most  simple  matches, the number is quite small, but for patterns         checking it out can be instructive. For most simple matches, the number
369         with very large numbers of matching possibilities, it can become  large         is  quite  small,  but for patterns with very large numbers of matching
370         very quickly with increasing length of subject string.         possibilities, it can become large very quickly with increasing  length
371           of subject string. The match_limit_recursion number is a measure of how
372           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
373           memory is needed to complete the match attempt.
374    
375         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
376         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
377         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.
378    
379         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-
380         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
381         and REG_NOTEOL to be passed to regexec() respectively.         effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
382           to be passed to regexec().
383    
384           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
385           the  use  of  the  /8 modifier on the pattern. It is recognized always.
386           There may be any number of hexadecimal digits inside  the  braces.  The
387           result  is  from  one  to  six bytes, encoded according to the original
388           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
389           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
390           or indeed valid UTF-8 characters according to the later  rules  in  RFC
391           3629.
392    
393    
394    THE ALTERNATIVE MATCHING FUNCTION
395    
396           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
397           pcre_exec() to match each data line. From release 6.0, PCRE supports an
398           alternative  matching  function,  pcre_dfa_test(),  which operates in a
399           different way, and has some restrictions. The differences  between  the
400           two functions are described in the pcrematching documentation.
401    
402           If  a data line contains the \D escape sequence, or if the command line
403           contains the -dfa option, the alternative matching function is  called.
404           This function finds all possible matches at a given point. If, however,
405           the \F escape sequence is present in the data line, it stops after  the
406           first match is found. This is always the shortest possible match.
407    
        The  use of \x{hh...} to represent UTF-8 characters is not dependent on  
        the use of the /8 modifier on the pattern.  It  is  recognized  always.  
        There  may  be  any number of hexadecimal digits inside the braces. The  
        result is from one to six bytes, encoded according to the UTF-8  rules.  
408    
409    DEFAULT OUTPUT FROM PCRETEST
410    
411  OUTPUT FROM PCRETEST         This  section  describes  the output when the normal matching function,
412           pcre_exec(), is being used.
413    
414         When a match succeeds, pcretest outputs the list of captured substrings         When a match succeeds, pcretest outputs the list of captured substrings
415         that pcre_exec() returns, starting with number 0 for  the  string  that         that  pcre_exec()  returns,  starting with number 0 for the string that
416         matched the whole pattern. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
417         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match:"  followed  by the partially matching substring when pcre_exec()
418         TIAL,  respectively, and otherwise the PCRE negative error number. Here         returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PARTIAL,  respectively,  and
419         is an example of an interactive pcretest run.         otherwise  the  PCRE  negative  error  number. Here is an example of an
420           interactive pcretest run.
421    
422           $ pcretest           $ pcretest
423           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
424    
425             re> /^abc(\d+)/             re> /^abc(\d+)/
426           data> abc123           data> abc123
# Line 308  OUTPUT FROM PCRETEST Line 429  OUTPUT FROM PCRETEST
429           data> xyz           data> xyz
430           No match           No match
431    
432         If the strings contain any non-printing characters, they are output  as         Note that unset capturing substrings that are not followed by one  that
433         \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.
434         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         In the following example, there are two capturing substrings, but  when
435         string  0 is followed by the the rest of the subject string, identified         the  first  data  line  is  matched, the second, unset substring is not
436         by "0+" like this:         shown. An "internal" unset substring is shown as "<unset>", as for  the
437           second data line.
438    
439               re> /(a)|(b)/
440             data> a
441              0: a
442              1: a
443             data> b
444              0: b
445              1: <unset>
446              2: b
447    
448           If  the strings contain any non-printing characters, they are output as
449           \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
450           the  pattern.  See below for the definition of non-printing characters.
451           If the pattern has the /+ modifier, the output for substring 0 is  fol-
452           lowed  by  the  the rest of the subject string, identified by "0+" like
453           this:
454    
455             re> /cat/+             re> /cat/+
456           data> cataract           data> cataract
# Line 340  OUTPUT FROM PCRETEST Line 478  OUTPUT FROM PCRETEST
478         (that  is,  the return from the extraction function) is given in paren-         (that  is,  the return from the extraction function) is given in paren-
479         theses after each string for \C and \G.         theses after each string for \C and \G.
480    
481         Note that while patterns can be continued over several lines  (a  plain         Note that whereas patterns can be continued over several lines (a plain
482         ">" prompt is used for continuations), data lines may not. However new-         ">" prompt is used for continuations), data lines may not. However new-
483         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,
484           etc., depending on the newline sequence setting).
485    
486    
487    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
488    
489           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
490           means of the \D escape sequence or the -dfa command line  option),  the
491           output  consists  of  a list of all the matches that start at the first
492           point in the subject where there is at least one match. For example:
493    
494               re> /(tang|tangerine|tan)/
495             data> yellow tangerine\D
496              0: tangerine
497              1: tang
498              2: tan
499    
500           (Using the normal matching function on this data  finds  only  "tang".)
501           The  longest matching string is always given first (and numbered zero).
502           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
503           lowed by the partially matching substring.
504    
505           If /g is present on the pattern, the search for further matches resumes
506           at the end of the longest match. For example:
507    
508               re> /(tang|tangerine|tan)/g
509             data> yellow tangerine and tangy sultana\D
510              0: tangerine
511              1: tang
512              2: tan
513              0: tang
514              1: tan
515              0: tan
516    
517           Since the matching function does not  support  substring  capture,  the
518           escape  sequences  that  are concerned with captured substrings are not
519           relevant.
520    
521    
522    RESTARTING AFTER A PARTIAL MATCH
523    
524           When the alternative matching function has given the PCRE_ERROR_PARTIAL
525           return,  indicating that the subject partially matched the pattern, you
526           can restart the match with additional subject data by means of  the  \R
527           escape sequence. For example:
528    
529               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
530             data> 23ja\P\D
531             Partial match: 23ja
532             data> n05\R\D
533              0: n05
534    
535           For  further  information  about  partial matching, see the pcrepartial
536           documentation.
537    
538    
539  CALLOUTS  CALLOUTS
540    
541         If the pattern contains any callout requests, pcretest's callout  func-         If the pattern contains any callout requests, pcretest's callout  func-
542         tion  is  called  during  matching. By default, it displays the callout         tion  is  called  during  matching. This works with both matching func-
543         number, the start and current positions in  the  text  at  the  callout         tions. By default, the called function displays the callout number, the
544         time, and the next pattern item to be tested. For example, the output         start  and  current  positions in the text at the callout time, and the
545           next pattern item to be tested. For example, the output
546    
547           --->pqrabcdef           --->pqrabcdef
548             0    ^  ^     \d             0    ^  ^     \d
549    
550         indicates  that  callout number 0 occurred for a match attempt starting         indicates that callout number 0 occurred for a match  attempt  starting
551         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
552         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
553         \d. Just one circumflex is output if the start  and  current  positions         \d.  Just  one  circumflex is output if the start and current positions
554         are the same.         are the same.
555    
556         Callouts numbered 255 are assumed to be automatic callouts, inserted as         Callouts numbered 255 are assumed to be automatic callouts, inserted as
557         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
558         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
559         output. For example:         output. For example:
560    
561             re> /\d?[A-E]\*/C             re> /\d?[A-E]\*/C
# Line 375  CALLOUTS Line 567  CALLOUTS
567           +10 ^ ^           +10 ^ ^
568            0: E*            0: E*
569    
570         The callout function in pcretest returns zero (carry  on  matching)  by         The  callout  function  in pcretest returns zero (carry on matching) by
571         default, but you can use an \C item in a data line (as described above)         default, but you can use a \C item in a data line (as described  above)
572         to change this.         to change this.
573    
574         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting  callouts can be helpful when using pcretest to check compli-
575         cated  regular expressions. For further information about callouts, see         cated regular expressions. For further information about callouts,  see
576         the pcrecallout documentation.         the pcrecallout documentation.
577    
578    
579    NON-PRINTING CHARACTERS
580    
581           When  pcretest is outputting text in the compiled version of a pattern,
582           bytes other than 32-126 are always treated as  non-printing  characters
583           are are therefore shown as hex escapes.
584    
585           When  pcretest  is  outputting text that is a matched part of a subject
586           string, it behaves in the same way, unless a different locale has  been
587           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
588           isprint() function to distinguish printing and non-printing characters.
589    
590    
591  SAVING AND RELOADING COMPILED PATTERNS  SAVING AND RELOADING COMPILED PATTERNS
592    
593         The facilities described in this section are  not  available  when  the         The facilities described in this section are  not  available  when  the
# Line 440  SAVING AND RELOADING COMPILED PATTERNS Line 644  SAVING AND RELOADING COMPILED PATTERNS
644         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.
645    
646    
647    SEE ALSO
648    
649           pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
650           pcrepattern(3), pcreprecompile(3).
651    
652    
653  AUTHOR  AUTHOR
654    
655         Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
656         University Computing Service,         University Computing Service
657         Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
658    
659    
660    REVISION
661    
662  Last updated: 10 September 2004         Last updated: 29 August 2009
663  Copyright (c) 1997-2004 University of Cambridge.         Copyright (c) 1997-2009 University of Cambridge.

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