/[pcre]/code/trunk/doc/pcretest.txt
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revision 75 by nigel, Sat Feb 24 21:40:37 2007 UTC revision 392 by ph10, Tue Mar 17 21:30:30 2009 UTC
# Line 1  Line 1 
1  PCRETEST(1)                                                        PCRETEST(1)  PCRETEST(1)                                                        PCRETEST(1)
2    
3    
   
4  NAME  NAME
5         pcretest - a program for testing Perl-compatible regular expressions.         pcretest - a program for testing Perl-compatible regular expressions.
6    
7    
8  SYNOPSIS  SYNOPSIS
9    
10         pcretest [-C] [-d] [-i] [-m] [-o osize] [-p] [-t] [source]         pcretest [options] [source] [destination]
             [destination]  
11    
12         pcretest  was written as a test program for the PCRE regular expression         pcretest  was written as a test program for the PCRE regular expression
13         library itself, but it can also be used for experimenting with  regular         library itself, but it can also be used for experimenting with  regular
# Line 20  SYNOPSIS Line 19  SYNOPSIS
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25         -C        Output the version number of the PCRE library, and all avail-         -C        Output the version number of the PCRE library, and all avail-
26                   able   information  about  the  optional  features  that  are                   able  information  about  the  optional  features  that   are
27                   included, and then exit.                   included, and then exit.
28    
29         -d        Behave as if each regex had  the  /D  (debug)  modifier;  the         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                   internal form is output after compilation.                   internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33           -dfa      Behave  as if each data line contains the \D escape sequence;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38           -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       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
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 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);           \>dd       start the match at offset dd (any number of digits);
340                        this sets the startoffset argument for pcre_exec()                        this sets the startoffset argument for pcre_exec()
341                          or pcre_dfa_exec()
342         A  backslash  followed by anything else just escapes the anything else.           \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
343         If the very last character is a backslash, it is ignored. This gives  a                        or pcre_dfa_exec()
344         way  of  passing  an empty line as data, since a real empty line termi-           \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
345                          or pcre_dfa_exec()
346             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
347                          or pcre_dfa_exec()
348             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
349                          or pcre_dfa_exec()
350             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
351                          or pcre_dfa_exec()
352    
353           The escapes that specify line ending  sequences  are  literal  strings,
354           exactly as shown. No more than one newline setting should be present in
355           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 \M is present, pcretest calls pcre_exec() several times,  with  dif-         If  \M  is present, pcretest calls pcre_exec() several times, with dif-
363         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
364         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
365         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-
366         backtracking that takes place, and checking it out can be  instructive.         ber  is  a  measure of the amount of backtracking that takes place, and
367         For  most  simple  matches, the number is quite small, but for patterns         checking it out can be instructive. For most simple matches, the number
368         with very large numbers of matching possibilities, it can become  large         is  quite  small,  but for patterns with very large numbers of matching
369         very quickly with increasing length of subject string.         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         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         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.         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-         If  the /P modifier was present on the pattern, causing the POSIX wrap-
379         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
380         and REG_NOTEOL to be passed to regexec() respectively.         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
384           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
386           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    
        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.  
407    
408    DEFAULT OUTPUT FROM PCRETEST
409    
410  OUTPUT FROM PCRETEST         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. Otherwise, it outputs "No match" or "Partial         matched the whole pattern. Otherwise, it outputs "No match" or "Partial
416         match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-         match"  when  pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR-
417         TIAL,  respectively, and otherwise the PCRE negative error number. Here         TIAL, respectively, and otherwise the PCRE negative error number.  Here
418         is an example of an interactive pcretest run.         is an example of an interactive pcretest run.
419    
420           $ pcretest           $ pcretest
421           PCRE version 5.00 07-Sep-2004           PCRE version 7.0 30-Nov-2006
422    
423             re> /^abc(\d+)/             re> /^abc(\d+)/
424           data> abc123           data> abc123
# Line 308  OUTPUT FROM PCRETEST Line 427  OUTPUT FROM PCRETEST
427           data> xyz           data> xyz
428           No match           No match
429    
430           Note  that unset capturing substrings that are not followed by one that
431           is set are not returned by pcre_exec(), and are not shown by  pcretest.
432           In  the following example, there are two capturing substrings, but when
433           the first data line is matched, the  second,  unset  substring  is  not
434           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         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         \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
448         the pattern. If the pattern has the /+ modifier, the  output  for  sub-         the pattern. See below for the definition of  non-printing  characters.
449         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-
450         by "0+" like this:         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
455            0: cat            0: cat
456            0+ aract            0+ aract
457    
458         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
459         matching attempts are output in sequence, like this:         matching attempts are output in sequence, like this:
460    
461             re> /\Bi(\w\w)/g             re> /\Bi(\w\w)/g
# Line 333  OUTPUT FROM PCRETEST Line 469  OUTPUT FROM PCRETEST
469    
470         "No match" is output only if the first match attempt fails.         "No match" is output only if the first match attempt fails.
471    
472         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
473         is successfully matched, the substrings extracted  by  the  convenience         is  successfully  matched,  the substrings extracted by the convenience
474         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
475         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
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  CALLOUTS
536    
537         If the pattern contains any callout requests, pcretest's callout  func-         If  the pattern contains any callout requests, pcretest's callout func-
538         tion  is  called  during  matching. By default, it displays the callout         tion is called during matching. This works  with  both  matching  func-
539         number, the start and current positions in  the  text  at  the  callout         tions. By default, the called function displays the callout number, the
540         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
541           next pattern item to be tested. For example, the output
542    
543           --->pqrabcdef           --->pqrabcdef
544             0    ^  ^     \d             0    ^  ^     \d
# Line 376  CALLOUTS Line 564  CALLOUTS
564            0: E*            0: E*
565    
566         The callout function in pcretest returns zero (carry  on  matching)  by         The callout function in pcretest returns zero (carry  on  matching)  by
567         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)
568         to change this.         to change this.
569    
570         Inserting callouts can be helpful when using pcretest to check  compli-         Inserting callouts can be helpful when using pcretest to check  compli-
# Line 384  CALLOUTS Line 572  CALLOUTS
572         the pcrecallout documentation.         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  SAVING AND RELOADING COMPILED PATTERNS
588    
589         The facilities described in this section are  not  available  when  the         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-         POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
591         ifier is specified.         ifier is specified.
592    
593         When the POSIX interface is not in use, you can cause pcretest to write         When the POSIX interface is not in use, you can cause pcretest to write
594         a  compiled  pattern to a file, by following the modifiers with > and a         a compiled pattern to a file, by following the modifiers with >  and  a
595         file name.  For example:         file name.  For example:
596    
597           /pattern/im >/some/file           /pattern/im >/some/file
598    
599         See the pcreprecompile documentation for a discussion about saving  and         See  the pcreprecompile documentation for a discussion about saving and
600         re-using compiled patterns.         re-using compiled patterns.
601    
602         The  data  that  is  written  is  binary. The first eight bytes are the         The data that is written is binary.  The  first  eight  bytes  are  the
603         length of the compiled pattern data  followed  by  the  length  of  the         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         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         (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-         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         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-         compiled pattern. If there is additional study data, this follows imme-
609         diately after the compiled pattern. After writing  the  file,  pcretest         diately  after  the  compiled pattern. After writing the file, pcretest
610         expects to read a new pattern.         expects to read a new pattern.
611    
612         A saved pattern can be reloaded into pcretest by specifing < and a file         A saved pattern can be reloaded into pcretest by specifing < and a file
613         name instead of a pattern. The name of the file must not  contain  a  <         name  instead  of  a pattern. The name of the file must not contain a <
614         character,  as  otherwise pcretest will interpret the line as a pattern         character, as otherwise pcretest will interpret the line as  a  pattern
615         delimited by < characters.  For example:         delimited by < characters.  For example:
616    
617            re> </some/file            re> </some/file
618           Compiled regex loaded from /some/file           Compiled regex loaded from /some/file
619           No study data           No study data
620    
621         When the pattern has been loaded, pcretest proceeds to read data  lines         When  the pattern has been loaded, pcretest proceeds to read data lines
622         in the usual way.         in the usual way.
623    
624         You  can copy a file written by pcretest to a different host and reload         You can copy a file written by pcretest to a different host and  reload
625         it there, even if the new host has opposite endianness to  the  one  on         it  there,  even  if the new host has opposite endianness to the one on
626         which  the pattern was compiled. For example, you can compile on an i86         which the pattern was compiled. For example, you can compile on an  i86
627         machine and run on a SPARC machine.         machine and run on a SPARC machine.
628    
629         File names for saving and reloading can be absolute  or  relative,  but         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         note that the shell facility of expanding a file name that starts  with
631         a tilde (~) is not available.         a tilde (~) is not available.
632    
633         The ability to save and reload files in pcretest is intended for  test-         The  ability to save and reload files in pcretest is intended for test-
634         ing  and experimentation. It is not intended for production use because         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         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         no facility for supplying  custom  character  tables  for  use  with  a
637         reloaded pattern. If the original  pattern  was  compiled  with  custom         reloaded  pattern.  If  the  original  pattern was compiled with custom
638         tables,  an  attempt to match a subject string using a reloaded pattern         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         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.         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: 10 September 2004         Last updated: 10 March 2009
659  Copyright (c) 1997-2004 University of Cambridge.         Copyright (c) 1997-2009 University of Cambridge.

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