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1  The pcretest program  PCRETEST(1)                                                        PCRETEST(1)
 --------------------  
2    
 This program is intended for testing PCRE, but it can also be used for  
 experimenting with regular expressions.  
3    
4  If it is given two filename arguments, it reads from the first and writes to  NAME
5  the second. If it is given only one filename argument, it reads from that file         pcretest - a program for testing Perl-compatible regular expressions.
 and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and  
 prompts for each line of input, using "re>" to prompt for regular expressions,  
 and "data>" to prompt for data lines.  
   
 The program handles any number of sets of input on a single input file. Each  
 set starts with a regular expression, and continues with any number of data  
 lines to be matched against the pattern. An empty line signals the end of the  
 data lines, at which point a new regular expression is read. The regular  
 expressions are given enclosed in any non-alphameric delimiters other than  
 backslash, for example  
   
   /(a|bc)x+yz/  
   
 White space before the initial delimiter is ignored. A regular expression may  
 be continued over several input lines, in which case the newline characters are  
 included within it. See the test input files in the testdata directory for many  
 examples. It is possible to include the delimiter within the pattern by  
 escaping it, for example  
   
   /abc\/def/  
   
 If you do so, the escape and the delimiter form part of the pattern, but since  
 delimiters are always non-alphameric, this does not affect its interpretation.  
 If the terminating delimiter is immediately followed by a backslash, for  
 example,  
   
   /abc/\  
   
 then a backslash is added to the end of the pattern. This is done to provide a  
 way of testing the error condition that arises if a pattern finishes with a  
 backslash, because  
   
   /abc\/  
   
 is interpreted as the first line of a pattern that starts with "abc/", causing  
 pcretest to read the next line as a continuation of the regular expression.  
   
 The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS,  
 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For  
 example:  
   
   /caseless/i  
   
 These modifier letters have the same effect as they do in Perl. There are  
 others which set PCRE options that do not correspond to anything in Perl: /A,  
 /E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively.  
   
 Searching for all possible matches within each subject string can be requested  
 by the /g or /G modifier. After finding a match, PCRE is called again to search  
 the remainder of the subject string. The difference between /g and /G is that  
 the former uses the startoffset argument to pcre_exec() to start searching at  
 a new point within the entire string (which is in effect what Perl does),  
 whereas the latter passes over a shortened substring. This makes a difference  
 to the matching process if the pattern begins with a lookbehind assertion  
 (including \b or \B).  
   
 If any call to pcre_exec() in a /g or /G sequence matches an empty string, the  
 next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED flags set in order  
 to search for another, non-empty, match at the same point. If this second match  
 fails, the start offset is advanced by one, and the normal match is retried.  
 This imitates the way Perl handles such cases when using the /g modifier or the  
 split() function.  
   
 There are a number of other modifiers for controlling the way pcretest  
 operates.  
   
 The /+ modifier requests that as well as outputting the substring that matched  
 the entire pattern, pcretest should in addition output the remainder of the  
 subject string. This is useful for tests where the subject contains multiple  
 copies of the same substring.  
   
 The /L modifier must be followed directly by the name of a locale, for example,  
   
   /pattern/Lfr  
   
 For this reason, it must be the last modifier letter. The given locale is set,  
 pcre_maketables() is called to build a set of character tables for the locale,  
 and this is then passed to pcre_compile() when compiling the regular  
 expression. Without an /L modifier, NULL is passed as the tables pointer; that  
 is, /L applies only to the expression on which it appears.  
   
 The /I modifier requests that pcretest output information about the compiled  
 expression (whether it is anchored, has a fixed first character, and so on). It  
 does this by calling pcre_fullinfo() after compiling an expression, and  
 outputting the information it gets back. If the pattern is studied, the results  
 of that are also output.  
   
 The /D modifier is a PCRE debugging feature, which also assumes /I. It causes  
 the internal form of compiled regular expressions to be output after  
 compilation.  
   
 The /S modifier causes pcre_study() to be called after the expression has been  
 compiled, and the results used when the expression is matched.  
   
 The /M modifier causes the size of memory block used to hold the compiled  
 pattern to be output.  
   
 Finally, the /P modifier causes pcretest to call PCRE via the POSIX wrapper API  
 rather than its native API. When this is done, all other modifiers except /i,  
 /m, and /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is  
 set if /m is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always,  
 and PCRE_DOTALL unless REG_NEWLINE is set.  
   
 Before each data line is passed to pcre_exec(), leading and trailing whitespace  
 is removed, and it is then scanned for \ escapes. The following are recognized:  
   
   \a     alarm (= BEL)  
   \b     backspace  
   \e     escape  
   \f     formfeed  
   \n     newline  
   \r     carriage return  
   \t     tab  
   \v     vertical tab  
   \nnn   octal character (up to 3 octal digits)  
   \xhh   hexadecimal character (up to 2 hex digits)  
   
   \A     pass the PCRE_ANCHORED option to pcre_exec()  
   \B     pass the PCRE_NOTBOL option to pcre_exec()  
   \Cdd   call pcre_copy_substring() for substring dd after a successful match  
            (any decimal number less than 32)  
   \Gdd   call pcre_get_substring() for substring dd after a successful match  
            (any decimal number less than 32)  
   \L     call pcre_get_substringlist() after a successful match  
   \N     pass the PCRE_NOTEMPTY option to pcre_exec()  
   \Odd   set the size of the output vector passed to pcre_exec() to dd  
            (any number of decimal digits)  
   \Z     pass the PCRE_NOTEOL option to pcre_exec()  
   
 A backslash followed by anything else just escapes the anything else. If the  
 very last character is a backslash, it is ignored. This gives a way of passing  
 an empty line as data, since a real empty line terminates the data input.  
   
 If /P was present on the regex, causing the POSIX wrapper API to be used, only  
 \B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to  
 regexec() respectively.  
   
 When a match succeeds, pcretest outputs the list of captured substrings that  
 pcre_exec() returns, starting with number 0 for the string that matched the  
 whole pattern. Here is an example of an interactive pcretest run.  
   
   $ pcretest  
   PCRE version 2.06 08-Jun-1999  
   
     re> /^abc(\d+)/  
   data> abc123  
    0: abc123  
    1: 123  
   data> xyz  
   No match  
   
 If the strings contain any non-printing characters, they are output as \0x  
 escapes. If the pattern has the /+ modifier, then the output for substring 0 is  
 followed by the the rest of the subject string, identified by "0+" like this:  
   
     re> /cat/+  
   data> cataract  
    0: cat  
    0+ aract  
   
 If the pattern has the /g or /G modifier, the results of successive matching  
 attempts are output in sequence, like this:  
   
     re> /\Bi(\w\w)/g  
   data> Mississippi  
    0: iss  
    1: ss  
    0: iss  
    1: ss  
    0: ipp  
    1: pp  
   
 "No match" is output only if the first match attempt fails.  
   
 If any of \C, \G, or \L are present in a data line that is successfully  
 matched, the substrings extracted by the convenience functions are output with  
 C, G, or L after the string number instead of a colon. This is in addition to  
 the normal full list. The string length (that is, the return from the  
 extraction function) is given in parentheses after each string for \C and \G.  
   
 Note that while patterns can be continued over several lines (a plain ">"  
 prompt is used for continuations), data lines may not. However newlines can be  
 included in data by means of the \n escape.  
   
 If the -p option is given to pcretest, it is equivalent to adding /P to each  
 regular expression: the POSIX wrapper API is used to call PCRE. None of the  
 following flags has any effect in this case.  
   
 If the option -d is given to pcretest, it is equivalent to adding /D to each  
 regular expression: the internal form is output after compilation.  
   
 If the option -i is given to pcretest, it is equivalent to adding /I to each  
 regular expression: information about the compiled pattern is given after  
 compilation.  
   
 If the option -m is given to pcretest, it outputs the size of each compiled  
 pattern after it has been compiled. It is equivalent to adding /M to each  
 regular expression. For compatibility with earlier versions of pcretest, -s is  
 a synonym for -m.  
   
 If the -t option is given, each compile, study, and match is run 20000 times  
 while being timed, and the resulting time per compile or match is output in  
 milliseconds. Do not set -t with -s, because you will then get the size output  
 20000 times and the timing will be distorted. If you want to change the number  
 of repetitions used for timing, edit the definition of LOOPREPEAT at the top of  
 pcretest.c  
6    
7  Philip Hazel <ph10@cam.ac.uk>  
8  January 2000  SYNOPSIS
9    
10           pcretest [options] [input file [output file]]
11    
12           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
14           expressions.  This document describes the features of the test program;
15           for details of the regular expressions themselves, see the  pcrepattern
16           documentation. For details of the PCRE library function calls and their
17           options, see the  pcreapi  and  pcre16  documentation.  The  input  for
18           pcretest is a sequence of regular expression patterns and strings to be
19           matched, as described below. The output shows the result of each match.
20           Options  on  the command line and the patterns control PCRE options and
21           exactly what is output.
22    
23    
24    PCRE's 8-BIT and 16-BIT LIBRARIES
25    
26           From release 8.30, two separate PCRE libraries can be built. The origi-
27           nal  one  supports  8-bit  character  strings, whereas the newer 16-bit
28           library  supports  character  strings  encoded  in  16-bit  units.  The
29           pcretest  program  can  be  used to test both libraries. However, it is
30           itself still an 8-bit program, reading 8-bit input  and  writing  8-bit
31           output.  When testing the 16-bit library, the patterns and data strings
32           are converted to 16-bit format before being passed to the PCRE  library
33           functions. Results are converted to 8-bit for output.
34    
35           References  to  functions  and structures of the form pcre[16]_xx below
36           mean "pcre_xx when using the 8-bit library or pcre16_xx when using  the
37           16-bit library".
38    
39    
40    COMMAND LINE OPTIONS
41    
42           -16       If  both  the 8-bit and the 16-bit libraries have been built,
43                     this option causes the 16-bit library to be used. If only the
44                     16-bit library has been built, this is the default (so has no
45                     effect). If only the  8-bit  library  has  been  built,  this
46                     option causes an error.
47    
48           -b        Behave  as  if each pattern has the /B (show byte code) modi-
49                     fier; the internal form is output after compilation.
50    
51           -C        Output the version number of the PCRE library, and all avail-
52                     able   information  about  the  optional  features  that  are
53                     included, and then exit. All other options are ignored.
54    
55           -C option Output information about a specific build-time  option,  then
56                     exit.  This functionality is intended for use in scripts such
57                     as RunTest. The following options output the value indicated:
58    
59                       linksize   the internal link size (2, 3, or 4)
60                       newline    the default newline setting:
61                                    CR, LF, CRLF, ANYCRLF, or ANY
62    
63                     The following options output 1 for true or zero for false:
64    
65                       jit        just-in-time support is available
66                       pcre16     the 16-bit library was built
67                       pcre8      the 8-bit library was built
68                       ucp        Unicode property support is available
69                       utf        UTF-8 and/or UTF-16 support is available
70    
71           -d        Behave as if each pattern has the /D  (debug)  modifier;  the
72                     internal  form  and information about the compiled pattern is
73                     output after compilation; -d is equivalent to -b -i.
74    
75           -dfa      Behave as if each data line contains the \D escape  sequence;
76                     this    causes    the    alternative    matching    function,
77                     pcre[16]_dfa_exec(), to  be  used  instead  of  the  standard
78                     pcre[16]_exec() function (more detail is given below).
79    
80           -help     Output a brief summary these options and then exit.
81    
82           -i        Behave  as  if  each pattern has the /I modifier; information
83                     about the compiled pattern is given after compilation.
84    
85           -M        Behave as if each data line contains the \M escape  sequence;
86                     this  causes  PCRE  to  discover  the minimum MATCH_LIMIT and
87                     MATCH_LIMIT_RECURSION  settings  by  calling  pcre[16]_exec()
88                     repeatedly with different limits.
89    
90           -m        Output  the  size  of each compiled pattern after it has been
91                     compiled. This is equivalent to adding  /M  to  each  regular
92                     expression. The size is given in bytes for both libraries.
93    
94           -o osize  Set  the number of elements in the output vector that is used
95                     when calling pcre[16]_exec()  or  pcre[16]_dfa_exec()  to  be
96                     osize.  The  default value is 45, which is enough for 14 cap-
97                     turing subexpressions for  pcre[16]_exec()  or  22  different
98                     matches  for  pcre[16]_dfa_exec().   The  vector  size can be
99                     changed for individual matching calls by including \O in  the
100                     data line (see below).
101    
102           -p        Behave  as  if  each  pattern  has the /P modifier; the POSIX
103                     wrapper API is used to call PCRE. None of the  other  options
104                     has  any  effect when -p is set. This option can be used only
105                     with the 8-bit library.
106    
107           -q        Do not output the version number of pcretest at the start  of
108                     execution.
109    
110           -S size   On  Unix-like  systems, set the size of the run-time stack to
111                     size megabytes.
112    
113           -s or -s+ Behave as if each pattern  has  the  /S  modifier;  in  other
114                     words,  force each pattern to be studied. If -s+ is used, the
115                     PCRE_STUDY_JIT_COMPILE flag is  passed  to  pcre[16]_study(),
116                     causing  just-in-time  optimization  to  be  set  up if it is
117                     available. If the /I or /D option is  present  on  a  pattern
118                     (requesting  output  about the compiled pattern), information
119                     about the result of studying is not included when studying is
120                     caused  only  by  -s  and neither -i nor -d is present on the
121                     command line. This behaviour means that the output from tests
122                     that  are run with and without -s should be identical, except
123                     when options that output information about the actual running
124                     of a match are set.
125    
126                     The  -M,  -t,  and  -tm options, which give information about
127                     resources used, are likely to produce different  output  with
128                     and  without  -s.  Output may also differ if the /C option is
129                     present on an individual pattern. This uses callouts to trace
130                     the  the  matching process, and this may be different between
131                     studied and non-studied patterns.  If  the  pattern  contains
132                     (*MARK)  items  there  may  also be differences, for the same
133                     reason. The -s command line option can be overridden for spe-
134                     cific  patterns that should never be studied (see the /S pat-
135                     tern modifier below).
136    
137           -t        Run each compile, study, and match many times with  a  timer,
138                     and  output resulting time per compile or match (in millisec-
139                     onds). Do not set -m with -t, because you will then  get  the
140                     size  output  a  zillion  times,  and the timing will be dis-
141                     torted. You can control the number  of  iterations  that  are
142                     used  for timing by following -t with a number (as a separate
143                     item on the command line). For example, "-t 1000" would iter-
144                     ate 1000 times. The default is to iterate 500000 times.
145    
146           -tm       This is like -t except that it times only the matching phase,
147                     not the compile or study phases.
148    
149    
150    DESCRIPTION
151    
152           If pcretest is given two filename arguments, it reads  from  the  first
153           and writes to the second. If it is given only one filename argument, it
154           reads from that file and writes to stdout.  Otherwise,  it  reads  from
155           stdin  and  writes to stdout, and prompts for each line of input, using
156           "re>" to prompt for regular expressions, and "data>" to prompt for data
157           lines.
158    
159           When  pcretest  is  built,  a  configuration option can specify that it
160           should be linked with the libreadline library. When this  is  done,  if
161           the input is from a terminal, it is read using the readline() function.
162           This provides line-editing and history facilities. The output from  the
163           -help option states whether or not readline() will be used.
164    
165           The program handles any number of sets of input on a single input file.
166           Each set starts with a regular expression, and continues with any  num-
167           ber of data lines to be matched against the pattern.
168    
169           Each  data line is matched separately and independently. If you want to
170           do multi-line matches, you have to use the \n escape sequence (or \r or
171           \r\n, etc., depending on the newline setting) in a single line of input
172           to encode the newline sequences. There is no limit  on  the  length  of
173           data  lines;  the  input  buffer is automatically extended if it is too
174           small.
175    
176           An empty line signals the end of the data lines, at which point  a  new
177           regular  expression is read. The regular expressions are given enclosed
178           in any non-alphanumeric delimiters other than backslash, for example:
179    
180             /(a|bc)x+yz/
181    
182           White space before the initial delimiter is ignored. A regular  expres-
183           sion  may be continued over several input lines, in which case the new-
184           line characters are included within it. It is possible to  include  the
185           delimiter within the pattern by escaping it, for example
186    
187             /abc\/def/
188    
189           If  you  do  so, the escape and the delimiter form part of the pattern,
190           but since delimiters are always non-alphanumeric, this does not  affect
191           its  interpretation.   If the terminating delimiter is immediately fol-
192           lowed by a backslash, for example,
193    
194             /abc/\
195    
196           then a backslash is added to the end of the pattern. This  is  done  to
197           provide  a  way of testing the error condition that arises if a pattern
198           finishes with a backslash, because
199    
200             /abc\/
201    
202           is interpreted as the first line of a pattern that starts with  "abc/",
203           causing pcretest to read the next line as a continuation of the regular
204           expression.
205    
206    
207    PATTERN MODIFIERS
208    
209           A pattern may be followed by any number of modifiers, which are  mostly
210           single  characters.  Following  Perl usage, these are referred to below
211           as, for example, "the /i modifier", even though the  delimiter  of  the
212           pattern  need  not always be a slash, and no slash is used when writing
213           modifiers. White space may appear between the final  pattern  delimiter
214           and the first modifier, and between the modifiers themselves.
215    
216           The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
217           PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre[16]_com-
218           pile()  is  called. These four modifier letters have the same effect as
219           they do in Perl. For example:
220    
221             /caseless/i
222    
223           The following table shows additional modifiers for  setting  PCRE  com-
224           pile-time options that do not correspond to anything in Perl:
225    
226             /8              PCRE_UTF8           ) when using the 8-bit
227             /?              PCRE_NO_UTF8_CHECK  )   library
228    
229             /8              PCRE_UTF16          ) when using the 16-bit
230             /?              PCRE_NO_UTF16_CHECK )   library
231    
232             /A              PCRE_ANCHORED
233             /C              PCRE_AUTO_CALLOUT
234             /E              PCRE_DOLLAR_ENDONLY
235             /f              PCRE_FIRSTLINE
236             /J              PCRE_DUPNAMES
237             /N              PCRE_NO_AUTO_CAPTURE
238             /U              PCRE_UNGREEDY
239             /W              PCRE_UCP
240             /X              PCRE_EXTRA
241             /Y              PCRE_NO_START_OPTIMIZE
242             /<JS>           PCRE_JAVASCRIPT_COMPAT
243             /<cr>           PCRE_NEWLINE_CR
244             /<lf>           PCRE_NEWLINE_LF
245             /<crlf>         PCRE_NEWLINE_CRLF
246             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
247             /<any>          PCRE_NEWLINE_ANY
248             /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
249             /<bsr_unicode>  PCRE_BSR_UNICODE
250    
251           The  modifiers  that are enclosed in angle brackets are literal strings
252           as shown, including the angle brackets, but the letters within  can  be
253           in  either case.  This example sets multiline matching with CRLF as the
254           line ending sequence:
255    
256             /^abc/m<CRLF>
257    
258           As well as turning on the PCRE_UTF8/16 option, the /8  modifier  causes
259           all  non-printing  characters in output strings to be printed using the
260           \x{hh...} notation. Otherwise, those less than 0x100 are output in  hex
261           without the curly brackets.
262    
263           Full  details  of  the PCRE options are given in the pcreapi documenta-
264           tion.
265    
266       Finding all matches in a string
267    
268           Searching for all possible matches within each subject  string  can  be
269           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
270           called again to search the remainder of the subject string. The differ-
271           ence between /g and /G is that the former uses the startoffset argument
272           to pcre[16]_exec() to start searching at a new point within the  entire
273           string  (which  is in effect what Perl does), whereas the latter passes
274           over a shortened substring. This makes a  difference  to  the  matching
275           process if the pattern begins with a lookbehind assertion (including \b
276           or \B).
277    
278           If any call to pcre[16]_exec() in a /g or /G sequence matches an  empty
279           string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
280           PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
281           match  at  the same point. If this second match fails, the start offset
282           is advanced, and the normal match is retried.  This  imitates  the  way
283           Perl handles such cases when using the /g modifier or the split() func-
284           tion. Normally, the start offset is advanced by one character,  but  if
285           the  newline  convention  recognizes CRLF as a newline, and the current
286           character is CR followed by LF, an advance of two is used.
287    
288       Other modifiers
289    
290           There are yet more modifiers for controlling the way pcretest operates.
291    
292           The /+ modifier requests that as well as outputting the substring  that
293           matched  the  entire  pattern,  pcretest  should in addition output the
294           remainder of the subject string. This is useful  for  tests  where  the
295           subject  contains multiple copies of the same substring. If the + modi-
296           fier appears twice, the same action is taken for  captured  substrings.
297           In  each case the remainder is output on the following line with a plus
298           character following the capture number. Note that  this  modifier  must
299           not immediately follow the /S modifier because /S+ has another meaning.
300    
301           The  /=  modifier  requests  that  the values of all potential captured
302           parentheses be output after a match. By default, only those up  to  the
303           highest one actually used in the match are output (corresponding to the
304           return code from pcre[16]_exec()). Values in the offsets vector  corre-
305           sponding to higher numbers should be set to -1, and these are output as
306           "<unset>". This modifier gives a way of checking that this  is  happen-
307           ing.
308    
309           The  /B modifier is a debugging feature. It requests that pcretest out-
310           put a representation of the compiled code after  compilation.  Normally
311           this  information  contains length and offset values; however, if /Z is
312           also present, this data is replaced by spaces. This is a  special  fea-
313           ture  for  use  in the automatic test scripts; it ensures that the same
314           output is generated for different internal link sizes.
315    
316           The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
317           that is, both the /B and the /I modifiers.
318    
319           The  /F  modifier  causes pcretest to flip the byte order of the 2-byte
320           and 4-byte fields in the compiled pattern. This facility is for testing
321           the  feature  in PCRE that allows it to execute patterns that were com-
322           piled on a host with a different endianness. This feature is not avail-
323           able  when the POSIX interface to PCRE is being used, that is, when the
324           /P pattern modifier is specified. See also the section about saving and
325           reloading compiled patterns below.
326    
327           The  /I  modifier  requests  that pcretest output information about the
328           compiled pattern (whether it is anchored, has a fixed first  character,
329           and so on). It does this by calling pcre[16]_fullinfo() after compiling
330           a pattern. If the pattern is studied, the results of that are also out-
331           put.
332    
333           The  /K modifier requests pcretest to show names from backtracking con-
334           trol verbs that are returned from calls to pcre[16]_exec().  It  causes
335           pcretest  to  create a pcre[16]_extra block if one has not already been
336           created by a call to pcre[16]_study(), and to set  the  PCRE_EXTRA_MARK
337           flag  and  the mark field within it, every time that pcre[16]_exec() is
338           called. If the variable that the mark field points to is non-NULL for a
339           match, non-match, or partial match, pcretest prints the string to which
340           it points. For a match, this is shown on a line by itself, tagged  with
341           "MK:". For a non-match it is added to the message.
342    
343           The  /L modifier must be followed directly by the name of a locale, for
344           example,
345    
346             /pattern/Lfr_FR
347    
348           For this reason, it must be the last modifier. The given locale is set,
349           pcre[16]_maketables()  is called to build a set of character tables for
350           the locale, and this is then passed to pcre[16]_compile() when  compil-
351           ing  the  regular  expression.  Without an /L (or /T) modifier, NULL is
352           passed as the tables pointer; that is, /L applies only to  the  expres-
353           sion on which it appears.
354    
355           The  /M  modifier  causes the size in bytes of the memory block used to
356           hold the compiled pattern to be output. This does not include the  size
357           of the pcre[16] block; it is just the actual compiled data. If the pat-
358           tern is successfully studied with  the  PCRE_STUDY_JIT_COMPILE  option,
359           the size of the JIT compiled code is also output.
360    
361           If  the  /S  modifier  appears  once,  it causes pcre[16]_study() to be
362           called after the expression has been compiled,  and  the  results  used
363           when  the  expression  is  matched.  If /S appears twice, it suppresses
364           studying, even if it was requested externally by the  -s  command  line
365           option.  This  makes  it  possible to specify that certain patterns are
366           always studied, and others are never studied, independently of -s. This
367           feature  is  used  in the test files in a few cases where the output is
368           different when the pattern is studied.
369    
370           If the /S modifier is immediately followed by a + character,  the  call
371           to  pcre[16]_study()  is  made  with the PCRE_STUDY_JIT_COMPILE option,
372           requesting just-in-time optimization support if it is  available.  Note
373           that  there  is  also  a  /+ modifier; it must not be given immediately
374           after /S because this will be misinterpreted. If JIT studying  is  suc-
375           cessful,  it  will  automatically  be used when pcre[16]_exec() is run,
376           except when incompatible run-time options are specified. These  include
377           the  partial  matching options; a complete list is given in the pcrejit
378           documentation. See also the \J escape sequence below for a way of  set-
379           ting the size of the JIT stack.
380    
381           The  /T  modifier  must be followed by a single digit. It causes a spe-
382           cific set of built-in character tables to be  passed  to  pcre[16]_com-
383           pile().  It  is used in the standard PCRE tests to check behaviour with
384           different character tables. The digit specifies the tables as follows:
385    
386             0   the default ASCII tables, as distributed in
387                   pcre_chartables.c.dist
388             1   a set of tables defining ISO 8859 characters
389    
390           In table 1, some characters whose codes are greater than 128 are  iden-
391           tified as letters, digits, spaces, etc.
392    
393       Using the POSIX wrapper API
394    
395           The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
396           rather than its native API. This supports only the 8-bit library.  When
397           /P  is set, the following modifiers set options for the regcomp() func-
398           tion:
399    
400             /i    REG_ICASE
401             /m    REG_NEWLINE
402             /N    REG_NOSUB
403             /s    REG_DOTALL     )
404             /U    REG_UNGREEDY   ) These options are not part of
405             /W    REG_UCP        )   the POSIX standard
406             /8    REG_UTF8       )
407    
408           The /+ modifier works as  described  above.  All  other  modifiers  are
409           ignored.
410    
411    
412    DATA LINES
413    
414           Before  each data line is passed to pcre[16]_exec(), leading and trail-
415           ing white space is removed, and it is then scanned for \ escapes.  Some
416           of  these  are pretty esoteric features, intended for checking out some
417           of the more complicated features of  PCRE.  If  you  are  just  testing
418           "ordinary"  regular  expressions, you probably don't need any of these.
419           The following escapes are recognized:
420    
421             \a         alarm (BEL, \x07)
422             \b         backspace (\x08)
423             \e         escape (\x27)
424             \f         form feed (\x0c)
425             \n         newline (\x0a)
426             \qdd       set the PCRE_MATCH_LIMIT limit to dd
427                          (any number of digits)
428             \r         carriage return (\x0d)
429             \t         tab (\x09)
430             \v         vertical tab (\x0b)
431             \nnn       octal character (up to 3 octal digits); always
432                          a byte unless > 255 in UTF-8 or 16-bit mode
433             \xhh       hexadecimal byte (up to 2 hex digits)
434             \x{hh...}  hexadecimal character (any number of hex digits)
435             \A         pass the PCRE_ANCHORED option to pcre[16]_exec()
436                          or pcre[16]_dfa_exec()
437             \B         pass the PCRE_NOTBOL option to pcre[16]_exec()
438                          or pcre[16]_dfa_exec()
439             \Cdd       call pcre[16]_copy_substring() for substring dd
440                          after a successful match (number less than 32)
441             \Cname     call pcre[16]_copy_named_substring() for substring
442                          "name" after a successful match (name termin-
443                          ated by next non alphanumeric character)
444             \C+        show the current captured substrings at callout
445                          time
446             \C-        do not supply a callout function
447             \C!n       return 1 instead of 0 when callout number n is
448                          reached
449             \C!n!m     return 1 instead of 0 when callout number n is
450                          reached for the nth time
451             \C*n       pass the number n (may be negative) as callout
452                          data; this is used as the callout return value
453             \D         use the pcre[16]_dfa_exec() match function
454             \F         only shortest match for pcre[16]_dfa_exec()
455             \Gdd       call pcre[16]_get_substring() for substring dd
456                          after a successful match (number less than 32)
457             \Gname     call pcre[16]_get_named_substring() for substring
458                          "name" after a successful match (name termin-
459                          ated by next non-alphanumeric character)
460             \Jdd       set up a JIT stack of dd kilobytes maximum (any
461                          number of digits)
462             \L         call pcre[16]_get_substringlist() after a
463                          successful match
464             \M         discover the minimum MATCH_LIMIT and
465                          MATCH_LIMIT_RECURSION settings
466             \N         pass the PCRE_NOTEMPTY option to pcre[16]_exec()
467                          or pcre[16]_dfa_exec(); if used twice, pass the
468                          PCRE_NOTEMPTY_ATSTART option
469             \Odd       set the size of the output vector passed to
470                          pcre[16]_exec() to dd (any number of digits)
471             \P         pass the PCRE_PARTIAL_SOFT option to pcre[16]_exec()
472                          or pcre[16]_dfa_exec(); if used twice, pass the
473                          PCRE_PARTIAL_HARD option
474             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
475                          (any number of digits)
476             \R         pass the PCRE_DFA_RESTART option to pcre[16]_dfa_exec()
477             \S         output details of memory get/free calls during matching
478             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre[16]_exec()
479                          or pcre[16]_dfa_exec()
480             \Z         pass the PCRE_NOTEOL option to pcre[16]_exec()
481                          or pcre[16]_dfa_exec()
482             \?         pass the PCRE_NO_UTF[8|16]_CHECK option to
483                          pcre[16]_exec() or pcre[16]_dfa_exec()
484             \>dd       start the match at offset dd (optional "-"; then
485                          any number of digits); this sets the startoffset
486                          argument for pcre[16]_exec() or pcre[16]_dfa_exec()
487             \<cr>      pass the PCRE_NEWLINE_CR option to pcre[16]_exec()
488                          or pcre[16]_dfa_exec()
489             \<lf>      pass the PCRE_NEWLINE_LF option to pcre[16]_exec()
490                          or pcre[16]_dfa_exec()
491             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre[16]_exec()
492                          or pcre[16]_dfa_exec()
493             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16]_exec()
494                          or pcre[16]_dfa_exec()
495             \<any>     pass the PCRE_NEWLINE_ANY option to pcre[16]_exec()
496                          or pcre[16]_dfa_exec()
497    
498           The use of \x{hh...} is not dependent on the use of the /8 modifier  on
499           the  pattern. It is recognized always. There may be any number of hexa-
500           decimal digits inside the braces; invalid  values  provoke  error  mes-
501           sages.
502    
503           Note that \xhh specifies one byte in UTF-8 mode; this makes it possible
504           to construct invalid UTF-8 sequences for testing purposes. On the other
505           hand,  \x{hh} is interpreted as a UTF-8 character in UTF-8 mode, gener-
506           ating more than one byte if the value is greater than 127. When testing
507           the 8-bit library not in UTF-8 mode, \x{hh} generates one byte for val-
508           ues less than 256, and causes an error for greater values.
509    
510           In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
511           possible to construct invalid UTF-16 sequences for testing purposes.
512    
513           The  escapes  that  specify  line ending sequences are literal strings,
514           exactly as shown. No more than one newline setting should be present in
515           any data line.
516    
517           A  backslash  followed by anything else just escapes the anything else.
518           If the very last character is a backslash, it is ignored. This gives  a
519           way  of  passing  an empty line as data, since a real empty line termi-
520           nates the data input.
521    
522           The \J escape provides a way of setting the maximum stack size that  is
523           used  by the just-in-time optimization code. It is ignored if JIT opti-
524           mization is not being used. Providing a stack that is larger  than  the
525           default 32K is necessary only for very complicated patterns.
526    
527           If  \M  is  present, pcretest calls pcre[16]_exec() several times, with
528           different values in the match_limit and match_limit_recursion fields of
529           the  pcre[16]_extra  data structure, until it finds the minimum numbers
530           for each parameter  that  allow  pcre[16]_exec()  to  complete  without
531           error.  Because this is testing a specific feature of the normal inter-
532           pretive pcre[16]_exec() execution, the use of any JIT optimization that
533           might have been set up by the /S+ qualifier of -s+ option is disabled.
534    
535           The  match_limit number is a measure of the amount of backtracking that
536           takes place, and checking it out can be instructive.  For  most  simple
537           matches,  the  number  is quite small, but for patterns with very large
538           numbers of matching possibilities, it can  become  large  very  quickly
539           with  increasing  length  of  subject string. The match_limit_recursion
540           number is a measure of how much stack (or, if  PCRE  is  compiled  with
541           NO_RECURSE,  how  much  heap)  memory  is  needed to complete the match
542           attempt.
543    
544           When \O is used, the value specified may be higher or  lower  than  the
545           size set by the -O command line option (or defaulted to 45); \O applies
546           only to the call of pcre[16]_exec() for the line in which it appears.
547    
548           If the /P modifier was present on the pattern, causing the POSIX  wrap-
549           per  API  to  be  used, the only option-setting sequences that have any
550           effect are \B,  \N,  and  \Z,  causing  REG_NOTBOL,  REG_NOTEMPTY,  and
551           REG_NOTEOL, respectively, to be passed to regexec().
552    
553    
554    THE ALTERNATIVE MATCHING FUNCTION
555    
556           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
557           pcre[16]_exec() to match each data line. PCRE also supports an alterna-
558           tive  matching  function, pcre[16]_dfa_test(), which operates in a dif-
559           ferent way, and has some restrictions. The differences between the  two
560           functions are described in the pcrematching documentation.
561    
562           If  a data line contains the \D escape sequence, or if the command line
563           contains the -dfa option, the alternative matching  function  is  used.
564           This function finds all possible matches at a given point. If, however,
565           the \F escape sequence is present in the data line, it stops after  the
566           first match is found. This is always the shortest possible match.
567    
568    
569    DEFAULT OUTPUT FROM PCRETEST
570    
571           This  section  describes  the output when the normal matching function,
572           pcre[16]_exec(), is being used.
573    
574           When a match succeeds, pcretest outputs the list of captured substrings
575           that  pcre[16]_exec()  returns,  starting  with number 0 for the string
576           that matched the whole pattern. Otherwise, it outputs "No  match"  when
577           the  return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
578           partially   matching    substring    when    pcre[16]_exec()    returns
579           PCRE_ERROR_PARTIAL.  (Note  that  this is the entire substring that was
580           inspected during the partial match; it may  include  characters  before
581           the  actual  match  start  if a lookbehind assertion, \K, \b, or \B was
582           involved.) For any other return, pcretest  outputs  the  PCRE  negative
583           error  number  and a short descriptive phrase. If the error is a failed
584           UTF string check, the offset of the start of the failing character  and
585           the  reason  code are also output, provided that the size of the output
586           vector is at least two. Here is an example of an  interactive  pcretest
587           run.
588    
589             $ pcretest
590             PCRE version 8.13 2011-04-30
591    
592               re> /^abc(\d+)/
593             data> abc123
594              0: abc123
595              1: 123
596             data> xyz
597             No match
598    
599           Unset capturing substrings that are not followed by one that is set are
600           not returned by pcre[16]_exec(), and are not shown by pcretest. In  the
601           following  example,  there  are  two capturing substrings, but when the
602           first data line is matched, the second, unset substring is  not  shown.
603           An  "internal" unset substring is shown as "<unset>", as for the second
604           data line.
605    
606               re> /(a)|(b)/
607             data> a
608              0: a
609              1: a
610             data> b
611              0: b
612              1: <unset>
613              2: b
614    
615           If the strings contain any non-printing characters, they are output  as
616           \xhh  escapes  if  the  value is less than 256 and UTF mode is not set.
617           Otherwise they are output as \x{hh...} escapes. See below for the defi-
618           nition  of non-printing characters. If the pattern has the /+ modifier,
619           the output for substring 0 is followed by the the rest of  the  subject
620           string, identified by "0+" like this:
621    
622               re> /cat/+
623             data> cataract
624              0: cat
625              0+ aract
626    
627           If  the  pattern  has  the /g or /G modifier, the results of successive
628           matching attempts are output in sequence, like this:
629    
630               re> /\Bi(\w\w)/g
631             data> Mississippi
632              0: iss
633              1: ss
634              0: iss
635              1: ss
636              0: ipp
637              1: pp
638    
639           "No match" is output only if the first match attempt fails. Here is  an
640           example  of a failure message (the offset 4 that is specified by \>4 is
641           past the end of the subject string):
642    
643               re> /xyz/
644             data> xyz\>4
645             Error -24 (bad offset value)
646    
647           If any of the sequences \C, \G, or \L are present in a data  line  that
648           is  successfully  matched,  the substrings extracted by the convenience
649           functions are output with C, G, or L after the string number instead of
650           a colon. This is in addition to the normal full list. The string length
651           (that is, the return from the extraction function) is given  in  paren-
652           theses after each string for \C and \G.
653    
654           Note that whereas patterns can be continued over several lines (a plain
655           ">" prompt is used for continuations), data lines may not. However new-
656           lines  can  be included in data by means of the \n escape (or \r, \r\n,
657           etc., depending on the newline sequence setting).
658    
659    
660    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
661    
662           When the alternative matching function,  pcre[16]_dfa_exec(),  is  used
663           (by  means  of the \D escape sequence or the -dfa command line option),
664           the output consists of a list of all the  matches  that  start  at  the
665           first point in the subject where there is at least one match. For exam-
666           ple:
667    
668               re> /(tang|tangerine|tan)/
669             data> yellow tangerine\D
670              0: tangerine
671              1: tang
672              2: tan
673    
674           (Using the normal matching function on this data  finds  only  "tang".)
675           The  longest matching string is always given first (and numbered zero).
676           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
677           lowed  by  the  partially  matching  substring.  (Note that this is the
678           entire substring that was inspected during the partial  match;  it  may
679           include characters before the actual match start if a lookbehind asser-
680           tion, \K, \b, or \B was involved.)
681    
682           If /g is present on the pattern, the search for further matches resumes
683           at the end of the longest match. For example:
684    
685               re> /(tang|tangerine|tan)/g
686             data> yellow tangerine and tangy sultana\D
687              0: tangerine
688              1: tang
689              2: tan
690              0: tang
691              1: tan
692              0: tan
693    
694           Since  the  matching  function  does not support substring capture, the
695           escape sequences that are concerned with captured  substrings  are  not
696           relevant.
697    
698    
699    RESTARTING AFTER A PARTIAL MATCH
700    
701           When the alternative matching function has given the PCRE_ERROR_PARTIAL
702           return, indicating that the subject partially matched the pattern,  you
703           can  restart  the match with additional subject data by means of the \R
704           escape sequence. For example:
705    
706               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
707             data> 23ja\P\D
708             Partial match: 23ja
709             data> n05\R\D
710              0: n05
711    
712           For further information about partial  matching,  see  the  pcrepartial
713           documentation.
714    
715    
716    CALLOUTS
717    
718           If  the pattern contains any callout requests, pcretest's callout func-
719           tion is called during matching. This works  with  both  matching  func-
720           tions. By default, the called function displays the callout number, the
721           start and current positions in the text at the callout  time,  and  the
722           next pattern item to be tested. For example:
723    
724             --->pqrabcdef
725               0    ^  ^     \d
726    
727           This  output  indicates  that  callout  number  0  occurred for a match
728           attempt starting at the fourth character of the  subject  string,  when
729           the pointer was at the seventh character of the data, and when the next
730           pattern item was \d. Just one circumflex is output  if  the  start  and
731           current positions are the same.
732    
733           Callouts numbered 255 are assumed to be automatic callouts, inserted as
734           a result of the /C pattern modifier. In this case, instead  of  showing
735           the  callout  number, the offset in the pattern, preceded by a plus, is
736           output. For example:
737    
738               re> /\d?[A-E]\*/C
739             data> E*
740             --->E*
741              +0 ^      \d?
742              +3 ^      [A-E]
743              +8 ^^     \*
744             +10 ^ ^
745              0: E*
746    
747           If a pattern contains (*MARK) items, an additional line is output when-
748           ever  a  change  of  latest mark is passed to the callout function. For
749           example:
750    
751               re> /a(*MARK:X)bc/C
752             data> abc
753             --->abc
754              +0 ^       a
755              +1 ^^      (*MARK:X)
756             +10 ^^      b
757             Latest Mark: X
758             +11 ^ ^     c
759             +12 ^  ^
760              0: abc
761    
762           The mark changes between matching "a" and "b", but stays the  same  for
763           the  rest  of  the match, so nothing more is output. If, as a result of
764           backtracking, the mark reverts to being unset, the  text  "<unset>"  is
765           output.
766    
767           The  callout  function  in pcretest returns zero (carry on matching) by
768           default, but you can use a \C item in a data line (as described  above)
769           to change this and other parameters of the callout.
770    
771           Inserting  callouts can be helpful when using pcretest to check compli-
772           cated regular expressions. For further information about callouts,  see
773           the pcrecallout documentation.
774    
775    
776    NON-PRINTING CHARACTERS
777    
778           When  pcretest is outputting text in the compiled version of a pattern,
779           bytes other than 32-126 are always treated as  non-printing  characters
780           are are therefore shown as hex escapes.
781    
782           When  pcretest  is  outputting text that is a matched part of a subject
783           string, it behaves in the same way, unless a different locale has  been
784           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
785           isprint() function to distinguish printing and non-printing characters.
786    
787    
788    SAVING AND RELOADING COMPILED PATTERNS
789    
790           The facilities described in this section are  not  available  when  the
791           POSIX  interface  to  PCRE  is being used, that is, when the /P pattern
792           modifier is specified.
793    
794           When the POSIX interface is not in use, you can cause pcretest to write
795           a  compiled  pattern to a file, by following the modifiers with > and a
796           file name.  For example:
797    
798             /pattern/im >/some/file
799    
800           See the pcreprecompile documentation for a discussion about saving  and
801           re-using  compiled patterns.  Note that if the pattern was successfully
802           studied with JIT optimization, the JIT data cannot be saved.
803    
804           The data that is written is binary.  The  first  eight  bytes  are  the
805           length  of  the  compiled  pattern  data  followed by the length of the
806           optional study data, each written as four  bytes  in  big-endian  order
807           (most  significant  byte  first). If there is no study data (either the
808           pattern was not studied, or studying did not return any data), the sec-
809           ond  length  is  zero. The lengths are followed by an exact copy of the
810           compiled pattern. If there is additional study  data,  this  (excluding
811           any  JIT  data)  follows  immediately after the compiled pattern. After
812           writing the file, pcretest expects to read a new pattern.
813    
814           A saved pattern can be reloaded into pcretest by  specifying  <  and  a
815           file name instead of a pattern. The name of the file must not contain a
816           < character, as otherwise pcretest will interpret the line as a pattern
817           delimited by < characters.  For example:
818    
819              re> </some/file
820             Compiled pattern loaded from /some/file
821             No study data
822    
823           If  the  pattern  was previously studied with the JIT optimization, the
824           JIT information cannot be saved and restored, and so is lost. When  the
825           pattern  has  been  loaded, pcretest proceeds to read data lines in the
826           usual way.
827    
828           You can copy a file written by pcretest to a different host and  reload
829           it  there,  even  if the new host has opposite endianness to the one on
830           which the pattern was compiled. For example, you can compile on an  i86
831           machine  and  run  on  a SPARC machine. When a pattern is reloaded on a
832           host with different endianness, the confirmation message is changed to:
833    
834             Compiled pattern (byte-inverted) loaded from /some/file
835    
836           The test suite contains some saved pre-compiled patterns with different
837           endianness.  These  are  reloaded  using "<!" instead of just "<". This
838           suppresses the "(byte-inverted)" text so that the output is the same on
839           all  hosts.  It  also forces debugging output once the pattern has been
840           reloaded.
841    
842           File names for saving and reloading can be absolute  or  relative,  but
843           note  that the shell facility of expanding a file name that starts with
844           a tilde (~) is not available.
845    
846           The ability to save and reload files in pcretest is intended for  test-
847           ing  and experimentation. It is not intended for production use because
848           only a single pattern can be written to a file. Furthermore,  there  is
849           no  facility  for  supplying  custom  character  tables  for use with a
850           reloaded pattern. If the original  pattern  was  compiled  with  custom
851           tables,  an  attempt to match a subject string using a reloaded pattern
852           is likely to cause pcretest to crash.  Finally, if you attempt to  load
853           a file that is not in the correct format, the result is undefined.
854    
855    
856    SEE ALSO
857    
858           pcre(3),  pcre16(3),  pcreapi(3),  pcrecallout(3),  pcrejit, pcrematch-
859           ing(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
860    
861    
862    AUTHOR
863    
864           Philip Hazel
865           University Computing Service
866           Cambridge CB2 3QH, England.
867    
868    
869    REVISION
870    
871           Last updated: 13 January 2012
872           Copyright (c) 1997-2012 University of Cambridge.

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