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1    PCRETEST(1)                                                        PCRETEST(1)
2    
3    
4  NAME  NAME
5       pcretest - a program  for  testing  Perl-compatible  regular         pcretest - a program for testing Perl-compatible regular expressions.
      expressions.  
6    
7    
8  SYNOPSIS  SYNOPSIS
      pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source]  [des-  
      tination]  
9    
10       pcretest was written as a test program for the PCRE  regular         pcretest [options] [input file [output file]]
11       expression  library  itself,  but  it  can  also be used for  
12       experimenting  with  regular  expressions.   This   document         pcretest  was written as a test program for the PCRE regular expression
13       describes  the  features of the test program; for details of         library itself, but it can also be used for experimenting with  regular
14       the regular  expressions  themselves,  see  the  pcrepattern         expressions.  This document describes the features of the test program;
15       documentation.  For details of PCRE and its options, see the         for details of the regular expressions themselves, see the  pcrepattern
16       pcreapi documentation.         documentation. For details of the PCRE library function calls and their
17           options, see the pcreapi documentation. The input  for  pcretest  is  a
18           sequence  of  regular expression patterns and strings to be matched, as
19  OPTIONS         described below. The output shows the result of each match. Options  on
20           the command line and the patterns control PCRE options and exactly what
21           is output.
22       -C        Output the version number of the PCRE library, and  
23                 all   available  information  about  the  optional  
24                 features that are included, and then exit.  COMMAND LINE OPTIONS
25    
26       -d        Behave as if each regex had the /D  modifier  (see         -b        Behave as if each pattern has the /B (show byte  code)  modi-
27                 below); the internal form is output after compila-                   fier; the internal form is output after compilation.
28                 tion.  
29           -C        Output the version number of the PCRE library, and all avail-
30       -i        Behave as if  each  regex  had  the  /I  modifier;                   able  information  about  the  optional  features  that   are
31                 information  about  the  compiled pattern is given                   included, and then exit.
32                 after compilation.  
33           -d        Behave  as  if  each pattern has the /D (debug) modifier; the
34       -m        Output the size of each compiled pattern after  it                   internal form and information about the compiled  pattern  is
35                 has been compiled. This is equivalent to adding /M                   output after compilation; -d is equivalent to -b -i.
36                 to each regular expression. For compatibility with  
37                 earlier  versions of pcretest, -s is a synonym for         -dfa      Behave  as if each data line contains the \D escape sequence;
38                 -m.                   this    causes    the    alternative    matching    function,
39                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
40       -o osize  Set the number of elements in  the  output  vector                   pcre_exec() function (more detail is given below).
41                 that  is  used  when calling PCRE to be osize. The  
42                 default value is 45, which is enough for  14  cap-         -help     Output a brief summary these options and then exit.
43                 turing  subexpressions.  The  vector  size  can be  
44                 changed for individual matching calls by including         -i        Behave as if each pattern has the  /I  modifier;  information
45                 \O in the data line (see below).                   about the compiled pattern is given after compilation.
46    
47       -p        Behave as if each regex has /P modifier; the POSIX         -M        Behave  as if each data line contains the \M escape sequence;
48                 wrapper  API  is  used  to  call PCRE. None of the                   this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
49                 other options has any effect when -p is set.                   MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
50                     edly with different limits.
51       -t        Run each compile, study, and match many times with  
52                 a  timer, and output resulting time per compile or         -m        Output the size of each compiled pattern after  it  has  been
53                 match (in milliseconds). Do not set  -t  with  -m,                   compiled.  This  is  equivalent  to adding /M to each regular
54                 because  you  will  then get the size output 20000                   expression.
55                 times and the timing will be distorted.  
56           -o osize  Set the number of elements in the output vector that is  used
57                     when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
58                     default value is 45, which is enough for 14 capturing  subex-
59                     pressions   for  pcre_exec()  or  22  different  matches  for
60                     pcre_dfa_exec(). The vector size can be changed for  individ-
61                     ual  matching  calls  by  including  \O in the data line (see
62                     below).
63    
64           -p        Behave as if each pattern has  the  /P  modifier;  the  POSIX
65                     wrapper  API  is used to call PCRE. None of the other options
66                     has any effect when -p is set.
67    
68           -q        Do not output the version number of pcretest at the start  of
69                     execution.
70    
71           -S size   On  Unix-like  systems, set the size of the run-time stack to
72                     size megabytes.
73    
74           -s        Behave as if each pattern  has  the  /S  modifier;  in  other
75                     words,  force  each  pattern  to  be studied. If the /I or /D
76                     option is present on a pattern (requesting output  about  the
77                     compiled  pattern),  information about the result of studying
78                     is not included when studying is caused only by -s  and  nei-
79                     ther -i nor -d is present on the command line. This behaviour
80                     means that the output from tests that are run with and  with-
81                     out  -s  should be identical, except when options that output
82                     information about the actual running of a match are set.  The
83                     -M,  -t,  and  -tm  options,  which  give  information  about
84                     resources used, are likely to produce different  output  with
85                     and  without  -s.  Output may also differ if the /C option is
86                     present on an individual pattern. This uses callouts to trace
87                     the  the  matching process, and this may be different between
88                     studied and non-studied patterns.  If  the  pattern  contains
89                     (*MARK)  items  there  may  also be differences, for the same
90                     reason. The -s command line option can be overridden for spe-
91                     cific  patterns  that  should  never  be  studied (see the /S
92                     option below).
93    
94           -t        Run each compile, study, and match many times with  a  timer,
95                     and  output resulting time per compile or match (in millisec-
96                     onds). Do not set -m with -t, because you will then  get  the
97                     size  output  a  zillion  times,  and the timing will be dis-
98                     torted. You can control the number  of  iterations  that  are
99                     used  for timing by following -t with a number (as a separate
100                     item on the command line). For example, "-t 1000" would iter-
101                     ate 1000 times. The default is to iterate 500000 times.
102    
103           -tm       This is like -t except that it times only the matching phase,
104                     not the compile or study phases.
105    
106    
107  DESCRIPTION  DESCRIPTION
108    
109       If pcretest is given two filename arguments, it  reads  from         If pcretest is given two filename arguments, it reads  from  the  first
110       the  first and writes to the second. If it is given only one         and writes to the second. If it is given only one filename argument, it
111       filename argument, it reads from that  file  and  writes  to         reads from that file and writes to stdout.  Otherwise,  it  reads  from
112       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin  and  writes to stdout, and prompts for each line of input, using
113       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
114       for  regular  expressions,  and  "data>"  to prompt for data         lines.
115       lines.  
116           When  pcretest  is  built,  a  configuration option can specify that it
117       The program handles any number of sets of input on a  single         should be linked with the libreadline library. When this  is  done,  if
118       input  file.  Each set starts with a regular expression, and         the input is from a terminal, it is read using the readline() function.
119       continues with any  number  of  data  lines  to  be  matched         This provides line-editing and history facilities. The output from  the
120       against the pattern.         -help option states whether or not readline() will be used.
121    
122       Each line is matched separately and  independently.  If  you         The program handles any number of sets of input on a single input file.
123       want  to  do  multiple-line  matches, you have to use the \n         Each set starts with a regular expression, and continues with any  num-
124       escape sequence in a single line of input to encode the new-         ber of data lines to be matched against the pattern.
125       line  characters.  The maximum length of data line is 30,000  
126       characters.         Each  data line is matched separately and independently. If you want to
127           do multi-line matches, you have to use the \n escape sequence (or \r or
128       An empty line signals the end of the data  lines,  at  which         \r\n, etc., depending on the newline setting) in a single line of input
129       point  a new regular expression is read. The regular expres-         to encode the newline sequences. There is no limit  on  the  length  of
130       sions are given enclosed in  any  non-alphameric  delimiters         data  lines;  the  input  buffer is automatically extended if it is too
131       other than backslash, for example         small.
132    
133         /(a|bc)x+yz/         An empty line signals the end of the data lines, at which point  a  new
134           regular  expression is read. The regular expressions are given enclosed
135       White space before the initial delimiter is ignored. A regu-         in any non-alphanumeric delimiters other than backslash, for example:
136       lar expression may be continued over several input lines, in  
137       which case the newline characters are included within it. It           /(a|bc)x+yz/
138       is  possible  to include the delimiter within the pattern by  
139       escaping it, for example         White space before the initial delimiter is ignored. A regular  expres-
140           sion  may be continued over several input lines, in which case the new-
141         /abc\/def/         line characters are included within it. It is possible to  include  the
142           delimiter within the pattern by escaping it, for example
143       If you do so, the escape and the delimiter form part of  the  
144       pattern,  but  since  delimiters  are always non-alphameric,           /abc\/def/
145       this does not affect its interpretation.  If the terminating  
146       delimiter  is immediately followed by a backslash, for exam-         If  you  do  so, the escape and the delimiter form part of the pattern,
147       ple,         but since delimiters are always non-alphanumeric, this does not  affect
148           its  interpretation.   If the terminating delimiter is immediately fol-
149         /abc/\         lowed by a backslash, for example,
150    
151       then a backslash is added to the end of the pattern. This is           /abc/\
152       done  to  provide  a way of testing the error condition that  
153       arises if a pattern finishes with a backslash, because         then a backslash is added to the end of the pattern. This  is  done  to
154           provide  a  way of testing the error condition that arises if a pattern
155         /abc\/         finishes with a backslash, because
156    
157       is interpreted as the first line of a  pattern  that  starts           /abc\/
158       with  "abc/",  causing  pcretest  to read the next line as a  
159       continuation of the regular expression.         is interpreted as the first line of a pattern that starts with  "abc/",
160           causing pcretest to read the next line as a continuation of the regular
161           expression.
162    
163    
164  PATTERN MODIFIERS  PATTERN MODIFIERS
165    
166       The pattern may be followed by i, m, s,  or  x  to  set  the         A pattern may be followed by any number of modifiers, which are  mostly
167       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single  characters.  Following  Perl usage, these are referred to below
168       options, respectively. For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
169           pattern  need  not always be a slash, and no slash is used when writing
170         /caseless/i         modifiers. White space may appear between the final  pattern  delimiter
171           and the first modifier, and between the modifiers themselves.
172       These modifier letters have the same effect as  they  do  in  
173       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
174       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
175       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile()  is  called. These four modifier letters have the same effect as
176       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
177    
178       Searching for  all  possible  matches  within  each  subject           /caseless/i
179       string  can  be  requested  by  the /g or /G modifier. After  
180       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for  setting  PCRE  com-
181       remainder  of  the subject string. The difference between /g         pile-time options that do not correspond to anything in Perl:
182       and /G is that the former uses the startoffset  argument  to  
183       pcre_exec()  to  start  searching  at a new point within the           /8              PCRE_UTF8
184       entire string (which is in effect what Perl  does),  whereas           /?              PCRE_NO_UTF8_CHECK
185       the  latter  passes over a shortened substring. This makes a           /A              PCRE_ANCHORED
186       difference to the matching process  if  the  pattern  begins           /C              PCRE_AUTO_CALLOUT
187       with a lookbehind assertion (including \b or \B).           /E              PCRE_DOLLAR_ENDONLY
188             /f              PCRE_FIRSTLINE
189       If any call to pcre_exec() in a /g or /G sequence matches an           /J              PCRE_DUPNAMES
190       empty  string,  the next call is done with the PCRE_NOTEMPTY           /N              PCRE_NO_AUTO_CAPTURE
191       and PCRE_ANCHORED flags set in order to search for  another,           /U              PCRE_UNGREEDY
192       non-empty,  match  at  the same point.  If this second match           /W              PCRE_UCP
193       fails, the start offset is advanced by one, and  the  normal           /X              PCRE_EXTRA
194       match  is  retried.  This imitates the way Perl handles such           /Y              PCRE_NO_START_OPTIMIZE
195       cases when using the /g modifier or the split() function.           /<JS>           PCRE_JAVASCRIPT_COMPAT
196             /<cr>           PCRE_NEWLINE_CR
197       There are a number of other modifiers  for  controlling  the           /<lf>           PCRE_NEWLINE_LF
198       way pcretest operates.           /<crlf>         PCRE_NEWLINE_CRLF
199             /<anycrlf>      PCRE_NEWLINE_ANYCRLF
200       The /+ modifier requests that as well as outputting the sub-           /<any>          PCRE_NEWLINE_ANY
201       string  that  matched the entire pattern, pcretest should in           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
202       addition output the remainder of the subject string. This is           /<bsr_unicode>  PCRE_BSR_UNICODE
203       useful  for tests where the subject contains multiple copies  
204       of the same substring.         The  modifiers  that are enclosed in angle brackets are literal strings
205           as shown, including the angle brackets, but the letters within  can  be
206       The /L modifier must be followed directly by the name  of  a         in  either case.  This example sets multiline matching with CRLF as the
207       locale, for example,         line ending sequence:
208    
209         /pattern/Lfr           /^abc/m<CRLF>
210    
211       For this reason, it must be the last  modifier  letter.  The         As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
212       given  locale is set, pcre_maketables() is called to build a         any  non-printing  characters in output strings to be printed using the
213       set of character tables for the locale,  and  this  is  then         \x{hh...} notation if they are valid UTF-8 sequences. Full  details  of
214       passed  to pcre_compile() when compiling the regular expres-         the PCRE options are given in the pcreapi documentation.
215       sion. Without an /L modifier, NULL is passed as  the  tables  
216       pointer; that is, /L applies only to the expression on which     Finding all matches in a string
217       it appears.  
218           Searching  for  all  possible matches within each subject string can be
219       The /I modifier requests that  pcretest  output  information         requested by the /g or /G modifier. After  finding  a  match,  PCRE  is
220       about the compiled expression (whether it is anchored, has a         called again to search the remainder of the subject string. The differ-
221       fixed first character, and so on). It does this  by  calling         ence between /g and /G is that the former uses the startoffset argument
222       pcre_fullinfo()  after  compiling an expression, and output-         to  pcre_exec()  to  start  searching  at a new point within the entire
223       ting the information it gets back. If the  pattern  is  stu-         string (which is in effect what Perl does), whereas the  latter  passes
224       died, the results of that are also output.         over  a  shortened  substring.  This makes a difference to the matching
225           process if the pattern begins with a lookbehind assertion (including \b
226       The /D modifier is a  PCRE  debugging  feature,  which  also         or \B).
227       assumes /I.  It causes the internal form of compiled regular  
228       expressions to be output after compilation. If  the  pattern         If  any  call  to  pcre_exec()  in a /g or /G sequence matches an empty
229       was studied, the information returned is also output.         string, the next  call  is  done  with  the  PCRE_NOTEMPTY_ATSTART  and
230           PCRE_ANCHORED  flags  set  in  order  to search for another, non-empty,
231       The /S modifier causes pcre_study() to be called  after  the         match at the same point. If this second match fails, the  start  offset
232       expression  has been compiled, and the results used when the         is  advanced,  and  the  normal match is retried. This imitates the way
233       expression is matched.         Perl handles such cases when using the /g modifier or the split() func-
234           tion.  Normally,  the start offset is advanced by one character, but if
235       The /M modifier causes the size of memory block used to hold         the newline convention recognizes CRLF as a newline,  and  the  current
236       the compiled pattern to be output.         character is CR followed by LF, an advance of two is used.
237    
238       The /P modifier causes pcretest to call PCRE via  the  POSIX     Other modifiers
239       wrapper  API  rather than its native API. When this is done,  
240       all other modifiers except  /i,  /m,  and  /+  are  ignored.         There are yet more modifiers for controlling the way pcretest operates.
241       REG_ICASE is set if /i is present, and REG_NEWLINE is set if  
242       /m    is    present.    The    wrapper    functions    force         The  /+ modifier requests that as well as outputting the substring that
243       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless         matched the entire pattern, pcretest  should  in  addition  output  the
244       REG_NEWLINE is set.         remainder  of  the  subject  string. This is useful for tests where the
245           subject contains multiple copies of the same substring. If the +  modi-
246       The /8 modifier  causes  pcretest  to  call  PCRE  with  the         fier  appears  twice, the same action is taken for captured substrings.
247       PCRE_UTF8  option set. This turns on support for UTF-8 char-         In each case the remainder is output on the following line with a  plus
248       acter handling in PCRE, provided that it was  compiled  with         character following the capture number.
249       this  support  enabled.  This  modifier also causes any non-  
250       printing characters in output strings to  be  printed  using         The  /=  modifier  requests  that  the values of all potential captured
251       the \x{hh...} notation if they are valid UTF-8 sequences.         parentheses be output after a match by pcre_exec().  By  default,  only
252           those up to the highest one actually used in the match are output (cor-
253       If the /? modifier is used with /8, it  causes  pcretest  to         responding to the return code from pcre_exec()). Values in the  offsets
254       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         vector  corresponding  to higher numbers should be set to -1, and these
255       suppress the checking of the string for UTF-8 validity.         are output as "<unset>". This modifier gives a  way  of  checking  that
256           this is happening.
257    
258           The  /B modifier is a debugging feature. It requests that pcretest out-
259           put a representation of the compiled byte code after compilation.  Nor-
260           mally  this  information contains length and offset values; however, if
261           /Z is also present, this data is replaced by spaces. This is a  special
262           feature for use in the automatic test scripts; it ensures that the same
263           output is generated for different internal link sizes.
264    
265           The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
266           that is, both the /B and the /I modifiers.
267    
268           The /F modifier causes pcretest to flip the byte order of the fields in
269           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
270           facility  is  for testing the feature in PCRE that allows it to execute
271           patterns that were compiled on a host with a different endianness. This
272           feature  is  not  available  when  the POSIX interface to PCRE is being
273           used, that is, when the /P pattern modifier is specified. See also  the
274           section about saving and reloading compiled patterns below.
275    
276           The  /I  modifier  requests  that pcretest output information about the
277           compiled pattern (whether it is anchored, has a fixed first  character,
278           and  so  on). It does this by calling pcre_fullinfo() after compiling a
279           pattern. If the pattern is studied, the results of that are  also  out-
280           put.
281    
282           The  /K modifier requests pcretest to show names from backtracking con-
283           trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
284           pcretest  to create a pcre_extra block if one has not already been cre-
285           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
286           the mark field within it, every time that pcre_exec() is called. If the
287           variable that the mark field points to is non-NULL for  a  match,  non-
288           match, or partial match, pcretest prints the string to which it points.
289           For a match, this is shown on a line by itself, tagged with "MK:".  For
290           a non-match it is added to the message.
291    
292           The  /L modifier must be followed directly by the name of a locale, for
293           example,
294    
295             /pattern/Lfr_FR
296    
297           For this reason, it must be the last modifier. The given locale is set,
298           pcre_maketables()  is called to build a set of character tables for the
299           locale, and this is then passed to pcre_compile()  when  compiling  the
300           regular  expression.  Without an /L (or /T) modifier, NULL is passed as
301           the tables pointer; that is, /L applies only to the expression on which
302           it appears.
303    
304           The  /M  modifier causes the size of memory block used to hold the com-
305           piled pattern to be output.
306    
307           If the /S modifier appears once, it causes pcre_study()  to  be  called
308           after  the  expression has been compiled, and the results used when the
309           expression is matched. If /S appears  twice,  it  suppresses  studying,
310           even if it was requested externally by the -s command line option. This
311           makes it possible to specify that certain patterns are always  studied,
312           and others are never studied, independently of -s. This feature is used
313           in the test files in a few cases where the output is different when the
314           pattern is studied.
315    
316           The  /T  modifier  must be followed by a single digit. It causes a spe-
317           cific set of built-in character tables to be passed to  pcre_compile().
318           It is used in the standard PCRE tests to check behaviour with different
319           character tables. The digit specifies the tables as follows:
320    
321             0   the default ASCII tables, as distributed in
322                   pcre_chartables.c.dist
323             1   a set of tables defining ISO 8859 characters
324    
325           In table 1, some characters whose codes are greater than 128 are  iden-
326           tified as letters, digits, spaces, etc.
327    
328       Using the POSIX wrapper API
329    
330           The  /P modifier causes pcretest to call PCRE via the POSIX wrapper API
331           rather than its native API. When /P is set, the following modifiers set
332           options for the regcomp() function:
333    
334             /i    REG_ICASE
335             /m    REG_NEWLINE
336             /N    REG_NOSUB
337             /s    REG_DOTALL     )
338             /U    REG_UNGREEDY   ) These options are not part of
339             /W    REG_UCP        )   the POSIX standard
340             /8    REG_UTF8       )
341    
342           The  /+  modifier  works  as  described  above. All other modifiers are
343           ignored.
344    
345    
346    DATA LINES
347    
348           Before each data line is passed to pcre_exec(),  leading  and  trailing
349           white  space  is removed, and it is then scanned for \ escapes. Some of
350           these are pretty esoteric features, intended for checking out  some  of
351           the  more  complicated features of PCRE. If you are just testing "ordi-
352           nary" regular expressions, you probably don't need any  of  these.  The
353           following escapes are recognized:
354    
355             \a         alarm (BEL, \x07)
356             \b         backspace (\x08)
357             \e         escape (\x27)
358             \f         form feed (\x0c)
359             \n         newline (\x0a)
360             \qdd       set the PCRE_MATCH_LIMIT limit to dd
361                          (any number of digits)
362             \r         carriage return (\x0d)
363             \t         tab (\x09)
364             \v         vertical tab (\x0b)
365             \nnn       octal character (up to 3 octal digits)
366                          always a byte unless > 255 in UTF-8 mode
367             \xhh       hexadecimal byte (up to 2 hex digits)
368             \x{hh...}  hexadecimal character, any number of digits
369                          in UTF-8 mode
370             \A         pass the PCRE_ANCHORED option to pcre_exec()
371                          or pcre_dfa_exec()
372             \B         pass the PCRE_NOTBOL option to pcre_exec()
373                          or pcre_dfa_exec()
374             \Cdd       call pcre_copy_substring() for substring dd
375                          after a successful match (number less than 32)
376             \Cname     call pcre_copy_named_substring() for substring
377                          "name" after a successful match (name termin-
378                          ated by next non alphanumeric character)
379             \C+        show the current captured substrings at callout
380                          time
381             \C-        do not supply a callout function
382             \C!n       return 1 instead of 0 when callout number n is
383                          reached
384             \C!n!m     return 1 instead of 0 when callout number n is
385                          reached for the nth time
386             \C*n       pass the number n (may be negative) as callout
387                          data; this is used as the callout return value
388             \D         use the pcre_dfa_exec() match function
389             \F         only shortest match for pcre_dfa_exec()
390             \Gdd       call pcre_get_substring() for substring dd
391                          after a successful match (number less than 32)
392             \Gname     call pcre_get_named_substring() for substring
393                          "name" after a successful match (name termin-
394                          ated by next non-alphanumeric character)
395             \L         call pcre_get_substringlist() after a
396                          successful match
397             \M         discover the minimum MATCH_LIMIT and
398                          MATCH_LIMIT_RECURSION settings
399             \N         pass the PCRE_NOTEMPTY option to pcre_exec()
400                          or pcre_dfa_exec(); if used twice, pass the
401                          PCRE_NOTEMPTY_ATSTART option
402             \Odd       set the size of the output vector passed to
403                          pcre_exec() to dd (any number of digits)
404             \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
405                          or pcre_dfa_exec(); if used twice, pass the
406                          PCRE_PARTIAL_HARD option
407             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
408                          (any number of digits)
409             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
410             \S         output details of memory get/free calls during matching
411             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
412                          or pcre_dfa_exec()
413             \Z         pass the PCRE_NOTEOL option to pcre_exec()
414                          or pcre_dfa_exec()
415             \?         pass the PCRE_NO_UTF8_CHECK option to
416                          pcre_exec() or pcre_dfa_exec()
417             \>dd       start the match at offset dd (optional "-"; then
418                          any number of digits); this sets the startoffset
419                          argument for pcre_exec() or pcre_dfa_exec()
420             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
421                          or pcre_dfa_exec()
422             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
423                          or pcre_dfa_exec()
424             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
425                          or pcre_dfa_exec()
426             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
427                          or pcre_dfa_exec()
428             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
429                          or pcre_dfa_exec()
430    
431           Note  that  \xhh  always  specifies  one byte, even in UTF-8 mode; this
432           makes it possible to construct invalid UTF-8 sequences for testing pur-
433           poses. On the other hand, \x{hh} is interpreted as a UTF-8 character in
434           UTF-8 mode, generating more than one byte if the value is greater  than
435           127. When not in UTF-8 mode, it generates one byte for values less than
436           256, and causes an error for greater values.
437    
438           The escapes that specify line ending  sequences  are  literal  strings,
439           exactly as shown. No more than one newline setting should be present in
440           any data line.
441    
442           A backslash followed by anything else just escapes the  anything  else.
443           If  the very last character is a backslash, it is ignored. This gives a
444           way of passing an empty line as data, since a real  empty  line  termi-
445           nates the data input.
446    
447           If  \M  is present, pcretest calls pcre_exec() several times, with dif-
448           ferent values in the match_limit and  match_limit_recursion  fields  of
449           the  pcre_extra  data structure, until it finds the minimum numbers for
450           each parameter that allow pcre_exec() to complete. The match_limit num-
451           ber  is  a  measure of the amount of backtracking that takes place, and
452           checking it out can be instructive. For most simple matches, the number
453           is  quite  small,  but for patterns with very large numbers of matching
454           possibilities, it can become large very quickly with increasing  length
455           of subject string. The match_limit_recursion number is a measure of how
456           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
457           memory is needed to complete the match attempt.
458    
459           When  \O  is  used, the value specified may be higher or lower than the
460           size set by the -O command line option (or defaulted to 45); \O applies
461           only to the call of pcre_exec() for the line in which it appears.
462    
463           If  the /P modifier was present on the pattern, causing the POSIX wrap-
464           per API to be used, the only option-setting  sequences  that  have  any
465           effect  are  \B,  \N,  and  \Z,  causing  REG_NOTBOL, REG_NOTEMPTY, and
466           REG_NOTEOL, respectively, to be passed to regexec().
467    
468           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
469           the  use  of  the  /8 modifier on the pattern. It is recognized always.
470           There may be any number of hexadecimal digits inside  the  braces.  The
471           result  is  from  one  to  six bytes, encoded according to the original
472           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
473           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
474           or indeed valid UTF-8 characters according to the later  rules  in  RFC
475           3629.
476    
477    
478    THE ALTERNATIVE MATCHING FUNCTION
479    
480           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
481           pcre_exec() to match each data line. From release 6.0, PCRE supports an
482           alternative  matching  function,  pcre_dfa_test(),  which operates in a
483           different way, and has some restrictions. The differences  between  the
484           two functions are described in the pcrematching documentation.
485    
486           If  a data line contains the \D escape sequence, or if the command line
487           contains the -dfa option, the alternative matching function is  called.
488           This function finds all possible matches at a given point. If, however,
489           the \F escape sequence is present in the data line, it stops after  the
490           first match is found. This is always the shortest possible match.
491    
492    
493    DEFAULT OUTPUT FROM PCRETEST
494    
495           This  section  describes  the output when the normal matching function,
496           pcre_exec(), is being used.
497    
498           When a match succeeds, pcretest outputs the list of captured substrings
499           that  pcre_exec()  returns,  starting with number 0 for the string that
500           matched the whole pattern. Otherwise, it outputs "No  match"  when  the
501           return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
502           tially matching substring when pcre_exec() returns  PCRE_ERROR_PARTIAL.
503           (Note  that  this is the entire substring that was inspected during the
504           partial match; it may include characters before the actual match  start
505           if  a  lookbehind assertion, \K, \b, or \B was involved.) For any other
506           return, pcretest outputs the PCRE negative error  number  and  a  short
507           descriptive  phrase.  If  the error is a failed UTF-8 string check, the
508           byte offset of the start of the failing character and the  reason  code
509           are  also  output,  provided  that  the size of the output vector is at
510           least two. Here is an example of an interactive pcretest run.
511    
512             $ pcretest
513             PCRE version 8.13 2011-04-30
514    
515               re> /^abc(\d+)/
516             data> abc123
517              0: abc123
518              1: 123
519             data> xyz
520             No match
521    
522           Unset capturing substrings that are not followed by one that is set are
523           not returned by pcre_exec(), and are not shown by pcretest. In the fol-
524           lowing example, there are two capturing substrings, but when the  first
525           data  line  is  matched,  the  second, unset substring is not shown. An
526           "internal" unset substring is shown as "<unset>",  as  for  the  second
527           data line.
528    
529               re> /(a)|(b)/
530             data> a
531              0: a
532              1: a
533             data> b
534              0: b
535              1: <unset>
536              2: b
537    
538           If  the strings contain any non-printing characters, they are output as
539           \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
540           the  pattern.  See below for the definition of non-printing characters.
541           If the pattern has the /+ modifier, the output for substring 0 is  fol-
542           lowed  by  the  the rest of the subject string, identified by "0+" like
543           this:
544    
545               re> /cat/+
546             data> cataract
547              0: cat
548              0+ aract
549    
550           If the pattern has the /g or /G modifier,  the  results  of  successive
551           matching attempts are output in sequence, like this:
552    
553               re> /\Bi(\w\w)/g
554             data> Mississippi
555              0: iss
556              1: ss
557              0: iss
558              1: ss
559              0: ipp
560              1: pp
561    
562           "No  match" is output only if the first match attempt fails. Here is an
563           example of a failure message (the offset 4 that is specified by \>4  is
564           past the end of the subject string):
565    
566               re> /xyz/
567             data> xyz\>4
568             Error -24 (bad offset value)
569    
570           If  any  of the sequences \C, \G, or \L are present in a data line that
571           is successfully matched, the substrings extracted  by  the  convenience
572           functions are output with C, G, or L after the string number instead of
573           a colon. This is in addition to the normal full list. The string length
574           (that  is,  the return from the extraction function) is given in paren-
575           theses after each string for \C and \G.
576    
577           Note that whereas patterns can be continued over several lines (a plain
578           ">" prompt is used for continuations), data lines may not. However new-
579           lines can be included in data by means of the \n escape (or  \r,  \r\n,
580           etc., depending on the newline sequence setting).
581    
582    
583    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
584    
585           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
586           means of the \D escape sequence or the -dfa command line  option),  the
587           output  consists  of  a list of all the matches that start at the first
588           point in the subject where there is at least one match. For example:
589    
590               re> /(tang|tangerine|tan)/
591             data> yellow tangerine\D
592              0: tangerine
593              1: tang
594              2: tan
595    
596           (Using the normal matching function on this data  finds  only  "tang".)
597           The  longest matching string is always given first (and numbered zero).
598           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
599           lowed  by  the  partially  matching  substring.  (Note that this is the
600           entire substring that was inspected during the partial  match;  it  may
601           include characters before the actual match start if a lookbehind asser-
602           tion, \K, \b, or \B was involved.)
603    
604           If /g is present on the pattern, the search for further matches resumes
605           at the end of the longest match. For example:
606    
607               re> /(tang|tangerine|tan)/g
608             data> yellow tangerine and tangy sultana\D
609              0: tangerine
610              1: tang
611              2: tan
612              0: tang
613              1: tan
614              0: tan
615    
616           Since  the  matching  function  does not support substring capture, the
617           escape sequences that are concerned with captured  substrings  are  not
618           relevant.
619    
620    
621    RESTARTING AFTER A PARTIAL MATCH
622    
623           When the alternative matching function has given the PCRE_ERROR_PARTIAL
624           return, indicating that the subject partially matched the pattern,  you
625           can  restart  the match with additional subject data by means of the \R
626           escape sequence. For example:
627    
628               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
629             data> 23ja\P\D
630             Partial match: 23ja
631             data> n05\R\D
632              0: n05
633    
634           For further information about partial  matching,  see  the  pcrepartial
635           documentation.
636    
637    
638  CALLOUTS  CALLOUTS
639    
640       If the pattern contains  any  callout  requests,  pcretest's         If  the pattern contains any callout requests, pcretest's callout func-
641       callout function will be called. By default, it displays the         tion is called during matching. This works  with  both  matching  func-
642       callout number, and the start and current positions  in  the         tions. By default, the called function displays the callout number, the
643       text at the callout time. For example, the output         start and current positions in the text at the callout  time,  and  the
644           next pattern item to be tested. For example, the output
645         --->pqrabcdef  
646           0    ^  ^           --->pqrabcdef
647               0    ^  ^     \d
648       indicates that callout number 0 occurred for a match attempt  
649       starting at the fourth character of the subject string, when         indicates  that  callout number 0 occurred for a match attempt starting
650       the pointer was at the seventh character. The callout  func-         at the fourth character of the subject string, when the pointer was  at
651       tion returns zero (carry on matching) by default.         the  seventh  character of the data, and when the next pattern item was
652           \d. Just one circumflex is output if the start  and  current  positions
653       Inserting callouts may be helpful  when  using  pcretest  to         are the same.
654       check  complicated regular expressions. For further informa-  
655       tion about callouts, see the pcrecallout documentation.         Callouts numbered 255 are assumed to be automatic callouts, inserted as
656           a result of the /C pattern modifier. In this case, instead  of  showing
657       For testing the PCRE library, additional control of  callout         the  callout  number, the offset in the pattern, preceded by a plus, is
658       behaviour  is available via escape sequences in the data, as         output. For example:
659       described in the following section.  In  particular,  it  is  
660       possible to pass in a number as callout data (the default is             re> /\d?[A-E]\*/C
661       zero). If the callout function receives a  non-zero  number,           data> E*
662       it returns that value instead of zero.           --->E*
663              +0 ^      \d?
664              +3 ^      [A-E]
665              +8 ^^     \*
666             +10 ^ ^
667              0: E*
668    
669           If a pattern contains (*MARK) items, an additional line is output when-
670           ever  a  change  of  latest mark is passed to the callout function. For
671           example:
672    
673               re> /a(*MARK:X)bc/C
674             data> abc
675             --->abc
676              +0 ^       a
677              +1 ^^      (*MARK:X)
678             +10 ^^      b
679             Latest Mark: X
680             +11 ^ ^     c
681             +12 ^  ^
682              0: abc
683    
684           The mark changes between matching "a" and "b", but stays the  same  for
685           the  rest  of  the match, so nothing more is output. If, as a result of
686           backtracking, the mark reverts to being unset, the  text  "<unset>"  is
687           output.
688    
689           The  callout  function  in pcretest returns zero (carry on matching) by
690           default, but you can use a \C item in a data line (as described  above)
691           to change this and other parameters of the callout.
692    
693           Inserting  callouts can be helpful when using pcretest to check compli-
694           cated regular expressions. For further information about callouts,  see
695           the pcrecallout documentation.
696    
697    
698    NON-PRINTING CHARACTERS
699    
700           When  pcretest is outputting text in the compiled version of a pattern,
701           bytes other than 32-126 are always treated as  non-printing  characters
702           are are therefore shown as hex escapes.
703    
704           When  pcretest  is  outputting text that is a matched part of a subject
705           string, it behaves in the same way, unless a different locale has  been
706           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
707           isprint() function to distinguish printing and non-printing characters.
708    
709    
710    SAVING AND RELOADING COMPILED PATTERNS
711    
712           The facilities described in this section are  not  available  when  the
713           POSIX  interface  to  PCRE  is being used, that is, when the /P pattern
714           modifier is specified.
715    
716           When the POSIX interface is not in use, you can cause pcretest to write
717           a  compiled  pattern to a file, by following the modifiers with > and a
718           file name.  For example:
719    
720             /pattern/im >/some/file
721    
722           See the pcreprecompile documentation for a discussion about saving  and
723           re-using compiled patterns.
724    
725           The  data  that  is  written  is  binary. The first eight bytes are the
726           length of the compiled pattern data  followed  by  the  length  of  the
727           optional  study  data,  each  written as four bytes in big-endian order
728           (most significant byte first). If there is no study  data  (either  the
729           pattern was not studied, or studying did not return any data), the sec-
730           ond length is zero. The lengths are followed by an exact  copy  of  the
731           compiled pattern. If there is additional study data, this follows imme-
732           diately after the compiled pattern. After writing  the  file,  pcretest
733           expects to read a new pattern.
734    
735           A  saved  pattern  can  be reloaded into pcretest by specifying < and a
736           file name instead of a pattern. The name of the file must not contain a
737           < character, as otherwise pcretest will interpret the line as a pattern
738           delimited by < characters.  For example:
739    
740              re> </some/file
741             Compiled pattern loaded from /some/file
742             No study data
743    
744           When the pattern has been loaded, pcretest proceeds to read data  lines
745           in the usual way.
746    
747           You  can copy a file written by pcretest to a different host and reload
748           it there, even if the new host has opposite endianness to  the  one  on
749           which  the pattern was compiled. For example, you can compile on an i86
750           machine and run on a SPARC machine.
751    
752           File names for saving and reloading can be absolute  or  relative,  but
753           note  that the shell facility of expanding a file name that starts with
754           a tilde (~) is not available.
755    
756           The ability to save and reload files in pcretest is intended for  test-
757           ing  and experimentation. It is not intended for production use because
758           only a single pattern can be written to a file. Furthermore,  there  is
759           no  facility  for  supplying  custom  character  tables  for use with a
760           reloaded pattern. If the original  pattern  was  compiled  with  custom
761           tables,  an  attempt to match a subject string using a reloaded pattern
762           is likely to cause pcretest to crash.  Finally, if you attempt to  load
763           a file that is not in the correct format, the result is undefined.
764    
765    
766  DATA LINES  SEE ALSO
767    
768       Before each data line is passed to pcre_exec(), leading  and         pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
769       trailing whitespace is removed, and it is then scanned for \         pcrepattern(3), pcreprecompile(3).
      escapes.  Some  of  these  are  pretty  esoteric   features,  
      intended  for  checking  out  some  of  the more complicated  
      features of PCRE. If you are just testing "ordinary" regular  
      expressions,  you probably don't need any of these. The fol-  
      lowing escapes 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)  
        \x{hh...}  hexadecimal character, any number of digits  
                     in UTF-8 mode  
        \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)  
        \Cname     call pcre_copy_named_substring() for substring  
   
                     "name" after a successful match (name termin-  
                     ated by next non alphanumeric character)  
        \C+        show the current captured substrings at callout  
                     time  
        \C-        do not supply a callout function  
        \C!n       return 1 instead of 0 when callout number n is  
                     reached  
        \C!n!m     return 1 instead of 0 when callout number n is  
                     reached for the nth time  
        \C*n       pass the number n (may be negative) as callout  
                     data  
        \Gdd       call pcre_get_substring() for substring dd  
                     after a successful match (any decimal number  
                     less than 32)  
        \Gname     call pcre_get_named_substring() for substring  
                     "name" after a successful match (name termin-  
                     ated by next non-alphanumeric character)  
        \L         call pcre_get_substringlist() after a  
                     successful match  
        \M         discover the minimum MATCH_LIMIT setting  
        \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()  
        \?         pass the PCRE_NO_UTF8_CHECK option to  
                     pcre_exec()  
   
      If \M is present, pcretest calls pcre_exec() several  times,  
      with  different  values  in  the  match_limit  field  of the  
      pcre_extra data structure, until it finds the minimum number  
      that is needed for pcre_exec() to complete. This number is a  
      measure of the amount of  recursion  and  backtracking  that  
      takes  place,  and  checking  it out can be instructive. For  
      most simple matches, the number is quite small, but for pat-  
      terns  with very large numbers of matching possibilities, it  
      can become large very quickly with increasing length of sub-  
      ject string.  
   
      When \O is used, it may be higher or lower than the size set  
      by  the  -O  option (or defaulted to 45); \O applies only to  
      the call of pcre_exec() for the line in which it appears.  
   
      A backslash followed by anything else just escapes the  any-  
      thing 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()  respec-  
      tively.  
      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.  
   
   
 OUTPUT FROM PCRETEST  
   
      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 4.00 08-Jan-2003  
   
          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,  or  as  \x{...} escapes if the /8  
      modifier was present on the pattern. 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 the sequences \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 addi-  
      tion 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.  
770    
771    
772  AUTHOR  AUTHOR
773    
774       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
775       University Computing Service,         University Computing Service
776       Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
777    
778    
779    REVISION
780    
781  Last updated: 20 August 2003         Last updated: 01 August 2011
782  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2011 University of Cambridge.

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