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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] [source] [destination]
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.
18    
19    
20  OPTIONS  OPTIONS
21    
22           -b        Behave as if each regex has the /B (show bytecode)  modifier;
23                     the internal form is output after compilation.
24    
25           -C        Output the version number of the PCRE library, and all avail-
26                     able  information  about  the  optional  features  that   are
27                     included, and then exit.
28    
29           -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                     internal form and information about the compiled  pattern  is
31                     output after compilation; -d is equivalent to -b -i.
32    
33           -dfa      Behave  as if each data line contains the \D escape sequence;
34                     this    causes    the    alternative    matching    function,
35                     pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37    
38           -help     Output a brief summary these options and then exit.
39    
40           -i        Behave as if each regex  has  the  /I  modifier;  information
41                     about the compiled pattern is given after compilation.
42    
43           -M        Behave  as if each data line contains the \M escape sequence;
44                     this causes PCRE to  discover  the  minimum  MATCH_LIMIT  and
45                     MATCH_LIMIT_RECURSION settings by calling pcre_exec() repeat-
46                     edly with different limits.
47    
48           -m        Output the size of each compiled pattern after  it  has  been
49                     compiled.  This  is  equivalent  to adding /M to each regular
50                     expression.  For  compatibility  with  earlier  versions   of
51                     pcretest, -s is a synonym for -m.
52    
53           -o osize  Set  the number of elements in the output vector that is used
54                     when calling pcre_exec() or pcre_dfa_exec() to be osize.  The
55                     default  value is 45, which is enough for 14 capturing subex-
56                     pressions  for  pcre_exec()  or  22  different  matches   for
57                     pcre_dfa_exec().  The vector size can be changed for individ-
58                     ual matching calls by including \O  in  the  data  line  (see
59                     below).
60    
61           -p        Behave  as if each regex has the /P modifier; the POSIX wrap-
62                     per API is used to call PCRE. None of the other  options  has
63                     any effect when -p is set.
64    
65           -q        Do  not output the version number of pcretest at the start of
66                     execution.
67    
68           -S size   On Unix-like systems, set the size of the  runtime  stack  to
69                     size megabytes.
70    
71           -t        Run  each  compile, study, and match many times with a timer,
72                     and output resulting time per compile or match (in  millisec-
73                     onds).  Do  not set -m with -t, because you will then get the
74                     size output a zillion times, and  the  timing  will  be  dis-
75                     torted.  You  can  control  the number of iterations that are
76                     used for timing by following -t with a number (as a  separate
77                     item on the command line). For example, "-t 1000" would iter-
78                     ate 1000 times. The default is to iterate 500000 times.
79    
80       -C        Output the version number of the PCRE library, and         -tm       This is like -t except that it times only the matching phase,
81                 all   available  information  about  the  optional                   not the compile or study phases.
                features that are included, and then exit.  
   
      -d        Behave as if each regex had the /D  modifier  (see  
                below); the internal form is output after compila-  
                tion.  
   
      -i        Behave as if  each  regex  had  the  /I  modifier;  
                information  about  the  compiled pattern is given  
                after compilation.  
   
      -m        Output the size of each compiled pattern after  it  
                has been compiled. This is equivalent to adding /M  
                to each regular expression. For compatibility with  
                earlier  versions of pcretest, -s is a synonym for  
                -m.  
   
      -o osize  Set the number of elements in  the  output  vector  
                that  is  used  when calling PCRE to be osize. The  
                default value is 45, which is enough for  14  cap-  
                turing  subexpressions.  The  vector  size  can be  
                changed for individual matching calls by including  
                \O in the data line (see below).  
   
      -p        Behave as if each regex has /P modifier; the POSIX  
                wrapper  API  is  used  to  call PCRE. None of the  
                other options has any effect when -p is set.  
   
      -t        Run each compile, study, and match many times with  
                a  timer, and output resulting time per compile or  
                match (in milliseconds). Do not set  -t  with  -m,  
                because  you  will  then get the size output 20000  
                times and the timing will be distorted.  
82    
83    
84  DESCRIPTION  DESCRIPTION
85    
86       If pcretest is given two filename arguments, it  reads  from         If  pcretest  is  given two filename arguments, it reads from the first
87       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
88       filename argument, it reads from that  file  and  writes  to         reads  from  that  file  and writes to stdout. Otherwise, it reads from
89       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin and writes to stdout, and prompts for each line of  input,  using
90       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
91       for  regular  expressions,  and  "data>"  to prompt for data         lines.
92       lines.  
93           When pcretest is built, a configuration  option  can  specify  that  it
94       The program handles any number of sets of input on a  single         should  be  linked  with the libreadline library. When this is done, if
95       input  file.  Each set starts with a regular expression, and         the input is from a terminal, it is read using the readline() function.
96       continues with any  number  of  data  lines  to  be  matched         This  provides line-editing and history facilities. The output from the
97       against the pattern.         -help option states whether or not readline() will be used.
98    
99       Each line is matched separately and  independently.  If  you         The program handles any number of sets of input on a single input file.
100       want  to  do  multiple-line  matches, you have to use the \n         Each  set starts with a regular expression, and continues with any num-
101       escape sequence in a single line of input to encode the new-         ber of data lines to be matched against the pattern.
102       line  characters.  The maximum length of data line is 30,000  
103       characters.         Each data line is matched separately and independently. If you want  to
104           do multi-line matches, you have to use the \n escape sequence (or \r or
105       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
106       point  a new regular expression is read. The regular expres-         to  encode  the  newline  sequences. There is no limit on the length of
107       sions are given enclosed in  any  non-alphameric  delimiters         data lines; the input buffer is automatically extended  if  it  is  too
108       other than backslash, for example         small.
109    
110         /(a|bc)x+yz/         An  empty  line signals the end of the data lines, at which point a new
111           regular expression is read. The regular expressions are given  enclosed
112       White space before the initial delimiter is ignored. A regu-         in any non-alphanumeric delimiters other than backslash, for example:
113       lar expression may be continued over several input lines, in  
114       which case the newline characters are included within it. It           /(a|bc)x+yz/
115       is  possible  to include the delimiter within the pattern by  
116       escaping it, for example         White  space before the initial delimiter is ignored. A regular expres-
117           sion may be continued over several input lines, in which case the  new-
118         /abc\/def/         line  characters  are included within it. It is possible to include the
119           delimiter within the pattern by escaping it, for example
120       If you do so, the escape and the delimiter form part of  the  
121       pattern,  but  since  delimiters  are always non-alphameric,           /abc\/def/
122       this does not affect its interpretation.  If the terminating  
123       delimiter  is immediately followed by a backslash, for exam-         If you do so, the escape and the delimiter form part  of  the  pattern,
124       ple,         but  since delimiters are always non-alphanumeric, this does not affect
125           its interpretation.  If the terminating delimiter is  immediately  fol-
126         /abc/\         lowed by a backslash, for example,
127    
128       then a backslash is added to the end of the pattern. This is           /abc/\
129       done  to  provide  a way of testing the error condition that  
130       arises if a pattern finishes with a backslash, because         then  a  backslash  is added to the end of the pattern. This is done to
131           provide a way of testing the error condition that arises if  a  pattern
132         /abc\/         finishes with a backslash, because
133    
134       is interpreted as the first line of a  pattern  that  starts           /abc\/
135       with  "abc/",  causing  pcretest  to read the next line as a  
136       continuation of the regular expression.         is  interpreted as the first line of a pattern that starts with "abc/",
137           causing pcretest to read the next line as a continuation of the regular
138           expression.
139    
140    
141  PATTERN MODIFIERS  PATTERN MODIFIERS
142    
143       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
144       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single characters. Following Perl usage, these are  referred  to  below
145       options, respectively. For example:         as,  for  example,  "the /i modifier", even though the delimiter of the
146           pattern need not always be a slash, and no slash is used  when  writing
147         /caseless/i         modifiers.  Whitespace  may  appear between the final pattern delimiter
148           and the first modifier, and between the modifiers themselves.
149       These modifier letters have the same effect as  they  do  in  
150       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
151       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL,  or  PCRE_EXTENDED  options,  respectively, when pcre_com-
152       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile() is called. These four modifier letters have the same  effect  as
153       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
154    
155       Searching for  all  possible  matches  within  each  subject           /caseless/i
156       string  can  be  requested  by  the /g or /G modifier. After  
157       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for setting PCRE options
158       remainder  of  the subject string. The difference between /g         that do not correspond to anything in Perl:
159       and /G is that the former uses the startoffset  argument  to  
160       pcre_exec()  to  start  searching  at a new point within the           /8              PCRE_UTF8
161       entire string (which is in effect what Perl  does),  whereas           /?              PCRE_NO_UTF8_CHECK
162       the  latter  passes over a shortened substring. This makes a           /A              PCRE_ANCHORED
163       difference to the matching process  if  the  pattern  begins           /C              PCRE_AUTO_CALLOUT
164       with a lookbehind assertion (including \b or \B).           /E              PCRE_DOLLAR_ENDONLY
165             /f              PCRE_FIRSTLINE
166       If any call to pcre_exec() in a /g or /G sequence matches an           /J              PCRE_DUPNAMES
167       empty  string,  the next call is done with the PCRE_NOTEMPTY           /N              PCRE_NO_AUTO_CAPTURE
168       and PCRE_ANCHORED flags set in order to search for  another,           /U              PCRE_UNGREEDY
169       non-empty,  match  at  the same point.  If this second match           /W              PCRE_UCP
170       fails, the start offset is advanced by one, and  the  normal           /X              PCRE_EXTRA
171       match  is  retried.  This imitates the way Perl handles such           /<JS>           PCRE_JAVASCRIPT_COMPAT
172       cases when using the /g modifier or the split() function.           /<cr>           PCRE_NEWLINE_CR
173             /<lf>           PCRE_NEWLINE_LF
174       There are a number of other modifiers  for  controlling  the           /<crlf>         PCRE_NEWLINE_CRLF
175       way pcretest operates.           /<anycrlf>      PCRE_NEWLINE_ANYCRLF
176             /<any>          PCRE_NEWLINE_ANY
177       The /+ modifier requests that as well as outputting the sub-           /<bsr_anycrlf>  PCRE_BSR_ANYCRLF
178       string  that  matched the entire pattern, pcretest should in           /<bsr_unicode>  PCRE_BSR_UNICODE
179       addition output the remainder of the subject string. This is  
180       useful  for tests where the subject contains multiple copies         The modifiers that are enclosed in angle brackets are  literal  strings
181       of the same substring.         as  shown,  including  the  angle  brackets,  but the letters can be in
182           either case. This example sets multiline matching with CRLF as the line
183       The /L modifier must be followed directly by the name  of  a         ending sequence:
184       locale, for example,  
185             /^abc/m<crlf>
186         /pattern/Lfr  
187           As well as turning on the PCRE_UTF8 option, the /8 modifier also causes
188       For this reason, it must be the last  modifier  letter.  The         any non-printing characters in output strings to be printed  using  the
189       given  locale is set, pcre_maketables() is called to build a         \x{hh...}  notation  if they are valid UTF-8 sequences. Full details of
190       set of character tables for the locale,  and  this  is  then         the PCRE options are given in the pcreapi documentation.
191       passed  to pcre_compile() when compiling the regular expres-  
192       sion. Without an /L modifier, NULL is passed as  the  tables     Finding all matches in a string
193       pointer; that is, /L applies only to the expression on which  
194       it appears.         Searching for all possible matches within each subject  string  can  be
195           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
196       The /I modifier requests that  pcretest  output  information         called again to search the remainder of the subject string. The differ-
197       about the compiled expression (whether it is anchored, has a         ence between /g and /G is that the former uses the startoffset argument
198       fixed first character, and so on). It does this  by  calling         to pcre_exec() to start searching at a  new  point  within  the  entire
199       pcre_fullinfo()  after  compiling an expression, and output-         string  (which  is in effect what Perl does), whereas the latter passes
200       ting the information it gets back. If the  pattern  is  stu-         over a shortened substring. This makes a  difference  to  the  matching
201       died, the results of that are also output.         process if the pattern begins with a lookbehind assertion (including \b
202           or \B).
203       The /D modifier is a  PCRE  debugging  feature,  which  also  
204       assumes /I.  It causes the internal form of compiled regular         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
205       expressions to be output after compilation. If  the  pattern         string,  the  next  call  is  done  with  the PCRE_NOTEMPTY_ATSTART and
206       was studied, the information returned is also output.         PCRE_ANCHORED flags set in order  to  search  for  another,  non-empty,
207           match  at  the same point. If this second match fails, the start offset
208       The /S modifier causes pcre_study() to be called  after  the         is advanced by one character, and the normal  match  is  retried.  This
209       expression  has been compiled, and the results used when the         imitates  the way Perl handles such cases when using the /g modifier or
210       expression is matched.         the split() function.
211    
212       The /M modifier causes the size of memory block used to hold     Other modifiers
213       the compiled pattern to be output.  
214           There are yet more modifiers for controlling the way pcretest operates.
215       The /P modifier causes pcretest to call PCRE via  the  POSIX  
216       wrapper  API  rather than its native API. When this is done,         The /+ modifier requests that as well as outputting the substring  that
217       all other modifiers except  /i,  /m,  and  /+  are  ignored.         matched  the  entire  pattern,  pcretest  should in addition output the
218       REG_ICASE is set if /i is present, and REG_NEWLINE is set if         remainder of the subject string. This is useful  for  tests  where  the
219       /m    is    present.    The    wrapper    functions    force         subject contains multiple copies of the same substring.
220       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless  
221       REG_NEWLINE is set.         The  /B modifier is a debugging feature. It requests that pcretest out-
222           put a representation of the compiled byte code after compilation.  Nor-
223       The /8 modifier  causes  pcretest  to  call  PCRE  with  the         mally  this  information contains length and offset values; however, if
224       PCRE_UTF8  option set. This turns on support for UTF-8 char-         /Z is also present, this data is replaced by spaces. This is a  special
225       acter handling in PCRE, provided that it was  compiled  with         feature for use in the automatic test scripts; it ensures that the same
226       this  support  enabled.  This  modifier also causes any non-         output is generated for different internal link sizes.
227       printing characters in output strings to  be  printed  using  
228       the \x{hh...} notation if they are valid UTF-8 sequences.         The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
229           that is, both the /B and the /I modifiers.
230       If the /? modifier is used with /8, it  causes  pcretest  to  
231       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         The /F modifier causes pcretest to flip the byte order of the fields in
232       suppress the checking of the string for UTF-8 validity.         the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
233           facility  is  for testing the feature in PCRE that allows it to execute
234           patterns that were compiled on a host with a different endianness. This
235           feature  is  not  available  when  the POSIX interface to PCRE is being
236           used, that is, when the /P pattern modifier is specified. See also  the
237           section about saving and reloading compiled patterns below.
238    
239           The  /I  modifier  requests  that pcretest output information about the
240           compiled pattern (whether it is anchored, has a fixed first  character,
241           and  so  on). It does this by calling pcre_fullinfo() after compiling a
242           pattern. If the pattern is studied, the results of that are  also  out-
243           put.
244    
245           The  /K modifier requests pcretest to show names from backtracking con-
246           trol verbs that are returned  from  calls  to  pcre_exec().  It  causes
247           pcretest  to create a pcre_extra block if one has not already been cre-
248           ated by a call to pcre_study(), and to set the PCRE_EXTRA_MARK flag and
249           the mark field within it, every time that pcre_exec() is called. If the
250           variable that the mark field points to is non-NULL for  a  match,  non-
251           match, or partial match, pcretest prints the string to which it points.
252           For a match, this is shown on a line by itself, tagged with "MK:".  For
253           a non-match it is added to the message.
254    
255           The  /L modifier must be followed directly by the name of a locale, for
256           example,
257    
258             /pattern/Lfr_FR
259    
260           For this reason, it must be the last modifier. The given locale is set,
261           pcre_maketables()  is called to build a set of character tables for the
262           locale, and this is then passed to pcre_compile()  when  compiling  the
263           regular  expression.  Without  an  /L  modifier,  NULL is passed as the
264           tables pointer; that is, /L applies only to the expression on which  it
265           appears.
266    
267           The  /M  modifier causes the size of memory block used to hold the com-
268           piled pattern to be output.
269    
270           The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API
271           rather  than  its  native  API.  When this is done, all other modifiers
272           except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,
273           and  REG_NEWLINE  is  set if /m is present. The wrapper functions force
274           PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
275    
276           The /S modifier causes pcre_study() to be called after  the  expression
277           has been compiled, and the results used when the expression is matched.
278    
279    
280    DATA LINES
281    
282           Before  each  data  line is passed to pcre_exec(), leading and trailing
283           whitespace is removed, and it is then scanned for \  escapes.  Some  of
284           these  are  pretty esoteric features, intended for checking out some of
285           the more complicated features of PCRE. If you are just  testing  "ordi-
286           nary"  regular  expressions,  you probably don't need any of these. The
287           following escapes are recognized:
288    
289             \a         alarm (BEL, \x07)
290             \b         backspace (\x08)
291             \e         escape (\x27)
292             \f         formfeed (\x0c)
293             \n         newline (\x0a)
294             \qdd       set the PCRE_MATCH_LIMIT limit to dd
295                          (any number of digits)
296             \r         carriage return (\x0d)
297             \t         tab (\x09)
298             \v         vertical tab (\x0b)
299             \nnn       octal character (up to 3 octal digits)
300             \xhh       hexadecimal character (up to 2 hex digits)
301             \x{hh...}  hexadecimal character, any number of digits
302                          in UTF-8 mode
303             \A         pass the PCRE_ANCHORED option to pcre_exec()
304                          or pcre_dfa_exec()
305             \B         pass the PCRE_NOTBOL option to pcre_exec()
306                          or pcre_dfa_exec()
307             \Cdd       call pcre_copy_substring() for substring dd
308                          after a successful match (number less than 32)
309             \Cname     call pcre_copy_named_substring() for substring
310                          "name" after a successful match (name termin-
311                          ated by next non alphanumeric character)
312             \C+        show the current captured substrings at callout
313                          time
314             \C-        do not supply a callout function
315             \C!n       return 1 instead of 0 when callout number n is
316                          reached
317             \C!n!m     return 1 instead of 0 when callout number n is
318                          reached for the nth time
319             \C*n       pass the number n (may be negative) as callout
320                          data; this is used as the callout return value
321             \D         use the pcre_dfa_exec() match function
322             \F         only shortest match for pcre_dfa_exec()
323             \Gdd       call pcre_get_substring() for substring dd
324                          after a successful match (number less than 32)
325             \Gname     call pcre_get_named_substring() for substring
326                          "name" after a successful match (name termin-
327                          ated by next non-alphanumeric character)
328             \L         call pcre_get_substringlist() after a
329                          successful match
330             \M         discover the minimum MATCH_LIMIT and
331                          MATCH_LIMIT_RECURSION settings
332             \N         pass the PCRE_NOTEMPTY option to pcre_exec()
333                          or pcre_dfa_exec(); if used twice, pass the
334                          PCRE_NOTEMPTY_ATSTART option
335             \Odd       set the size of the output vector passed to
336                          pcre_exec() to dd (any number of digits)
337             \P         pass the PCRE_PARTIAL_SOFT option to pcre_exec()
338                          or pcre_dfa_exec(); if used twice, pass the
339                          PCRE_PARTIAL_HARD option
340             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
341                          (any number of digits)
342             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
343             \S         output details of memory get/free calls during matching
344             \Y         pass the PCRE_NO_START_OPTIMIZE option to pcre_exec()
345                          or pcre_dfa_exec()
346             \Z         pass the PCRE_NOTEOL option to pcre_exec()
347                          or pcre_dfa_exec()
348             \?         pass the PCRE_NO_UTF8_CHECK option to
349                          pcre_exec() or pcre_dfa_exec()
350             \>dd       start the match at offset dd (any number of digits);
351                          this sets the startoffset argument for pcre_exec()
352                          or pcre_dfa_exec()
353             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
354                          or pcre_dfa_exec()
355             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
356                          or pcre_dfa_exec()
357             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
358                          or pcre_dfa_exec()
359             \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec()
360                          or pcre_dfa_exec()
361             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
362                          or pcre_dfa_exec()
363    
364           The escapes that specify line ending  sequences  are  literal  strings,
365           exactly as shown. No more than one newline setting should be present in
366           any data line.
367    
368           A backslash followed by anything else just escapes the  anything  else.
369           If  the very last character is a backslash, it is ignored. This gives a
370           way of passing an empty line as data, since a real  empty  line  termi-
371           nates the data input.
372    
373           If  \M  is present, pcretest calls pcre_exec() several times, with dif-
374           ferent values in the match_limit and  match_limit_recursion  fields  of
375           the  pcre_extra  data structure, until it finds the minimum numbers for
376           each parameter that allow pcre_exec() to complete. The match_limit num-
377           ber  is  a  measure of the amount of backtracking that takes place, and
378           checking it out can be instructive. For most simple matches, the number
379           is  quite  small,  but for patterns with very large numbers of matching
380           possibilities, it can become large very quickly with increasing  length
381           of subject string. The match_limit_recursion number is a measure of how
382           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
383           memory is needed to complete the match attempt.
384    
385           When  \O  is  used, the value specified may be higher or lower than the
386           size set by the -O command line option (or defaulted to 45); \O applies
387           only to the call of pcre_exec() for the line in which it appears.
388    
389           If  the /P modifier was present on the pattern, causing the POSIX wrap-
390           per API to be used, the only option-setting  sequences  that  have  any
391           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
392           to be passed to regexec().
393    
394           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
395           the  use  of  the  /8 modifier on the pattern. It is recognized always.
396           There may be any number of hexadecimal digits inside  the  braces.  The
397           result  is  from  one  to  six bytes, encoded according to the original
398           UTF-8 rules of RFC 2279. This allows for  values  in  the  range  0  to
399           0x7FFFFFFF.  Note  that not all of those are valid Unicode code points,
400           or indeed valid UTF-8 characters according to the later  rules  in  RFC
401           3629.
402    
403    
404    THE ALTERNATIVE MATCHING FUNCTION
405    
406           By   default,  pcretest  uses  the  standard  PCRE  matching  function,
407           pcre_exec() to match each data line. From release 6.0, PCRE supports an
408           alternative  matching  function,  pcre_dfa_test(),  which operates in a
409           different way, and has some restrictions. The differences  between  the
410           two functions are described in the pcrematching documentation.
411    
412           If  a data line contains the \D escape sequence, or if the command line
413           contains the -dfa option, the alternative matching function is  called.
414           This function finds all possible matches at a given point. If, however,
415           the \F escape sequence is present in the data line, it stops after  the
416           first match is found. This is always the shortest possible match.
417    
418    
419    DEFAULT OUTPUT FROM PCRETEST
420    
421           This  section  describes  the output when the normal matching function,
422           pcre_exec(), is being used.
423    
424           When a match succeeds, pcretest outputs the list of captured substrings
425           that  pcre_exec()  returns,  starting with number 0 for the string that
426           matched the whole pattern. Otherwise, it outputs "No  match"  when  the
427           return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the par-
428           tially matching substring when pcre_exec() returns  PCRE_ERROR_PARTIAL.
429           For  any other returns, it outputs the PCRE negative error number. Here
430           is an example of an interactive pcretest run.
431    
432             $ pcretest
433             PCRE version 7.0 30-Nov-2006
434    
435               re> /^abc(\d+)/
436             data> abc123
437              0: abc123
438              1: 123
439             data> xyz
440             No match
441    
442           Note that unset capturing substrings that are not followed by one  that
443           is  set are not returned by pcre_exec(), and are not shown by pcretest.
444           In the following example, there are two capturing substrings, but  when
445           the  first  data  line  is  matched, the second, unset substring is not
446           shown. An "internal" unset substring is shown as "<unset>", as for  the
447           second data line.
448    
449               re> /(a)|(b)/
450             data> a
451              0: a
452              1: a
453             data> b
454              0: b
455              1: <unset>
456              2: b
457    
458           If  the strings contain any non-printing characters, they are output as
459           \0x escapes, or as \x{...} escapes if the /8 modifier  was  present  on
460           the  pattern.  See below for the definition of non-printing characters.
461           If the pattern has the /+ modifier, the output for substring 0 is  fol-
462           lowed  by  the  the rest of the subject string, identified by "0+" like
463           this:
464    
465               re> /cat/+
466             data> cataract
467              0: cat
468              0+ aract
469    
470           If the pattern has the /g or /G modifier,  the  results  of  successive
471           matching attempts are output in sequence, like this:
472    
473               re> /\Bi(\w\w)/g
474             data> Mississippi
475              0: iss
476              1: ss
477              0: iss
478              1: ss
479              0: ipp
480              1: pp
481    
482           "No match" is output only if the first match attempt fails.
483    
484           If  any  of the sequences \C, \G, or \L are present in a data line that
485           is successfully matched, the substrings extracted  by  the  convenience
486           functions are output with C, G, or L after the string number instead of
487           a colon. This is in addition to the normal full list. The string length
488           (that  is,  the return from the extraction function) is given in paren-
489           theses after each string for \C and \G.
490    
491           Note that whereas patterns can be continued over several lines (a plain
492           ">" prompt is used for continuations), data lines may not. However new-
493           lines can be included in data by means of the \n escape (or  \r,  \r\n,
494           etc., depending on the newline sequence setting).
495    
496    
497    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
498    
499           When  the  alternative  matching function, pcre_dfa_exec(), is used (by
500           means of the \D escape sequence or the -dfa command line  option),  the
501           output  consists  of  a list of all the matches that start at the first
502           point in the subject where there is at least one match. For example:
503    
504               re> /(tang|tangerine|tan)/
505             data> yellow tangerine\D
506              0: tangerine
507              1: tang
508              2: tan
509    
510           (Using the normal matching function on this data  finds  only  "tang".)
511           The  longest matching string is always given first (and numbered zero).
512           After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
513           lowed by the partially matching substring.
514    
515           If /g is present on the pattern, the search for further matches resumes
516           at the end of the longest match. For example:
517    
518               re> /(tang|tangerine|tan)/g
519             data> yellow tangerine and tangy sultana\D
520              0: tangerine
521              1: tang
522              2: tan
523              0: tang
524              1: tan
525              0: tan
526    
527           Since the matching function does not  support  substring  capture,  the
528           escape  sequences  that  are concerned with captured substrings are not
529           relevant.
530    
531    
532    RESTARTING AFTER A PARTIAL MATCH
533    
534           When the alternative matching function has given the PCRE_ERROR_PARTIAL
535           return,  indicating that the subject partially matched the pattern, you
536           can restart the match with additional subject data by means of  the  \R
537           escape sequence. For example:
538    
539               re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
540             data> 23ja\P\D
541             Partial match: 23ja
542             data> n05\R\D
543              0: n05
544    
545           For  further  information  about  partial matching, see the pcrepartial
546           documentation.
547    
548    
549  CALLOUTS  CALLOUTS
550    
551       If the pattern contains  any  callout  requests,  pcretest's         If the pattern contains any callout requests, pcretest's callout  func-
552       callout function will be called. By default, it displays the         tion  is  called  during  matching. This works with both matching func-
553       callout number, and the start and current positions  in  the         tions. By default, the called function displays the callout number, the
554       text at the callout time. For example, the output         start  and  current  positions in the text at the callout time, and the
555           next pattern item to be tested. For example, the output
556         --->pqrabcdef  
557           0    ^  ^           --->pqrabcdef
558               0    ^  ^     \d
559       indicates that callout number 0 occurred for a match attempt  
560       starting at the fourth character of the subject string, when         indicates that callout number 0 occurred for a match  attempt  starting
561       the pointer was at the seventh character. The callout  func-         at  the fourth character of the subject string, when the pointer was at
562       tion returns zero (carry on matching) by default.         the seventh character of the data, and when the next pattern  item  was
563           \d.  Just  one  circumflex is output if the start and current positions
564       Inserting callouts may be helpful  when  using  pcretest  to         are the same.
565       check  complicated regular expressions. For further informa-  
566       tion about callouts, see the pcrecallout documentation.         Callouts numbered 255 are assumed to be automatic callouts, inserted as
567           a  result  of the /C pattern modifier. In this case, instead of showing
568       For testing the PCRE library, additional control of  callout         the callout number, the offset in the pattern, preceded by a  plus,  is
569       behaviour  is available via escape sequences in the data, as         output. For example:
570       described in the following section.  In  particular,  it  is  
571       possible to pass in a number as callout data (the default is             re> /\d?[A-E]\*/C
572       zero). If the callout function receives a  non-zero  number,           data> E*
573       it returns that value instead of zero.           --->E*
574              +0 ^      \d?
575              +3 ^      [A-E]
576              +8 ^^     \*
577             +10 ^ ^
578              0: E*
579    
580           The  callout  function  in pcretest returns zero (carry on matching) by
581           default, but you can use a \C item in a data line (as described  above)
582           to change this.
583    
584           Inserting  callouts can be helpful when using pcretest to check compli-
585           cated regular expressions. For further information about callouts,  see
586           the pcrecallout documentation.
587    
588    
589    NON-PRINTING CHARACTERS
590    
591           When  pcretest is outputting text in the compiled version of a pattern,
592           bytes other than 32-126 are always treated as  non-printing  characters
593           are are therefore shown as hex escapes.
594    
595           When  pcretest  is  outputting text that is a matched part of a subject
596           string, it behaves in the same way, unless a different locale has  been
597           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
598           isprint() function to distinguish printing and non-printing characters.
599    
600    
601    SAVING AND RELOADING COMPILED PATTERNS
602    
603           The facilities described in this section are  not  available  when  the
604           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
605           ifier is specified.
606    
607           When the POSIX interface is not in use, you can cause pcretest to write
608           a  compiled  pattern to a file, by following the modifiers with > and a
609           file name.  For example:
610    
611             /pattern/im >/some/file
612    
613           See the pcreprecompile documentation for a discussion about saving  and
614           re-using compiled patterns.
615    
616           The  data  that  is  written  is  binary. The first eight bytes are the
617           length of the compiled pattern data  followed  by  the  length  of  the
618           optional  study  data,  each  written as four bytes in big-endian order
619           (most significant byte first). If there is no study  data  (either  the
620           pattern was not studied, or studying did not return any data), the sec-
621           ond length is zero. The lengths are followed by an exact  copy  of  the
622           compiled pattern. If there is additional study data, this follows imme-
623           diately after the compiled pattern. After writing  the  file,  pcretest
624           expects to read a new pattern.
625    
626           A saved pattern can be reloaded into pcretest by specifing < and a file
627           name instead of a pattern. The name of the file must not  contain  a  <
628           character,  as  otherwise pcretest will interpret the line as a pattern
629           delimited by < characters.  For example:
630    
631              re> </some/file
632             Compiled regex loaded from /some/file
633             No study data
634    
635           When the pattern has been loaded, pcretest proceeds to read data  lines
636           in the usual way.
637    
638           You  can copy a file written by pcretest to a different host and reload
639           it there, even if the new host has opposite endianness to  the  one  on
640           which  the pattern was compiled. For example, you can compile on an i86
641           machine and run on a SPARC machine.
642    
643           File names for saving and reloading can be absolute  or  relative,  but
644           note  that the shell facility of expanding a file name that starts with
645           a tilde (~) is not available.
646    
647           The ability to save and reload files in pcretest is intended for  test-
648           ing  and experimentation. It is not intended for production use because
649           only a single pattern can be written to a file. Furthermore,  there  is
650           no  facility  for  supplying  custom  character  tables  for use with a
651           reloaded pattern. If the original  pattern  was  compiled  with  custom
652           tables,  an  attempt to match a subject string using a reloaded pattern
653           is likely to cause pcretest to crash.  Finally, if you attempt to  load
654           a file that is not in the correct format, the result is undefined.
655    
656    
657  DATA LINES  SEE ALSO
658    
659       Before each data line is passed to pcre_exec(), leading  and         pcre(3),  pcreapi(3),  pcrecallout(3), pcrematching(3), pcrepartial(d),
660       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.  
661    
662    
663  AUTHOR  AUTHOR
664    
665       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
666       University Computing Service,         University Computing Service
667       Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
668    
669    
670    REVISION
671    
672  Last updated: 20 August 2003         Last updated: 12 May 2010
673  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2010 University of Cambridge.

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