/[pcre]/code/trunk/doc/pcretest.txt
ViewVC logotype

Diff of /code/trunk/doc/pcretest.txt

Parent Directory Parent Directory | Revision Log Revision Log | View Patch Patch

revision 71 by nigel, Sat Feb 24 21:40:24 2007 UTC revision 123 by ph10, Mon Mar 12 15:19:06 2007 UTC
# Line 1  Line 1 
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         -C        Output the version number of the PCRE library, and all avail-
26                 all   available  information  about  the  optional                   able  information  about  the  optional  features  that   are
27                 features that are included, and then exit.                   included, and then exit.
28    
29       -d        Behave as if each regex had the /D  modifier  (see         -d        Behave  as  if  each  regex  has the /D (debug) modifier; the
30                 below); the internal form is output after compila-                   internal form and information about the compiled  pattern  is
31                 tion.                   output after compilation; -d is equivalent to -b -i.
32    
33       -i        Behave as if  each  regex  had  the  /I  modifier;         -dfa      Behave  as if each data line contains the \D escape sequence;
34                 information  about  the  compiled pattern is given                   this    causes    the    alternative    matching    function,
35                 after compilation.                   pcre_dfa_exec(),   to   be   used  instead  of  the  standard
36                     pcre_exec() function (more detail is given below).
37       -m        Output the size of each compiled pattern after  it  
38                 has been compiled. This is equivalent to adding /M         -help     Output a brief summary these options and then exit.
39                 to each regular expression. For compatibility with  
40                 earlier  versions of pcretest, -s is a synonym for         -i        Behave as if each regex  has  the  /I  modifier;  information
41                 -m.                   about the compiled pattern is given after compilation.
42    
43       -o osize  Set the number of elements in  the  output  vector         -m        Output  the  size  of each compiled pattern after it has been
44                 that  is  used  when calling PCRE to be osize. The                   compiled. This is equivalent to adding  /M  to  each  regular
45                 default value is 45, which is enough for  14  cap-                   expression.   For  compatibility  with  earlier  versions  of
46                 turing  subexpressions.  The  vector  size  can be                   pcretest, -s is a synonym for -m.
47                 changed for individual matching calls by including  
48                 \O in the data line (see below).         -o osize  Set the number of elements in the output vector that is  used
49                     when  calling pcre_exec() or pcre_dfa_exec() to be osize. The
50       -p        Behave as if each regex has /P modifier; the POSIX                   default value is 45, which is enough for 14 capturing  subex-
51                 wrapper  API  is  used  to  call PCRE. None of the                   pressions   for  pcre_exec()  or  22  different  matches  for
52                 other options has any effect when -p is set.                   pcre_dfa_exec(). The vector size can be changed for  individ-
53                     ual  matching  calls  by  including  \O in the data line (see
54       -t        Run each compile, study, and match many times with                   below).
55                 a  timer, and output resulting time per compile or  
56                 match (in milliseconds). Do not set  -t  with  -m,         -p        Behave as if each regex has the /P modifier; the POSIX  wrap-
57                 because  you  will  then get the size output 20000                   per  API  is used to call PCRE. None of the other options has
58                 times and the timing will be distorted.                   any effect when -p is set.
59    
60           -q        Do not output the version number of pcretest at the start  of
61                     execution.
62    
63           -S size   On  Unix-like  systems,  set the size of the runtime stack to
64                     size megabytes.
65    
66           -t        Run each compile, study, and match many times with  a  timer,
67                     and  output resulting time per compile or match (in millisec-
68                     onds). Do not set -m with -t, because you will then  get  the
69                     size  output  a  zillion  times,  and the timing will be dis-
70                     torted. You can control the number  of  iterations  that  are
71                     used  for timing by following -t with a number (as a separate
72                     item on the command line). For example, "-t 1000" would iter-
73                     ate 1000 times. The default is to iterate 500000 times.
74    
75           -tm       This is like -t except that it times only the matching phase,
76                     not the compile or study phases.
77    
78    
79  DESCRIPTION  DESCRIPTION
80    
81       If pcretest is given two filename arguments, it  reads  from         If pcretest is given two filename arguments, it reads  from  the  first
82       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
83       filename argument, it reads from that  file  and  writes  to         reads from that file and writes to stdout.  Otherwise,  it  reads  from
84       stdout. Otherwise, it reads from stdin and writes to stdout,         stdin  and  writes to stdout, and prompts for each line of input, using
85       and prompts for each line of input, using  "re>"  to  prompt         "re>" to prompt for regular expressions, and "data>" to prompt for data
86       for  regular  expressions,  and  "data>"  to prompt for data         lines.
87       lines.  
88           The program handles any number of sets of input on a single input file.
89       The program handles any number of sets of input on a  single         Each set starts with a regular expression, and continues with any  num-
90       input  file.  Each set starts with a regular expression, and         ber of data lines to be matched against the pattern.
91       continues with any  number  of  data  lines  to  be  matched  
92       against the pattern.         Each  data line is matched separately and independently. If you want to
93           do multi-line matches, you have to use the \n escape sequence (or \r or
94       Each line is matched separately and  independently.  If  you         \r\n, etc., depending on the newline setting) in a single line of input
95       want  to  do  multiple-line  matches, you have to use the \n         to encode the newline sequences. There is no limit  on  the  length  of
96       escape sequence in a single line of input to encode the new-         data  lines;  the  input  buffer is automatically extended if it is too
97       line  characters.  The maximum length of data line is 30,000         small.
98       characters.  
99           An empty line signals the end of the data lines, at which point  a  new
100       An empty line signals the end of the data  lines,  at  which         regular  expression is read. The regular expressions are given enclosed
101       point  a new regular expression is read. The regular expres-         in any non-alphanumeric delimiters other than backslash, for example:
102       sions are given enclosed in  any  non-alphameric  delimiters  
103       other than backslash, for example           /(a|bc)x+yz/
104    
105         /(a|bc)x+yz/         White space before the initial delimiter is ignored. A regular  expres-
106           sion  may be continued over several input lines, in which case the new-
107       White space before the initial delimiter is ignored. A regu-         line characters are included within it. It is possible to  include  the
108       lar expression may be continued over several input lines, in         delimiter within the pattern by escaping it, for example
109       which case the newline characters are included within it. It  
110       is  possible  to include the delimiter within the pattern by           /abc\/def/
111       escaping it, for example  
112           If  you  do  so, the escape and the delimiter form part of the pattern,
113         /abc\/def/         but since delimiters are always non-alphanumeric, this does not  affect
114           its  interpretation.   If the terminating delimiter is immediately fol-
115       If you do so, the escape and the delimiter form part of  the         lowed by a backslash, for example,
116       pattern,  but  since  delimiters  are always non-alphameric,  
117       this does not affect its interpretation.  If the terminating           /abc/\
118       delimiter  is immediately followed by a backslash, for exam-  
119       ple,         then a backslash is added to the end of the pattern. This  is  done  to
120           provide  a  way of testing the error condition that arises if a pattern
121         /abc/\         finishes with a backslash, because
122    
123       then a backslash is added to the end of the pattern. This is           /abc\/
124       done  to  provide  a way of testing the error condition that  
125       arises if a pattern finishes with a backslash, because         is interpreted as the first line of a pattern that starts with  "abc/",
126           causing pcretest to read the next line as a continuation of the regular
127         /abc\/         expression.
   
      is interpreted as the first line of a  pattern  that  starts  
      with  "abc/",  causing  pcretest  to read the next line as a  
      continuation of the regular expression.  
128    
129    
130  PATTERN MODIFIERS  PATTERN MODIFIERS
131    
132       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
133       PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED         single  characters.  Following  Perl usage, these are referred to below
134       options, respectively. For example:         as, for example, "the /i modifier", even though the  delimiter  of  the
135           pattern  need  not always be a slash, and no slash is used when writing
136         /caseless/i         modifiers. Whitespace may appear between the  final  pattern  delimiter
137           and the first modifier, and between the modifiers themselves.
138       These modifier letters have the same effect as  they  do  in  
139       Perl.  There  are  others  that set PCRE options that do not         The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
140       correspond to anything in Perl:  /A, /E, /N, /U, and /X  set         PCRE_DOTALL, or PCRE_EXTENDED  options,  respectively,  when  pcre_com-
141       PCRE_ANCHORED,   PCRE_DOLLAR_ENDONLY,  PCRE_NO_AUTO_CAPTURE,         pile()  is  called. These four modifier letters have the same effect as
142       PCRE_UNGREEDY, and PCRE_EXTRA respectively.         they do in Perl. For example:
143    
144       Searching for  all  possible  matches  within  each  subject           /caseless/i
145       string  can  be  requested  by  the /g or /G modifier. After  
146       finding  a  match,  PCRE  is  called  again  to  search  the         The following table shows additional modifiers for setting PCRE options
147       remainder  of  the subject string. The difference between /g         that do not correspond to anything in Perl:
148       and /G is that the former uses the startoffset  argument  to  
149       pcre_exec()  to  start  searching  at a new point within the           /A       PCRE_ANCHORED
150       entire string (which is in effect what Perl  does),  whereas           /C       PCRE_AUTO_CALLOUT
151       the  latter  passes over a shortened substring. This makes a           /E       PCRE_DOLLAR_ENDONLY
152       difference to the matching process  if  the  pattern  begins           /f       PCRE_FIRSTLINE
153       with a lookbehind assertion (including \b or \B).           /J       PCRE_DUPNAMES
154             /N       PCRE_NO_AUTO_CAPTURE
155       If any call to pcre_exec() in a /g or /G sequence matches an           /U       PCRE_UNGREEDY
156       empty  string,  the next call is done with the PCRE_NOTEMPTY           /X       PCRE_EXTRA
157       and PCRE_ANCHORED flags set in order to search for  another,           /<cr>    PCRE_NEWLINE_CR
158       non-empty,  match  at  the same point.  If this second match           /<lf>    PCRE_NEWLINE_LF
159       fails, the start offset is advanced by one, and  the  normal           /<crlf>  PCRE_NEWLINE_CRLF
160       match  is  retried.  This imitates the way Perl handles such           /<any>   PCRE_NEWLINE_ANY
161       cases when using the /g modifier or the split() function.  
162           Those  specifying  line ending sequencess are literal strings as shown.
163       There are a number of other modifiers  for  controlling  the         This example sets multiline matching  with  CRLF  as  the  line  ending
164       way pcretest operates.         sequence:
165    
166       The /+ modifier requests that as well as outputting the sub-           /^abc/m<crlf>
167       string  that  matched the entire pattern, pcretest should in  
168       addition output the remainder of the subject string. This is         Details  of the meanings of these PCRE options are given in the pcreapi
169       useful  for tests where the subject contains multiple copies         documentation.
170       of the same substring.  
171       Finding all matches in a string
172       The /L modifier must be followed directly by the name  of  a  
173       locale, for example,         Searching for all possible matches within each subject  string  can  be
174           requested  by  the  /g  or  /G modifier. After finding a match, PCRE is
175         /pattern/Lfr         called again to search the remainder of the subject string. The differ-
176           ence between /g and /G is that the former uses the startoffset argument
177       For this reason, it must be the last  modifier  letter.  The         to pcre_exec() to start searching at a  new  point  within  the  entire
178       given  locale is set, pcre_maketables() is called to build a         string  (which  is in effect what Perl does), whereas the latter passes
179       set of character tables for the locale,  and  this  is  then         over a shortened substring. This makes a  difference  to  the  matching
180       passed  to pcre_compile() when compiling the regular expres-         process if the pattern begins with a lookbehind assertion (including \b
181       sion. Without an /L modifier, NULL is passed as  the  tables         or \B).
182       pointer; that is, /L applies only to the expression on which  
183       it appears.         If any call to pcre_exec() in a /g or  /G  sequence  matches  an  empty
184           string,  the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
185       The /I modifier requests that  pcretest  output  information         flags set in order to search for another, non-empty, match at the  same
186       about the compiled expression (whether it is anchored, has a         point.   If  this  second  match fails, the start offset is advanced by
187       fixed first character, and so on). It does this  by  calling         one, and the normal match is retried. This imitates the way  Perl  han-
188       pcre_fullinfo()  after  compiling an expression, and output-         dles such cases when using the /g modifier or the split() function.
189       ting the information it gets back. If the  pattern  is  stu-  
190       died, the results of that are also output.     Other modifiers
191    
192       The /D modifier is a  PCRE  debugging  feature,  which  also         There are yet more modifiers for controlling the way pcretest operates.
193       assumes /I.  It causes the internal form of compiled regular  
194       expressions to be output after compilation. If  the  pattern         The /+ modifier requests that as well as outputting the substring  that
195       was studied, the information returned is also output.         matched  the  entire  pattern,  pcretest  should in addition output the
196           remainder of the subject string. This is useful  for  tests  where  the
197       The /S modifier causes pcre_study() to be called  after  the         subject contains multiple copies of the same substring.
198       expression  has been compiled, and the results used when the  
199       expression is matched.         The  /B modifier is a debugging feature. It requests that pcretest out-
200           put a representation of the compiled byte code after compilation.  Nor-
201       The /M modifier causes the size of memory block used to hold         mally  this  information contains length and offset values; however, if
202       the compiled pattern to be output.         /Z is also present, this data is replaced by spaces. This is a  special
203           feature for use in the automatic test scripts; it ensures that the same
204       The /P modifier causes pcretest to call PCRE via  the  POSIX         output is generated for different internal link sizes.
205       wrapper  API  rather than its native API. When this is done,  
206       all other modifiers except  /i,  /m,  and  /+  are  ignored.         The /L modifier must be followed directly by the name of a locale,  for
207       REG_ICASE is set if /i is present, and REG_NEWLINE is set if         example,
208       /m    is    present.    The    wrapper    functions    force  
209       PCRE_DOLLAR_ENDONLY    always,    and   PCRE_DOTALL   unless           /pattern/Lfr_FR
210       REG_NEWLINE is set.  
211           For this reason, it must be the last modifier. The given locale is set,
212       The /8 modifier  causes  pcretest  to  call  PCRE  with  the         pcre_maketables() is called to build a set of character tables for  the
213       PCRE_UTF8  option set. This turns on support for UTF-8 char-         locale,  and  this  is then passed to pcre_compile() when compiling the
214       acter handling in PCRE, provided that it was  compiled  with         regular expression. Without an /L  modifier,  NULL  is  passed  as  the
215       this  support  enabled.  This  modifier also causes any non-         tables  pointer; that is, /L applies only to the expression on which it
216       printing characters in output strings to  be  printed  using         appears.
217       the \x{hh...} notation if they are valid UTF-8 sequences.  
218           The /I modifier requests that pcretest  output  information  about  the
219       If the /? modifier is used with /8, it  causes  pcretest  to         compiled  pattern (whether it is anchored, has a fixed first character,
220       call  pcre_compile()  with the PCRE_NO_UTF8_CHECK option, to         and so on). It does this by calling pcre_fullinfo() after  compiling  a
221       suppress the checking of the string for UTF-8 validity.         pattern.  If  the pattern is studied, the results of that are also out-
222           put.
223    
224           The /D modifier is a PCRE debugging feature, and is equivalent to  /BI,
225           that is, both the /B and the /I modifiers.
226    
227           The /F modifier causes pcretest to flip the byte order of the fields in
228           the compiled pattern that  contain  2-byte  and  4-byte  numbers.  This
229           facility  is  for testing the feature in PCRE that allows it to execute
230           patterns that were compiled on a host with a different endianness. This
231           feature  is  not  available  when  the POSIX interface to PCRE is being
232           used, that is, when the /P pattern modifier is specified. See also  the
233           section about saving and reloading compiled patterns below.
234    
235           The  /S  modifier causes pcre_study() to be called after the expression
236           has been compiled, and the results used when the expression is matched.
237    
238           The  /M  modifier causes the size of memory block used to hold the com-
239           piled pattern to be output.
240    
241           The /P modifier causes pcretest to call PCRE via the POSIX wrapper  API
242           rather  than  its  native  API.  When this is done, all other modifiers
243           except /i, /m, and /+ are ignored. REG_ICASE is set if /i  is  present,
244           and  REG_NEWLINE  is  set if /m is present. The wrapper functions force
245           PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is  set.
246    
247           The  /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option
248           set. This turns on support for UTF-8 character handling in  PCRE,  pro-
249           vided  that  it  was  compiled with this support enabled. This modifier
250           also causes any non-printing characters in output strings to be printed
251           using the \x{hh...} notation if they are valid UTF-8 sequences.
252    
253           If  the  /?  modifier  is  used  with  /8,  it  causes pcretest to call
254           pcre_compile() with the  PCRE_NO_UTF8_CHECK  option,  to  suppress  the
255           checking of the string for UTF-8 validity.
256    
257    
258    DATA LINES
259    
260           Before  each  data  line is passed to pcre_exec(), leading and trailing
261           whitespace is removed, and it is then scanned for \  escapes.  Some  of
262           these  are  pretty esoteric features, intended for checking out some of
263           the more complicated features of PCRE. If you are just  testing  "ordi-
264           nary"  regular  expressions,  you probably don't need any of these. The
265           following escapes are recognized:
266    
267             \a         alarm (BEL, \x07)
268             \b         backspace (\x08)
269             \e         escape (\x27)
270             \f         formfeed (\x0c)
271             \n         newline (\x0a)
272             \qdd       set the PCRE_MATCH_LIMIT limit to dd
273                          (any number of digits)
274             \r         carriage return (\x0d)
275             \t         tab (\x09)
276             \v         vertical tab (\x0b)
277             \nnn       octal character (up to 3 octal digits)
278             \xhh       hexadecimal character (up to 2 hex digits)
279             \x{hh...}  hexadecimal character, any number of digits
280                          in UTF-8 mode
281             \A         pass the PCRE_ANCHORED option to pcre_exec()
282                          or pcre_dfa_exec()
283             \B         pass the PCRE_NOTBOL option to pcre_exec()
284                          or pcre_dfa_exec()
285             \Cdd       call pcre_copy_substring() for substring dd
286                          after a successful match (number less than 32)
287             \Cname     call pcre_copy_named_substring() for substring
288                          "name" after a successful match (name termin-
289                          ated by next non alphanumeric character)
290             \C+        show the current captured substrings at callout
291                          time
292             \C-        do not supply a callout function
293             \C!n       return 1 instead of 0 when callout number n is
294                          reached
295             \C!n!m     return 1 instead of 0 when callout number n is
296                          reached for the nth time
297             \C*n       pass the number n (may be negative) as callout
298                          data; this is used as the callout return value
299             \D         use the pcre_dfa_exec() match function
300             \F         only shortest match for pcre_dfa_exec()
301             \Gdd       call pcre_get_substring() for substring dd
302                          after a successful match (number less than 32)
303             \Gname     call pcre_get_named_substring() for substring
304                          "name" after a successful match (name termin-
305                          ated by next non-alphanumeric character)
306             \L         call pcre_get_substringlist() after a
307                          successful match
308             \M         discover the minimum MATCH_LIMIT and
309                          MATCH_LIMIT_RECURSION settings
310             \N         pass the PCRE_NOTEMPTY option to pcre_exec()
311                          or pcre_dfa_exec()
312             \Odd       set the size of the output vector passed to
313                          pcre_exec() to dd (any number of digits)
314             \P         pass the PCRE_PARTIAL option to pcre_exec()
315                          or pcre_dfa_exec()
316             \Qdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd
317                          (any number of digits)
318             \R         pass the PCRE_DFA_RESTART option to pcre_dfa_exec()
319             \S         output details of memory get/free calls during matching
320             \Z         pass the PCRE_NOTEOL option to pcre_exec()
321                          or pcre_dfa_exec()
322             \?         pass the PCRE_NO_UTF8_CHECK option to
323                          pcre_exec() or pcre_dfa_exec()
324             \>dd       start the match at offset dd (any number of digits);
325                          this sets the startoffset argument for pcre_exec()
326                          or pcre_dfa_exec()
327             \<cr>      pass the PCRE_NEWLINE_CR option to pcre_exec()
328                          or pcre_dfa_exec()
329             \<lf>      pass the PCRE_NEWLINE_LF option to pcre_exec()
330                          or pcre_dfa_exec()
331             \<crlf>    pass the PCRE_NEWLINE_CRLF option to pcre_exec()
332                          or pcre_dfa_exec()
333             \<any>     pass the PCRE_NEWLINE_ANY option to pcre_exec()
334                          or pcre_dfa_exec()
335    
336           The escapes that specify line ending  sequences  are  literal  strings,
337           exactly as shown. No more than one newline setting should be present in
338           any data line.
339    
340           A backslash followed by anything else just escapes the  anything  else.
341           If  the very last character is a backslash, it is ignored. This gives a
342           way of passing an empty line as data, since a real  empty  line  termi-
343           nates the data input.
344    
345           If  \M  is present, pcretest calls pcre_exec() several times, with dif-
346           ferent values in the match_limit and  match_limit_recursion  fields  of
347           the  pcre_extra  data structure, until it finds the minimum numbers for
348           each parameter that allow pcre_exec() to complete. The match_limit num-
349           ber  is  a  measure of the amount of backtracking that takes place, and
350           checking it out can be instructive. For most simple matches, the number
351           is  quite  small,  but for patterns with very large numbers of matching
352           possibilities, it can become large very quickly with increasing  length
353           of subject string. The match_limit_recursion number is a measure of how
354           much stack (or, if PCRE is compiled with  NO_RECURSE,  how  much  heap)
355           memory is needed to complete the match attempt.
356    
357           When  \O  is  used, the value specified may be higher or lower than the
358           size set by the -O command line option (or defaulted to 45); \O applies
359           only to the call of pcre_exec() for the line in which it appears.
360    
361           If  the /P modifier was present on the pattern, causing the POSIX wrap-
362           per API to be used, the only option-setting  sequences  that  have  any
363           effect  are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively,
364           to be passed to regexec().
365    
366           The use of \x{hh...} to represent UTF-8 characters is not dependent  on
367           the  use  of  the  /8 modifier on the pattern. It is recognized always.
368           There may be any number of hexadecimal digits inside  the  braces.  The
369           result  is from one to six bytes, encoded according to the UTF-8 rules.
370    
371    
372    THE ALTERNATIVE MATCHING FUNCTION
373    
374           By  default,  pcretest  uses  the  standard  PCRE  matching   function,
375           pcre_exec() to match each data line. From release 6.0, PCRE supports an
376           alternative matching function, pcre_dfa_test(),  which  operates  in  a
377           different  way,  and has some restrictions. The differences between the
378           two functions are described in the pcrematching documentation.
379    
380           If a data line contains the \D escape sequence, or if the command  line
381           contains  the -dfa option, the alternative matching function is called.
382           This function finds all possible matches at a given point. If, however,
383           the  \F escape sequence is present in the data line, it stops after the
384           first match is found. This is always the shortest possible match.
385    
386    
387    DEFAULT OUTPUT FROM PCRETEST
388    
389           This section describes the output when the  normal  matching  function,
390           pcre_exec(), is being used.
391    
392           When a match succeeds, pcretest outputs the list of captured substrings
393           that pcre_exec() returns, starting with number 0 for  the  string  that
394           matched the whole pattern. Otherwise, it outputs "No match" or "Partial
395           match" when pcre_exec() returns PCRE_ERROR_NOMATCH  or  PCRE_ERROR_PAR-
396           TIAL,  respectively, and otherwise the PCRE negative error number. Here
397           is an example of an interactive pcretest run.
398    
399             $ pcretest
400             PCRE version 7.0 30-Nov-2006
401    
402               re> /^abc(\d+)/
403             data> abc123
404              0: abc123
405              1: 123
406             data> xyz
407             No match
408    
409           If the strings contain any non-printing characters, they are output  as
410           \0x  escapes,  or  as \x{...} escapes if the /8 modifier was present on
411           the pattern. See below for the definition of  non-printing  characters.
412           If  the pattern has the /+ modifier, the output for substring 0 is fol-
413           lowed by the the rest of the subject string, identified  by  "0+"  like
414           this:
415    
416               re> /cat/+
417             data> cataract
418              0: cat
419              0+ aract
420    
421           If  the  pattern  has  the /g or /G modifier, the results of successive
422           matching attempts are output in sequence, like this:
423    
424               re> /\Bi(\w\w)/g
425             data> Mississippi
426              0: iss
427              1: ss
428              0: iss
429              1: ss
430              0: ipp
431              1: pp
432    
433           "No match" is output only if the first match attempt fails.
434    
435           If any of the sequences \C, \G, or \L are present in a data  line  that
436           is  successfully  matched,  the substrings extracted by the convenience
437           functions are output with C, G, or L after the string number instead of
438           a colon. This is in addition to the normal full list. The string length
439           (that is, the return from the extraction function) is given  in  paren-
440           theses after each string for \C and \G.
441    
442           Note that whereas patterns can be continued over several lines (a plain
443           ">" prompt is used for continuations), data lines may not. However new-
444           lines  can  be included in data by means of the \n escape (or \r, \r\n,
445           etc., depending on the newline sequence setting).
446    
447    
448    OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
449    
450           When the alternative matching function, pcre_dfa_exec(),  is  used  (by
451           means  of  the \D escape sequence or the -dfa command line option), the
452           output consists of a list of all the matches that start  at  the  first
453           point in the subject where there is at least one match. For example:
454    
455               re> /(tang|tangerine|tan)/
456             data> yellow tangerine\D
457              0: tangerine
458              1: tang
459              2: tan
460    
461           (Using  the  normal  matching function on this data finds only "tang".)
462           The longest matching string is always given first (and numbered  zero).
463    
464           If /g is present on the pattern, the search for further matches resumes
465           at the end of the longest match. For example:
466    
467               re> /(tang|tangerine|tan)/g
468             data> yellow tangerine and tangy sultana\D
469              0: tangerine
470              1: tang
471              2: tan
472              0: tang
473              1: tan
474              0: tan
475    
476           Since the matching function does not  support  substring  capture,  the
477           escape  sequences  that  are concerned with captured substrings are not
478           relevant.
479    
480    
481    RESTARTING AFTER A PARTIAL MATCH
482    
483           When the alternative matching function has given the PCRE_ERROR_PARTIAL
484           return,  indicating that the subject partially matched the pattern, you
485           can restart the match with additional subject data by means of  the  \R
486           escape sequence. For example:
487    
488               re> /^?(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)$/
489             data> 23ja\P\D
490             Partial match: 23ja
491             data> n05\R\D
492              0: n05
493    
494           For  further  information  about  partial matching, see the pcrepartial
495           documentation.
496    
497    
498  CALLOUTS  CALLOUTS
499    
500       If the pattern contains  any  callout  requests,  pcretest's         If the pattern contains any callout requests, pcretest's callout  func-
501       callout function will be called. By default, it displays the         tion  is  called  during  matching. This works with both matching func-
502       callout number, and the start and current positions  in  the         tions. By default, the called function displays the callout number, the
503       text at the callout time. For example, the output         start  and  current  positions in the text at the callout time, and the
504           next pattern item to be tested. For example, the output
505         --->pqrabcdef  
506           0    ^  ^           --->pqrabcdef
507               0    ^  ^     \d
508       indicates that callout number 0 occurred for a match attempt  
509       starting at the fourth character of the subject string, when         indicates that callout number 0 occurred for a match  attempt  starting
510       the pointer was at the seventh character. The callout  func-         at  the fourth character of the subject string, when the pointer was at
511       tion returns zero (carry on matching) by default.         the seventh character of the data, and when the next pattern  item  was
512           \d.  Just  one  circumflex is output if the start and current positions
513       Inserting callouts may be helpful  when  using  pcretest  to         are the same.
514       check  complicated regular expressions. For further informa-  
515       tion about callouts, see the pcrecallout documentation.         Callouts numbered 255 are assumed to be automatic callouts, inserted as
516           a  result  of the /C pattern modifier. In this case, instead of showing
517       For testing the PCRE library, additional control of  callout         the callout number, the offset in the pattern, preceded by a  plus,  is
518       behaviour  is available via escape sequences in the data, as         output. For example:
519       described in the following section.  In  particular,  it  is  
520       possible to pass in a number as callout data (the default is             re> /\d?[A-E]\*/C
521       zero). If the callout function receives a  non-zero  number,           data> E*
522       it returns that value instead of zero.           --->E*
523              +0 ^      \d?
524              +3 ^      [A-E]
525              +8 ^^     \*
526             +10 ^ ^
527              0: E*
528    
529           The  callout  function  in pcretest returns zero (carry on matching) by
530           default, but you can use a \C item in a data line (as described  above)
531           to change this.
532    
533           Inserting  callouts can be helpful when using pcretest to check compli-
534           cated regular expressions. For further information about callouts,  see
535           the pcrecallout documentation.
536    
537    
538    NON-PRINTING CHARACTERS
539    
540           When  pcretest is outputting text in the compiled version of a pattern,
541           bytes other than 32-126 are always treated as  non-printing  characters
542           are are therefore shown as hex escapes.
543    
544           When  pcretest  is  outputting text that is a matched part of a subject
545           string, it behaves in the same way, unless a different locale has  been
546           set  for  the  pattern  (using  the  /L  modifier).  In  this case, the
547           isprint() function to distinguish printing and non-printing characters.
548    
549    
550    SAVING AND RELOADING COMPILED PATTERNS
551    
552           The  facilities  described  in  this section are not available when the
553           POSIX inteface to PCRE is being used, that is, when the /P pattern mod-
554           ifier is specified.
555    
556           When the POSIX interface is not in use, you can cause pcretest to write
557           a compiled pattern to a file, by following the modifiers with >  and  a
558           file name.  For example:
559    
560             /pattern/im >/some/file
561    
562           See  the pcreprecompile documentation for a discussion about saving and
563           re-using compiled patterns.
564    
565           The data that is written is binary.  The  first  eight  bytes  are  the
566           length  of  the  compiled  pattern  data  followed by the length of the
567           optional study data, each written as four  bytes  in  big-endian  order
568           (most  significant  byte  first). If there is no study data (either the
569           pattern was not studied, or studying did not return any data), the sec-
570           ond  length  is  zero. The lengths are followed by an exact copy of the
571           compiled pattern. If there is additional study data, this follows imme-
572           diately  after  the  compiled pattern. After writing the file, pcretest
573           expects to read a new pattern.
574    
575           A saved pattern can be reloaded into pcretest by specifing < and a file
576           name  instead  of  a pattern. The name of the file must not contain a <
577           character, as otherwise pcretest will interpret the line as  a  pattern
578           delimited by < characters.  For example:
579    
580              re> </some/file
581             Compiled regex loaded from /some/file
582             No study data
583    
584           When  the pattern has been loaded, pcretest proceeds to read data lines
585           in the usual way.
586    
587           You can copy a file written by pcretest to a different host and  reload
588           it  there,  even  if the new host has opposite endianness to the one on
589           which the pattern was compiled. For example, you can compile on an  i86
590           machine and run on a SPARC machine.
591    
592           File  names  for  saving and reloading can be absolute or relative, but
593           note that the shell facility of expanding a file name that starts  with
594           a tilde (~) is not available.
595    
596           The  ability to save and reload files in pcretest is intended for test-
597           ing and experimentation. It is not intended for production use  because
598           only  a  single pattern can be written to a file. Furthermore, there is
599           no facility for supplying  custom  character  tables  for  use  with  a
600           reloaded  pattern.  If  the  original  pattern was compiled with custom
601           tables, an attempt to match a subject string using a  reloaded  pattern
602           is  likely to cause pcretest to crash.  Finally, if you attempt to load
603           a file that is not in the correct format, the result is undefined.
604    
605    
606  DATA LINES  SEE ALSO
607    
608       Before each data line is passed to pcre_exec(), leading  and         pcre(3), pcreapi(3), pcrecallout(3),  pcrematching(3),  pcrepartial(d),
609       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.  
610    
611    
612  AUTHOR  AUTHOR
613    
614       Philip Hazel <ph10@cam.ac.uk>         Philip Hazel
615       University Computing Service,         University Computing Service
616       Cambridge CB2 3QG, England.         Cambridge CB2 3QH, England.
617    
618    
619    REVISION
620    
621  Last updated: 20 August 2003         Last updated: 06 March 2007
622  Copyright (c) 1997-2003 University of Cambridge.         Copyright (c) 1997-2007 University of Cambridge.

Legend:
Removed from v.71  
changed lines
  Added in v.123

  ViewVC Help
Powered by ViewVC 1.1.5