/[pcre]/code/trunk/doc/pcretest.1
ViewVC logotype

Contents of /code/trunk/doc/pcretest.1

Parent Directory Parent Directory | Revision Log Revision Log


Revision 227 - (hide annotations) (download)
Tue Aug 21 15:00:15 2007 UTC (7 years, 1 month ago) by ph10
File size: 27345 byte(s)
Add (*CR) etc.

1 nigel 53 .TH PCRETEST 1
2     .SH NAME
3     pcretest - a program for testing Perl-compatible regular expressions.
4     .SH SYNOPSIS
5 nigel 75 .rs
6     .sp
7 nigel 91 .B pcretest "[options] [source] [destination]"
8     .sp
9 nigel 75 \fBpcretest\fP was written as a test program for the PCRE regular expression
10 nigel 53 library itself, but it can also be used for experimenting with regular
11 nigel 63 expressions. This document describes the features of the test program; for
12     details of the regular expressions themselves, see the
13     .\" HREF
14 nigel 75 \fBpcrepattern\fP
15 nigel 63 .\"
16 nigel 75 documentation. For details of the PCRE library function calls and their
17     options, see the
18 nigel 63 .\" HREF
19 nigel 75 \fBpcreapi\fP
20 nigel 63 .\"
21     documentation.
22 nigel 75 .
23     .
24 nigel 53 .SH OPTIONS
25 nigel 63 .rs
26 nigel 53 .TP 10
27 nigel 93 \fB-b\fP
28     Behave as if each regex has the \fB/B\fP (show bytecode) modifier; the internal
29     form is output after compilation.
30     .TP 10
31 nigel 75 \fB-C\fP
32 nigel 63 Output the version number of the PCRE library, and all available information
33     about the optional features that are included, and then exit.
34     .TP 10
35 nigel 75 \fB-d\fP
36 nigel 77 Behave as if each regex has the \fB/D\fP (debug) modifier; the internal
37 nigel 93 form and information about the compiled pattern is output after compilation;
38     \fB-d\fP is equivalent to \fB-b -i\fP.
39 nigel 53 .TP 10
40 nigel 77 \fB-dfa\fP
41     Behave as if each data line contains the \eD escape sequence; this causes the
42     alternative matching function, \fBpcre_dfa_exec()\fP, to be used instead of the
43     standard \fBpcre_exec()\fP function (more detail is given below).
44     .TP 10
45 nigel 93 \fB-help\fP
46     Output a brief summary these options and then exit.
47     .TP 10
48 nigel 75 \fB-i\fP
49 nigel 77 Behave as if each regex has the \fB/I\fP modifier; information about the
50 nigel 53 compiled pattern is given after compilation.
51     .TP 10
52 nigel 75 \fB-m\fP
53 nigel 53 Output the size of each compiled pattern after it has been compiled. This is
54 nigel 75 equivalent to adding \fB/M\fP to each regular expression. For compatibility
55     with earlier versions of pcretest, \fB-s\fP is a synonym for \fB-m\fP.
56 nigel 53 .TP 10
57 nigel 75 \fB-o\fP \fIosize\fP
58     Set the number of elements in the output vector that is used when calling
59 nigel 93 \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP to be \fIosize\fP. The default value
60     is 45, which is enough for 14 capturing subexpressions for \fBpcre_exec()\fP or
61     22 different matches for \fBpcre_dfa_exec()\fP. The vector size can be
62     changed for individual matching calls by including \eO in the data line (see
63     below).
64 nigel 53 .TP 10
65 nigel 75 \fB-p\fP
66 nigel 77 Behave as if each regex has the \fB/P\fP modifier; the POSIX wrapper API is
67     used to call PCRE. None of the other options has any effect when \fB-p\fP is
68     set.
69 nigel 53 .TP 10
70 nigel 91 \fB-q\fP
71 nigel 87 Do not output the version number of \fBpcretest\fP at the start of execution.
72     .TP 10
73 nigel 91 \fB-S\fP \fIsize\fP
74     On Unix-like systems, set the size of the runtime stack to \fIsize\fP
75     megabytes.
76     .TP 10
77 nigel 75 \fB-t\fP
78 nigel 63 Run each compile, study, and match many times with a timer, and output
79 nigel 75 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
80     \fB-t\fP, because you will then get the size output a zillion times, and the
81 nigel 93 timing will be distorted. You can control the number of iterations that are
82     used for timing by following \fB-t\fP with a number (as a separate item on the
83     command line). For example, "-t 1000" would iterate 1000 times. The default is
84     to iterate 500000 times.
85     .TP 10
86     \fB-tm\fP
87     This is like \fB-t\fP except that it times only the matching phase, not the
88     compile or study phases.
89 nigel 75 .
90     .
91 nigel 53 .SH DESCRIPTION
92 nigel 63 .rs
93     .sp
94 nigel 75 If \fBpcretest\fP is given two filename arguments, it reads from the first and
95 nigel 53 writes to the second. If it is given only one filename argument, it reads from
96     that file and writes to stdout. Otherwise, it reads from stdin and writes to
97     stdout, and prompts for each line of input, using "re>" to prompt for regular
98     expressions, and "data>" to prompt for data lines.
99 nigel 75 .P
100 nigel 53 The program handles any number of sets of input on a single input file. Each
101     set starts with a regular expression, and continues with any number of data
102 nigel 63 lines to be matched against the pattern.
103 nigel 75 .P
104     Each data line is matched separately and independently. If you want to do
105 nigel 91 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
106 nigel 93 etc., depending on the newline setting) in a single line of input to encode the
107     newline sequences. There is no limit on the length of data lines; the input
108 nigel 91 buffer is automatically extended if it is too small.
109 nigel 75 .P
110 nigel 63 An empty line signals the end of the data lines, at which point a new regular
111     expression is read. The regular expressions are given enclosed in any
112 nigel 91 non-alphanumeric delimiters other than backslash, for example:
113 nigel 75 .sp
114 nigel 53 /(a|bc)x+yz/
115 nigel 75 .sp
116 nigel 53 White space before the initial delimiter is ignored. A regular expression may
117     be continued over several input lines, in which case the newline characters are
118     included within it. It is possible to include the delimiter within the pattern
119     by escaping it, for example
120 nigel 75 .sp
121     /abc\e/def/
122     .sp
123 nigel 53 If you do so, the escape and the delimiter form part of the pattern, but since
124 nigel 75 delimiters are always non-alphanumeric, this does not affect its interpretation.
125 nigel 53 If the terminating delimiter is immediately followed by a backslash, for
126     example,
127 nigel 75 .sp
128     /abc/\e
129     .sp
130 nigel 53 then a backslash is added to the end of the pattern. This is done to provide a
131     way of testing the error condition that arises if a pattern finishes with a
132     backslash, because
133 nigel 75 .sp
134     /abc\e/
135     .sp
136 nigel 53 is interpreted as the first line of a pattern that starts with "abc/", causing
137     pcretest to read the next line as a continuation of the regular expression.
138 nigel 75 .
139     .
140     .SH "PATTERN MODIFIERS"
141 nigel 63 .rs
142     .sp
143 nigel 75 A pattern may be followed by any number of modifiers, which are mostly single
144     characters. Following Perl usage, these are referred to below as, for example,
145     "the \fB/i\fP modifier", even though the delimiter of the pattern need not
146     always be a slash, and no slash is used when writing modifiers. Whitespace may
147     appear between the final pattern delimiter and the first modifier, and between
148     the modifiers themselves.
149     .P
150     The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
151     PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
152     \fBpcre_compile()\fP is called. These four modifier letters have the same
153     effect as they do in Perl. For example:
154     .sp
155 nigel 53 /caseless/i
156 nigel 75 .sp
157     The following table shows additional modifiers for setting PCRE options that do
158     not correspond to anything in Perl:
159     .sp
160 ph10 149 \fB/A\fP PCRE_ANCHORED
161     \fB/C\fP PCRE_AUTO_CALLOUT
162     \fB/E\fP PCRE_DOLLAR_ENDONLY
163     \fB/f\fP PCRE_FIRSTLINE
164     \fB/J\fP PCRE_DUPNAMES
165     \fB/N\fP PCRE_NO_AUTO_CAPTURE
166     \fB/U\fP PCRE_UNGREEDY
167     \fB/X\fP PCRE_EXTRA
168     \fB/<cr>\fP PCRE_NEWLINE_CR
169     \fB/<lf>\fP PCRE_NEWLINE_LF
170     \fB/<crlf>\fP PCRE_NEWLINE_CRLF
171 ph10 152 \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
172 ph10 149 \fB/<any>\fP PCRE_NEWLINE_ANY
173 nigel 75 .sp
174 ph10 227 Those specifying line ending sequences are literal strings as shown, but the
175     letters can be in either case. This example sets multiline matching with CRLF
176     as the line ending sequence:
177 nigel 93 .sp
178     /^abc/m<crlf>
179     .sp
180     Details of the meanings of these PCRE options are given in the
181 nigel 91 .\" HREF
182     \fBpcreapi\fP
183     .\"
184     documentation.
185     .
186     .
187     .SS "Finding all matches in a string"
188     .rs
189     .sp
190 nigel 53 Searching for all possible matches within each subject string can be requested
191 nigel 75 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
192 nigel 53 again to search the remainder of the subject string. The difference between
193 nigel 75 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
194     \fBpcre_exec()\fP to start searching at a new point within the entire string
195 nigel 53 (which is in effect what Perl does), whereas the latter passes over a shortened
196     substring. This makes a difference to the matching process if the pattern
197 nigel 75 begins with a lookbehind assertion (including \eb or \eB).
198     .P
199     If any call to \fBpcre_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches an
200 nigel 53 empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
201     flags set in order to search for another, non-empty, match at the same point.
202     If this second match fails, the start offset is advanced by one, and the normal
203     match is retried. This imitates the way Perl handles such cases when using the
204 nigel 75 \fB/g\fP modifier or the \fBsplit()\fP function.
205 nigel 91 .
206     .
207     .SS "Other modifiers"
208     .rs
209     .sp
210 nigel 75 There are yet more modifiers for controlling the way \fBpcretest\fP
211 nigel 53 operates.
212 nigel 75 .P
213     The \fB/+\fP modifier requests that as well as outputting the substring that
214 nigel 53 matched the entire pattern, pcretest should in addition output the remainder of
215     the subject string. This is useful for tests where the subject contains
216     multiple copies of the same substring.
217 nigel 75 .P
218 nigel 93 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
219 ph10 123 output a representation of the compiled byte code after compilation. Normally
220 ph10 116 this information contains length and offset values; however, if \fB/Z\fP is
221     also present, this data is replaced by spaces. This is a special feature for
222     use in the automatic test scripts; it ensures that the same output is generated
223     for different internal link sizes.
224 nigel 93 .P
225 nigel 75 The \fB/L\fP modifier must be followed directly by the name of a locale, for
226 nigel 53 example,
227 nigel 75 .sp
228     /pattern/Lfr_FR
229     .sp
230     For this reason, it must be the last modifier. The given locale is set,
231     \fBpcre_maketables()\fP is called to build a set of character tables for the
232     locale, and this is then passed to \fBpcre_compile()\fP when compiling the
233     regular expression. Without an \fB/L\fP modifier, NULL is passed as the tables
234     pointer; that is, \fB/L\fP applies only to the expression on which it appears.
235     .P
236     The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
237     compiled pattern (whether it is anchored, has a fixed first character, and
238     so on). It does this by calling \fBpcre_fullinfo()\fP after compiling a
239     pattern. If the pattern is studied, the results of that are also output.
240     .P
241 nigel 93 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
242 ph10 148 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
243 nigel 75 .P
244     The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
245     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
246     facility is for testing the feature in PCRE that allows it to execute patterns
247     that were compiled on a host with a different endianness. This feature is not
248     available when the POSIX interface to PCRE is being used, that is, when the
249     \fB/P\fP pattern modifier is specified. See also the section about saving and
250     reloading compiled patterns below.
251     .P
252     The \fB/S\fP modifier causes \fBpcre_study()\fP to be called after the
253 nigel 53 expression has been compiled, and the results used when the expression is
254     matched.
255 nigel 75 .P
256     The \fB/M\fP modifier causes the size of memory block used to hold the compiled
257 nigel 53 pattern to be output.
258 nigel 75 .P
259     The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
260 nigel 53 API rather than its native API. When this is done, all other modifiers except
261 nigel 75 \fB/i\fP, \fB/m\fP, and \fB/+\fP are ignored. REG_ICASE is set if \fB/i\fP is
262     present, and REG_NEWLINE is set if \fB/m\fP is present. The wrapper functions
263 nigel 53 force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
264 nigel 75 .P
265     The \fB/8\fP modifier causes \fBpcretest\fP to call PCRE with the PCRE_UTF8
266 nigel 63 option set. This turns on support for UTF-8 character handling in PCRE,
267     provided that it was compiled with this support enabled. This modifier also
268     causes any non-printing characters in output strings to be printed using the
269 nigel 75 \ex{hh...} notation if they are valid UTF-8 sequences.
270     .P
271     If the \fB/?\fP modifier is used with \fB/8\fP, it causes \fBpcretest\fP to
272     call \fBpcre_compile()\fP with the PCRE_NO_UTF8_CHECK option, to suppress the
273 nigel 71 checking of the string for UTF-8 validity.
274 nigel 75 .
275     .
276     .SH "DATA LINES"
277 nigel 63 .rs
278     .sp
279 nigel 75 Before each data line is passed to \fBpcre_exec()\fP, leading and trailing
280     whitespace is removed, and it is then scanned for \e escapes. Some of these are
281 nigel 63 pretty esoteric features, intended for checking out some of the more
282     complicated features of PCRE. If you are just testing "ordinary" regular
283     expressions, you probably don't need any of these. The following escapes are
284 nigel 53 recognized:
285 nigel 75 .sp
286 nigel 93 \ea alarm (BEL, \ex07)
287     \eb backspace (\ex08)
288     \ee escape (\ex27)
289     \ef formfeed (\ex0c)
290     \en newline (\ex0a)
291 nigel 91 .\" JOIN
292     \eqdd set the PCRE_MATCH_LIMIT limit to dd
293     (any number of digits)
294 nigel 93 \er carriage return (\ex0d)
295     \et tab (\ex09)
296     \ev vertical tab (\ex0b)
297 nigel 75 \ennn octal character (up to 3 octal digits)
298     \exhh hexadecimal character (up to 2 hex digits)
299     .\" JOIN
300     \ex{hh...} hexadecimal character, any number of digits
301 nigel 63 in UTF-8 mode
302 nigel 91 .\" JOIN
303 nigel 75 \eA pass the PCRE_ANCHORED option to \fBpcre_exec()\fP
304 nigel 91 or \fBpcre_dfa_exec()\fP
305     .\" JOIN
306 nigel 75 \eB pass the PCRE_NOTBOL option to \fBpcre_exec()\fP
307 nigel 91 or \fBpcre_dfa_exec()\fP
308 nigel 75 .\" JOIN
309     \eCdd call pcre_copy_substring() for substring dd
310     after a successful match (number less than 32)
311     .\" JOIN
312     \eCname call pcre_copy_named_substring() for substring
313 nigel 63 "name" after a successful match (name termin-
314     ated by next non alphanumeric character)
315 nigel 75 .\" JOIN
316     \eC+ show the current captured substrings at callout
317 nigel 63 time
318 nigel 75 \eC- do not supply a callout function
319     .\" JOIN
320     \eC!n return 1 instead of 0 when callout number n is
321 nigel 63 reached
322 nigel 75 .\" JOIN
323     \eC!n!m return 1 instead of 0 when callout number n is
324 nigel 63 reached for the nth time
325 nigel 75 .\" JOIN
326     \eC*n pass the number n (may be negative) as callout
327     data; this is used as the callout return value
328 nigel 77 \eD use the \fBpcre_dfa_exec()\fP match function
329     \eF only shortest match for \fBpcre_dfa_exec()\fP
330 nigel 75 .\" JOIN
331     \eGdd call pcre_get_substring() for substring dd
332     after a successful match (number less than 32)
333     .\" JOIN
334     \eGname call pcre_get_named_substring() for substring
335 nigel 63 "name" after a successful match (name termin-
336     ated by next non-alphanumeric character)
337 nigel 75 .\" JOIN
338     \eL call pcre_get_substringlist() after a
339 nigel 63 successful match
340 nigel 91 .\" JOIN
341 nigel 87 \eM discover the minimum MATCH_LIMIT and
342     MATCH_LIMIT_RECURSION settings
343 nigel 91 .\" JOIN
344 nigel 75 \eN pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fP
345 nigel 91 or \fBpcre_dfa_exec()\fP
346 nigel 75 .\" JOIN
347     \eOdd set the size of the output vector passed to
348     \fBpcre_exec()\fP to dd (any number of digits)
349 nigel 77 .\" JOIN
350 nigel 75 \eP pass the PCRE_PARTIAL option to \fBpcre_exec()\fP
351 nigel 77 or \fBpcre_dfa_exec()\fP
352 nigel 91 .\" JOIN
353     \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
354     (any number of digits)
355 nigel 77 \eR pass the PCRE_DFA_RESTART option to \fBpcre_dfa_exec()\fP
356 nigel 75 \eS output details of memory get/free calls during matching
357 nigel 91 .\" JOIN
358 nigel 75 \eZ pass the PCRE_NOTEOL option to \fBpcre_exec()\fP
359 nigel 91 or \fBpcre_dfa_exec()\fP
360 nigel 75 .\" JOIN
361     \e? pass the PCRE_NO_UTF8_CHECK option to
362 nigel 91 \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP
363 nigel 75 \e>dd start the match at offset dd (any number of digits);
364 nigel 91 .\" JOIN
365 nigel 75 this sets the \fIstartoffset\fP argument for \fBpcre_exec()\fP
366 nigel 91 or \fBpcre_dfa_exec()\fP
367     .\" JOIN
368     \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre_exec()\fP
369     or \fBpcre_dfa_exec()\fP
370     .\" JOIN
371     \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre_exec()\fP
372     or \fBpcre_dfa_exec()\fP
373     .\" JOIN
374     \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre_exec()\fP
375     or \fBpcre_dfa_exec()\fP
376 nigel 93 .\" JOIN
377 ph10 149 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre_exec()\fP
378     or \fBpcre_dfa_exec()\fP
379     .\" JOIN
380 nigel 93 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre_exec()\fP
381     or \fBpcre_dfa_exec()\fP
382 nigel 75 .sp
383 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
384     shown. No more than one newline setting should be present in any data line.
385 nigel 75 .P
386 nigel 93 A backslash followed by anything else just escapes the anything else. If
387     the very last character is a backslash, it is ignored. This gives a way of
388     passing an empty line as data, since a real empty line terminates the data
389     input.
390     .P
391 nigel 75 If \eM is present, \fBpcretest\fP calls \fBpcre_exec()\fP several times, with
392 nigel 87 different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
393     fields of the \fBpcre_extra\fP data structure, until it finds the minimum
394     numbers for each parameter that allow \fBpcre_exec()\fP to complete. The
395     \fImatch_limit\fP number is a measure of the amount of backtracking that takes
396     place, and checking it out can be instructive. For most simple matches, the
397     number is quite small, but for patterns with very large numbers of matching
398     possibilities, it can become large very quickly with increasing length of
399     subject string. The \fImatch_limit_recursion\fP number is a measure of how much
400     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
401     to complete the match attempt.
402 nigel 75 .P
403     When \eO is used, the value specified may be higher or lower than the size set
404     by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
405     the call of \fBpcre_exec()\fP for the line in which it appears.
406     .P
407     If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
408 nigel 87 API to be used, the only option-setting sequences that have any effect are \eB
409     and \eZ, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
410     \fBregexec()\fP.
411 nigel 75 .P
412     The use of \ex{hh...} to represent UTF-8 characters is not dependent on the use
413     of the \fB/8\fP modifier on the pattern. It is recognized always. There may be
414 nigel 53 any number of hexadecimal digits inside the braces. The result is from one to
415 ph10 211 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
416     allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
417     valid Unicode code points, or indeed valid UTF-8 characters according to the
418     later rules in RFC 3629.
419 nigel 75 .
420     .
421 nigel 77 .SH "THE ALTERNATIVE MATCHING FUNCTION"
422 nigel 63 .rs
423     .sp
424 nigel 77 By default, \fBpcretest\fP uses the standard PCRE matching function,
425     \fBpcre_exec()\fP to match each data line. From release 6.0, PCRE supports an
426     alternative matching function, \fBpcre_dfa_test()\fP, which operates in a
427     different way, and has some restrictions. The differences between the two
428     functions are described in the
429     .\" HREF
430     \fBpcrematching\fP
431     .\"
432     documentation.
433     .P
434     If a data line contains the \eD escape sequence, or if the command line
435     contains the \fB-dfa\fP option, the alternative matching function is called.
436     This function finds all possible matches at a given point. If, however, the \eF
437     escape sequence is present in the data line, it stops after the first match is
438     found. This is always the shortest possible match.
439     .
440     .
441     .SH "DEFAULT OUTPUT FROM PCRETEST"
442     .rs
443     .sp
444     This section describes the output when the normal matching function,
445     \fBpcre_exec()\fP, is being used.
446     .P
447 nigel 53 When a match succeeds, pcretest outputs the list of captured substrings that
448 nigel 75 \fBpcre_exec()\fP returns, starting with number 0 for the string that matched
449     the whole pattern. Otherwise, it outputs "No match" or "Partial match"
450     when \fBpcre_exec()\fP returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
451     respectively, and otherwise the PCRE negative error number. Here is an example
452 nigel 77 of an interactive \fBpcretest\fP run.
453 nigel 75 .sp
454 nigel 53 $ pcretest
455 nigel 93 PCRE version 7.0 30-Nov-2006
456 nigel 75 .sp
457     re> /^abc(\ed+)/
458 nigel 53 data> abc123
459     0: abc123
460     1: 123
461     data> xyz
462     No match
463 nigel 75 .sp
464     If the strings contain any non-printing characters, they are output as \e0x
465     escapes, or as \ex{...} escapes if the \fB/8\fP modifier was present on the
466 nigel 93 pattern. See below for the definition of non-printing characters. If the
467     pattern has the \fB/+\fP modifier, the output for substring 0 is followed by
468     the the rest of the subject string, identified by "0+" like this:
469 nigel 75 .sp
470 nigel 53 re> /cat/+
471     data> cataract
472     0: cat
473     0+ aract
474 nigel 75 .sp
475     If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
476 nigel 53 matching attempts are output in sequence, like this:
477 nigel 75 .sp
478     re> /\eBi(\ew\ew)/g
479 nigel 53 data> Mississippi
480     0: iss
481     1: ss
482     0: iss
483     1: ss
484     0: ipp
485     1: pp
486 nigel 75 .sp
487 nigel 53 "No match" is output only if the first match attempt fails.
488 nigel 75 .P
489     If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
490 nigel 53 data line that is successfully matched, the substrings extracted by the
491     convenience functions are output with C, G, or L after the string number
492     instead of a colon. This is in addition to the normal full list. The string
493     length (that is, the return from the extraction function) is given in
494 nigel 75 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
495     .P
496 nigel 93 Note that whereas patterns can be continued over several lines (a plain ">"
497 nigel 53 prompt is used for continuations), data lines may not. However newlines can be
498 nigel 93 included in data by means of the \en escape (or \er, \er\en, etc., depending on
499     the newline sequence setting).
500 nigel 75 .
501     .
502 nigel 93 .
503 nigel 77 .SH "OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION"
504     .rs
505     .sp
506     When the alternative matching function, \fBpcre_dfa_exec()\fP, is used (by
507     means of the \eD escape sequence or the \fB-dfa\fP command line option), the
508     output consists of a list of all the matches that start at the first point in
509     the subject where there is at least one match. For example:
510     .sp
511     re> /(tang|tangerine|tan)/
512     data> yellow tangerine\eD
513     0: tangerine
514     1: tang
515     2: tan
516     .sp
517     (Using the normal matching function on this data finds only "tang".) The
518     longest matching string is always given first (and numbered zero).
519     .P
520 nigel 93 If \fB/g\fP is present on the pattern, the search for further matches resumes
521 nigel 77 at the end of the longest match. For example:
522     .sp
523     re> /(tang|tangerine|tan)/g
524     data> yellow tangerine and tangy sultana\eD
525     0: tangerine
526     1: tang
527     2: tan
528     0: tang
529     1: tan
530     0: tan
531     .sp
532     Since the matching function does not support substring capture, the escape
533     sequences that are concerned with captured substrings are not relevant.
534     .
535     .
536     .SH "RESTARTING AFTER A PARTIAL MATCH"
537     .rs
538     .sp
539     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
540     indicating that the subject partially matched the pattern, you can restart the
541     match with additional subject data by means of the \eR escape sequence. For
542     example:
543     .sp
544 ph10 155 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
545 nigel 77 data> 23ja\eP\eD
546     Partial match: 23ja
547     data> n05\eR\eD
548     0: n05
549     .sp
550     For further information about partial matching, see the
551     .\" HREF
552     \fBpcrepartial\fP
553     .\"
554     documentation.
555     .
556     .
557 nigel 75 .SH CALLOUTS
558     .rs
559     .sp
560     If the pattern contains any callout requests, \fBpcretest\fP's callout function
561 nigel 77 is called during matching. This works with both matching functions. By default,
562     the called function displays the callout number, the start and current
563     positions in the text at the callout time, and the next pattern item to be
564     tested. For example, the output
565 nigel 75 .sp
566     --->pqrabcdef
567     0 ^ ^ \ed
568     .sp
569     indicates that callout number 0 occurred for a match attempt starting at the
570     fourth character of the subject string, when the pointer was at the seventh
571     character of the data, and when the next pattern item was \ed. Just one
572     circumflex is output if the start and current positions are the same.
573     .P
574     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
575     result of the \fB/C\fP pattern modifier. In this case, instead of showing the
576     callout number, the offset in the pattern, preceded by a plus, is output. For
577     example:
578     .sp
579     re> /\ed?[A-E]\e*/C
580     data> E*
581     --->E*
582     +0 ^ \ed?
583     +3 ^ [A-E]
584     +8 ^^ \e*
585     +10 ^ ^
586     0: E*
587     .sp
588     The callout function in \fBpcretest\fP returns zero (carry on matching) by
589 nigel 77 default, but you can use a \eC item in a data line (as described above) to
590 nigel 75 change this.
591     .P
592     Inserting callouts can be helpful when using \fBpcretest\fP to check
593     complicated regular expressions. For further information about callouts, see
594     the
595     .\" HREF
596     \fBpcrecallout\fP
597     .\"
598     documentation.
599     .
600     .
601 nigel 93 .
602     .SH "NON-PRINTING CHARACTERS"
603     .rs
604     .sp
605     When \fBpcretest\fP is outputting text in the compiled version of a pattern,
606     bytes other than 32-126 are always treated as non-printing characters are are
607     therefore shown as hex escapes.
608     .P
609     When \fBpcretest\fP is outputting text that is a matched part of a subject
610     string, it behaves in the same way, unless a different locale has been set for
611     the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
612     function to distinguish printing and non-printing characters.
613     .
614     .
615     .
616 nigel 75 .SH "SAVING AND RELOADING COMPILED PATTERNS"
617     .rs
618     .sp
619     The facilities described in this section are not available when the POSIX
620     inteface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
621     specified.
622     .P
623     When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
624     compiled pattern to a file, by following the modifiers with > and a file name.
625     For example:
626     .sp
627     /pattern/im >/some/file
628     .sp
629     See the
630     .\" HREF
631     \fBpcreprecompile\fP
632     .\"
633     documentation for a discussion about saving and re-using compiled patterns.
634     .P
635     The data that is written is binary. The first eight bytes are the length of the
636     compiled pattern data followed by the length of the optional study data, each
637     written as four bytes in big-endian order (most significant byte first). If
638     there is no study data (either the pattern was not studied, or studying did not
639     return any data), the second length is zero. The lengths are followed by an
640     exact copy of the compiled pattern. If there is additional study data, this
641     follows immediately after the compiled pattern. After writing the file,
642     \fBpcretest\fP expects to read a new pattern.
643     .P
644     A saved pattern can be reloaded into \fBpcretest\fP by specifing < and a file
645     name instead of a pattern. The name of the file must not contain a < character,
646     as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
647     characters.
648     For example:
649     .sp
650     re> </some/file
651     Compiled regex loaded from /some/file
652     No study data
653     .sp
654     When the pattern has been loaded, \fBpcretest\fP proceeds to read data lines in
655     the usual way.
656     .P
657     You can copy a file written by \fBpcretest\fP to a different host and reload it
658     there, even if the new host has opposite endianness to the one on which the
659     pattern was compiled. For example, you can compile on an i86 machine and run on
660     a SPARC machine.
661     .P
662     File names for saving and reloading can be absolute or relative, but note that
663     the shell facility of expanding a file name that starts with a tilde (~) is not
664     available.
665     .P
666     The ability to save and reload files in \fBpcretest\fP is intended for testing
667     and experimentation. It is not intended for production use because only a
668     single pattern can be written to a file. Furthermore, there is no facility for
669     supplying custom character tables for use with a reloaded pattern. If the
670     original pattern was compiled with custom tables, an attempt to match a subject
671     string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
672     Finally, if you attempt to load a file that is not in the correct format, the
673     result is undefined.
674     .
675     .
676 nigel 93 .SH "SEE ALSO"
677     .rs
678     .sp
679     \fBpcre\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3), \fBpcrematching\fP(3),
680 ph10 148 \fBpcrepartial\fP(d), \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
681 nigel 93 .
682     .
683 nigel 53 .SH AUTHOR
684 nigel 63 .rs
685     .sp
686 ph10 99 .nf
687 nigel 77 Philip Hazel
688 ph10 99 University Computing Service
689 nigel 93 Cambridge CB2 3QH, England.
690 ph10 99 .fi
691     .
692     .
693     .SH REVISION
694     .rs
695     .sp
696     .nf
697 ph10 227 Last updated: 21 August 2007
698 ph10 99 Copyright (c) 1997-2007 University of Cambridge.
699     .fi

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12