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Add the ++ feature to pcretest.

1 nigel 53 .TH PCRETEST 1
2     .SH NAME
3     pcretest - a program for testing Perl-compatible regular expressions.
5 nigel 75 .rs
6     .sp
7 ph10 612 .B pcretest "[options] [input file [output file]]"
8 nigel 91 .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 ph10 612 documentation. The input for \fBpcretest\fP is a sequence of regular expression
22     patterns and strings to be matched, as described below. The output shows the
23     result of each match. Options on the command line and the patterns control PCRE
24     options and exactly what is output.
25 nigel 75 .
26     .
28 nigel 63 .rs
29 nigel 53 .TP 10
30 nigel 93 \fB-b\fP
31 ph10 612 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the
32 ph10 599 internal form is output after compilation.
33 nigel 93 .TP 10
34 nigel 75 \fB-C\fP
35 nigel 63 Output the version number of the PCRE library, and all available information
36     about the optional features that are included, and then exit.
37     .TP 10
38 nigel 75 \fB-d\fP
39 ph10 612 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal
40 nigel 93 form and information about the compiled pattern is output after compilation;
41     \fB-d\fP is equivalent to \fB-b -i\fP.
42 nigel 53 .TP 10
43 nigel 77 \fB-dfa\fP
44     Behave as if each data line contains the \eD escape sequence; this causes the
45     alternative matching function, \fBpcre_dfa_exec()\fP, to be used instead of the
46     standard \fBpcre_exec()\fP function (more detail is given below).
47     .TP 10
48 nigel 93 \fB-help\fP
49     Output a brief summary these options and then exit.
50     .TP 10
51 nigel 75 \fB-i\fP
52 ph10 612 Behave as if each pattern has the \fB/I\fP modifier; information about the
53 nigel 53 compiled pattern is given after compilation.
54     .TP 10
55 ph10 386 \fB-M\fP
56     Behave as if each data line contains the \eM escape sequence; this causes
57 ph10 392 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
58 ph10 386 calling \fBpcre_exec()\fP repeatedly with different limits.
59     .TP 10
60 nigel 75 \fB-m\fP
61 nigel 53 Output the size of each compiled pattern after it has been compiled. This is
62 ph10 606 equivalent to adding \fB/M\fP to each regular expression.
63 nigel 53 .TP 10
64 nigel 75 \fB-o\fP \fIosize\fP
65     Set the number of elements in the output vector that is used when calling
66 nigel 93 \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP to be \fIosize\fP. The default value
67     is 45, which is enough for 14 capturing subexpressions for \fBpcre_exec()\fP or
68     22 different matches for \fBpcre_dfa_exec()\fP. The vector size can be
69     changed for individual matching calls by including \eO in the data line (see
70     below).
71 nigel 53 .TP 10
72 nigel 75 \fB-p\fP
73 ph10 612 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is
74 nigel 77 used to call PCRE. None of the other options has any effect when \fB-p\fP is
75     set.
76 nigel 53 .TP 10
77 nigel 91 \fB-q\fP
78 nigel 87 Do not output the version number of \fBpcretest\fP at the start of execution.
79     .TP 10
80 nigel 91 \fB-S\fP \fIsize\fP
81 ph10 599 On Unix-like systems, set the size of the run-time stack to \fIsize\fP
82 nigel 91 megabytes.
83     .TP 10
84 ph10 606 \fB-s\fP
85 ph10 612 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each
86     pattern to be studied. If the \fB/I\fP or \fB/D\fP option is present on a
87     pattern (requesting output about the compiled pattern), information about the
88     result of studying is not included when studying is caused only by \fB-s\fP and
89     neither \fB-i\fP nor \fB-d\fP is present on the command line. This behaviour
90     means that the output from tests that are run with and without \fB-s\fP should
91     be identical, except when options that output information about the actual
92     running of a match are set. The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options,
93     which give information about resources used, are likely to produce different
94     output with and without \fB-s\fP. Output may also differ if the \fB/C\fP option
95     is present on an individual pattern. This uses callouts to trace the the
96     matching process, and this may be different between studied and non-studied
97     patterns. If the pattern contains (*MARK) items there may also be differences,
98     for the same reason. The \fB-s\fP command line option can be overridden for
99     specific patterns that should never be studied (see the /S option below).
100 ph10 606 .TP 10
101 nigel 75 \fB-t\fP
102 nigel 63 Run each compile, study, and match many times with a timer, and output
103 nigel 75 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
104     \fB-t\fP, because you will then get the size output a zillion times, and the
105 nigel 93 timing will be distorted. You can control the number of iterations that are
106     used for timing by following \fB-t\fP with a number (as a separate item on the
107     command line). For example, "-t 1000" would iterate 1000 times. The default is
108     to iterate 500000 times.
109     .TP 10
110     \fB-tm\fP
111     This is like \fB-t\fP except that it times only the matching phase, not the
112     compile or study phases.
113 nigel 75 .
114     .
115 nigel 53 .SH DESCRIPTION
116 nigel 63 .rs
117     .sp
118 nigel 75 If \fBpcretest\fP is given two filename arguments, it reads from the first and
119 nigel 53 writes to the second. If it is given only one filename argument, it reads from
120     that file and writes to stdout. Otherwise, it reads from stdin and writes to
121     stdout, and prompts for each line of input, using "re>" to prompt for regular
122     expressions, and "data>" to prompt for data lines.
123 nigel 75 .P
124 ph10 289 When \fBpcretest\fP is built, a configuration option can specify that it should
125 ph10 287 be linked with the \fBlibreadline\fP library. When this is done, if the input
126     is from a terminal, it is read using the \fBreadline()\fP function. This
127     provides line-editing and history facilities. The output from the \fB-help\fP
128     option states whether or not \fBreadline()\fP will be used.
129     .P
130 nigel 53 The program handles any number of sets of input on a single input file. Each
131     set starts with a regular expression, and continues with any number of data
132 nigel 63 lines to be matched against the pattern.
133 nigel 75 .P
134     Each data line is matched separately and independently. If you want to do
135 nigel 91 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,
136 nigel 93 etc., depending on the newline setting) in a single line of input to encode the
137     newline sequences. There is no limit on the length of data lines; the input
138 nigel 91 buffer is automatically extended if it is too small.
139 nigel 75 .P
140 nigel 63 An empty line signals the end of the data lines, at which point a new regular
141     expression is read. The regular expressions are given enclosed in any
142 nigel 91 non-alphanumeric delimiters other than backslash, for example:
143 nigel 75 .sp
144 nigel 53 /(a|bc)x+yz/
145 nigel 75 .sp
146 nigel 53 White space before the initial delimiter is ignored. A regular expression may
147     be continued over several input lines, in which case the newline characters are
148     included within it. It is possible to include the delimiter within the pattern
149     by escaping it, for example
150 nigel 75 .sp
151     /abc\e/def/
152     .sp
153 nigel 53 If you do so, the escape and the delimiter form part of the pattern, but since
154 nigel 75 delimiters are always non-alphanumeric, this does not affect its interpretation.
155 nigel 53 If the terminating delimiter is immediately followed by a backslash, for
156     example,
157 nigel 75 .sp
158     /abc/\e
159     .sp
160 nigel 53 then a backslash is added to the end of the pattern. This is done to provide a
161     way of testing the error condition that arises if a pattern finishes with a
162     backslash, because
163 nigel 75 .sp
164     /abc\e/
165     .sp
166 nigel 53 is interpreted as the first line of a pattern that starts with "abc/", causing
167     pcretest to read the next line as a continuation of the regular expression.
168 nigel 75 .
169     .
171 nigel 63 .rs
172     .sp
173 nigel 75 A pattern may be followed by any number of modifiers, which are mostly single
174     characters. Following Perl usage, these are referred to below as, for example,
175     "the \fB/i\fP modifier", even though the delimiter of the pattern need not
176 ph10 599 always be a slash, and no slash is used when writing modifiers. White space may
177 nigel 75 appear between the final pattern delimiter and the first modifier, and between
178     the modifiers themselves.
179     .P
180     The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
181     PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
182     \fBpcre_compile()\fP is called. These four modifier letters have the same
183     effect as they do in Perl. For example:
184     .sp
185 nigel 53 /caseless/i
186 nigel 75 .sp
187 ph10 518 The following table shows additional modifiers for setting PCRE compile-time
188     options that do not correspond to anything in Perl:
189 nigel 75 .sp
190 ph10 518 \fB/8\fP PCRE_UTF8
191 ph10 535 \fB/?\fP PCRE_NO_UTF8_CHECK
192 ph10 231 \fB/A\fP PCRE_ANCHORED
195     \fB/f\fP PCRE_FIRSTLINE
196     \fB/J\fP PCRE_DUPNAMES
198     \fB/U\fP PCRE_UNGREEDY
199 ph10 535 \fB/W\fP PCRE_UCP
200 ph10 231 \fB/X\fP PCRE_EXTRA
201 ph10 579 \fB/Y\fP PCRE_NO_START_OPTIMIZE
203 ph10 231 \fB/<cr>\fP PCRE_NEWLINE_CR
204     \fB/<lf>\fP PCRE_NEWLINE_LF
205     \fB/<crlf>\fP PCRE_NEWLINE_CRLF
206     \fB/<anycrlf>\fP PCRE_NEWLINE_ANYCRLF
207     \fB/<any>\fP PCRE_NEWLINE_ANY
208     \fB/<bsr_anycrlf>\fP PCRE_BSR_ANYCRLF
209     \fB/<bsr_unicode>\fP PCRE_BSR_UNICODE
210 nigel 75 .sp
211 ph10 518 The modifiers that are enclosed in angle brackets are literal strings as shown,
212 ph10 612 including the angle brackets, but the letters within can be in either case.
213     This example sets multiline matching with CRLF as the line ending sequence:
214 nigel 93 .sp
215 ph10 612 /^abc/m<CRLF>
216 nigel 93 .sp
217 ph10 518 As well as turning on the PCRE_UTF8 option, the \fB/8\fP modifier also causes
218     any non-printing characters in output strings to be printed using the
219     \ex{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE
220     options are given in the
221 nigel 91 .\" HREF
222     \fBpcreapi\fP
223     .\"
224 ph10 535 documentation.
225 nigel 91 .
226     .
227     .SS "Finding all matches in a string"
228     .rs
229     .sp
230 nigel 53 Searching for all possible matches within each subject string can be requested
231 nigel 75 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
232 nigel 53 again to search the remainder of the subject string. The difference between
233 nigel 75 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
234     \fBpcre_exec()\fP to start searching at a new point within the entire string
235 nigel 53 (which is in effect what Perl does), whereas the latter passes over a shortened
236     substring. This makes a difference to the matching process if the pattern
237 nigel 75 begins with a lookbehind assertion (including \eb or \eB).
238     .P
239     If any call to \fBpcre_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches an
240 ph10 442 empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
241     PCRE_ANCHORED flags set in order to search for another, non-empty, match at the
242 ph10 566 same point. If this second match fails, the start offset is advanced, and the
243     normal match is retried. This imitates the way Perl handles such cases when
244 ph10 579 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start
245     offset is advanced by one character, but if the newline convention recognizes
246     CRLF as a newline, and the current character is CR followed by LF, an advance
247 ph10 566 of two is used.
248 nigel 91 .
249     .
250     .SS "Other modifiers"
251     .rs
252     .sp
253 nigel 75 There are yet more modifiers for controlling the way \fBpcretest\fP
254 nigel 53 operates.
255 nigel 75 .P
256     The \fB/+\fP modifier requests that as well as outputting the substring that
257 ph10 616 matched the entire pattern, \fBpcretest\fP should in addition output the
258     remainder of the subject string. This is useful for tests where the subject
259     contains multiple copies of the same substring. If the \fB+\fP modifier appears
260     twice, the same action is taken for captured substrings. In each case the
261     remainder is output on the following line with a plus character following the
262     capture number.
263 nigel 75 .P
264 nigel 93 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP
265 ph10 123 output a representation of the compiled byte code after compilation. Normally
266 ph10 116 this information contains length and offset values; however, if \fB/Z\fP is
267     also present, this data is replaced by spaces. This is a special feature for
268     use in the automatic test scripts; it ensures that the same output is generated
269     for different internal link sizes.
270 nigel 93 .P
271     The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to
272 ph10 148 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.
273 nigel 75 .P
274     The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
275     fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
276     facility is for testing the feature in PCRE that allows it to execute patterns
277     that were compiled on a host with a different endianness. This feature is not
278     available when the POSIX interface to PCRE is being used, that is, when the
279     \fB/P\fP pattern modifier is specified. See also the section about saving and
280     reloading compiled patterns below.
281     .P
282 ph10 510 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
283     compiled pattern (whether it is anchored, has a fixed first character, and
284     so on). It does this by calling \fBpcre_fullinfo()\fP after compiling a
285     pattern. If the pattern is studied, the results of that are also output.
286 nigel 75 .P
287 ph10 510 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking
288     control verbs that are returned from calls to \fBpcre_exec()\fP. It causes
289     \fBpcretest\fP to create a \fBpcre_extra\fP block if one has not already been
290     created by a call to \fBpcre_study()\fP, and to set the PCRE_EXTRA_MARK flag
291     and the \fBmark\fP field within it, every time that \fBpcre_exec()\fP is
292     called. If the variable that the \fBmark\fP field points to is non-NULL for a
293 ph10 512 match, non-match, or partial match, \fBpcretest\fP prints the string to which
294     it points. For a match, this is shown on a line by itself, tagged with "MK:".
295 ph10 510 For a non-match it is added to the message.
296     .P
297     The \fB/L\fP modifier must be followed directly by the name of a locale, for
298     example,
299     .sp
300     /pattern/Lfr_FR
301     .sp
302     For this reason, it must be the last modifier. The given locale is set,
303     \fBpcre_maketables()\fP is called to build a set of character tables for the
304     locale, and this is then passed to \fBpcre_compile()\fP when compiling the
305 ph10 541 regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is passed
306     as the tables pointer; that is, \fB/L\fP applies only to the expression on
307     which it appears.
308 ph10 510 .P
309 nigel 75 The \fB/M\fP modifier causes the size of memory block used to hold the compiled
310 nigel 53 pattern to be output.
311 nigel 75 .P
312 ph10 612 If the \fB/S\fP modifier appears once, it causes \fBpcre_study()\fP to be
313     called after the expression has been compiled, and the results used when the
314     expression is matched. If \fB/S\fP appears twice, it suppresses studying, even
315     if it was requested externally by the \fB-s\fP command line option. This makes
316     it possible to specify that certain patterns are always studied, and others are
317     never studied, independently of \fB-s\fP. This feature is used in the test
318     files in a few cases where the output is different when the pattern is studied.
319 ph10 541 .P
320 ph10 545 The \fB/T\fP modifier must be followed by a single digit. It causes a specific
321     set of built-in character tables to be passed to \fBpcre_compile()\fP. It is
322     used in the standard PCRE tests to check behaviour with different character
323 ph10 541 tables. The digit specifies the tables as follows:
324     .sp
325 ph10 545 0 the default ASCII tables, as distributed in
326 ph10 541 pcre_chartables.c.dist
327     1 a set of tables defining ISO 8859 characters
328     .sp
329 ph10 545 In table 1, some characters whose codes are greater than 128 are identified as
330 ph10 541 letters, digits, spaces, etc.
331 nigel 75 .
332     .
333 ph10 518 .SS "Using the POSIX wrapper API"
334     .rs
335     .sp
336     The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
337 ph10 535 API rather than its native API. When \fB/P\fP is set, the following modifiers
338 ph10 518 set options for the \fBregcomp()\fP function:
339     .sp
340     /i REG_ICASE
341     /m REG_NEWLINE
342     /N REG_NOSUB
343     /s REG_DOTALL )
344 ph10 535 /U REG_UNGREEDY ) These options are not part of
345 ph10 518 /W REG_UCP ) the POSIX standard
346     /8 REG_UTF8 )
347     .sp
348     The \fB/+\fP modifier works as described above. All other modifiers are
349     ignored.
350     .
351     .
352 nigel 75 .SH "DATA LINES"
353 nigel 63 .rs
354     .sp
355 nigel 75 Before each data line is passed to \fBpcre_exec()\fP, leading and trailing
356 ph10 599 white space is removed, and it is then scanned for \e escapes. Some of these
357     are pretty esoteric features, intended for checking out some of the more
358 nigel 63 complicated features of PCRE. If you are just testing "ordinary" regular
359     expressions, you probably don't need any of these. The following escapes are
360 nigel 53 recognized:
361 nigel 75 .sp
362 nigel 93 \ea alarm (BEL, \ex07)
363     \eb backspace (\ex08)
364     \ee escape (\ex27)
365 ph10 599 \ef form feed (\ex0c)
366 nigel 93 \en newline (\ex0a)
367 nigel 91 .\" JOIN
368     \eqdd set the PCRE_MATCH_LIMIT limit to dd
369     (any number of digits)
370 nigel 93 \er carriage return (\ex0d)
371     \et tab (\ex09)
372     \ev vertical tab (\ex0b)
373 nigel 75 \ennn octal character (up to 3 octal digits)
374 ph10 579 always a byte unless > 255 in UTF-8 mode
375 ph10 570 \exhh hexadecimal byte (up to 2 hex digits)
376 nigel 75 .\" JOIN
377     \ex{hh...} hexadecimal character, any number of digits
378 nigel 63 in UTF-8 mode
379 nigel 91 .\" JOIN
380 nigel 75 \eA pass the PCRE_ANCHORED option to \fBpcre_exec()\fP
381 nigel 91 or \fBpcre_dfa_exec()\fP
382     .\" JOIN
383 nigel 75 \eB pass the PCRE_NOTBOL option to \fBpcre_exec()\fP
384 nigel 91 or \fBpcre_dfa_exec()\fP
385 nigel 75 .\" JOIN
386     \eCdd call pcre_copy_substring() for substring dd
387     after a successful match (number less than 32)
388     .\" JOIN
389     \eCname call pcre_copy_named_substring() for substring
390 nigel 63 "name" after a successful match (name termin-
391     ated by next non alphanumeric character)
392 nigel 75 .\" JOIN
393     \eC+ show the current captured substrings at callout
394 nigel 63 time
395 nigel 75 \eC- do not supply a callout function
396     .\" JOIN
397     \eC!n return 1 instead of 0 when callout number n is
398 nigel 63 reached
399 nigel 75 .\" JOIN
400     \eC!n!m return 1 instead of 0 when callout number n is
401 nigel 63 reached for the nth time
402 nigel 75 .\" JOIN
403     \eC*n pass the number n (may be negative) as callout
404     data; this is used as the callout return value
405 nigel 77 \eD use the \fBpcre_dfa_exec()\fP match function
406     \eF only shortest match for \fBpcre_dfa_exec()\fP
407 nigel 75 .\" JOIN
408     \eGdd call pcre_get_substring() for substring dd
409     after a successful match (number less than 32)
410     .\" JOIN
411     \eGname call pcre_get_named_substring() for substring
412 nigel 63 "name" after a successful match (name termin-
413     ated by next non-alphanumeric character)
414 nigel 75 .\" JOIN
415     \eL call pcre_get_substringlist() after a
416 nigel 63 successful match
417 nigel 91 .\" JOIN
418 nigel 87 \eM discover the minimum MATCH_LIMIT and
419     MATCH_LIMIT_RECURSION settings
420 nigel 91 .\" JOIN
421 nigel 75 \eN pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fP
422 ph10 442 or \fBpcre_dfa_exec()\fP; if used twice, pass the
423 ph10 461 PCRE_NOTEMPTY_ATSTART option
424 nigel 75 .\" JOIN
425     \eOdd set the size of the output vector passed to
426     \fBpcre_exec()\fP to dd (any number of digits)
427 nigel 77 .\" JOIN
428 ph10 428 \eP pass the PCRE_PARTIAL_SOFT option to \fBpcre_exec()\fP
429     or \fBpcre_dfa_exec()\fP; if used twice, pass the
430 ph10 461 PCRE_PARTIAL_HARD option
431 nigel 91 .\" JOIN
432     \eQdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
433     (any number of digits)
434 nigel 77 \eR pass the PCRE_DFA_RESTART option to \fBpcre_dfa_exec()\fP
435 nigel 75 \eS output details of memory get/free calls during matching
436 nigel 91 .\" JOIN
437 ph10 455 \eY pass the PCRE_NO_START_OPTIMIZE option to \fBpcre_exec()\fP
438     or \fBpcre_dfa_exec()\fP
439     .\" JOIN
440 nigel 75 \eZ pass the PCRE_NOTEOL option to \fBpcre_exec()\fP
441 nigel 91 or \fBpcre_dfa_exec()\fP
442 nigel 75 .\" JOIN
443     \e? pass the PCRE_NO_UTF8_CHECK option to
444 nigel 91 \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP
445     .\" JOIN
446 ph10 567 \e>dd start the match at offset dd (optional "-"; then
447 ph10 579 any number of digits); this sets the \fIstartoffset\fP
448 ph10 567 argument for \fBpcre_exec()\fP or \fBpcre_dfa_exec()\fP
449 nigel 91 .\" JOIN
450     \e<cr> pass the PCRE_NEWLINE_CR option to \fBpcre_exec()\fP
451     or \fBpcre_dfa_exec()\fP
452     .\" JOIN
453     \e<lf> pass the PCRE_NEWLINE_LF option to \fBpcre_exec()\fP
454     or \fBpcre_dfa_exec()\fP
455     .\" JOIN
456     \e<crlf> pass the PCRE_NEWLINE_CRLF option to \fBpcre_exec()\fP
457     or \fBpcre_dfa_exec()\fP
458 nigel 93 .\" JOIN
459 ph10 149 \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre_exec()\fP
460     or \fBpcre_dfa_exec()\fP
461     .\" JOIN
462 nigel 93 \e<any> pass the PCRE_NEWLINE_ANY option to \fBpcre_exec()\fP
463     or \fBpcre_dfa_exec()\fP
464 nigel 75 .sp
465 ph10 579 Note that \exhh always specifies one byte, even in UTF-8 mode; this makes it
466     possible to construct invalid UTF-8 sequences for testing purposes. On the
467 ph10 570 other hand, \ex{hh} is interpreted as a UTF-8 character in UTF-8 mode,
468 ph10 579 generating more than one byte if the value is greater than 127. When not in
469     UTF-8 mode, it generates one byte for values less than 256, and causes an error
470 ph10 570 for greater values.
471     .P
472 nigel 93 The escapes that specify line ending sequences are literal strings, exactly as
473     shown. No more than one newline setting should be present in any data line.
474 nigel 75 .P
475 nigel 93 A backslash followed by anything else just escapes the anything else. If
476     the very last character is a backslash, it is ignored. This gives a way of
477     passing an empty line as data, since a real empty line terminates the data
478     input.
479     .P
480 nigel 75 If \eM is present, \fBpcretest\fP calls \fBpcre_exec()\fP several times, with
481 nigel 87 different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
482     fields of the \fBpcre_extra\fP data structure, until it finds the minimum
483     numbers for each parameter that allow \fBpcre_exec()\fP to complete. The
484     \fImatch_limit\fP number is a measure of the amount of backtracking that takes
485     place, and checking it out can be instructive. For most simple matches, the
486     number is quite small, but for patterns with very large numbers of matching
487     possibilities, it can become large very quickly with increasing length of
488     subject string. The \fImatch_limit_recursion\fP number is a measure of how much
489     stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
490     to complete the match attempt.
491 nigel 75 .P
492     When \eO is used, the value specified may be higher or lower than the size set
493     by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
494     the call of \fBpcre_exec()\fP for the line in which it appears.
495     .P
496     If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
497 ph10 518 API to be used, the only option-setting sequences that have any effect are \eB,
498     \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
499     to be passed to \fBregexec()\fP.
500 nigel 75 .P
501     The use of \ex{hh...} to represent UTF-8 characters is not dependent on the use
502     of the \fB/8\fP modifier on the pattern. It is recognized always. There may be
503 nigel 53 any number of hexadecimal digits inside the braces. The result is from one to
504 ph10 211 six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
505     allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
506     valid Unicode code points, or indeed valid UTF-8 characters according to the
507     later rules in RFC 3629.
508 nigel 75 .
509     .
511 nigel 63 .rs
512     .sp
513 nigel 77 By default, \fBpcretest\fP uses the standard PCRE matching function,
514     \fBpcre_exec()\fP to match each data line. From release 6.0, PCRE supports an
515     alternative matching function, \fBpcre_dfa_test()\fP, which operates in a
516     different way, and has some restrictions. The differences between the two
517     functions are described in the
518     .\" HREF
519     \fBpcrematching\fP
520     .\"
521     documentation.
522     .P
523     If a data line contains the \eD escape sequence, or if the command line
524     contains the \fB-dfa\fP option, the alternative matching function is called.
525     This function finds all possible matches at a given point. If, however, the \eF
526     escape sequence is present in the data line, it stops after the first match is
527     found. This is always the shortest possible match.
528     .
529     .
531     .rs
532     .sp
533     This section describes the output when the normal matching function,
534     \fBpcre_exec()\fP, is being used.
535     .P
536 ph10 598 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings
537     that \fBpcre_exec()\fP returns, starting with number 0 for the string that
538     matched the whole pattern. Otherwise, it outputs "No match" when the return is
539 ph10 435 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
540 ph10 553 substring when \fBpcre_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that this is
541     the entire substring that was inspected during the partial match; it may
542     include characters before the actual match start if a lookbehind assertion,
543 ph10 598 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs
544     the PCRE negative error number and a short descriptive phrase. If the error is
545     a failed UTF-8 string check, the byte offset of the start of the failing
546     character and the reason code are also output, provided that the size of the
547     output vector is at least two. Here is an example of an interactive
548     \fBpcretest\fP run.
549 nigel 75 .sp
550 nigel 53 $ pcretest
551 ph10 598 PCRE version 8.13 2011-04-30
552 nigel 75 .sp
553     re> /^abc(\ed+)/
554 nigel 53 data> abc123
555     0: abc123
556     1: 123
557     data> xyz
558     No match
559 nigel 75 .sp
560 ph10 598 Unset capturing substrings that are not followed by one that is set are not
561     returned by \fBpcre_exec()\fP, and are not shown by \fBpcretest\fP. In the
562     following example, there are two capturing substrings, but when the first data
563     line is matched, the second, unset substring is not shown. An "internal" unset
564     substring is shown as "<unset>", as for the second data line.
565 ph10 273 .sp
566     re> /(a)|(b)/
567     data> a
568     0: a
569     1: a
570     data> b
571     0: b
572     1: <unset>
573 ph10 286 2: b
574 ph10 273 .sp
575 nigel 75 If the strings contain any non-printing characters, they are output as \e0x
576     escapes, or as \ex{...} escapes if the \fB/8\fP modifier was present on the
577 nigel 93 pattern. See below for the definition of non-printing characters. If the
578     pattern has the \fB/+\fP modifier, the output for substring 0 is followed by
579     the the rest of the subject string, identified by "0+" like this:
580 nigel 75 .sp
581 nigel 53 re> /cat/+
582     data> cataract
583     0: cat
584     0+ aract
585 nigel 75 .sp
586     If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
587 nigel 53 matching attempts are output in sequence, like this:
588 nigel 75 .sp
589     re> /\eBi(\ew\ew)/g
590 nigel 53 data> Mississippi
591     0: iss
592     1: ss
593     0: iss
594     1: ss
595     0: ipp
596     1: pp
597 nigel 75 .sp
598 ph10 598 "No match" is output only if the first match attempt fails. Here is an example
599     of a failure message (the offset 4 that is specified by \e>4 is past the end of
600     the subject string):
601     .sp
602     re> /xyz/
603     data> xyz\>4
604     Error -24 (bad offset value)
605 nigel 75 .P
606     If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
607 nigel 53 data line that is successfully matched, the substrings extracted by the
608     convenience functions are output with C, G, or L after the string number
609     instead of a colon. This is in addition to the normal full list. The string
610     length (that is, the return from the extraction function) is given in
611 nigel 75 parentheses after each string for \fB\eC\fP and \fB\eG\fP.
612     .P
613 nigel 93 Note that whereas patterns can be continued over several lines (a plain ">"
614 nigel 53 prompt is used for continuations), data lines may not. However newlines can be
615 nigel 93 included in data by means of the \en escape (or \er, \er\en, etc., depending on
616     the newline sequence setting).
617 nigel 75 .
618     .
619 nigel 93 .
621     .rs
622     .sp
623     When the alternative matching function, \fBpcre_dfa_exec()\fP, is used (by
624     means of the \eD escape sequence or the \fB-dfa\fP command line option), the
625     output consists of a list of all the matches that start at the first point in
626     the subject where there is at least one match. For example:
627     .sp
628     re> /(tang|tangerine|tan)/
629     data> yellow tangerine\eD
630     0: tangerine
631     1: tang
632     2: tan
633     .sp
634     (Using the normal matching function on this data finds only "tang".) The
635 ph10 428 longest matching string is always given first (and numbered zero). After a
636 ph10 461 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
637 ph10 553 partially matching substring. (Note that this is the entire substring that was
638     inspected during the partial match; it may include characters before the actual
639     match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)
640 nigel 77 .P
641 nigel 93 If \fB/g\fP is present on the pattern, the search for further matches resumes
642 nigel 77 at the end of the longest match. For example:
643     .sp
644     re> /(tang|tangerine|tan)/g
645     data> yellow tangerine and tangy sultana\eD
646     0: tangerine
647     1: tang
648     2: tan
649     0: tang
650     1: tan
651     0: tan
652     .sp
653     Since the matching function does not support substring capture, the escape
654     sequences that are concerned with captured substrings are not relevant.
655     .
656     .
658     .rs
659     .sp
660     When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
661     indicating that the subject partially matched the pattern, you can restart the
662     match with additional subject data by means of the \eR escape sequence. For
663     example:
664     .sp
665 ph10 155 re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/
666 nigel 77 data> 23ja\eP\eD
667     Partial match: 23ja
668     data> n05\eR\eD
669     0: n05
670     .sp
671     For further information about partial matching, see the
672     .\" HREF
673     \fBpcrepartial\fP
674     .\"
675     documentation.
676     .
677     .
678 nigel 75 .SH CALLOUTS
679     .rs
680     .sp
681     If the pattern contains any callout requests, \fBpcretest\fP's callout function
682 nigel 77 is called during matching. This works with both matching functions. By default,
683     the called function displays the callout number, the start and current
684     positions in the text at the callout time, and the next pattern item to be
685     tested. For example, the output
686 nigel 75 .sp
687     --->pqrabcdef
688     0 ^ ^ \ed
689     .sp
690     indicates that callout number 0 occurred for a match attempt starting at the
691     fourth character of the subject string, when the pointer was at the seventh
692     character of the data, and when the next pattern item was \ed. Just one
693     circumflex is output if the start and current positions are the same.
694     .P
695     Callouts numbered 255 are assumed to be automatic callouts, inserted as a
696     result of the \fB/C\fP pattern modifier. In this case, instead of showing the
697     callout number, the offset in the pattern, preceded by a plus, is output. For
698     example:
699     .sp
700     re> /\ed?[A-E]\e*/C
701     data> E*
702     --->E*
703     +0 ^ \ed?
704     +3 ^ [A-E]
705     +8 ^^ \e*
706     +10 ^ ^
707     0: E*
708     .sp
709     The callout function in \fBpcretest\fP returns zero (carry on matching) by
710 nigel 77 default, but you can use a \eC item in a data line (as described above) to
711 nigel 75 change this.
712     .P
713     Inserting callouts can be helpful when using \fBpcretest\fP to check
714     complicated regular expressions. For further information about callouts, see
715     the
716     .\" HREF
717     \fBpcrecallout\fP
718     .\"
719     documentation.
720     .
721     .
722 nigel 93 .
724     .rs
725     .sp
726     When \fBpcretest\fP is outputting text in the compiled version of a pattern,
727     bytes other than 32-126 are always treated as non-printing characters are are
728     therefore shown as hex escapes.
729     .P
730     When \fBpcretest\fP is outputting text that is a matched part of a subject
731     string, it behaves in the same way, unless a different locale has been set for
732     the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP
733     function to distinguish printing and non-printing characters.
734     .
735     .
736     .
738     .rs
739     .sp
740     The facilities described in this section are not available when the POSIX
741 ph10 599 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
742 nigel 75 specified.
743     .P
744     When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
745     compiled pattern to a file, by following the modifiers with > and a file name.
746     For example:
747     .sp
748     /pattern/im >/some/file
749     .sp
750     See the
751     .\" HREF
752     \fBpcreprecompile\fP
753     .\"
754     documentation for a discussion about saving and re-using compiled patterns.
755     .P
756     The data that is written is binary. The first eight bytes are the length of the
757     compiled pattern data followed by the length of the optional study data, each
758     written as four bytes in big-endian order (most significant byte first). If
759     there is no study data (either the pattern was not studied, or studying did not
760     return any data), the second length is zero. The lengths are followed by an
761     exact copy of the compiled pattern. If there is additional study data, this
762     follows immediately after the compiled pattern. After writing the file,
763     \fBpcretest\fP expects to read a new pattern.
764     .P
765 ph10 599 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file
766 nigel 75 name instead of a pattern. The name of the file must not contain a < character,
767     as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
768     characters.
769     For example:
770     .sp
771     re> </some/file
772 ph10 612 Compiled pattern loaded from /some/file
773 nigel 75 No study data
774     .sp
775     When the pattern has been loaded, \fBpcretest\fP proceeds to read data lines in
776     the usual way.
777     .P
778     You can copy a file written by \fBpcretest\fP to a different host and reload it
779     there, even if the new host has opposite endianness to the one on which the
780     pattern was compiled. For example, you can compile on an i86 machine and run on
781     a SPARC machine.
782     .P
783     File names for saving and reloading can be absolute or relative, but note that
784     the shell facility of expanding a file name that starts with a tilde (~) is not
785     available.
786     .P
787     The ability to save and reload files in \fBpcretest\fP is intended for testing
788     and experimentation. It is not intended for production use because only a
789     single pattern can be written to a file. Furthermore, there is no facility for
790     supplying custom character tables for use with a reloaded pattern. If the
791     original pattern was compiled with custom tables, an attempt to match a subject
792     string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
793     Finally, if you attempt to load a file that is not in the correct format, the
794     result is undefined.
795     .
796     .
797 nigel 93 .SH "SEE ALSO"
798     .rs
799     .sp
800     \fBpcre\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3), \fBpcrematching\fP(3),
801 ph10 148 \fBpcrepartial\fP(d), \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).
802 nigel 93 .
803     .
804 nigel 53 .SH AUTHOR
805 nigel 63 .rs
806     .sp
807 ph10 99 .nf
808 nigel 77 Philip Hazel
809 ph10 99 University Computing Service
810 nigel 93 Cambridge CB2 3QH, England.
811 ph10 99 .fi
812     .
813     .
814     .SH REVISION
815     .rs
816     .sp
817     .nf
818 ph10 616 Last updated: 11 July 2011
819 ph10 598 Copyright (c) 1997-2011 University of Cambridge.
820 ph10 99 .fi


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