ViewVC logotype

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

Parent Directory Parent Directory | Revision Log Revision Log

Revision 930 - (hide annotations) (download)
Fri Feb 24 12:05:54 2012 UTC (3 years, 2 months ago) by ph10
File MIME type: text/plain
File size: 44583 byte(s)
Improve documentation for (*MARK); update HTML.

1 nigel 73 PCRETEST(1) PCRETEST(1)
2 nigel 41
4 nigel 73 NAME
5     pcretest - a program for testing Perl-compatible regular expressions.
7 nigel 79
8 nigel 53 SYNOPSIS
9 nigel 41
10 ph10 654 pcretest [options] [input file [output file]]
11 nigel 75
12 nigel 73 pcretest was written as a test program for the PCRE regular expression
13     library itself, but it can also be used for experimenting with regular
14     expressions. This document describes the features of the test program;
15     for details of the regular expressions themselves, see the pcrepattern
16 nigel 75 documentation. For details of the PCRE library function calls and their
17 ph10 869 options, see the pcreapi and pcre16 documentation. The input for
18     pcretest is a sequence of regular expression patterns and strings to be
19     matched, as described below. The output shows the result of each match.
20     Options on the command line and the patterns control PCRE options and
21     exactly what is output.
22 nigel 41
24 ph10 869 PCRE's 8-BIT and 16-BIT LIBRARIES
26     From release 8.30, two separate PCRE libraries can be built. The origi-
27     nal one supports 8-bit character strings, whereas the newer 16-bit
28     library supports character strings encoded in 16-bit units. The
29     pcretest program can be used to test both libraries. However, it is
30     itself still an 8-bit program, reading 8-bit input and writing 8-bit
31     output. When testing the 16-bit library, the patterns and data strings
32     are converted to 16-bit format before being passed to the PCRE library
33     functions. Results are converted to 8-bit for output.
35     References to functions and structures of the form pcre[16]_xx below
36     mean "pcre_xx when using the 8-bit library or pcre16_xx when using the
37     16-bit library".
41 nigel 41
42 ph10 869 -16 If both the 8-bit and the 16-bit libraries have been built,
43     this option causes the 16-bit library to be used. If only the
44     16-bit library has been built, this is the default (so has no
45     effect). If only the 8-bit library has been built, this
46     option causes an error.
48     -b Behave as if each pattern has the /B (show byte code) modi-
49 ph10 654 fier; the internal form is output after compilation.
50 nigel 93
51 nigel 73 -C Output the version number of the PCRE library, and all avail-
52 ph10 869 able information about the optional features that are
53     included, and then exit. All other options are ignored.
54 nigel 63
55 ph10 869 -C option Output information about a specific build-time option, then
56     exit. This functionality is intended for use in scripts such
57     as RunTest. The following options output the value indicated:
59     linksize the internal link size (2, 3, or 4)
60     newline the default newline setting:
61     CR, LF, CRLF, ANYCRLF, or ANY
63     The following options output 1 for true or zero for false:
65     jit just-in-time support is available
66     pcre16 the 16-bit library was built
67     pcre8 the 8-bit library was built
68     ucp Unicode property support is available
69     utf UTF-8 and/or UTF-16 support is available
71     -d Behave as if each pattern has the /D (debug) modifier; the
72     internal form and information about the compiled pattern is
73 nigel 93 output after compilation; -d is equivalent to -b -i.
74 nigel 41
75 ph10 869 -dfa Behave as if each data line contains the \D escape sequence;
76 nigel 77 this causes the alternative matching function,
77 ph10 869 pcre[16]_dfa_exec(), to be used instead of the standard
78     pcre[16]_exec() function (more detail is given below).
79 nigel 77
80 nigel 93 -help Output a brief summary these options and then exit.
82 ph10 869 -i Behave as if each pattern has the /I modifier; information
83 nigel 73 about the compiled pattern is given after compilation.
84 nigel 41
85 ph10 869 -M Behave as if each data line contains the \M escape sequence;
86     this causes PCRE to discover the minimum MATCH_LIMIT and
87     MATCH_LIMIT_RECURSION settings by calling pcre[16]_exec()
88     repeatedly with different limits.
89 ph10 392
90 ph10 869 -m Output the size of each compiled pattern after it has been
91     compiled. This is equivalent to adding /M to each regular
92     expression. The size is given in bytes for both libraries.
93 nigel 41
94 ph10 869 -o osize Set the number of elements in the output vector that is used
95     when calling pcre[16]_exec() or pcre[16]_dfa_exec() to be
96     osize. The default value is 45, which is enough for 14 cap-
97     turing subexpressions for pcre[16]_exec() or 22 different
98     matches for pcre[16]_dfa_exec(). The vector size can be
99     changed for individual matching calls by including \O in the
100     data line (see below).
101 nigel 41
102 ph10 869 -p Behave as if each pattern has the /P modifier; the POSIX
103     wrapper API is used to call PCRE. None of the other options
104     has any effect when -p is set. This option can be used only
105     with the 8-bit library.
106 nigel 41
107 ph10 654 -q Do not output the version number of pcretest at the start of
108 nigel 87 execution.
110 ph10 654 -S size On Unix-like systems, set the size of the run-time stack to
111 nigel 91 size megabytes.
113 ph10 691 -s or -s+ Behave as if each pattern has the /S modifier; in other
114 ph10 930 words, force each pattern to be studied. If -s+ is used, all
115     the JIT compile options are passed to pcre[16]_study(), caus-
116     ing just-in-time optimization to be set up if it is avail-
117     able, for both full and partial matching. Specific JIT com-
118     pile options can be selected by following -s+ with a digit in
119     the range 1 to 7, which selects the JIT compile modes as fol-
120     lows:
121 ph10 654
122 ph10 930 1 normal match only
123     2 soft partial match only
124     3 normal match and soft partial match
125     4 hard partial match only
126     6 soft and hard partial match
127     7 all three modes (default)
128 ph10 869
129 ph10 930 If -s++ is used instead of -s+ (with or without a following
130     digit), the text "(JIT)" is added to the first output line
131     after a match or no match when JIT-compiled code was actually
132     used.
134     If the /I or /D option is present on a pattern (requesting output about
135     the compiled pattern), information about the result of studying is not
136     included when studying is caused only by -s and neither -i nor -d is
137     present on the command line. This behaviour means that the output from
138     tests that are run with and without -s should be identical, except when
139     options that output information about the actual running of a match are
140     set.
142     The -M, -t, and -tm options, which give information about resources
143     used, are likely to produce different output with and without -s. Out-
144     put may also differ if the /C option is present on an individual pat-
145     tern. This uses callouts to trace the the matching process, and this
146     may be different between studied and non-studied patterns. If the pat-
147     tern contains (*MARK) items there may also be differences, for the same
148     reason. The -s command line option can be overridden for specific pat-
149     terns that should never be studied (see the /S pattern modifier below).
151     -t Run each compile, study, and match many times with a timer,
152     and output resulting time per compile or match (in millisec-
153     onds). Do not set -m with -t, because you will then get the
154     size output a zillion times, and the timing will be dis-
155     torted. You can control the number of iterations that are
156     used for timing by following -t with a number (as a separate
157 nigel 93 item on the command line). For example, "-t 1000" would iter-
158     ate 1000 times. The default is to iterate 500000 times.
159 nigel 49
160 nigel 93 -tm This is like -t except that it times only the matching phase,
161     not the compile or study phases.
162 nigel 49
163 nigel 93
164 nigel 63 DESCRIPTION
165 nigel 41
166 ph10 930 If pcretest is given two filename arguments, it reads from the first
167 nigel 73 and writes to the second. If it is given only one filename argument, it
168 ph10 930 reads from that file and writes to stdout. Otherwise, it reads from
169     stdin and writes to stdout, and prompts for each line of input, using
170 nigel 73 "re>" to prompt for regular expressions, and "data>" to prompt for data
171     lines.
172 nigel 41
173 ph10 930 When pcretest is built, a configuration option can specify that it
174     should be linked with the libreadline library. When this is done, if
175 ph10 289 the input is from a terminal, it is read using the readline() function.
176 ph10 930 This provides line-editing and history facilities. The output from the
177 ph10 289 -help option states whether or not readline() will be used.
179 nigel 73 The program handles any number of sets of input on a single input file.
180 ph10 930 Each set starts with a regular expression, and continues with any num-
181 nigel 73 ber of data lines to be matched against the pattern.
182 nigel 41
183 ph10 930 Each data line is matched separately and independently. If you want to
184 nigel 91 do multi-line matches, you have to use the \n escape sequence (or \r or
185 nigel 93 \r\n, etc., depending on the newline setting) in a single line of input
186 ph10 930 to encode the newline sequences. There is no limit on the length of
187     data lines; the input buffer is automatically extended if it is too
188 nigel 93 small.
189 nigel 63
190 ph10 930 An empty line signals the end of the data lines, at which point a new
191     regular expression is read. The regular expressions are given enclosed
192 nigel 91 in any non-alphanumeric delimiters other than backslash, for example:
193 nigel 63
194 nigel 73 /(a|bc)x+yz/
195 nigel 41
196 ph10 930 White space before the initial delimiter is ignored. A regular expres-
197     sion may be continued over several input lines, in which case the new-
198     line characters are included within it. It is possible to include the
199 nigel 73 delimiter within the pattern by escaping it, for example
200 nigel 41
201 nigel 73 /abc\/def/
202 nigel 41
203 ph10 930 If you do so, the escape and the delimiter form part of the pattern,
204     but since delimiters are always non-alphanumeric, this does not affect
205     its interpretation. If the terminating delimiter is immediately fol-
206 nigel 73 lowed by a backslash, for example,
207 nigel 41
208 nigel 73 /abc/\
209 nigel 41
210 ph10 930 then a backslash is added to the end of the pattern. This is done to
211     provide a way of testing the error condition that arises if a pattern
212 nigel 73 finishes with a backslash, because
213 nigel 49
214 nigel 73 /abc\/
215 nigel 49
216 ph10 930 is interpreted as the first line of a pattern that starts with "abc/",
217 nigel 73 causing pcretest to read the next line as a continuation of the regular
218     expression.
219 nigel 49
220 nigel 41
222 nigel 41
223 ph10 930 A pattern may be followed by any number of modifiers, which are mostly
224     single characters. Following Perl usage, these are referred to below
225     as, for example, "the /i modifier", even though the delimiter of the
226     pattern need not always be a slash, and no slash is used when writing
227     modifiers. White space may appear between the final pattern delimiter
228 nigel 75 and the first modifier, and between the modifiers themselves.
229 nigel 41
230 nigel 75 The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
231 ph10 869 PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre[16]_com-
232 ph10 930 pile() is called. These four modifier letters have the same effect as
233 nigel 75 they do in Perl. For example:
235 nigel 73 /caseless/i
236 nigel 41
237 ph10 930 The following table shows additional modifiers for setting PCRE com-
238 ph10 535 pile-time options that do not correspond to anything in Perl:
239 nigel 41
240 ph10 869 /8 PCRE_UTF8 ) when using the 8-bit
241     /? PCRE_NO_UTF8_CHECK ) library
243     /8 PCRE_UTF16 ) when using the 16-bit
244     /? PCRE_NO_UTF16_CHECK ) library
246 ph10 231 /A PCRE_ANCHORED
253 ph10 518 /W PCRE_UCP
254 ph10 231 /X PCRE_EXTRA
257 ph10 231 /<cr> PCRE_NEWLINE_CR
258     /<lf> PCRE_NEWLINE_LF
259     /<crlf> PCRE_NEWLINE_CRLF
260     /<anycrlf> PCRE_NEWLINE_ANYCRLF
261     /<any> PCRE_NEWLINE_ANY
262     /<bsr_anycrlf> PCRE_BSR_ANYCRLF
263     /<bsr_unicode> PCRE_BSR_UNICODE
264 nigel 75
265 ph10 930 The modifiers that are enclosed in angle brackets are literal strings
266     as shown, including the angle brackets, but the letters within can be
267     in either case. This example sets multiline matching with CRLF as the
268 ph10 654 line ending sequence:
269 nigel 91
270 ph10 654 /^abc/m<CRLF>
271 nigel 93
272 ph10 930 As well as turning on the PCRE_UTF8/16 option, the /8 modifier causes
273     all non-printing characters in output strings to be printed using the
274     \x{hh...} notation. Otherwise, those less than 0x100 are output in hex
275 ph10 869 without the curly brackets.
276 nigel 93
277 ph10 930 Full details of the PCRE options are given in the pcreapi documenta-
278 ph10 869 tion.
280 nigel 91 Finding all matches in a string
282 ph10 930 Searching for all possible matches within each subject string can be
283     requested by the /g or /G modifier. After finding a match, PCRE is
284 nigel 73 called again to search the remainder of the subject string. The differ-
285     ence between /g and /G is that the former uses the startoffset argument
286 ph10 930 to pcre[16]_exec() to start searching at a new point within the entire
287     string (which is in effect what Perl does), whereas the latter passes
288     over a shortened substring. This makes a difference to the matching
289 nigel 73 process if the pattern begins with a lookbehind assertion (including \b
290     or \B).
291 nigel 49
292 ph10 930 If any call to pcre[16]_exec() in a /g or /G sequence matches an empty
293     string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
294     PCRE_ANCHORED flags set in order to search for another, non-empty,
295     match at the same point. If this second match fails, the start offset
296     is advanced, and the normal match is retried. This imitates the way
297 ph10 567 Perl handles such cases when using the /g modifier or the split() func-
298 ph10 930 tion. Normally, the start offset is advanced by one character, but if
299     the newline convention recognizes CRLF as a newline, and the current
300 ph10 567 character is CR followed by LF, an advance of two is used.
301 nigel 49
302 nigel 91 Other modifiers
304 nigel 75 There are yet more modifiers for controlling the way pcretest operates.
305 nigel 49
306 ph10 930 The /+ modifier requests that as well as outputting the substring that
307     matched the entire pattern, pcretest should in addition output the
308     remainder of the subject string. This is useful for tests where the
309     subject contains multiple copies of the same substring. If the + modi-
310     fier appears twice, the same action is taken for captured substrings.
311     In each case the remainder is output on the following line with a plus
312     character following the capture number. Note that this modifier must
313     not immediately follow the /S modifier because /S+ and /S++ have other
314     meanings.
315 nigel 41
316 ph10 869 The /= modifier requests that the values of all potential captured
317     parentheses be output after a match. By default, only those up to the
318     highest one actually used in the match are output (corresponding to the
319     return code from pcre[16]_exec()). Values in the offsets vector corre-
320     sponding to higher numbers should be set to -1, and these are output as
321     "<unset>". This modifier gives a way of checking that this is happen-
322     ing.
323 ph10 654
324 ph10 869 The /B modifier is a debugging feature. It requests that pcretest out-
325     put a representation of the compiled code after compilation. Normally
326     this information contains length and offset values; however, if /Z is
327     also present, this data is replaced by spaces. This is a special fea-
328     ture for use in the automatic test scripts; it ensures that the same
329 ph10 123 output is generated for different internal link sizes.
330 nigel 93
331 ph10 869 The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
332 nigel 93 that is, both the /B and the /I modifiers.
333 nigel 41
334 ph10 869 The /F modifier causes pcretest to flip the byte order of the 2-byte
335     and 4-byte fields in the compiled pattern. This facility is for testing
336     the feature in PCRE that allows it to execute patterns that were com-
337     piled on a host with a different endianness. This feature is not avail-
338     able when the POSIX interface to PCRE is being used, that is, when the
339     /P pattern modifier is specified. See also the section about saving and
340     reloading compiled patterns below.
341 nigel 75
342 ph10 869 The /I modifier requests that pcretest output information about the
343     compiled pattern (whether it is anchored, has a fixed first character,
344     and so on). It does this by calling pcre[16]_fullinfo() after compiling
345     a pattern. If the pattern is studied, the results of that are also out-
346 ph10 512 put.
347 nigel 41
348 ph10 869 The /K modifier requests pcretest to show names from backtracking con-
349     trol verbs that are returned from calls to pcre[16]_exec(). It causes
350     pcretest to create a pcre[16]_extra block if one has not already been
351     created by a call to pcre[16]_study(), and to set the PCRE_EXTRA_MARK
352     flag and the mark field within it, every time that pcre[16]_exec() is
353     called. If the variable that the mark field points to is non-NULL for a
354     match, non-match, or partial match, pcretest prints the string to which
355     it points. For a match, this is shown on a line by itself, tagged with
356     "MK:". For a non-match it is added to the message.
357 ph10 512
358 ph10 869 The /L modifier must be followed directly by the name of a locale, for
359 ph10 512 example,
361     /pattern/Lfr_FR
363     For this reason, it must be the last modifier. The given locale is set,
364 ph10 869 pcre[16]_maketables() is called to build a set of character tables for
365     the locale, and this is then passed to pcre[16]_compile() when compil-
366     ing the regular expression. Without an /L (or /T) modifier, NULL is
367     passed as the tables pointer; that is, /L applies only to the expres-
368     sion on which it appears.
369 ph10 512
370 ph10 869 The /M modifier causes the size in bytes of the memory block used to
371     hold the compiled pattern to be output. This does not include the size
372     of the pcre[16] block; it is just the actual compiled data. If the pat-
373     tern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
374     the size of the JIT compiled code is also output.
375 nigel 41
376 ph10 869 If the /S modifier appears once, it causes pcre[16]_study() to be
377     called after the expression has been compiled, and the results used
378     when the expression is matched. If /S appears twice, it suppresses
379     studying, even if it was requested externally by the -s command line
380     option. This makes it possible to specify that certain patterns are
381     always studied, and others are never studied, independently of -s. This
382     feature is used in the test files in a few cases where the output is
383     different when the pattern is studied.
384 nigel 41
385 ph10 869 If the /S modifier is immediately followed by a + character, the call
386 ph10 930 to pcre[16]_study() is made with all the JIT study options, requesting
387     just-in-time optimization support if it is available, for both normal
388     and partial matching. If you want to restrict the JIT compiling modes,
389     you can follow /S+ with a digit in the range 1 to 7:
390 ph10 691
391 ph10 930 1 normal match only
392     2 soft partial match only
393     3 normal match and soft partial match
394     4 hard partial match only
395     6 soft and hard partial match
396     7 all three modes (default)
398     If /S++ is used instead of /S+ (with or without a following digit), the
399     text "(JIT)" is added to the first output line after a match or no
400     match when JIT-compiled code was actually used.
402     Note that there is also an independent /+ modifier; it must not be
403     given immediately after /S or /S+ because this will be misinterpreted.
405     If JIT studying is successful, the compiled JIT code will automatically
406     be used when pcre[16]_exec() is run, except when incompatible run-time
407     options are specified. For more details, see the pcrejit documentation.
408     See also the \J escape sequence below for a way of setting the size of
409     the JIT stack.
411 ph10 869 The /T modifier must be followed by a single digit. It causes a spe-
412     cific set of built-in character tables to be passed to pcre[16]_com-
413     pile(). It is used in the standard PCRE tests to check behaviour with
414     different character tables. The digit specifies the tables as follows:
415 ph10 545
416     0 the default ASCII tables, as distributed in
417     pcre_chartables.c.dist
418     1 a set of tables defining ISO 8859 characters
420 ph10 869 In table 1, some characters whose codes are greater than 128 are iden-
421 ph10 545 tified as letters, digits, spaces, etc.
423 ph10 535 Using the POSIX wrapper API
424 nigel 41
425 ph10 869 The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
426     rather than its native API. This supports only the 8-bit library. When
427     /P is set, the following modifiers set options for the regcomp() func-
428     tion:
429 ph10 535
430     /i REG_ICASE
431     /m REG_NEWLINE
432     /N REG_NOSUB
433     /s REG_DOTALL )
434     /U REG_UNGREEDY ) These options are not part of
435     /W REG_UCP ) the POSIX standard
436     /8 REG_UTF8 )
438 ph10 836 The /+ modifier works as described above. All other modifiers are
439 ph10 535 ignored.
442 nigel 53 DATA LINES
443 nigel 63
444 ph10 869 Before each data line is passed to pcre[16]_exec(), leading and trail-
445     ing white space is removed, and it is then scanned for \ escapes. Some
446     of these are pretty esoteric features, intended for checking out some
447     of the more complicated features of PCRE. If you are just testing
448     "ordinary" regular expressions, you probably don't need any of these.
449     The following escapes are recognized:
450 nigel 49
451 nigel 93 \a alarm (BEL, \x07)
452     \b backspace (\x08)
453     \e escape (\x27)
454 ph10 654 \f form feed (\x0c)
455 nigel 93 \n newline (\x0a)
456 nigel 91 \qdd set the PCRE_MATCH_LIMIT limit to dd
457     (any number of digits)
458 nigel 93 \r carriage return (\x0d)
459     \t tab (\x09)
460     \v vertical tab (\x0b)
461 ph10 869 \nnn octal character (up to 3 octal digits); always
462     a byte unless > 255 in UTF-8 or 16-bit mode
463 ph10 572 \xhh hexadecimal byte (up to 2 hex digits)
464 ph10 869 \x{hh...} hexadecimal character (any number of hex digits)
465     \A pass the PCRE_ANCHORED option to pcre[16]_exec()
466     or pcre[16]_dfa_exec()
467     \B pass the PCRE_NOTBOL option to pcre[16]_exec()
468     or pcre[16]_dfa_exec()
469     \Cdd call pcre[16]_copy_substring() for substring dd
470 nigel 75 after a successful match (number less than 32)
471 ph10 869 \Cname call pcre[16]_copy_named_substring() for substring
472 nigel 73 "name" after a successful match (name termin-
473     ated by next non alphanumeric character)
474     \C+ show the current captured substrings at callout
475     time
476     \C- do not supply a callout function
477     \C!n return 1 instead of 0 when callout number n is
478     reached
479     \C!n!m return 1 instead of 0 when callout number n is
480     reached for the nth time
481     \C*n pass the number n (may be negative) as callout
482 nigel 75 data; this is used as the callout return value
483 ph10 869 \D use the pcre[16]_dfa_exec() match function
484     \F only shortest match for pcre[16]_dfa_exec()
485     \Gdd call pcre[16]_get_substring() for substring dd
486 nigel 75 after a successful match (number less than 32)
487 ph10 869 \Gname call pcre[16]_get_named_substring() for substring
488 nigel 73 "name" after a successful match (name termin-
489     ated by next non-alphanumeric character)
490 ph10 691 \Jdd set up a JIT stack of dd kilobytes maximum (any
491     number of digits)
492 ph10 869 \L call pcre[16]_get_substringlist() after a
493 nigel 73 successful match
494 nigel 87 \M discover the minimum MATCH_LIMIT and
495     MATCH_LIMIT_RECURSION settings
496 ph10 869 \N pass the PCRE_NOTEMPTY option to pcre[16]_exec()
497     or pcre[16]_dfa_exec(); if used twice, pass the
498 ph10 453 PCRE_NOTEMPTY_ATSTART option
499 nigel 73 \Odd set the size of the output vector passed to
500 ph10 869 pcre[16]_exec() to dd (any number of digits)
501     \P pass the PCRE_PARTIAL_SOFT option to pcre[16]_exec()
502     or pcre[16]_dfa_exec(); if used twice, pass the
503 ph10 429 PCRE_PARTIAL_HARD option
504 nigel 91 \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
505     (any number of digits)
506 ph10 869 \R pass the PCRE_DFA_RESTART option to pcre[16]_dfa_exec()
507 nigel 73 \S output details of memory get/free calls during matching
508 ph10 869 \Y pass the PCRE_NO_START_OPTIMIZE option to pcre[16]_exec()
509     or pcre[16]_dfa_exec()
510     \Z pass the PCRE_NOTEOL option to pcre[16]_exec()
511     or pcre[16]_dfa_exec()
512     \? pass the PCRE_NO_UTF[8|16]_CHECK option to
513     pcre[16]_exec() or pcre[16]_dfa_exec()
514 ph10 567 \>dd start the match at offset dd (optional "-"; then
515     any number of digits); this sets the startoffset
516 ph10 869 argument for pcre[16]_exec() or pcre[16]_dfa_exec()
517     \<cr> pass the PCRE_NEWLINE_CR option to pcre[16]_exec()
518     or pcre[16]_dfa_exec()
519     \<lf> pass the PCRE_NEWLINE_LF option to pcre[16]_exec()
520     or pcre[16]_dfa_exec()
521     \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16]_exec()
522     or pcre[16]_dfa_exec()
523     \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16]_exec()
524     or pcre[16]_dfa_exec()
525     \<any> pass the PCRE_NEWLINE_ANY option to pcre[16]_exec()
526     or pcre[16]_dfa_exec()
527 nigel 71
528 ph10 869 The use of \x{hh...} is not dependent on the use of the /8 modifier on
529     the pattern. It is recognized always. There may be any number of hexa-
530     decimal digits inside the braces; invalid values provoke error mes-
531     sages.
532 ph10 572
533 ph10 878 Note that \xhh specifies one byte rather than one character in UTF-8
534     mode; this makes it possible to construct invalid UTF-8 sequences for
535     testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
536     character in UTF-8 mode, generating more than one byte if the value is
537     greater than 127. When testing the 8-bit library not in UTF-8 mode,
538     \x{hh} generates one byte for values less than 256, and causes an error
539     for greater values.
540 ph10 869
541     In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
542     possible to construct invalid UTF-16 sequences for testing purposes.
544 ph10 878 The escapes that specify line ending sequences are literal strings,
545 nigel 93 exactly as shown. No more than one newline setting should be present in
546     any data line.
547 nigel 75
548 ph10 878 A backslash followed by anything else just escapes the anything else.
549     If the very last character is a backslash, it is ignored. This gives a
550     way of passing an empty line as data, since a real empty line termi-
551 nigel 93 nates the data input.
553 ph10 878 The \J escape provides a way of setting the maximum stack size that is
554     used by the just-in-time optimization code. It is ignored if JIT opti-
555     mization is not being used. Providing a stack that is larger than the
556 ph10 691 default 32K is necessary only for very complicated patterns.
557 nigel 41
558 ph10 878 If \M is present, pcretest calls pcre[16]_exec() several times, with
559 ph10 869 different values in the match_limit and match_limit_recursion fields of
560 ph10 878 the pcre[16]_extra data structure, until it finds the minimum numbers
561     for each parameter that allow pcre[16]_exec() to complete without
562     error. Because this is testing a specific feature of the normal inter-
563 ph10 869 pretive pcre[16]_exec() execution, the use of any JIT optimization that
564     might have been set up by the /S+ qualifier of -s+ option is disabled.
565 ph10 691
566 ph10 878 The match_limit number is a measure of the amount of backtracking that
567     takes place, and checking it out can be instructive. For most simple
568     matches, the number is quite small, but for patterns with very large
569     numbers of matching possibilities, it can become large very quickly
570     with increasing length of subject string. The match_limit_recursion
571     number is a measure of how much stack (or, if PCRE is compiled with
572     NO_RECURSE, how much heap) memory is needed to complete the match
573 ph10 691 attempt.
575 ph10 878 When \O is used, the value specified may be higher or lower than the
576 nigel 75 size set by the -O command line option (or defaulted to 45); \O applies
577 ph10 869 only to the call of pcre[16]_exec() for the line in which it appears.
578 nigel 63
579 ph10 878 If the /P modifier was present on the pattern, causing the POSIX wrap-
580     per API to be used, the only option-setting sequences that have any
581     effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
582 ph10 535 REG_NOTEOL, respectively, to be passed to regexec().
583 nigel 41
586 nigel 53
587 ph10 878 By default, pcretest uses the standard PCRE matching function,
588 ph10 869 pcre[16]_exec() to match each data line. PCRE also supports an alterna-
589 ph10 878 tive matching function, pcre[16]_dfa_test(), which operates in a dif-
590     ferent way, and has some restrictions. The differences between the two
591 ph10 869 functions are described in the pcrematching documentation.
592 nigel 77
593 ph10 878 If a data line contains the \D escape sequence, or if the command line
594     contains the -dfa option, the alternative matching function is used.
595 nigel 77 This function finds all possible matches at a given point. If, however,
596 ph10 878 the \F escape sequence is present in the data line, it stops after the
597 nigel 77 first match is found. This is always the shortest possible match.
602 ph10 878 This section describes the output when the normal matching function,
603 ph10 869 pcre[16]_exec(), is being used.
604 nigel 77
605 nigel 73 When a match succeeds, pcretest outputs the list of captured substrings
606 ph10 878 that pcre[16]_exec() returns, starting with number 0 for the string
607     that matched the whole pattern. Otherwise, it outputs "No match" when
608     the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
609     partially matching substring when pcre[16]_exec() returns
610     PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
611     inspected during the partial match; it may include characters before
612     the actual match start if a lookbehind assertion, \K, \b, or \B was
613     involved.) For any other return, pcretest outputs the PCRE negative
614     error number and a short descriptive phrase. If the error is a failed
615     UTF string check, the offset of the start of the failing character and
616     the reason code are also output, provided that the size of the output
617     vector is at least two. Here is an example of an interactive pcretest
618 ph10 869 run.
619 nigel 53
620 nigel 73 $ pcretest
621 ph10 654 PCRE version 8.13 2011-04-30
622 nigel 53
623 nigel 73 re> /^abc(\d+)/
624     data> abc123
625     0: abc123
626     1: 123
627     data> xyz
628     No match
629 nigel 53
630 ph10 654 Unset capturing substrings that are not followed by one that is set are
631 ph10 878 not returned by pcre[16]_exec(), and are not shown by pcretest. In the
632     following example, there are two capturing substrings, but when the
633     first data line is matched, the second, unset substring is not shown.
634     An "internal" unset substring is shown as "<unset>", as for the second
635 ph10 654 data line.
636 ph10 286
637     re> /(a)|(b)/
638     data> a
639     0: a
640     1: a
641     data> b
642     0: b
643     1: <unset>
644     2: b
646 ph10 878 If the strings contain any non-printing characters, they are output as
647     \xhh escapes if the value is less than 256 and UTF mode is not set.
648 ph10 869 Otherwise they are output as \x{hh...} escapes. See below for the defi-
649 ph10 878 nition of non-printing characters. If the pattern has the /+ modifier,
650     the output for substring 0 is followed by the the rest of the subject
651 ph10 869 string, identified by "0+" like this:
652 nigel 53
653 nigel 73 re> /cat/+
654     data> cataract
655     0: cat
656     0+ aract
657 nigel 53
658 ph10 878 If the pattern has the /g or /G modifier, the results of successive
659 nigel 73 matching attempts are output in sequence, like this:
660 nigel 53
661 nigel 73 re> /\Bi(\w\w)/g
662     data> Mississippi
663     0: iss
664     1: ss
665     0: iss
666     1: ss
667     0: ipp
668     1: pp
669 nigel 53
670 ph10 878 "No match" is output only if the first match attempt fails. Here is an
671     example of a failure message (the offset 4 that is specified by \>4 is
672 ph10 654 past the end of the subject string):
673 nigel 53
674 ph10 654 re> /xyz/
675     data> xyz\>4
676     Error -24 (bad offset value)
678 ph10 878 If any of the sequences \C, \G, or \L are present in a data line that
679     is successfully matched, the substrings extracted by the convenience
680 nigel 73 functions are output with C, G, or L after the string number instead of
681     a colon. This is in addition to the normal full list. The string length
682 ph10 878 (that is, the return from the extraction function) is given in paren-
683 nigel 73 theses after each string for \C and \G.
684 nigel 53
685 nigel 93 Note that whereas patterns can be continued over several lines (a plain
686 nigel 73 ">" prompt is used for continuations), data lines may not. However new-
687 ph10 878 lines can be included in data by means of the \n escape (or \r, \r\n,
688 nigel 93 etc., depending on the newline sequence setting).
689 nigel 53
693 ph10 878 When the alternative matching function, pcre[16]_dfa_exec(), is used
694     (by means of the \D escape sequence or the -dfa command line option),
695     the output consists of a list of all the matches that start at the
696 ph10 869 first point in the subject where there is at least one match. For exam-
697     ple:
698 nigel 77
699     re> /(tang|tangerine|tan)/
700     data> yellow tangerine\D
701     0: tangerine
702     1: tang
703     2: tan
705 ph10 878 (Using the normal matching function on this data finds only "tang".)
706     The longest matching string is always given first (and numbered zero).
707 ph10 429 After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
708 ph10 878 lowed by the partially matching substring. (Note that this is the
709     entire substring that was inspected during the partial match; it may
710 ph10 567 include characters before the actual match start if a lookbehind asser-
711     tion, \K, \b, or \B was involved.)
712 nigel 77
713 nigel 93 If /g is present on the pattern, the search for further matches resumes
714     at the end of the longest match. For example:
715 nigel 77
716     re> /(tang|tangerine|tan)/g
717     data> yellow tangerine and tangy sultana\D
718     0: tangerine
719     1: tang
720     2: tan
721     0: tang
722     1: tan
723     0: tan
725 ph10 878 Since the matching function does not support substring capture, the
726     escape sequences that are concerned with captured substrings are not
727 nigel 77 relevant.
732     When the alternative matching function has given the PCRE_ERROR_PARTIAL
733 ph10 878 return, indicating that the subject partially matched the pattern, you
734     can restart the match with additional subject data by means of the \R
735 nigel 77 escape sequence. For example:
737 ph10 155 re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
738 nigel 77 data> 23ja\P\D
739     Partial match: 23ja
740     data> n05\R\D
741     0: n05
743 ph10 878 For further information about partial matching, see the pcrepartial
744 nigel 77 documentation.
747 nigel 75 CALLOUTS
749 ph10 878 If the pattern contains any callout requests, pcretest's callout func-
750     tion is called during matching. This works with both matching func-
751 nigel 77 tions. By default, the called function displays the callout number, the
752 ph10 878 start and current positions in the text at the callout time, and the
753 ph10 869 next pattern item to be tested. For example:
754 nigel 75
755     --->pqrabcdef
756     0 ^ ^ \d
758 ph10 878 This output indicates that callout number 0 occurred for a match
759     attempt starting at the fourth character of the subject string, when
760 ph10 869 the pointer was at the seventh character of the data, and when the next
761 ph10 878 pattern item was \d. Just one circumflex is output if the start and
762 ph10 869 current positions are the same.
763 nigel 75
764     Callouts numbered 255 are assumed to be automatic callouts, inserted as
765 ph10 878 a result of the /C pattern modifier. In this case, instead of showing
766     the callout number, the offset in the pattern, preceded by a plus, is
767 nigel 75 output. For example:
769     re> /\d?[A-E]\*/C
770     data> E*
771     --->E*
772     +0 ^ \d?
773     +3 ^ [A-E]
774     +8 ^^ \*
775     +10 ^ ^
776     0: E*
778 ph10 654 If a pattern contains (*MARK) items, an additional line is output when-
779 ph10 878 ever a change of latest mark is passed to the callout function. For
780 ph10 654 example:
782     re> /a(*MARK:X)bc/C
783     data> abc
784     --->abc
785     +0 ^ a
786     +1 ^^ (*MARK:X)
787     +10 ^^ b
788     Latest Mark: X
789     +11 ^ ^ c
790     +12 ^ ^
791     0: abc
793 ph10 878 The mark changes between matching "a" and "b", but stays the same for
794     the rest of the match, so nothing more is output. If, as a result of
795     backtracking, the mark reverts to being unset, the text "<unset>" is
796 ph10 654 output.
798 ph10 878 The callout function in pcretest returns zero (carry on matching) by
799     default, but you can use a \C item in a data line (as described above)
800 ph10 654 to change this and other parameters of the callout.
801 nigel 75
802 ph10 878 Inserting callouts can be helpful when using pcretest to check compli-
803     cated regular expressions. For further information about callouts, see
804 nigel 75 the pcrecallout documentation.
809 ph10 878 When pcretest is outputting text in the compiled version of a pattern,
810     bytes other than 32-126 are always treated as non-printing characters
811 nigel 93 are are therefore shown as hex escapes.
813 ph10 878 When pcretest is outputting text that is a matched part of a subject
814     string, it behaves in the same way, unless a different locale has been
815     set for the pattern (using the /L modifier). In this case, the
816 nigel 93 isprint() function to distinguish printing and non-printing characters.
821 ph10 878 The facilities described in this section are not available when the
822     POSIX interface to PCRE is being used, that is, when the /P pattern
823 ph10 654 modifier is specified.
824 nigel 75
825     When the POSIX interface is not in use, you can cause pcretest to write
826 ph10 878 a compiled pattern to a file, by following the modifiers with > and a
827 nigel 75 file name. For example:
829     /pattern/im >/some/file
831 ph10 878 See the pcreprecompile documentation for a discussion about saving and
832     re-using compiled patterns. Note that if the pattern was successfully
833 ph10 691 studied with JIT optimization, the JIT data cannot be saved.
834 nigel 75
835 ph10 878 The data that is written is binary. The first eight bytes are the
836     length of the compiled pattern data followed by the length of the
837     optional study data, each written as four bytes in big-endian order
838     (most significant byte first). If there is no study data (either the
839 nigel 75 pattern was not studied, or studying did not return any data), the sec-
840 ph10 878 ond length is zero. The lengths are followed by an exact copy of the
841     compiled pattern. If there is additional study data, this (excluding
842     any JIT data) follows immediately after the compiled pattern. After
843 ph10 691 writing the file, pcretest expects to read a new pattern.
844 nigel 75
845 ph10 878 A saved pattern can be reloaded into pcretest by specifying < and a
846 ph10 654 file name instead of a pattern. The name of the file must not contain a
847     < character, as otherwise pcretest will interpret the line as a pattern
848 nigel 75 delimited by < characters. For example:
850     re> </some/file
851 ph10 654 Compiled pattern loaded from /some/file
852 nigel 75 No study data
854 ph10 878 If the pattern was previously studied with the JIT optimization, the
855     JIT information cannot be saved and restored, and so is lost. When the
856     pattern has been loaded, pcretest proceeds to read data lines in the
857 ph10 691 usual way.
858 nigel 75
859 ph10 878 You can copy a file written by pcretest to a different host and reload
860     it there, even if the new host has opposite endianness to the one on
861     which the pattern was compiled. For example, you can compile on an i86
862     machine and run on a SPARC machine. When a pattern is reloaded on a
863 ph10 869 host with different endianness, the confirmation message is changed to:
864 nigel 75
865 ph10 869 Compiled pattern (byte-inverted) loaded from /some/file
867     The test suite contains some saved pre-compiled patterns with different
868 ph10 878 endianness. These are reloaded using "<!" instead of just "<". This
869 ph10 869 suppresses the "(byte-inverted)" text so that the output is the same on
870 ph10 878 all hosts. It also forces debugging output once the pattern has been
871 ph10 869 reloaded.
873 ph10 878 File names for saving and reloading can be absolute or relative, but
874     note that the shell facility of expanding a file name that starts with
875 nigel 75 a tilde (~) is not available.
877 ph10 878 The ability to save and reload files in pcretest is intended for test-
878     ing and experimentation. It is not intended for production use because
879     only a single pattern can be written to a file. Furthermore, there is
880     no facility for supplying custom character tables for use with a
881     reloaded pattern. If the original pattern was compiled with custom
882     tables, an attempt to match a subject string using a reloaded pattern
883     is likely to cause pcretest to crash. Finally, if you attempt to load
884 nigel 75 a file that is not in the correct format, the result is undefined.
887 nigel 93 SEE ALSO
889 ph10 878 pcre(3), pcre16(3), pcreapi(3), pcrecallout(3), pcrejit, pcrematch-
890 ph10 869 ing(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
891 nigel 93
893 nigel 63 AUTHOR
894 nigel 53
895 nigel 77 Philip Hazel
896 ph10 99 University Computing Service
897 nigel 93 Cambridge CB2 3QH, England.
898 nigel 53
899 ph10 99
900     REVISION
902 ph10 930 Last updated: 21 February 2012
903 ph10 869 Copyright (c) 1997-2012 University of Cambridge.


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

ViewVC Help
Powered by ViewVC 1.1.12