1: PCRETEST(1) General Commands Manual PCRETEST(1)
2:
3:
4:
5: NAME
6: pcretest - a program for testing Perl-compatible regular expressions.
7:
8: SYNOPSIS
9:
10: pcretest [options] [input file [output file]]
11:
12: 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: documentation. For details of the PCRE library function calls and their
17: options, see the pcreapi , pcre16 and pcre32 documentation.
18:
19: The input for pcretest is a sequence of regular expression patterns and
20: strings to be matched, as described below. The output shows the result
21: of each match. Options on the command line and the patterns control
22: PCRE options and exactly what is output.
23:
24: As PCRE has evolved, it has acquired many different features, and as a
25: result, pcretest now has rather a lot of obscure options for testing
26: every possible feature. Some of these options are specifically designed
27: for use in conjunction with the test script and data files that are
28: distributed as part of PCRE, and are unlikely to be of use otherwise.
29: They are all documented here, but without much justification.
30:
31:
32: INPUT DATA FORMAT
33:
34: Input to pcretest is processed line by line, either by calling the C
35: library's fgets() function, or via the libreadline library (see below).
36: In Unix-like environments, fgets() treats any bytes other than newline
37: as data characters. However, in some Windows environments character 26
38: (hex 1A) causes an immediate end of file, and no further data is read.
39: For maximum portability, therefore, it is safest to use only ASCII
40: characters in pcretest input files.
41:
42:
43: PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES
44:
45: From release 8.30, two separate PCRE libraries can be built. The origi-
46: nal one supports 8-bit character strings, whereas the newer 16-bit
47: library supports character strings encoded in 16-bit units. From
48: release 8.32, a third library can be built, supporting character
49: strings encoded in 32-bit units. The pcretest program can be used to
50: test all three libraries. However, it is itself still an 8-bit program,
51: reading 8-bit input and writing 8-bit output. When testing the 16-bit
52: or 32-bit library, the patterns and data strings are converted to 16-
53: or 32-bit format before being passed to the PCRE library functions.
54: Results are converted to 8-bit for output.
55:
56: References to functions and structures of the form pcre[16|32]_xx below
57: mean "pcre_xx when using the 8-bit library, pcre16_xx when using the
58: 16-bit library, or pcre32_xx when using the 32-bit library".
59:
60:
61: COMMAND LINE OPTIONS
62:
63: -8 If both the 8-bit library has been built, this option causes
64: the 8-bit library to be used (which is the default); if the
65: 8-bit library has not been built, this option causes an
66: error.
67:
68: -16 If both the 8-bit or the 32-bit, and the 16-bit libraries
69: have been built, this option causes the 16-bit library to be
70: used. If only the 16-bit library has been built, this is the
71: default (so has no effect). If only the 8-bit or the 32-bit
72: library has been built, this option causes an error.
73:
74: -32 If both the 8-bit or the 16-bit, and the 32-bit libraries
75: have been built, this option causes the 32-bit library to be
76: used. If only the 32-bit library has been built, this is the
77: default (so has no effect). If only the 8-bit or the 16-bit
78: library has been built, this option causes an error.
79:
80: -b Behave as if each pattern has the /B (show byte code) modi-
81: fier; the internal form is output after compilation.
82:
83: -C Output the version number of the PCRE library, and all avail-
84: able information about the optional features that are
85: included, and then exit with zero exit code. All other
86: options are ignored.
87:
88: -C option Output information about a specific build-time option, then
89: exit. This functionality is intended for use in scripts such
90: as RunTest. The following options output the value and set
91: the exit code as indicated:
92:
93: ebcdic-nl the code for LF (= NL) in an EBCDIC environment:
94: 0x15 or 0x25
95: 0 if used in an ASCII environment
96: exit code is always 0
97: linksize the configured internal link size (2, 3, or 4)
98: exit code is set to the link size
99: newline the default newline setting:
100: CR, LF, CRLF, ANYCRLF, or ANY
101: exit code is always 0
102:
103: The following options output 1 for true or 0 for false, and
104: set the exit code to the same value:
105:
106: ebcdic compiled for an EBCDIC environment
107: jit just-in-time support is available
108: pcre16 the 16-bit library was built
109: pcre32 the 32-bit library was built
110: pcre8 the 8-bit library was built
111: ucp Unicode property support is available
112: utf UTF-8 and/or UTF-16 and/or UTF-32 support
113: is available
114:
115: If an unknown option is given, an error message is output;
116: the exit code is 0.
117:
118: -d Behave as if each pattern has the /D (debug) modifier; the
119: internal form and information about the compiled pattern is
120: output after compilation; -d is equivalent to -b -i.
121:
122: -dfa Behave as if each data line contains the \D escape sequence;
123: this causes the alternative matching function,
124: pcre[16|32]_dfa_exec(), to be used instead of the standard
125: pcre[16|32]_exec() function (more detail is given below).
126:
127: -help Output a brief summary these options and then exit.
128:
129: -i Behave as if each pattern has the /I modifier; information
130: about the compiled pattern is given after compilation.
131:
132: -M Behave as if each data line contains the \M escape sequence;
133: this causes PCRE to discover the minimum MATCH_LIMIT and
134: MATCH_LIMIT_RECURSION settings by calling pcre[16|32]_exec()
135: repeatedly with different limits.
136:
137: -m Output the size of each compiled pattern after it has been
138: compiled. This is equivalent to adding /M to each regular
139: expression. The size is given in bytes for both libraries.
140:
141: -O Behave as if each pattern has the /O modifier, that is dis-
142: able auto-possessification for all patterns.
143:
144: -o osize Set the number of elements in the output vector that is used
145: when calling pcre[16|32]_exec() or pcre[16|32]_dfa_exec() to
146: be osize. The default value is 45, which is enough for 14
147: capturing subexpressions for pcre[16|32]_exec() or 22 differ-
148: ent matches for pcre[16|32]_dfa_exec(). The vector size can
149: be changed for individual matching calls by including \O in
150: the data line (see below).
151:
152: -p Behave as if each pattern has the /P modifier; the POSIX
153: wrapper API is used to call PCRE. None of the other options
154: has any effect when -p is set. This option can be used only
155: with the 8-bit library.
156:
157: -q Do not output the version number of pcretest at the start of
158: execution.
159:
160: -S size On Unix-like systems, set the size of the run-time stack to
161: size megabytes.
162:
163: -s or -s+ Behave as if each pattern has the /S modifier; in other
164: words, force each pattern to be studied. If -s+ is used, all
165: the JIT compile options are passed to pcre[16|32]_study(),
166: causing just-in-time optimization to be set up if it is
167: available, for both full and partial matching. Specific JIT
168: compile options can be selected by following -s+ with a digit
169: in the range 1 to 7, which selects the JIT compile modes as
170: follows:
171:
172: 1 normal match only
173: 2 soft partial match only
174: 3 normal match and soft partial match
175: 4 hard partial match only
176: 6 soft and hard partial match
177: 7 all three modes (default)
178:
179: If -s++ is used instead of -s+ (with or without a following
180: digit), the text "(JIT)" is added to the first output line
181: after a match or no match when JIT-compiled code was actually
182: used.
183:
184: Note that there are pattern options that can override -s,
185: either specifying no studying at all, or suppressing JIT com-
186: pilation.
187:
188: If the /I or /D option is present on a pattern (requesting
189: output about the compiled pattern), information about the
190: result of studying is not included when studying is caused
191: only by -s and neither -i nor -d is present on the command
192: line. This behaviour means that the output from tests that
193: are run with and without -s should be identical, except when
194: options that output information about the actual running of a
195: match are set.
196:
197: The -M, -t, and -tm options, which give information about
198: resources used, are likely to produce different output with
199: and without -s. Output may also differ if the /C option is
200: present on an individual pattern. This uses callouts to trace
201: the the matching process, and this may be different between
202: studied and non-studied patterns. If the pattern contains
203: (*MARK) items there may also be differences, for the same
204: reason. The -s command line option can be overridden for spe-
205: cific patterns that should never be studied (see the /S pat-
206: tern modifier below).
207:
208: -t Run each compile, study, and match many times with a timer,
209: and output the resulting times per compile, study, or match
210: (in milliseconds). Do not set -m with -t, because you will
211: then get the size output a zillion times, and the timing will
212: be distorted. You can control the number of iterations that
213: are used for timing by following -t with a number (as a sepa-
214: rate item on the command line). For example, "-t 1000" iter-
215: ates 1000 times. The default is to iterate 500000 times.
216:
217: -tm This is like -t except that it times only the matching phase,
218: not the compile or study phases.
219:
220: -T -TM These behave like -t and -tm, but in addition, at the end of
221: a run, the total times for all compiles, studies, and matches
222: are output.
223:
224:
225: DESCRIPTION
226:
227: If pcretest is given two filename arguments, it reads from the first
228: and writes to the second. If it is given only one filename argument, it
229: reads from that file and writes to stdout. Otherwise, it reads from
230: stdin and writes to stdout, and prompts for each line of input, using
231: "re>" to prompt for regular expressions, and "data>" to prompt for data
232: lines.
233:
234: When pcretest is built, a configuration option can specify that it
235: should be linked with the libreadline library. When this is done, if
236: the input is from a terminal, it is read using the readline() function.
237: This provides line-editing and history facilities. The output from the
238: -help option states whether or not readline() will be used.
239:
240: The program handles any number of sets of input on a single input file.
241: Each set starts with a regular expression, and continues with any num-
242: ber of data lines to be matched against that pattern.
243:
244: Each data line is matched separately and independently. If you want to
245: do multi-line matches, you have to use the \n escape sequence (or \r or
246: \r\n, etc., depending on the newline setting) in a single line of input
247: to encode the newline sequences. There is no limit on the length of
248: data lines; the input buffer is automatically extended if it is too
249: small.
250:
251: An empty line signals the end of the data lines, at which point a new
252: regular expression is read. The regular expressions are given enclosed
253: in any non-alphanumeric delimiters other than backslash, for example:
254:
255: /(a|bc)x+yz/
256:
257: White space before the initial delimiter is ignored. A regular expres-
258: sion may be continued over several input lines, in which case the new-
259: line characters are included within it. It is possible to include the
260: delimiter within the pattern by escaping it, for example
261:
262: /abc\/def/
263:
264: If you do so, the escape and the delimiter form part of the pattern,
265: but since delimiters are always non-alphanumeric, this does not affect
266: its interpretation. If the terminating delimiter is immediately fol-
267: lowed by a backslash, for example,
268:
269: /abc/\
270:
271: then a backslash is added to the end of the pattern. This is done to
272: provide a way of testing the error condition that arises if a pattern
273: finishes with a backslash, because
274:
275: /abc\/
276:
277: is interpreted as the first line of a pattern that starts with "abc/",
278: causing pcretest to read the next line as a continuation of the regular
279: expression.
280:
281:
282: PATTERN MODIFIERS
283:
284: A pattern may be followed by any number of modifiers, which are mostly
285: single characters, though some of these can be qualified by further
286: characters. Following Perl usage, these are referred to below as, for
287: example, "the /i modifier", even though the delimiter of the pattern
288: need not always be a slash, and no slash is used when writing modi-
289: fiers. White space may appear between the final pattern delimiter and
290: the first modifier, and between the modifiers themselves. For refer-
291: ence, here is a complete list of modifiers. They fall into several
292: groups that are described in detail in the following sections.
293:
294: /8 set UTF mode
295: /9 set PCRE_NEVER_UTF (locks out UTF mode)
296: /? disable UTF validity check
297: /+ show remainder of subject after match
298: /= show all captures (not just those that are set)
299:
300: /A set PCRE_ANCHORED
301: /B show compiled code
302: /C set PCRE_AUTO_CALLOUT
303: /D same as /B plus /I
304: /E set PCRE_DOLLAR_ENDONLY
305: /F flip byte order in compiled pattern
306: /f set PCRE_FIRSTLINE
307: /G find all matches (shorten string)
308: /g find all matches (use startoffset)
309: /I show information about pattern
310: /i set PCRE_CASELESS
311: /J set PCRE_DUPNAMES
312: /K show backtracking control names
313: /L set locale
314: /M show compiled memory size
315: /m set PCRE_MULTILINE
316: /N set PCRE_NO_AUTO_CAPTURE
317: /O set PCRE_NO_AUTO_POSSESS
318: /P use the POSIX wrapper
319: /S study the pattern after compilation
320: /s set PCRE_DOTALL
321: /T select character tables
322: /U set PCRE_UNGREEDY
323: /W set PCRE_UCP
324: /X set PCRE_EXTRA
325: /x set PCRE_EXTENDED
326: /Y set PCRE_NO_START_OPTIMIZE
327: /Z don't show lengths in /B output
328:
329: /<any> set PCRE_NEWLINE_ANY
330: /<anycrlf> set PCRE_NEWLINE_ANYCRLF
331: /<cr> set PCRE_NEWLINE_CR
332: /<crlf> set PCRE_NEWLINE_CRLF
333: /<lf> set PCRE_NEWLINE_LF
334: /<bsr_anycrlf> set PCRE_BSR_ANYCRLF
335: /<bsr_unicode> set PCRE_BSR_UNICODE
336: /<JS> set PCRE_JAVASCRIPT_COMPAT
337:
338:
339: Perl-compatible modifiers
340:
341: The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
342: PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
343: pcre[16|32]_compile() is called. These four modifier letters have the
344: same effect as they do in Perl. For example:
345:
346: /caseless/i
347:
348:
349: Modifiers for other PCRE options
350:
351: The following table shows additional modifiers for setting PCRE com-
352: pile-time options that do not correspond to anything in Perl:
353:
354: /8 PCRE_UTF8 ) when using the 8-bit
355: /? PCRE_NO_UTF8_CHECK ) library
356:
357: /8 PCRE_UTF16 ) when using the 16-bit
358: /? PCRE_NO_UTF16_CHECK ) library
359:
360: /8 PCRE_UTF32 ) when using the 32-bit
361: /? PCRE_NO_UTF32_CHECK ) library
362:
363: /9 PCRE_NEVER_UTF
364: /A PCRE_ANCHORED
365: /C PCRE_AUTO_CALLOUT
366: /E PCRE_DOLLAR_ENDONLY
367: /f PCRE_FIRSTLINE
368: /J PCRE_DUPNAMES
369: /N PCRE_NO_AUTO_CAPTURE
370: /O PCRE_NO_AUTO_POSSESS
371: /U PCRE_UNGREEDY
372: /W PCRE_UCP
373: /X PCRE_EXTRA
374: /Y PCRE_NO_START_OPTIMIZE
375: /<any> PCRE_NEWLINE_ANY
376: /<anycrlf> PCRE_NEWLINE_ANYCRLF
377: /<cr> PCRE_NEWLINE_CR
378: /<crlf> PCRE_NEWLINE_CRLF
379: /<lf> PCRE_NEWLINE_LF
380: /<bsr_anycrlf> PCRE_BSR_ANYCRLF
381: /<bsr_unicode> PCRE_BSR_UNICODE
382: /<JS> PCRE_JAVASCRIPT_COMPAT
383:
384: The modifiers that are enclosed in angle brackets are literal strings
385: as shown, including the angle brackets, but the letters within can be
386: in either case. This example sets multiline matching with CRLF as the
387: line ending sequence:
388:
389: /^abc/m<CRLF>
390:
391: As well as turning on the PCRE_UTF8/16/32 option, the /8 modifier
392: causes all non-printing characters in output strings to be printed
393: using the \x{hh...} notation. Otherwise, those less than 0x100 are out-
394: put in hex without the curly brackets.
395:
396: Full details of the PCRE options are given in the pcreapi documenta-
397: tion.
398:
399: Finding all matches in a string
400:
401: Searching for all possible matches within each subject string can be
402: requested by the /g or /G modifier. After finding a match, PCRE is
403: called again to search the remainder of the subject string. The differ-
404: ence between /g and /G is that the former uses the startoffset argument
405: to pcre[16|32]_exec() to start searching at a new point within the
406: entire string (which is in effect what Perl does), whereas the latter
407: passes over a shortened substring. This makes a difference to the
408: matching process if the pattern begins with a lookbehind assertion
409: (including \b or \B).
410:
411: If any call to pcre[16|32]_exec() in a /g or /G sequence matches an
412: empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
413: PCRE_ANCHORED flags set in order to search for another, non-empty,
414: match at the same point. If this second match fails, the start offset
415: is advanced, and the normal match is retried. This imitates the way
416: Perl handles such cases when using the /g modifier or the split() func-
417: tion. Normally, the start offset is advanced by one character, but if
418: the newline convention recognizes CRLF as a newline, and the current
419: character is CR followed by LF, an advance of two is used.
420:
421: Other modifiers
422:
423: There are yet more modifiers for controlling the way pcretest operates.
424:
425: The /+ modifier requests that as well as outputting the substring that
426: matched the entire pattern, pcretest should in addition output the
427: remainder of the subject string. This is useful for tests where the
428: subject contains multiple copies of the same substring. If the + modi-
429: fier appears twice, the same action is taken for captured substrings.
430: In each case the remainder is output on the following line with a plus
431: character following the capture number. Note that this modifier must
432: not immediately follow the /S modifier because /S+ and /S++ have other
433: meanings.
434:
435: The /= modifier requests that the values of all potential captured
436: parentheses be output after a match. By default, only those up to the
437: highest one actually used in the match are output (corresponding to the
438: return code from pcre[16|32]_exec()). Values in the offsets vector cor-
439: responding to higher numbers should be set to -1, and these are output
440: as "<unset>". This modifier gives a way of checking that this is hap-
441: pening.
442:
443: The /B modifier is a debugging feature. It requests that pcretest out-
444: put a representation of the compiled code after compilation. Normally
445: this information contains length and offset values; however, if /Z is
446: also present, this data is replaced by spaces. This is a special fea-
447: ture for use in the automatic test scripts; it ensures that the same
448: output is generated for different internal link sizes.
449:
450: The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
451: that is, both the /B and the /I modifiers.
452:
453: The /F modifier causes pcretest to flip the byte order of the 2-byte
454: and 4-byte fields in the compiled pattern. This facility is for testing
455: the feature in PCRE that allows it to execute patterns that were com-
456: piled on a host with a different endianness. This feature is not avail-
457: able when the POSIX interface to PCRE is being used, that is, when the
458: /P pattern modifier is specified. See also the section about saving and
459: reloading compiled patterns below.
460:
461: The /I modifier requests that pcretest output information about the
462: compiled pattern (whether it is anchored, has a fixed first character,
463: and so on). It does this by calling pcre[16|32]_fullinfo() after com-
464: piling a pattern. If the pattern is studied, the results of that are
465: also output.
466:
467: The /K modifier requests pcretest to show names from backtracking con-
468: trol verbs that are returned from calls to pcre[16|32]_exec(). It
469: causes pcretest to create a pcre[16|32]_extra block if one has not
470: already been created by a call to pcre[16|32]_study(), and to set the
471: PCRE_EXTRA_MARK flag and the mark field within it, every time that
472: pcre[16|32]_exec() is called. If the variable that the mark field
473: points to is non-NULL for a match, non-match, or partial match,
474: pcretest prints the string to which it points. For a match, this is
475: shown on a line by itself, tagged with "MK:". For a non-match it is
476: added to the message.
477:
478: The /L modifier must be followed directly by the name of a locale, for
479: example,
480:
481: /pattern/Lfr_FR
482:
483: For this reason, it must be the last modifier. The given locale is set,
484: pcre[16|32]_maketables() is called to build a set of character tables
485: for the locale, and this is then passed to pcre[16|32]_compile() when
486: compiling the regular expression. Without an /L (or /T) modifier, NULL
487: is passed as the tables pointer; that is, /L applies only to the
488: expression on which it appears.
489:
490: The /M modifier causes the size in bytes of the memory block used to
491: hold the compiled pattern to be output. This does not include the size
492: of the pcre[16|32] block; it is just the actual compiled data. If the
493: pattern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
494: the size of the JIT compiled code is also output.
495:
496: The /S modifier causes pcre[16|32]_study() to be called after the
497: expression has been compiled, and the results used when the expression
498: is matched. There are a number of qualifying characters that may follow
499: /S. They may appear in any order.
500:
501: If /S is followed by an exclamation mark, pcre[16|32]_study() is called
502: with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a
503: pcre_extra block, even when studying discovers no useful information.
504:
505: If /S is followed by a second S character, it suppresses studying, even
506: if it was requested externally by the -s command line option. This
507: makes it possible to specify that certain patterns are always studied,
508: and others are never studied, independently of -s. This feature is used
509: in the test files in a few cases where the output is different when the
510: pattern is studied.
511:
512: If the /S modifier is followed by a + character, the call to
513: pcre[16|32]_study() is made with all the JIT study options, requesting
514: just-in-time optimization support if it is available, for both normal
515: and partial matching. If you want to restrict the JIT compiling modes,
516: you can follow /S+ with a digit in the range 1 to 7:
517:
518: 1 normal match only
519: 2 soft partial match only
520: 3 normal match and soft partial match
521: 4 hard partial match only
522: 6 soft and hard partial match
523: 7 all three modes (default)
524:
525: If /S++ is used instead of /S+ (with or without a following digit), the
526: text "(JIT)" is added to the first output line after a match or no
527: match when JIT-compiled code was actually used.
528:
529: Note that there is also an independent /+ modifier; it must not be
530: given immediately after /S or /S+ because this will be misinterpreted.
531:
532: If JIT studying is successful, the compiled JIT code will automatically
533: be used when pcre[16|32]_exec() is run, except when incompatible run-
534: time options are specified. For more details, see the pcrejit documen-
535: tation. See also the \J escape sequence below for a way of setting the
536: size of the JIT stack.
537:
538: Finally, if /S is followed by a minus character, JIT compilation is
539: suppressed, even if it was requested externally by the -s command line
540: option. This makes it possible to specify that JIT is never to be used
541: for certain patterns.
542:
543: The /T modifier must be followed by a single digit. It causes a spe-
544: cific set of built-in character tables to be passed to pcre[16|32]_com-
545: pile(). It is used in the standard PCRE tests to check behaviour with
546: different character tables. The digit specifies the tables as follows:
547:
548: 0 the default ASCII tables, as distributed in
549: pcre_chartables.c.dist
550: 1 a set of tables defining ISO 8859 characters
551:
552: In table 1, some characters whose codes are greater than 128 are iden-
553: tified as letters, digits, spaces, etc.
554:
555: Using the POSIX wrapper API
556:
557: The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
558: rather than its native API. This supports only the 8-bit library. When
559: /P is set, the following modifiers set options for the regcomp() func-
560: tion:
561:
562: /i REG_ICASE
563: /m REG_NEWLINE
564: /N REG_NOSUB
565: /s REG_DOTALL )
566: /U REG_UNGREEDY ) These options are not part of
567: /W REG_UCP ) the POSIX standard
568: /8 REG_UTF8 )
569:
570: The /+ modifier works as described above. All other modifiers are
571: ignored.
572:
573: Locking out certain modifiers
574:
575: PCRE can be compiled with or without support for certain features such
576: as UTF-8/16/32 or Unicode properties. Accordingly, the standard tests
577: are split up into a number of different files that are selected for
578: running depending on which features are available. When updating the
579: tests, it is all too easy to put a new test into the wrong file by mis-
580: take; for example, to put a test that requires UTF support into a file
581: that is used when it is not available. To help detect such mistakes as
582: early as possible, there is a facility for locking out specific modi-
583: fiers. If an input line for pcretest starts with the string "< forbid "
584: the following sequence of characters is taken as a list of forbidden
585: modifiers. For example, in the test files that must not use UTF or Uni-
586: code property support, this line appears:
587:
588: < forbid 8W
589:
590: This locks out the /8 and /W modifiers. An immediate error is given if
591: they are subsequently encountered. If the character string contains <
592: but not >, all the multi-character modifiers that begin with < are
593: locked out. Otherwise, such modifiers must be explicitly listed, for
594: example:
595:
596: < forbid <JS><cr>
597:
598: There must be a single space between < and "forbid" for this feature to
599: be recognised. If there is not, the line is interpreted either as a
600: request to re-load a pre-compiled pattern (see "SAVING AND RELOADING
601: COMPILED PATTERNS" below) or, if there is a another < character, as a
602: pattern that uses < as its delimiter.
603:
604:
605: DATA LINES
606:
607: Before each data line is passed to pcre[16|32]_exec(), leading and
608: trailing white space is removed, and it is then scanned for \ escapes.
609: Some of these are pretty esoteric features, intended for checking out
610: some of the more complicated features of PCRE. If you are just testing
611: "ordinary" regular expressions, you probably don't need any of these.
612: The following escapes are recognized:
613:
614: \a alarm (BEL, \x07)
615: \b backspace (\x08)
616: \e escape (\x27)
617: \f form feed (\x0c)
618: \n newline (\x0a)
619: \qdd set the PCRE_MATCH_LIMIT limit to dd
620: (any number of digits)
621: \r carriage return (\x0d)
622: \t tab (\x09)
623: \v vertical tab (\x0b)
624: \nnn octal character (up to 3 octal digits); always
625: a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode
626: \o{dd...} octal character (any number of octal digits}
627: \xhh hexadecimal byte (up to 2 hex digits)
628: \x{hh...} hexadecimal character (any number of hex digits)
629: \A pass the PCRE_ANCHORED option to pcre[16|32]_exec()
630: or pcre[16|32]_dfa_exec()
631: \B pass the PCRE_NOTBOL option to pcre[16|32]_exec()
632: or pcre[16|32]_dfa_exec()
633: \Cdd call pcre[16|32]_copy_substring() for substring dd
634: after a successful match (number less than 32)
635: \Cname call pcre[16|32]_copy_named_substring() for substring
636: "name" after a successful match (name termin-
637: ated by next non alphanumeric character)
638: \C+ show the current captured substrings at callout
639: time
640: \C- do not supply a callout function
641: \C!n return 1 instead of 0 when callout number n is
642: reached
643: \C!n!m return 1 instead of 0 when callout number n is
644: reached for the nth time
645: \C*n pass the number n (may be negative) as callout
646: data; this is used as the callout return value
647: \D use the pcre[16|32]_dfa_exec() match function
648: \F only shortest match for pcre[16|32]_dfa_exec()
649: \Gdd call pcre[16|32]_get_substring() for substring dd
650: after a successful match (number less than 32)
651: \Gname call pcre[16|32]_get_named_substring() for substring
652: "name" after a successful match (name termin-
653: ated by next non-alphanumeric character)
654: \Jdd set up a JIT stack of dd kilobytes maximum (any
655: number of digits)
656: \L call pcre[16|32]_get_substringlist() after a
657: successful match
658: \M discover the minimum MATCH_LIMIT and
659: MATCH_LIMIT_RECURSION settings
660: \N pass the PCRE_NOTEMPTY option to pcre[16|32]_exec()
661: or pcre[16|32]_dfa_exec(); if used twice, pass the
662: PCRE_NOTEMPTY_ATSTART option
663: \Odd set the size of the output vector passed to
664: pcre[16|32]_exec() to dd (any number of digits)
665: \P pass the PCRE_PARTIAL_SOFT option to pcre[16|32]_exec()
666: or pcre[16|32]_dfa_exec(); if used twice, pass the
667: PCRE_PARTIAL_HARD option
668: \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
669: (any number of digits)
670: \R pass the PCRE_DFA_RESTART option to pcre[16|32]_dfa_exec()
671: \S output details of memory get/free calls during matching
672: \Y pass the PCRE_NO_START_OPTIMIZE option to
673: pcre[16|32]_exec()
674: or pcre[16|32]_dfa_exec()
675: \Z pass the PCRE_NOTEOL option to pcre[16|32]_exec()
676: or pcre[16|32]_dfa_exec()
677: \? pass the PCRE_NO_UTF[8|16|32]_CHECK option to
678: pcre[16|32]_exec() or pcre[16|32]_dfa_exec()
679: \>dd start the match at offset dd (optional "-"; then
680: any number of digits); this sets the startoffset
681: argument for pcre[16|32]_exec() or
682: pcre[16|32]_dfa_exec()
683: \<cr> pass the PCRE_NEWLINE_CR option to pcre[16|32]_exec()
684: or pcre[16|32]_dfa_exec()
685: \<lf> pass the PCRE_NEWLINE_LF option to pcre[16|32]_exec()
686: or pcre[16|32]_dfa_exec()
687: \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16|32]_exec()
688: or pcre[16|32]_dfa_exec()
689: \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16|32]_exec()
690: or pcre[16|32]_dfa_exec()
691: \<any> pass the PCRE_NEWLINE_ANY option to pcre[16|32]_exec()
692: or pcre[16|32]_dfa_exec()
693:
694: The use of \x{hh...} is not dependent on the use of the /8 modifier on
695: the pattern. It is recognized always. There may be any number of hexa-
696: decimal digits inside the braces; invalid values provoke error mes-
697: sages.
698:
699: Note that \xhh specifies one byte rather than one character in UTF-8
700: mode; this makes it possible to construct invalid UTF-8 sequences for
701: testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
702: character in UTF-8 mode, generating more than one byte if the value is
703: greater than 127. When testing the 8-bit library not in UTF-8 mode,
704: \x{hh} generates one byte for values less than 256, and causes an error
705: for greater values.
706:
707: In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
708: possible to construct invalid UTF-16 sequences for testing purposes.
709:
710: In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This
711: makes it possible to construct invalid UTF-32 sequences for testing
712: purposes.
713:
714: The escapes that specify line ending sequences are literal strings,
715: exactly as shown. No more than one newline setting should be present in
716: any data line.
717:
718: A backslash followed by anything else just escapes the anything else.
719: If the very last character is a backslash, it is ignored. This gives a
720: way of passing an empty line as data, since a real empty line termi-
721: nates the data input.
722:
723: The \J escape provides a way of setting the maximum stack size that is
724: used by the just-in-time optimization code. It is ignored if JIT opti-
725: mization is not being used. Providing a stack that is larger than the
726: default 32K is necessary only for very complicated patterns.
727:
728: If \M is present, pcretest calls pcre[16|32]_exec() several times, with
729: different values in the match_limit and match_limit_recursion fields of
730: the pcre[16|32]_extra data structure, until it finds the minimum num-
731: bers for each parameter that allow pcre[16|32]_exec() to complete with-
732: out error. Because this is testing a specific feature of the normal
733: interpretive pcre[16|32]_exec() execution, the use of any JIT optimiza-
734: tion that might have been set up by the /S+ qualifier of -s+ option is
735: disabled.
736:
737: The match_limit number is a measure of the amount of backtracking that
738: takes place, and checking it out can be instructive. For most simple
739: matches, the number is quite small, but for patterns with very large
740: numbers of matching possibilities, it can become large very quickly
741: with increasing length of subject string. The match_limit_recursion
742: number is a measure of how much stack (or, if PCRE is compiled with
743: NO_RECURSE, how much heap) memory is needed to complete the match
744: attempt.
745:
746: When \O is used, the value specified may be higher or lower than the
747: size set by the -O command line option (or defaulted to 45); \O applies
748: only to the call of pcre[16|32]_exec() for the line in which it
749: appears.
750:
751: If the /P modifier was present on the pattern, causing the POSIX wrap-
752: per API to be used, the only option-setting sequences that have any
753: effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
754: REG_NOTEOL, respectively, to be passed to regexec().
755:
756:
757: THE ALTERNATIVE MATCHING FUNCTION
758:
759: By default, pcretest uses the standard PCRE matching function,
760: pcre[16|32]_exec() to match each data line. PCRE also supports an
761: alternative matching function, pcre[16|32]_dfa_test(), which operates
762: in a different way, and has some restrictions. The differences between
763: the two functions are described in the pcrematching documentation.
764:
765: If a data line contains the \D escape sequence, or if the command line
766: contains the -dfa option, the alternative matching function is used.
767: This function finds all possible matches at a given point. If, however,
768: the \F escape sequence is present in the data line, it stops after the
769: first match is found. This is always the shortest possible match.
770:
771:
772: DEFAULT OUTPUT FROM PCRETEST
773:
774: This section describes the output when the normal matching function,
775: pcre[16|32]_exec(), is being used.
776:
777: When a match succeeds, pcretest outputs the list of captured substrings
778: that pcre[16|32]_exec() returns, starting with number 0 for the string
779: that matched the whole pattern. Otherwise, it outputs "No match" when
780: the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
781: partially matching substring when pcre[16|32]_exec() returns
782: PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
783: inspected during the partial match; it may include characters before
784: the actual match start if a lookbehind assertion, \K, \b, or \B was
785: involved.) For any other return, pcretest outputs the PCRE negative
786: error number and a short descriptive phrase. If the error is a failed
787: UTF string check, the offset of the start of the failing character and
788: the reason code are also output, provided that the size of the output
789: vector is at least two. Here is an example of an interactive pcretest
790: run.
791:
792: $ pcretest
793: PCRE version 8.13 2011-04-30
794:
795: re> /^abc(\d+)/
796: data> abc123
797: 0: abc123
798: 1: 123
799: data> xyz
800: No match
801:
802: Unset capturing substrings that are not followed by one that is set are
803: not returned by pcre[16|32]_exec(), and are not shown by pcretest. In
804: the following example, there are two capturing substrings, but when the
805: first data line is matched, the second, unset substring is not shown.
806: An "internal" unset substring is shown as "<unset>", as for the second
807: data line.
808:
809: re> /(a)|(b)/
810: data> a
811: 0: a
812: 1: a
813: data> b
814: 0: b
815: 1: <unset>
816: 2: b
817:
818: If the strings contain any non-printing characters, they are output as
819: \xhh escapes if the value is less than 256 and UTF mode is not set.
820: Otherwise they are output as \x{hh...} escapes. See below for the defi-
821: nition of non-printing characters. If the pattern has the /+ modifier,
822: the output for substring 0 is followed by the the rest of the subject
823: string, identified by "0+" like this:
824:
825: re> /cat/+
826: data> cataract
827: 0: cat
828: 0+ aract
829:
830: If the pattern has the /g or /G modifier, the results of successive
831: matching attempts are output in sequence, like this:
832:
833: re> /\Bi(\w\w)/g
834: data> Mississippi
835: 0: iss
836: 1: ss
837: 0: iss
838: 1: ss
839: 0: ipp
840: 1: pp
841:
842: "No match" is output only if the first match attempt fails. Here is an
843: example of a failure message (the offset 4 that is specified by \>4 is
844: past the end of the subject string):
845:
846: re> /xyz/
847: data> xyz\>4
848: Error -24 (bad offset value)
849:
850: If any of the sequences \C, \G, or \L are present in a data line that
851: is successfully matched, the substrings extracted by the convenience
852: functions are output with C, G, or L after the string number instead of
853: a colon. This is in addition to the normal full list. The string length
854: (that is, the return from the extraction function) is given in paren-
855: theses after each string for \C and \G.
856:
857: Note that whereas patterns can be continued over several lines (a plain
858: ">" prompt is used for continuations), data lines may not. However new-
859: lines can be included in data by means of the \n escape (or \r, \r\n,
860: etc., depending on the newline sequence setting).
861:
862:
863: OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
864:
865: When the alternative matching function, pcre[16|32]_dfa_exec(), is used
866: (by means of the \D escape sequence or the -dfa command line option),
867: the output consists of a list of all the matches that start at the
868: first point in the subject where there is at least one match. For exam-
869: ple:
870:
871: re> /(tang|tangerine|tan)/
872: data> yellow tangerine\D
873: 0: tangerine
874: 1: tang
875: 2: tan
876:
877: (Using the normal matching function on this data finds only "tang".)
878: The longest matching string is always given first (and numbered zero).
879: After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
880: lowed by the partially matching substring. (Note that this is the
881: entire substring that was inspected during the partial match; it may
882: include characters before the actual match start if a lookbehind asser-
883: tion, \K, \b, or \B was involved.)
884:
885: If /g is present on the pattern, the search for further matches resumes
886: at the end of the longest match. For example:
887:
888: re> /(tang|tangerine|tan)/g
889: data> yellow tangerine and tangy sultana\D
890: 0: tangerine
891: 1: tang
892: 2: tan
893: 0: tang
894: 1: tan
895: 0: tan
896:
897: Since the matching function does not support substring capture, the
898: escape sequences that are concerned with captured substrings are not
899: relevant.
900:
901:
902: RESTARTING AFTER A PARTIAL MATCH
903:
904: When the alternative matching function has given the PCRE_ERROR_PARTIAL
905: return, indicating that the subject partially matched the pattern, you
906: can restart the match with additional subject data by means of the \R
907: escape sequence. For example:
908:
909: re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
910: data> 23ja\P\D
911: Partial match: 23ja
912: data> n05\R\D
913: 0: n05
914:
915: For further information about partial matching, see the pcrepartial
916: documentation.
917:
918:
919: CALLOUTS
920:
921: If the pattern contains any callout requests, pcretest's callout func-
922: tion is called during matching. This works with both matching func-
923: tions. By default, the called function displays the callout number, the
924: start and current positions in the text at the callout time, and the
925: next pattern item to be tested. For example:
926:
927: --->pqrabcdef
928: 0 ^ ^ \d
929:
930: This output indicates that callout number 0 occurred for a match
931: attempt starting at the fourth character of the subject string, when
932: the pointer was at the seventh character of the data, and when the next
933: pattern item was \d. Just one circumflex is output if the start and
934: current positions are the same.
935:
936: Callouts numbered 255 are assumed to be automatic callouts, inserted as
937: a result of the /C pattern modifier. In this case, instead of showing
938: the callout number, the offset in the pattern, preceded by a plus, is
939: output. For example:
940:
941: re> /\d?[A-E]\*/C
942: data> E*
943: --->E*
944: +0 ^ \d?
945: +3 ^ [A-E]
946: +8 ^^ \*
947: +10 ^ ^
948: 0: E*
949:
950: If a pattern contains (*MARK) items, an additional line is output when-
951: ever a change of latest mark is passed to the callout function. For
952: example:
953:
954: re> /a(*MARK:X)bc/C
955: data> abc
956: --->abc
957: +0 ^ a
958: +1 ^^ (*MARK:X)
959: +10 ^^ b
960: Latest Mark: X
961: +11 ^ ^ c
962: +12 ^ ^
963: 0: abc
964:
965: The mark changes between matching "a" and "b", but stays the same for
966: the rest of the match, so nothing more is output. If, as a result of
967: backtracking, the mark reverts to being unset, the text "<unset>" is
968: output.
969:
970: The callout function in pcretest returns zero (carry on matching) by
971: default, but you can use a \C item in a data line (as described above)
972: to change this and other parameters of the callout.
973:
974: Inserting callouts can be helpful when using pcretest to check compli-
975: cated regular expressions. For further information about callouts, see
976: the pcrecallout documentation.
977:
978:
979: NON-PRINTING CHARACTERS
980:
981: When pcretest is outputting text in the compiled version of a pattern,
982: bytes other than 32-126 are always treated as non-printing characters
983: are are therefore shown as hex escapes.
984:
985: When pcretest is outputting text that is a matched part of a subject
986: string, it behaves in the same way, unless a different locale has been
987: set for the pattern (using the /L modifier). In this case, the
988: isprint() function to distinguish printing and non-printing characters.
989:
990:
991: SAVING AND RELOADING COMPILED PATTERNS
992:
993: The facilities described in this section are not available when the
994: POSIX interface to PCRE is being used, that is, when the /P pattern
995: modifier is specified.
996:
997: When the POSIX interface is not in use, you can cause pcretest to write
998: a compiled pattern to a file, by following the modifiers with > and a
999: file name. For example:
1000:
1001: /pattern/im >/some/file
1002:
1003: See the pcreprecompile documentation for a discussion about saving and
1004: re-using compiled patterns. Note that if the pattern was successfully
1005: studied with JIT optimization, the JIT data cannot be saved.
1006:
1007: The data that is written is binary. The first eight bytes are the
1008: length of the compiled pattern data followed by the length of the
1009: optional study data, each written as four bytes in big-endian order
1010: (most significant byte first). If there is no study data (either the
1011: pattern was not studied, or studying did not return any data), the sec-
1012: ond length is zero. The lengths are followed by an exact copy of the
1013: compiled pattern. If there is additional study data, this (excluding
1014: any JIT data) follows immediately after the compiled pattern. After
1015: writing the file, pcretest expects to read a new pattern.
1016:
1017: A saved pattern can be reloaded into pcretest by specifying < and a
1018: file name instead of a pattern. There must be no space between < and
1019: the file name, which must not contain a < character, as otherwise
1020: pcretest will interpret the line as a pattern delimited by < charac-
1021: ters. For example:
1022:
1023: re> </some/file
1024: Compiled pattern loaded from /some/file
1025: No study data
1026:
1027: If the pattern was previously studied with the JIT optimization, the
1028: JIT information cannot be saved and restored, and so is lost. When the
1029: pattern has been loaded, pcretest proceeds to read data lines in the
1030: usual way.
1031:
1032: You can copy a file written by pcretest to a different host and reload
1033: it there, even if the new host has opposite endianness to the one on
1034: which the pattern was compiled. For example, you can compile on an i86
1035: machine and run on a SPARC machine. When a pattern is reloaded on a
1036: host with different endianness, the confirmation message is changed to:
1037:
1038: Compiled pattern (byte-inverted) loaded from /some/file
1039:
1040: The test suite contains some saved pre-compiled patterns with different
1041: endianness. These are reloaded using "<!" instead of just "<". This
1042: suppresses the "(byte-inverted)" text so that the output is the same on
1043: all hosts. It also forces debugging output once the pattern has been
1044: reloaded.
1045:
1046: File names for saving and reloading can be absolute or relative, but
1047: note that the shell facility of expanding a file name that starts with
1048: a tilde (~) is not available.
1049:
1050: The ability to save and reload files in pcretest is intended for test-
1051: ing and experimentation. It is not intended for production use because
1052: only a single pattern can be written to a file. Furthermore, there is
1053: no facility for supplying custom character tables for use with a
1054: reloaded pattern. If the original pattern was compiled with custom
1055: tables, an attempt to match a subject string using a reloaded pattern
1056: is likely to cause pcretest to crash. Finally, if you attempt to load
1057: a file that is not in the correct format, the result is undefined.
1058:
1059:
1060: SEE ALSO
1061:
1062: pcre(3), pcre16(3), pcre32(3), pcreapi(3), pcrecallout(3), pcrejit,
1063: pcrematching(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1064:
1065:
1066: AUTHOR
1067:
1068: Philip Hazel
1069: University Computing Service
1070: Cambridge CB2 3QH, England.
1071:
1072:
1073: REVISION
1074:
1075: Last updated: 12 November 2013
1076: Copyright (c) 1997-2013 University of Cambridge.
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