Annotation of embedaddon/pcre/doc/pcretest.txt, revision 1.1.1.2
1.1 misho 1: PCRETEST(1) PCRETEST(1)
2:
3:
4: NAME
5: pcretest - a program for testing Perl-compatible regular expressions.
6:
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
1.1.1.2 ! misho 17: 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:
! 23:
! 24: PCRE's 8-BIT and 16-BIT LIBRARIES
! 25:
! 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.
! 34:
! 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".
1.1 misho 38:
39:
40: COMMAND LINE OPTIONS
41:
1.1.1.2 ! misho 42: -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.
! 47:
! 48: -b Behave as if each pattern has the /B (show byte code) modi-
1.1 misho 49: fier; the internal form is output after compilation.
50:
51: -C Output the version number of the PCRE library, and all avail-
1.1.1.2 ! misho 52: able information about the optional features that are
! 53: included, and then exit. All other options are ignored.
! 54:
! 55: -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:
! 58:
! 59: linksize the internal link size (2, 3, or 4)
! 60: newline the default newline setting:
! 61: CR, LF, CRLF, ANYCRLF, or ANY
! 62:
! 63: The following options output 1 for true or zero for false:
! 64:
! 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
1.1 misho 70:
1.1.1.2 ! misho 71: -d Behave as if each pattern has the /D (debug) modifier; the
! 72: internal form and information about the compiled pattern is
1.1 misho 73: output after compilation; -d is equivalent to -b -i.
74:
1.1.1.2 ! misho 75: -dfa Behave as if each data line contains the \D escape sequence;
1.1 misho 76: this causes the alternative matching function,
1.1.1.2 ! misho 77: pcre[16]_dfa_exec(), to be used instead of the standard
! 78: pcre[16]_exec() function (more detail is given below).
1.1 misho 79:
80: -help Output a brief summary these options and then exit.
81:
1.1.1.2 ! misho 82: -i Behave as if each pattern has the /I modifier; information
1.1 misho 83: about the compiled pattern is given after compilation.
84:
1.1.1.2 ! misho 85: -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:
! 90: -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:
! 94: -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:
! 102: -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.
1.1 misho 106:
107: -q Do not output the version number of pcretest at the start of
108: execution.
109:
110: -S size On Unix-like systems, set the size of the run-time stack to
111: size megabytes.
112:
113: -s or -s+ Behave as if each pattern has the /S modifier; in other
114: words, force each pattern to be studied. If -s+ is used, the
1.1.1.2 ! misho 115: PCRE_STUDY_JIT_COMPILE flag is passed to pcre[16]_study(),
! 116: causing just-in-time optimization to be set up if it is
! 117: available. If the /I or /D option is present on a pattern
1.1 misho 118: (requesting output about the compiled pattern), information
119: about the result of studying is not included when studying is
120: caused only by -s and neither -i nor -d is present on the
121: command line. This behaviour means that the output from tests
122: that are run with and without -s should be identical, except
123: when options that output information about the actual running
1.1.1.2 ! misho 124: of a match are set.
! 125:
! 126: The -M, -t, and -tm options, which give information about
! 127: resources used, are likely to produce different output with
! 128: and without -s. Output may also differ if the /C option is
! 129: present on an individual pattern. This uses callouts to trace
! 130: the the matching process, and this may be different between
! 131: studied and non-studied patterns. If the pattern contains
! 132: (*MARK) items there may also be differences, for the same
! 133: reason. The -s command line option can be overridden for spe-
! 134: cific patterns that should never be studied (see the /S pat-
! 135: tern modifier below).
1.1 misho 136:
137: -t Run each compile, study, and match many times with a timer,
138: and output resulting time per compile or match (in millisec-
139: onds). Do not set -m with -t, because you will then get the
140: size output a zillion times, and the timing will be dis-
141: torted. You can control the number of iterations that are
142: used for timing by following -t with a number (as a separate
143: item on the command line). For example, "-t 1000" would iter-
144: ate 1000 times. The default is to iterate 500000 times.
145:
146: -tm This is like -t except that it times only the matching phase,
147: not the compile or study phases.
148:
149:
150: DESCRIPTION
151:
152: If pcretest is given two filename arguments, it reads from the first
153: and writes to the second. If it is given only one filename argument, it
154: reads from that file and writes to stdout. Otherwise, it reads from
155: stdin and writes to stdout, and prompts for each line of input, using
156: "re>" to prompt for regular expressions, and "data>" to prompt for data
157: lines.
158:
159: When pcretest is built, a configuration option can specify that it
160: should be linked with the libreadline library. When this is done, if
161: the input is from a terminal, it is read using the readline() function.
162: This provides line-editing and history facilities. The output from the
163: -help option states whether or not readline() will be used.
164:
165: The program handles any number of sets of input on a single input file.
166: Each set starts with a regular expression, and continues with any num-
167: ber of data lines to be matched against the pattern.
168:
169: Each data line is matched separately and independently. If you want to
170: do multi-line matches, you have to use the \n escape sequence (or \r or
171: \r\n, etc., depending on the newline setting) in a single line of input
172: to encode the newline sequences. There is no limit on the length of
173: data lines; the input buffer is automatically extended if it is too
174: small.
175:
176: An empty line signals the end of the data lines, at which point a new
177: regular expression is read. The regular expressions are given enclosed
178: in any non-alphanumeric delimiters other than backslash, for example:
179:
180: /(a|bc)x+yz/
181:
182: White space before the initial delimiter is ignored. A regular expres-
183: sion may be continued over several input lines, in which case the new-
184: line characters are included within it. It is possible to include the
185: delimiter within the pattern by escaping it, for example
186:
187: /abc\/def/
188:
189: If you do so, the escape and the delimiter form part of the pattern,
190: but since delimiters are always non-alphanumeric, this does not affect
191: its interpretation. If the terminating delimiter is immediately fol-
192: lowed by a backslash, for example,
193:
194: /abc/\
195:
196: then a backslash is added to the end of the pattern. This is done to
197: provide a way of testing the error condition that arises if a pattern
198: finishes with a backslash, because
199:
200: /abc\/
201:
202: is interpreted as the first line of a pattern that starts with "abc/",
203: causing pcretest to read the next line as a continuation of the regular
204: expression.
205:
206:
207: PATTERN MODIFIERS
208:
209: A pattern may be followed by any number of modifiers, which are mostly
210: single characters. Following Perl usage, these are referred to below
211: as, for example, "the /i modifier", even though the delimiter of the
212: pattern need not always be a slash, and no slash is used when writing
213: modifiers. White space may appear between the final pattern delimiter
214: and the first modifier, and between the modifiers themselves.
215:
216: The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE,
1.1.1.2 ! misho 217: PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre[16]_com-
1.1 misho 218: pile() is called. These four modifier letters have the same effect as
219: they do in Perl. For example:
220:
221: /caseless/i
222:
223: The following table shows additional modifiers for setting PCRE com-
224: pile-time options that do not correspond to anything in Perl:
225:
1.1.1.2 ! misho 226: /8 PCRE_UTF8 ) when using the 8-bit
! 227: /? PCRE_NO_UTF8_CHECK ) library
! 228:
! 229: /8 PCRE_UTF16 ) when using the 16-bit
! 230: /? PCRE_NO_UTF16_CHECK ) library
! 231:
1.1 misho 232: /A PCRE_ANCHORED
233: /C PCRE_AUTO_CALLOUT
234: /E PCRE_DOLLAR_ENDONLY
235: /f PCRE_FIRSTLINE
236: /J PCRE_DUPNAMES
237: /N PCRE_NO_AUTO_CAPTURE
238: /U PCRE_UNGREEDY
239: /W PCRE_UCP
240: /X PCRE_EXTRA
241: /Y PCRE_NO_START_OPTIMIZE
242: /<JS> PCRE_JAVASCRIPT_COMPAT
243: /<cr> PCRE_NEWLINE_CR
244: /<lf> PCRE_NEWLINE_LF
245: /<crlf> PCRE_NEWLINE_CRLF
246: /<anycrlf> PCRE_NEWLINE_ANYCRLF
247: /<any> PCRE_NEWLINE_ANY
248: /<bsr_anycrlf> PCRE_BSR_ANYCRLF
249: /<bsr_unicode> PCRE_BSR_UNICODE
250:
251: The modifiers that are enclosed in angle brackets are literal strings
252: as shown, including the angle brackets, but the letters within can be
253: in either case. This example sets multiline matching with CRLF as the
254: line ending sequence:
255:
256: /^abc/m<CRLF>
257:
1.1.1.2 ! misho 258: As well as turning on the PCRE_UTF8/16 option, the /8 modifier causes
! 259: all non-printing characters in output strings to be printed using the
! 260: \x{hh...} notation. Otherwise, those less than 0x100 are output in hex
! 261: without the curly brackets.
! 262:
! 263: Full details of the PCRE options are given in the pcreapi documenta-
! 264: tion.
1.1 misho 265:
266: Finding all matches in a string
267:
1.1.1.2 ! misho 268: Searching for all possible matches within each subject string can be
! 269: requested by the /g or /G modifier. After finding a match, PCRE is
1.1 misho 270: called again to search the remainder of the subject string. The differ-
271: ence between /g and /G is that the former uses the startoffset argument
1.1.1.2 ! misho 272: to pcre[16]_exec() to start searching at a new point within the entire
! 273: string (which is in effect what Perl does), whereas the latter passes
! 274: over a shortened substring. This makes a difference to the matching
1.1 misho 275: process if the pattern begins with a lookbehind assertion (including \b
276: or \B).
277:
1.1.1.2 ! misho 278: If any call to pcre[16]_exec() in a /g or /G sequence matches an empty
! 279: string, the next call is done with the PCRE_NOTEMPTY_ATSTART and
! 280: PCRE_ANCHORED flags set in order to search for another, non-empty,
! 281: match at the same point. If this second match fails, the start offset
! 282: is advanced, and the normal match is retried. This imitates the way
1.1 misho 283: Perl handles such cases when using the /g modifier or the split() func-
1.1.1.2 ! misho 284: tion. Normally, the start offset is advanced by one character, but if
! 285: the newline convention recognizes CRLF as a newline, and the current
1.1 misho 286: character is CR followed by LF, an advance of two is used.
287:
288: Other modifiers
289:
290: There are yet more modifiers for controlling the way pcretest operates.
291:
1.1.1.2 ! misho 292: The /+ modifier requests that as well as outputting the substring that
! 293: matched the entire pattern, pcretest should in addition output the
! 294: remainder of the subject string. This is useful for tests where the
! 295: subject contains multiple copies of the same substring. If the + modi-
! 296: fier appears twice, the same action is taken for captured substrings.
! 297: In each case the remainder is output on the following line with a plus
! 298: character following the capture number. Note that this modifier must
1.1 misho 299: not immediately follow the /S modifier because /S+ has another meaning.
300:
1.1.1.2 ! misho 301: The /= modifier requests that the values of all potential captured
! 302: parentheses be output after a match. By default, only those up to the
! 303: highest one actually used in the match are output (corresponding to the
! 304: return code from pcre[16]_exec()). Values in the offsets vector corre-
! 305: sponding to higher numbers should be set to -1, and these are output as
! 306: "<unset>". This modifier gives a way of checking that this is happen-
! 307: ing.
! 308:
! 309: The /B modifier is a debugging feature. It requests that pcretest out-
! 310: put a representation of the compiled code after compilation. Normally
! 311: this information contains length and offset values; however, if /Z is
! 312: also present, this data is replaced by spaces. This is a special fea-
! 313: ture for use in the automatic test scripts; it ensures that the same
1.1 misho 314: output is generated for different internal link sizes.
315:
1.1.1.2 ! misho 316: The /D modifier is a PCRE debugging feature, and is equivalent to /BI,
1.1 misho 317: that is, both the /B and the /I modifiers.
318:
1.1.1.2 ! misho 319: The /F modifier causes pcretest to flip the byte order of the 2-byte
! 320: and 4-byte fields in the compiled pattern. This facility is for testing
! 321: the feature in PCRE that allows it to execute patterns that were com-
! 322: piled on a host with a different endianness. This feature is not avail-
! 323: able when the POSIX interface to PCRE is being used, that is, when the
! 324: /P pattern modifier is specified. See also the section about saving and
! 325: reloading compiled patterns below.
! 326:
! 327: The /I modifier requests that pcretest output information about the
! 328: compiled pattern (whether it is anchored, has a fixed first character,
! 329: and so on). It does this by calling pcre[16]_fullinfo() after compiling
! 330: a pattern. If the pattern is studied, the results of that are also out-
1.1 misho 331: put.
332:
1.1.1.2 ! misho 333: The /K modifier requests pcretest to show names from backtracking con-
! 334: trol verbs that are returned from calls to pcre[16]_exec(). It causes
! 335: pcretest to create a pcre[16]_extra block if one has not already been
! 336: created by a call to pcre[16]_study(), and to set the PCRE_EXTRA_MARK
! 337: flag and the mark field within it, every time that pcre[16]_exec() is
! 338: called. If the variable that the mark field points to is non-NULL for a
! 339: match, non-match, or partial match, pcretest prints the string to which
! 340: it points. For a match, this is shown on a line by itself, tagged with
! 341: "MK:". For a non-match it is added to the message.
1.1 misho 342:
1.1.1.2 ! misho 343: The /L modifier must be followed directly by the name of a locale, for
1.1 misho 344: example,
345:
346: /pattern/Lfr_FR
347:
348: For this reason, it must be the last modifier. The given locale is set,
1.1.1.2 ! misho 349: pcre[16]_maketables() is called to build a set of character tables for
! 350: the locale, and this is then passed to pcre[16]_compile() when compil-
! 351: ing the regular expression. Without an /L (or /T) modifier, NULL is
! 352: passed as the tables pointer; that is, /L applies only to the expres-
! 353: sion on which it appears.
! 354:
! 355: The /M modifier causes the size in bytes of the memory block used to
! 356: hold the compiled pattern to be output. This does not include the size
! 357: of the pcre[16] block; it is just the actual compiled data. If the pat-
! 358: tern is successfully studied with the PCRE_STUDY_JIT_COMPILE option,
! 359: the size of the JIT compiled code is also output.
! 360:
! 361: If the /S modifier appears once, it causes pcre[16]_study() to be
! 362: called after the expression has been compiled, and the results used
! 363: when the expression is matched. If /S appears twice, it suppresses
! 364: studying, even if it was requested externally by the -s command line
! 365: option. This makes it possible to specify that certain patterns are
! 366: always studied, and others are never studied, independently of -s. This
! 367: feature is used in the test files in a few cases where the output is
! 368: different when the pattern is studied.
! 369:
! 370: If the /S modifier is immediately followed by a + character, the call
! 371: to pcre[16]_study() is made with the PCRE_STUDY_JIT_COMPILE option,
! 372: requesting just-in-time optimization support if it is available. Note
! 373: that there is also a /+ modifier; it must not be given immediately
! 374: after /S because this will be misinterpreted. If JIT studying is suc-
! 375: cessful, it will automatically be used when pcre[16]_exec() is run,
! 376: except when incompatible run-time options are specified. These include
! 377: the partial matching options; a complete list is given in the pcrejit
! 378: documentation. See also the \J escape sequence below for a way of set-
! 379: ting the size of the JIT stack.
! 380:
! 381: The /T modifier must be followed by a single digit. It causes a spe-
! 382: cific set of built-in character tables to be passed to pcre[16]_com-
! 383: pile(). It is used in the standard PCRE tests to check behaviour with
! 384: different character tables. The digit specifies the tables as follows:
1.1 misho 385:
386: 0 the default ASCII tables, as distributed in
387: pcre_chartables.c.dist
388: 1 a set of tables defining ISO 8859 characters
389:
1.1.1.2 ! misho 390: In table 1, some characters whose codes are greater than 128 are iden-
1.1 misho 391: tified as letters, digits, spaces, etc.
392:
393: Using the POSIX wrapper API
394:
1.1.1.2 ! misho 395: The /P modifier causes pcretest to call PCRE via the POSIX wrapper API
! 396: rather than its native API. This supports only the 8-bit library. When
! 397: /P is set, the following modifiers set options for the regcomp() func-
! 398: tion:
1.1 misho 399:
400: /i REG_ICASE
401: /m REG_NEWLINE
402: /N REG_NOSUB
403: /s REG_DOTALL )
404: /U REG_UNGREEDY ) These options are not part of
405: /W REG_UCP ) the POSIX standard
406: /8 REG_UTF8 )
407:
408: The /+ modifier works as described above. All other modifiers are
409: ignored.
410:
411:
412: DATA LINES
413:
1.1.1.2 ! misho 414: Before each data line is passed to pcre[16]_exec(), leading and trail-
! 415: ing white space is removed, and it is then scanned for \ escapes. Some
! 416: of these are pretty esoteric features, intended for checking out some
! 417: of the more complicated features of PCRE. If you are just testing
! 418: "ordinary" regular expressions, you probably don't need any of these.
! 419: The following escapes are recognized:
1.1 misho 420:
421: \a alarm (BEL, \x07)
422: \b backspace (\x08)
423: \e escape (\x27)
424: \f form feed (\x0c)
425: \n newline (\x0a)
426: \qdd set the PCRE_MATCH_LIMIT limit to dd
427: (any number of digits)
428: \r carriage return (\x0d)
429: \t tab (\x09)
430: \v vertical tab (\x0b)
1.1.1.2 ! misho 431: \nnn octal character (up to 3 octal digits); always
! 432: a byte unless > 255 in UTF-8 or 16-bit mode
1.1 misho 433: \xhh hexadecimal byte (up to 2 hex digits)
1.1.1.2 ! misho 434: \x{hh...} hexadecimal character (any number of hex digits)
! 435: \A pass the PCRE_ANCHORED option to pcre[16]_exec()
! 436: or pcre[16]_dfa_exec()
! 437: \B pass the PCRE_NOTBOL option to pcre[16]_exec()
! 438: or pcre[16]_dfa_exec()
! 439: \Cdd call pcre[16]_copy_substring() for substring dd
1.1 misho 440: after a successful match (number less than 32)
1.1.1.2 ! misho 441: \Cname call pcre[16]_copy_named_substring() for substring
1.1 misho 442: "name" after a successful match (name termin-
443: ated by next non alphanumeric character)
444: \C+ show the current captured substrings at callout
445: time
446: \C- do not supply a callout function
447: \C!n return 1 instead of 0 when callout number n is
448: reached
449: \C!n!m return 1 instead of 0 when callout number n is
450: reached for the nth time
451: \C*n pass the number n (may be negative) as callout
452: data; this is used as the callout return value
1.1.1.2 ! misho 453: \D use the pcre[16]_dfa_exec() match function
! 454: \F only shortest match for pcre[16]_dfa_exec()
! 455: \Gdd call pcre[16]_get_substring() for substring dd
1.1 misho 456: after a successful match (number less than 32)
1.1.1.2 ! misho 457: \Gname call pcre[16]_get_named_substring() for substring
1.1 misho 458: "name" after a successful match (name termin-
459: ated by next non-alphanumeric character)
460: \Jdd set up a JIT stack of dd kilobytes maximum (any
461: number of digits)
1.1.1.2 ! misho 462: \L call pcre[16]_get_substringlist() after a
1.1 misho 463: successful match
464: \M discover the minimum MATCH_LIMIT and
465: MATCH_LIMIT_RECURSION settings
1.1.1.2 ! misho 466: \N pass the PCRE_NOTEMPTY option to pcre[16]_exec()
! 467: or pcre[16]_dfa_exec(); if used twice, pass the
1.1 misho 468: PCRE_NOTEMPTY_ATSTART option
469: \Odd set the size of the output vector passed to
1.1.1.2 ! misho 470: pcre[16]_exec() to dd (any number of digits)
! 471: \P pass the PCRE_PARTIAL_SOFT option to pcre[16]_exec()
! 472: or pcre[16]_dfa_exec(); if used twice, pass the
1.1 misho 473: PCRE_PARTIAL_HARD option
474: \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd
475: (any number of digits)
1.1.1.2 ! misho 476: \R pass the PCRE_DFA_RESTART option to pcre[16]_dfa_exec()
1.1 misho 477: \S output details of memory get/free calls during matching
1.1.1.2 ! misho 478: \Y pass the PCRE_NO_START_OPTIMIZE option to pcre[16]_exec()
! 479: or pcre[16]_dfa_exec()
! 480: \Z pass the PCRE_NOTEOL option to pcre[16]_exec()
! 481: or pcre[16]_dfa_exec()
! 482: \? pass the PCRE_NO_UTF[8|16]_CHECK option to
! 483: pcre[16]_exec() or pcre[16]_dfa_exec()
1.1 misho 484: \>dd start the match at offset dd (optional "-"; then
485: any number of digits); this sets the startoffset
1.1.1.2 ! misho 486: argument for pcre[16]_exec() or pcre[16]_dfa_exec()
! 487: \<cr> pass the PCRE_NEWLINE_CR option to pcre[16]_exec()
! 488: or pcre[16]_dfa_exec()
! 489: \<lf> pass the PCRE_NEWLINE_LF option to pcre[16]_exec()
! 490: or pcre[16]_dfa_exec()
! 491: \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre[16]_exec()
! 492: or pcre[16]_dfa_exec()
! 493: \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre[16]_exec()
! 494: or pcre[16]_dfa_exec()
! 495: \<any> pass the PCRE_NEWLINE_ANY option to pcre[16]_exec()
! 496: or pcre[16]_dfa_exec()
! 497:
! 498: The use of \x{hh...} is not dependent on the use of the /8 modifier on
! 499: the pattern. It is recognized always. There may be any number of hexa-
! 500: decimal digits inside the braces; invalid values provoke error mes-
! 501: sages.
! 502:
! 503: Note that \xhh specifies one byte rather than one character in UTF-8
! 504: mode; this makes it possible to construct invalid UTF-8 sequences for
! 505: testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8
! 506: character in UTF-8 mode, generating more than one byte if the value is
! 507: greater than 127. When testing the 8-bit library not in UTF-8 mode,
! 508: \x{hh} generates one byte for values less than 256, and causes an error
! 509: for greater values.
! 510:
! 511: In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it
! 512: possible to construct invalid UTF-16 sequences for testing purposes.
1.1 misho 513:
1.1.1.2 ! misho 514: The escapes that specify line ending sequences are literal strings,
1.1 misho 515: exactly as shown. No more than one newline setting should be present in
516: any data line.
517:
1.1.1.2 ! misho 518: A backslash followed by anything else just escapes the anything else.
! 519: If the very last character is a backslash, it is ignored. This gives a
! 520: way of passing an empty line as data, since a real empty line termi-
1.1 misho 521: nates the data input.
522:
1.1.1.2 ! misho 523: The \J escape provides a way of setting the maximum stack size that is
! 524: used by the just-in-time optimization code. It is ignored if JIT opti-
! 525: mization is not being used. Providing a stack that is larger than the
1.1 misho 526: default 32K is necessary only for very complicated patterns.
527:
1.1.1.2 ! misho 528: If \M is present, pcretest calls pcre[16]_exec() several times, with
! 529: different values in the match_limit and match_limit_recursion fields of
! 530: the pcre[16]_extra data structure, until it finds the minimum numbers
! 531: for each parameter that allow pcre[16]_exec() to complete without
! 532: error. Because this is testing a specific feature of the normal inter-
! 533: pretive pcre[16]_exec() execution, the use of any JIT optimization that
! 534: might have been set up by the /S+ qualifier of -s+ option is disabled.
! 535:
! 536: The match_limit number is a measure of the amount of backtracking that
! 537: takes place, and checking it out can be instructive. For most simple
! 538: matches, the number is quite small, but for patterns with very large
! 539: numbers of matching possibilities, it can become large very quickly
! 540: with increasing length of subject string. The match_limit_recursion
! 541: number is a measure of how much stack (or, if PCRE is compiled with
! 542: NO_RECURSE, how much heap) memory is needed to complete the match
1.1 misho 543: attempt.
544:
1.1.1.2 ! misho 545: When \O is used, the value specified may be higher or lower than the
1.1 misho 546: size set by the -O command line option (or defaulted to 45); \O applies
1.1.1.2 ! misho 547: only to the call of pcre[16]_exec() for the line in which it appears.
1.1 misho 548:
1.1.1.2 ! misho 549: If the /P modifier was present on the pattern, causing the POSIX wrap-
! 550: per API to be used, the only option-setting sequences that have any
! 551: effect are \B, \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and
1.1 misho 552: REG_NOTEOL, respectively, to be passed to regexec().
553:
554:
555: THE ALTERNATIVE MATCHING FUNCTION
556:
557: By default, pcretest uses the standard PCRE matching function,
1.1.1.2 ! misho 558: pcre[16]_exec() to match each data line. PCRE also supports an alterna-
! 559: tive matching function, pcre[16]_dfa_test(), which operates in a dif-
! 560: ferent way, and has some restrictions. The differences between the two
! 561: functions are described in the pcrematching documentation.
1.1 misho 562:
563: If a data line contains the \D escape sequence, or if the command line
1.1.1.2 ! misho 564: contains the -dfa option, the alternative matching function is used.
1.1 misho 565: This function finds all possible matches at a given point. If, however,
566: the \F escape sequence is present in the data line, it stops after the
567: first match is found. This is always the shortest possible match.
568:
569:
570: DEFAULT OUTPUT FROM PCRETEST
571:
572: This section describes the output when the normal matching function,
1.1.1.2 ! misho 573: pcre[16]_exec(), is being used.
1.1 misho 574:
575: When a match succeeds, pcretest outputs the list of captured substrings
1.1.1.2 ! misho 576: that pcre[16]_exec() returns, starting with number 0 for the string
! 577: that matched the whole pattern. Otherwise, it outputs "No match" when
! 578: the return is PCRE_ERROR_NOMATCH, and "Partial match:" followed by the
! 579: partially matching substring when pcre[16]_exec() returns
! 580: PCRE_ERROR_PARTIAL. (Note that this is the entire substring that was
! 581: inspected during the partial match; it may include characters before
! 582: the actual match start if a lookbehind assertion, \K, \b, or \B was
! 583: involved.) For any other return, pcretest outputs the PCRE negative
! 584: error number and a short descriptive phrase. If the error is a failed
! 585: UTF string check, the offset of the start of the failing character and
! 586: the reason code are also output, provided that the size of the output
! 587: vector is at least two. Here is an example of an interactive pcretest
! 588: run.
1.1 misho 589:
590: $ pcretest
591: PCRE version 8.13 2011-04-30
592:
593: re> /^abc(\d+)/
594: data> abc123
595: 0: abc123
596: 1: 123
597: data> xyz
598: No match
599:
600: Unset capturing substrings that are not followed by one that is set are
1.1.1.2 ! misho 601: not returned by pcre[16]_exec(), and are not shown by pcretest. In the
! 602: following example, there are two capturing substrings, but when the
! 603: first data line is matched, the second, unset substring is not shown.
! 604: An "internal" unset substring is shown as "<unset>", as for the second
1.1 misho 605: data line.
606:
607: re> /(a)|(b)/
608: data> a
609: 0: a
610: 1: a
611: data> b
612: 0: b
613: 1: <unset>
614: 2: b
615:
1.1.1.2 ! misho 616: If the strings contain any non-printing characters, they are output as
! 617: \xhh escapes if the value is less than 256 and UTF mode is not set.
! 618: Otherwise they are output as \x{hh...} escapes. See below for the defi-
! 619: nition of non-printing characters. If the pattern has the /+ modifier,
! 620: the output for substring 0 is followed by the the rest of the subject
! 621: string, identified by "0+" like this:
1.1 misho 622:
623: re> /cat/+
624: data> cataract
625: 0: cat
626: 0+ aract
627:
1.1.1.2 ! misho 628: If the pattern has the /g or /G modifier, the results of successive
1.1 misho 629: matching attempts are output in sequence, like this:
630:
631: re> /\Bi(\w\w)/g
632: data> Mississippi
633: 0: iss
634: 1: ss
635: 0: iss
636: 1: ss
637: 0: ipp
638: 1: pp
639:
1.1.1.2 ! misho 640: "No match" is output only if the first match attempt fails. Here is an
! 641: example of a failure message (the offset 4 that is specified by \>4 is
1.1 misho 642: past the end of the subject string):
643:
644: re> /xyz/
645: data> xyz\>4
646: Error -24 (bad offset value)
647:
1.1.1.2 ! misho 648: If any of the sequences \C, \G, or \L are present in a data line that
! 649: is successfully matched, the substrings extracted by the convenience
1.1 misho 650: functions are output with C, G, or L after the string number instead of
651: a colon. This is in addition to the normal full list. The string length
1.1.1.2 ! misho 652: (that is, the return from the extraction function) is given in paren-
1.1 misho 653: theses after each string for \C and \G.
654:
655: Note that whereas patterns can be continued over several lines (a plain
656: ">" prompt is used for continuations), data lines may not. However new-
1.1.1.2 ! misho 657: lines can be included in data by means of the \n escape (or \r, \r\n,
1.1 misho 658: etc., depending on the newline sequence setting).
659:
660:
661: OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION
662:
1.1.1.2 ! misho 663: When the alternative matching function, pcre[16]_dfa_exec(), is used
! 664: (by means of the \D escape sequence or the -dfa command line option),
! 665: the output consists of a list of all the matches that start at the
! 666: first point in the subject where there is at least one match. For exam-
! 667: ple:
1.1 misho 668:
669: re> /(tang|tangerine|tan)/
670: data> yellow tangerine\D
671: 0: tangerine
672: 1: tang
673: 2: tan
674:
675: (Using the normal matching function on this data finds only "tang".)
676: The longest matching string is always given first (and numbered zero).
677: After a PCRE_ERROR_PARTIAL return, the output is "Partial match:", fol-
678: lowed by the partially matching substring. (Note that this is the
679: entire substring that was inspected during the partial match; it may
680: include characters before the actual match start if a lookbehind asser-
681: tion, \K, \b, or \B was involved.)
682:
683: If /g is present on the pattern, the search for further matches resumes
684: at the end of the longest match. For example:
685:
686: re> /(tang|tangerine|tan)/g
687: data> yellow tangerine and tangy sultana\D
688: 0: tangerine
689: 1: tang
690: 2: tan
691: 0: tang
692: 1: tan
693: 0: tan
694:
695: Since the matching function does not support substring capture, the
696: escape sequences that are concerned with captured substrings are not
697: relevant.
698:
699:
700: RESTARTING AFTER A PARTIAL MATCH
701:
702: When the alternative matching function has given the PCRE_ERROR_PARTIAL
703: return, indicating that the subject partially matched the pattern, you
704: can restart the match with additional subject data by means of the \R
705: escape sequence. For example:
706:
707: re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
708: data> 23ja\P\D
709: Partial match: 23ja
710: data> n05\R\D
711: 0: n05
712:
713: For further information about partial matching, see the pcrepartial
714: documentation.
715:
716:
717: CALLOUTS
718:
719: If the pattern contains any callout requests, pcretest's callout func-
720: tion is called during matching. This works with both matching func-
721: tions. By default, the called function displays the callout number, the
722: start and current positions in the text at the callout time, and the
1.1.1.2 ! misho 723: next pattern item to be tested. For example:
1.1 misho 724:
725: --->pqrabcdef
726: 0 ^ ^ \d
727:
1.1.1.2 ! misho 728: This output indicates that callout number 0 occurred for a match
! 729: attempt starting at the fourth character of the subject string, when
! 730: the pointer was at the seventh character of the data, and when the next
! 731: pattern item was \d. Just one circumflex is output if the start and
! 732: current positions are the same.
1.1 misho 733:
734: Callouts numbered 255 are assumed to be automatic callouts, inserted as
735: a result of the /C pattern modifier. In this case, instead of showing
736: the callout number, the offset in the pattern, preceded by a plus, is
737: output. For example:
738:
739: re> /\d?[A-E]\*/C
740: data> E*
741: --->E*
742: +0 ^ \d?
743: +3 ^ [A-E]
744: +8 ^^ \*
745: +10 ^ ^
746: 0: E*
747:
748: If a pattern contains (*MARK) items, an additional line is output when-
749: ever a change of latest mark is passed to the callout function. For
750: example:
751:
752: re> /a(*MARK:X)bc/C
753: data> abc
754: --->abc
755: +0 ^ a
756: +1 ^^ (*MARK:X)
757: +10 ^^ b
758: Latest Mark: X
759: +11 ^ ^ c
760: +12 ^ ^
761: 0: abc
762:
763: The mark changes between matching "a" and "b", but stays the same for
764: the rest of the match, so nothing more is output. If, as a result of
765: backtracking, the mark reverts to being unset, the text "<unset>" is
766: output.
767:
768: The callout function in pcretest returns zero (carry on matching) by
769: default, but you can use a \C item in a data line (as described above)
770: to change this and other parameters of the callout.
771:
772: Inserting callouts can be helpful when using pcretest to check compli-
773: cated regular expressions. For further information about callouts, see
774: the pcrecallout documentation.
775:
776:
777: NON-PRINTING CHARACTERS
778:
779: When pcretest is outputting text in the compiled version of a pattern,
780: bytes other than 32-126 are always treated as non-printing characters
781: are are therefore shown as hex escapes.
782:
783: When pcretest is outputting text that is a matched part of a subject
784: string, it behaves in the same way, unless a different locale has been
785: set for the pattern (using the /L modifier). In this case, the
786: isprint() function to distinguish printing and non-printing characters.
787:
788:
789: SAVING AND RELOADING COMPILED PATTERNS
790:
791: The facilities described in this section are not available when the
792: POSIX interface to PCRE is being used, that is, when the /P pattern
793: modifier is specified.
794:
795: When the POSIX interface is not in use, you can cause pcretest to write
796: a compiled pattern to a file, by following the modifiers with > and a
797: file name. For example:
798:
799: /pattern/im >/some/file
800:
801: See the pcreprecompile documentation for a discussion about saving and
802: re-using compiled patterns. Note that if the pattern was successfully
803: studied with JIT optimization, the JIT data cannot be saved.
804:
805: The data that is written is binary. The first eight bytes are the
806: length of the compiled pattern data followed by the length of the
807: optional study data, each written as four bytes in big-endian order
808: (most significant byte first). If there is no study data (either the
809: pattern was not studied, or studying did not return any data), the sec-
810: ond length is zero. The lengths are followed by an exact copy of the
811: compiled pattern. If there is additional study data, this (excluding
812: any JIT data) follows immediately after the compiled pattern. After
813: writing the file, pcretest expects to read a new pattern.
814:
815: A saved pattern can be reloaded into pcretest by specifying < and a
816: file name instead of a pattern. The name of the file must not contain a
817: < character, as otherwise pcretest will interpret the line as a pattern
818: delimited by < characters. For example:
819:
820: re> </some/file
821: Compiled pattern loaded from /some/file
822: No study data
823:
824: If the pattern was previously studied with the JIT optimization, the
825: JIT information cannot be saved and restored, and so is lost. When the
826: pattern has been loaded, pcretest proceeds to read data lines in the
827: usual way.
828:
829: You can copy a file written by pcretest to a different host and reload
830: it there, even if the new host has opposite endianness to the one on
831: which the pattern was compiled. For example, you can compile on an i86
1.1.1.2 ! misho 832: machine and run on a SPARC machine. When a pattern is reloaded on a
! 833: host with different endianness, the confirmation message is changed to:
! 834:
! 835: Compiled pattern (byte-inverted) loaded from /some/file
! 836:
! 837: The test suite contains some saved pre-compiled patterns with different
! 838: endianness. These are reloaded using "<!" instead of just "<". This
! 839: suppresses the "(byte-inverted)" text so that the output is the same on
! 840: all hosts. It also forces debugging output once the pattern has been
! 841: reloaded.
1.1 misho 842:
1.1.1.2 ! misho 843: File names for saving and reloading can be absolute or relative, but
! 844: note that the shell facility of expanding a file name that starts with
1.1 misho 845: a tilde (~) is not available.
846:
1.1.1.2 ! misho 847: The ability to save and reload files in pcretest is intended for test-
! 848: ing and experimentation. It is not intended for production use because
! 849: only a single pattern can be written to a file. Furthermore, there is
! 850: no facility for supplying custom character tables for use with a
! 851: reloaded pattern. If the original pattern was compiled with custom
! 852: tables, an attempt to match a subject string using a reloaded pattern
! 853: is likely to cause pcretest to crash. Finally, if you attempt to load
1.1 misho 854: a file that is not in the correct format, the result is undefined.
855:
856:
857: SEE ALSO
858:
1.1.1.2 ! misho 859: pcre(3), pcre16(3), pcreapi(3), pcrecallout(3), pcrejit, pcrematch-
! 860: ing(3), pcrepartial(d), pcrepattern(3), pcreprecompile(3).
1.1 misho 861:
862:
863: AUTHOR
864:
865: Philip Hazel
866: University Computing Service
867: Cambridge CB2 3QH, England.
868:
869:
870: REVISION
871:
1.1.1.2 ! misho 872: Last updated: 14 January 2012
! 873: Copyright (c) 1997-2012 University of Cambridge.
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