| 1 | This file contains the PCRE man page that described the pcretest program. Note |
| 2 | that not all of the features of PCRE are available in the limited version that |
| 3 | is built with Exim. |
| 4 | ------------------------------------------------------------------------------- |
| 5 | |
| 6 | PCRETEST(1) PCRETEST(1) |
| 7 | |
| 8 | |
| 9 | NAME |
| 10 | pcretest - a program for testing Perl-compatible regular expressions. |
| 11 | |
| 12 | |
| 13 | SYNOPSIS |
| 14 | |
| 15 | pcretest [options] [source] [destination] |
| 16 | |
| 17 | pcretest was written as a test program for the PCRE regular expression |
| 18 | library itself, but it can also be used for experimenting with regular |
| 19 | expressions. This document describes the features of the test program; |
| 20 | for details of the regular expressions themselves, see the pcrepattern |
| 21 | documentation. For details of the PCRE library function calls and their |
| 22 | options, see the pcreapi documentation. |
| 23 | |
| 24 | |
| 25 | OPTIONS |
| 26 | |
| 27 | -b Behave as if each regex has the /B (show bytecode) modifier; |
| 28 | the internal form is output after compilation. |
| 29 | |
| 30 | -C Output the version number of the PCRE library, and all avail- |
| 31 | able information about the optional features that are |
| 32 | included, and then exit. |
| 33 | |
| 34 | -d Behave as if each regex has the /D (debug) modifier; the |
| 35 | internal form and information about the compiled pattern is |
| 36 | output after compilation; -d is equivalent to -b -i. |
| 37 | |
| 38 | -dfa Behave as if each data line contains the \D escape sequence; |
| 39 | this causes the alternative matching function, |
| 40 | pcre_dfa_exec(), to be used instead of the standard |
| 41 | pcre_exec() function (more detail is given below). |
| 42 | |
| 43 | -help Output a brief summary these options and then exit. |
| 44 | |
| 45 | -i Behave as if each regex has the /I modifier; information |
| 46 | about the compiled pattern is given after compilation. |
| 47 | |
| 48 | -m Output the size of each compiled pattern after it has been |
| 49 | compiled. This is equivalent to adding /M to each regular |
| 50 | expression. For compatibility with earlier versions of |
| 51 | pcretest, -s is a synonym for -m. |
| 52 | |
| 53 | -o osize Set the number of elements in the output vector that is used |
| 54 | when calling pcre_exec() or pcre_dfa_exec() to be osize. The |
| 55 | default value is 45, which is enough for 14 capturing subex- |
| 56 | pressions for pcre_exec() or 22 different matches for |
| 57 | pcre_dfa_exec(). The vector size can be changed for individ- |
| 58 | ual matching calls by including \O in the data line (see |
| 59 | below). |
| 60 | |
| 61 | -p Behave as if each regex has the /P modifier; the POSIX wrap- |
| 62 | per API is used to call PCRE. None of the other options has |
| 63 | any effect when -p is set. |
| 64 | |
| 65 | -q Do not output the version number of pcretest at the start of |
| 66 | execution. |
| 67 | |
| 68 | -S size On Unix-like systems, set the size of the runtime stack to |
| 69 | size megabytes. |
| 70 | |
| 71 | -t Run each compile, study, and match many times with a timer, |
| 72 | and output resulting time per compile or match (in millisec- |
| 73 | onds). Do not set -m with -t, because you will then get the |
| 74 | size output a zillion times, and the timing will be dis- |
| 75 | torted. You can control the number of iterations that are |
| 76 | used for timing by following -t with a number (as a separate |
| 77 | item on the command line). For example, "-t 1000" would iter- |
| 78 | ate 1000 times. The default is to iterate 500000 times. |
| 79 | |
| 80 | -tm This is like -t except that it times only the matching phase, |
| 81 | not the compile or study phases. |
| 82 | |
| 83 | |
| 84 | DESCRIPTION |
| 85 | |
| 86 | If pcretest is given two filename arguments, it reads from the first |
| 87 | and writes to the second. If it is given only one filename argument, it |
| 88 | reads from that file and writes to stdout. Otherwise, it reads from |
| 89 | stdin and writes to stdout, and prompts for each line of input, using |
| 90 | "re>" to prompt for regular expressions, and "data>" to prompt for data |
| 91 | lines. |
| 92 | |
| 93 | The program handles any number of sets of input on a single input file. |
| 94 | Each set starts with a regular expression, and continues with any num- |
| 95 | ber of data lines to be matched against the pattern. |
| 96 | |
| 97 | Each data line is matched separately and independently. If you want to |
| 98 | do multi-line matches, you have to use the \n escape sequence (or \r or |
| 99 | \r\n, etc., depending on the newline setting) in a single line of input |
| 100 | to encode the newline sequences. There is no limit on the length of |
| 101 | data lines; the input buffer is automatically extended if it is too |
| 102 | small. |
| 103 | |
| 104 | An empty line signals the end of the data lines, at which point a new |
| 105 | regular expression is read. The regular expressions are given enclosed |
| 106 | in any non-alphanumeric delimiters other than backslash, for example: |
| 107 | |
| 108 | /(a|bc)x+yz/ |
| 109 | |
| 110 | White space before the initial delimiter is ignored. A regular expres- |
| 111 | sion may be continued over several input lines, in which case the new- |
| 112 | line characters are included within it. It is possible to include the |
| 113 | delimiter within the pattern by escaping it, for example |
| 114 | |
| 115 | /abc\/def/ |
| 116 | |
| 117 | If you do so, the escape and the delimiter form part of the pattern, |
| 118 | but since delimiters are always non-alphanumeric, this does not affect |
| 119 | its interpretation. If the terminating delimiter is immediately fol- |
| 120 | lowed by a backslash, for example, |
| 121 | |
| 122 | /abc/\ |
| 123 | |
| 124 | then a backslash is added to the end of the pattern. This is done to |
| 125 | provide a way of testing the error condition that arises if a pattern |
| 126 | finishes with a backslash, because |
| 127 | |
| 128 | /abc\/ |
| 129 | |
| 130 | is interpreted as the first line of a pattern that starts with "abc/", |
| 131 | causing pcretest to read the next line as a continuation of the regular |
| 132 | expression. |
| 133 | |
| 134 | |
| 135 | PATTERN MODIFIERS |
| 136 | |
| 137 | A pattern may be followed by any number of modifiers, which are mostly |
| 138 | single characters. Following Perl usage, these are referred to below |
| 139 | as, for example, "the /i modifier", even though the delimiter of the |
| 140 | pattern need not always be a slash, and no slash is used when writing |
| 141 | modifiers. Whitespace may appear between the final pattern delimiter |
| 142 | and the first modifier, and between the modifiers themselves. |
| 143 | |
| 144 | The /i, /m, /s, and /x modifiers set the PCRE_CASELESS, PCRE_MULTILINE, |
| 145 | PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when pcre_com- |
| 146 | pile() is called. These four modifier letters have the same effect as |
| 147 | they do in Perl. For example: |
| 148 | |
| 149 | /caseless/i |
| 150 | |
| 151 | The following table shows additional modifiers for setting PCRE options |
| 152 | that do not correspond to anything in Perl: |
| 153 | |
| 154 | /A PCRE_ANCHORED |
| 155 | /C PCRE_AUTO_CALLOUT |
| 156 | /E PCRE_DOLLAR_ENDONLY |
| 157 | /f PCRE_FIRSTLINE |
| 158 | /J PCRE_DUPNAMES |
| 159 | /N PCRE_NO_AUTO_CAPTURE |
| 160 | /U PCRE_UNGREEDY |
| 161 | /X PCRE_EXTRA |
| 162 | /<cr> PCRE_NEWLINE_CR |
| 163 | /<lf> PCRE_NEWLINE_LF |
| 164 | /<crlf> PCRE_NEWLINE_CRLF |
| 165 | /<anycrlf> PCRE_NEWLINE_ANYCRLF |
| 166 | /<any> PCRE_NEWLINE_ANY |
| 167 | |
| 168 | Those specifying line ending sequencess are literal strings as shown. |
| 169 | This example sets multiline matching with CRLF as the line ending |
| 170 | sequence: |
| 171 | |
| 172 | /^abc/m<crlf> |
| 173 | |
| 174 | Details of the meanings of these PCRE options are given in the pcreapi |
| 175 | documentation. |
| 176 | |
| 177 | Finding all matches in a string |
| 178 | |
| 179 | Searching for all possible matches within each subject string can be |
| 180 | requested by the /g or /G modifier. After finding a match, PCRE is |
| 181 | called again to search the remainder of the subject string. The differ- |
| 182 | ence between /g and /G is that the former uses the startoffset argument |
| 183 | to pcre_exec() to start searching at a new point within the entire |
| 184 | string (which is in effect what Perl does), whereas the latter passes |
| 185 | over a shortened substring. This makes a difference to the matching |
| 186 | process if the pattern begins with a lookbehind assertion (including \b |
| 187 | or \B). |
| 188 | |
| 189 | If any call to pcre_exec() in a /g or /G sequence matches an empty |
| 190 | string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED |
| 191 | flags set in order to search for another, non-empty, match at the same |
| 192 | point. If this second match fails, the start offset is advanced by |
| 193 | one, and the normal match is retried. This imitates the way Perl han- |
| 194 | dles such cases when using the /g modifier or the split() function. |
| 195 | |
| 196 | Other modifiers |
| 197 | |
| 198 | There are yet more modifiers for controlling the way pcretest operates. |
| 199 | |
| 200 | The /+ modifier requests that as well as outputting the substring that |
| 201 | matched the entire pattern, pcretest should in addition output the |
| 202 | remainder of the subject string. This is useful for tests where the |
| 203 | subject contains multiple copies of the same substring. |
| 204 | |
| 205 | The /B modifier is a debugging feature. It requests that pcretest out- |
| 206 | put a representation of the compiled byte code after compilation. Nor- |
| 207 | mally this information contains length and offset values; however, if |
| 208 | /Z is also present, this data is replaced by spaces. This is a special |
| 209 | feature for use in the automatic test scripts; it ensures that the same |
| 210 | output is generated for different internal link sizes. |
| 211 | |
| 212 | The /L modifier must be followed directly by the name of a locale, for |
| 213 | example, |
| 214 | |
| 215 | /pattern/Lfr_FR |
| 216 | |
| 217 | For this reason, it must be the last modifier. The given locale is set, |
| 218 | pcre_maketables() is called to build a set of character tables for the |
| 219 | locale, and this is then passed to pcre_compile() when compiling the |
| 220 | regular expression. Without an /L modifier, NULL is passed as the |
| 221 | tables pointer; that is, /L applies only to the expression on which it |
| 222 | appears. |
| 223 | |
| 224 | The /I modifier requests that pcretest output information about the |
| 225 | compiled pattern (whether it is anchored, has a fixed first character, |
| 226 | and so on). It does this by calling pcre_fullinfo() after compiling a |
| 227 | pattern. If the pattern is studied, the results of that are also out- |
| 228 | put. |
| 229 | |
| 230 | The /D modifier is a PCRE debugging feature, and is equivalent to /BI, |
| 231 | that is, both the /B and the /I modifiers. |
| 232 | |
| 233 | The /F modifier causes pcretest to flip the byte order of the fields in |
| 234 | the compiled pattern that contain 2-byte and 4-byte numbers. This |
| 235 | facility is for testing the feature in PCRE that allows it to execute |
| 236 | patterns that were compiled on a host with a different endianness. This |
| 237 | feature is not available when the POSIX interface to PCRE is being |
| 238 | used, that is, when the /P pattern modifier is specified. See also the |
| 239 | section about saving and reloading compiled patterns below. |
| 240 | |
| 241 | The /S modifier causes pcre_study() to be called after the expression |
| 242 | has been compiled, and the results used when the expression is matched. |
| 243 | |
| 244 | The /M modifier causes the size of memory block used to hold the com- |
| 245 | piled pattern to be output. |
| 246 | |
| 247 | The /P modifier causes pcretest to call PCRE via the POSIX wrapper API |
| 248 | rather than its native API. When this is done, all other modifiers |
| 249 | except /i, /m, and /+ are ignored. REG_ICASE is set if /i is present, |
| 250 | and REG_NEWLINE is set if /m is present. The wrapper functions force |
| 251 | PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set. |
| 252 | |
| 253 | The /8 modifier causes pcretest to call PCRE with the PCRE_UTF8 option |
| 254 | set. This turns on support for UTF-8 character handling in PCRE, pro- |
| 255 | vided that it was compiled with this support enabled. This modifier |
| 256 | also causes any non-printing characters in output strings to be printed |
| 257 | using the \x{hh...} notation if they are valid UTF-8 sequences. |
| 258 | |
| 259 | If the /? modifier is used with /8, it causes pcretest to call |
| 260 | pcre_compile() with the PCRE_NO_UTF8_CHECK option, to suppress the |
| 261 | checking of the string for UTF-8 validity. |
| 262 | |
| 263 | |
| 264 | DATA LINES |
| 265 | |
| 266 | Before each data line is passed to pcre_exec(), leading and trailing |
| 267 | whitespace is removed, and it is then scanned for \ escapes. Some of |
| 268 | these are pretty esoteric features, intended for checking out some of |
| 269 | the more complicated features of PCRE. If you are just testing "ordi- |
| 270 | nary" regular expressions, you probably don't need any of these. The |
| 271 | following escapes are recognized: |
| 272 | |
| 273 | \a alarm (BEL, \x07) |
| 274 | \b backspace (\x08) |
| 275 | \e escape (\x27) |
| 276 | \f formfeed (\x0c) |
| 277 | \n newline (\x0a) |
| 278 | \qdd set the PCRE_MATCH_LIMIT limit to dd |
| 279 | (any number of digits) |
| 280 | \r carriage return (\x0d) |
| 281 | \t tab (\x09) |
| 282 | \v vertical tab (\x0b) |
| 283 | \nnn octal character (up to 3 octal digits) |
| 284 | \xhh hexadecimal character (up to 2 hex digits) |
| 285 | \x{hh...} hexadecimal character, any number of digits |
| 286 | in UTF-8 mode |
| 287 | \A pass the PCRE_ANCHORED option to pcre_exec() |
| 288 | or pcre_dfa_exec() |
| 289 | \B pass the PCRE_NOTBOL option to pcre_exec() |
| 290 | or pcre_dfa_exec() |
| 291 | \Cdd call pcre_copy_substring() for substring dd |
| 292 | after a successful match (number less than 32) |
| 293 | \Cname call pcre_copy_named_substring() for substring |
| 294 | "name" after a successful match (name termin- |
| 295 | ated by next non alphanumeric character) |
| 296 | \C+ show the current captured substrings at callout |
| 297 | time |
| 298 | \C- do not supply a callout function |
| 299 | \C!n return 1 instead of 0 when callout number n is |
| 300 | reached |
| 301 | \C!n!m return 1 instead of 0 when callout number n is |
| 302 | reached for the nth time |
| 303 | \C*n pass the number n (may be negative) as callout |
| 304 | data; this is used as the callout return value |
| 305 | \D use the pcre_dfa_exec() match function |
| 306 | \F only shortest match for pcre_dfa_exec() |
| 307 | \Gdd call pcre_get_substring() for substring dd |
| 308 | after a successful match (number less than 32) |
| 309 | \Gname call pcre_get_named_substring() for substring |
| 310 | "name" after a successful match (name termin- |
| 311 | ated by next non-alphanumeric character) |
| 312 | \L call pcre_get_substringlist() after a |
| 313 | successful match |
| 314 | \M discover the minimum MATCH_LIMIT and |
| 315 | MATCH_LIMIT_RECURSION settings |
| 316 | \N pass the PCRE_NOTEMPTY option to pcre_exec() |
| 317 | or pcre_dfa_exec() |
| 318 | \Odd set the size of the output vector passed to |
| 319 | pcre_exec() to dd (any number of digits) |
| 320 | \P pass the PCRE_PARTIAL option to pcre_exec() |
| 321 | or pcre_dfa_exec() |
| 322 | \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd |
| 323 | (any number of digits) |
| 324 | \R pass the PCRE_DFA_RESTART option to pcre_dfa_exec() |
| 325 | \S output details of memory get/free calls during matching |
| 326 | \Z pass the PCRE_NOTEOL option to pcre_exec() |
| 327 | or pcre_dfa_exec() |
| 328 | \? pass the PCRE_NO_UTF8_CHECK option to |
| 329 | pcre_exec() or pcre_dfa_exec() |
| 330 | \>dd start the match at offset dd (any number of digits); |
| 331 | this sets the startoffset argument for pcre_exec() |
| 332 | or pcre_dfa_exec() |
| 333 | \<cr> pass the PCRE_NEWLINE_CR option to pcre_exec() |
| 334 | or pcre_dfa_exec() |
| 335 | \<lf> pass the PCRE_NEWLINE_LF option to pcre_exec() |
| 336 | or pcre_dfa_exec() |
| 337 | \<crlf> pass the PCRE_NEWLINE_CRLF option to pcre_exec() |
| 338 | or pcre_dfa_exec() |
| 339 | \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to pcre_exec() |
| 340 | or pcre_dfa_exec() |
| 341 | \<any> pass the PCRE_NEWLINE_ANY option to pcre_exec() |
| 342 | or pcre_dfa_exec() |
| 343 | |
| 344 | The escapes that specify line ending sequences are literal strings, |
| 345 | exactly as shown. No more than one newline setting should be present in |
| 346 | any data line. |
| 347 | |
| 348 | A backslash followed by anything else just escapes the anything else. |
| 349 | If the very last character is a backslash, it is ignored. This gives a |
| 350 | way of passing an empty line as data, since a real empty line termi- |
| 351 | nates the data input. |
| 352 | |
| 353 | If \M is present, pcretest calls pcre_exec() several times, with dif- |
| 354 | ferent values in the match_limit and match_limit_recursion fields of |
| 355 | the pcre_extra data structure, until it finds the minimum numbers for |
| 356 | each parameter that allow pcre_exec() to complete. The match_limit num- |
| 357 | ber is a measure of the amount of backtracking that takes place, and |
| 358 | checking it out can be instructive. For most simple matches, the number |
| 359 | is quite small, but for patterns with very large numbers of matching |
| 360 | possibilities, it can become large very quickly with increasing length |
| 361 | of subject string. The match_limit_recursion number is a measure of how |
| 362 | much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) |
| 363 | memory is needed to complete the match attempt. |
| 364 | |
| 365 | When \O is used, the value specified may be higher or lower than the |
| 366 | size set by the -O command line option (or defaulted to 45); \O applies |
| 367 | only to the call of pcre_exec() for the line in which it appears. |
| 368 | |
| 369 | If the /P modifier was present on the pattern, causing the POSIX wrap- |
| 370 | per API to be used, the only option-setting sequences that have any |
| 371 | effect are \B and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, |
| 372 | to be passed to regexec(). |
| 373 | |
| 374 | The use of \x{hh...} to represent UTF-8 characters is not dependent on |
| 375 | the use of the /8 modifier on the pattern. It is recognized always. |
| 376 | There may be any number of hexadecimal digits inside the braces. The |
| 377 | result is from one to six bytes, encoded according to the UTF-8 rules. |
| 378 | |
| 379 | |
| 380 | THE ALTERNATIVE MATCHING FUNCTION |
| 381 | |
| 382 | By default, pcretest uses the standard PCRE matching function, |
| 383 | pcre_exec() to match each data line. From release 6.0, PCRE supports an |
| 384 | alternative matching function, pcre_dfa_test(), which operates in a |
| 385 | different way, and has some restrictions. The differences between the |
| 386 | two functions are described in the pcrematching documentation. |
| 387 | |
| 388 | If a data line contains the \D escape sequence, or if the command line |
| 389 | contains the -dfa option, the alternative matching function is called. |
| 390 | This function finds all possible matches at a given point. If, however, |
| 391 | the \F escape sequence is present in the data line, it stops after the |
| 392 | first match is found. This is always the shortest possible match. |
| 393 | |
| 394 | |
| 395 | DEFAULT OUTPUT FROM PCRETEST |
| 396 | |
| 397 | This section describes the output when the normal matching function, |
| 398 | pcre_exec(), is being used. |
| 399 | |
| 400 | When a match succeeds, pcretest outputs the list of captured substrings |
| 401 | that pcre_exec() returns, starting with number 0 for the string that |
| 402 | matched the whole pattern. Otherwise, it outputs "No match" or "Partial |
| 403 | match" when pcre_exec() returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PAR- |
| 404 | TIAL, respectively, and otherwise the PCRE negative error number. Here |
| 405 | is an example of an interactive pcretest run. |
| 406 | |
| 407 | $ pcretest |
| 408 | PCRE version 7.0 30-Nov-2006 |
| 409 | |
| 410 | re> /^abc(\d+)/ |
| 411 | data> abc123 |
| 412 | 0: abc123 |
| 413 | 1: 123 |
| 414 | data> xyz |
| 415 | No match |
| 416 | |
| 417 | If the strings contain any non-printing characters, they are output as |
| 418 | \0x escapes, or as \x{...} escapes if the /8 modifier was present on |
| 419 | the pattern. See below for the definition of non-printing characters. |
| 420 | If the pattern has the /+ modifier, the output for substring 0 is fol- |
| 421 | lowed by the the rest of the subject string, identified by "0+" like |
| 422 | this: |
| 423 | |
| 424 | re> /cat/+ |
| 425 | data> cataract |
| 426 | 0: cat |
| 427 | 0+ aract |
| 428 | |
| 429 | If the pattern has the /g or /G modifier, the results of successive |
| 430 | matching attempts are output in sequence, like this: |
| 431 | |
| 432 | re> /\Bi(\w\w)/g |
| 433 | data> Mississippi |
| 434 | 0: iss |
| 435 | 1: ss |
| 436 | 0: iss |
| 437 | 1: ss |
| 438 | 0: ipp |
| 439 | 1: pp |
| 440 | |
| 441 | "No match" is output only if the first match attempt fails. |
| 442 | |
| 443 | If any of the sequences \C, \G, or \L are present in a data line that |
| 444 | is successfully matched, the substrings extracted by the convenience |
| 445 | functions are output with C, G, or L after the string number instead of |
| 446 | a colon. This is in addition to the normal full list. The string length |
| 447 | (that is, the return from the extraction function) is given in paren- |
| 448 | theses after each string for \C and \G. |
| 449 | |
| 450 | Note that whereas patterns can be continued over several lines (a plain |
| 451 | ">" prompt is used for continuations), data lines may not. However new- |
| 452 | lines can be included in data by means of the \n escape (or \r, \r\n, |
| 453 | etc., depending on the newline sequence setting). |
| 454 | |
| 455 | |
| 456 | OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION |
| 457 | |
| 458 | When the alternative matching function, pcre_dfa_exec(), is used (by |
| 459 | means of the \D escape sequence or the -dfa command line option), the |
| 460 | output consists of a list of all the matches that start at the first |
| 461 | point in the subject where there is at least one match. For example: |
| 462 | |
| 463 | re> /(tang|tangerine|tan)/ |
| 464 | data> yellow tangerine\D |
| 465 | 0: tangerine |
| 466 | 1: tang |
| 467 | 2: tan |
| 468 | |
| 469 | (Using the normal matching function on this data finds only "tang".) |
| 470 | The longest matching string is always given first (and numbered zero). |
| 471 | |
| 472 | If /g is present on the pattern, the search for further matches resumes |
| 473 | at the end of the longest match. For example: |
| 474 | |
| 475 | re> /(tang|tangerine|tan)/g |
| 476 | data> yellow tangerine and tangy sultana\D |
| 477 | 0: tangerine |
| 478 | 1: tang |
| 479 | 2: tan |
| 480 | 0: tang |
| 481 | 1: tan |
| 482 | 0: tan |
| 483 | |
| 484 | Since the matching function does not support substring capture, the |
| 485 | escape sequences that are concerned with captured substrings are not |
| 486 | relevant. |
| 487 | |
| 488 | |
| 489 | RESTARTING AFTER A PARTIAL MATCH |
| 490 | |
| 491 | When the alternative matching function has given the PCRE_ERROR_PARTIAL |
| 492 | return, indicating that the subject partially matched the pattern, you |
| 493 | can restart the match with additional subject data by means of the \R |
| 494 | escape sequence. For example: |
| 495 | |
| 496 | re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/ |
| 497 | data> 23ja\P\D |
| 498 | Partial match: 23ja |
| 499 | data> n05\R\D |
| 500 | 0: n05 |
| 501 | |
| 502 | For further information about partial matching, see the pcrepartial |
| 503 | documentation. |
| 504 | |
| 505 | |
| 506 | CALLOUTS |
| 507 | |
| 508 | If the pattern contains any callout requests, pcretest's callout func- |
| 509 | tion is called during matching. This works with both matching func- |
| 510 | tions. By default, the called function displays the callout number, the |
| 511 | start and current positions in the text at the callout time, and the |
| 512 | next pattern item to be tested. For example, the output |
| 513 | |
| 514 | --->pqrabcdef |
| 515 | 0 ^ ^ \d |
| 516 | |
| 517 | indicates that callout number 0 occurred for a match attempt starting |
| 518 | at the fourth character of the subject string, when the pointer was at |
| 519 | the seventh character of the data, and when the next pattern item was |
| 520 | \d. Just one circumflex is output if the start and current positions |
| 521 | are the same. |
| 522 | |
| 523 | Callouts numbered 255 are assumed to be automatic callouts, inserted as |
| 524 | a result of the /C pattern modifier. In this case, instead of showing |
| 525 | the callout number, the offset in the pattern, preceded by a plus, is |
| 526 | output. For example: |
| 527 | |
| 528 | re> /\d?[A-E]\*/C |
| 529 | data> E* |
| 530 | --->E* |
| 531 | +0 ^ \d? |
| 532 | +3 ^ [A-E] |
| 533 | +8 ^^ \* |
| 534 | +10 ^ ^ |
| 535 | 0: E* |
| 536 | |
| 537 | The callout function in pcretest returns zero (carry on matching) by |
| 538 | default, but you can use a \C item in a data line (as described above) |
| 539 | to change this. |
| 540 | |
| 541 | Inserting callouts can be helpful when using pcretest to check compli- |
| 542 | cated regular expressions. For further information about callouts, see |
| 543 | the pcrecallout documentation. |
| 544 | |
| 545 | |
| 546 | NON-PRINTING CHARACTERS |
| 547 | |
| 548 | When pcretest is outputting text in the compiled version of a pattern, |
| 549 | bytes other than 32-126 are always treated as non-printing characters |
| 550 | are are therefore shown as hex escapes. |
| 551 | |
| 552 | When pcretest is outputting text that is a matched part of a subject |
| 553 | string, it behaves in the same way, unless a different locale has been |
| 554 | set for the pattern (using the /L modifier). In this case, the |
| 555 | isprint() function to distinguish printing and non-printing characters. |
| 556 | |
| 557 | |
| 558 | SAVING AND RELOADING COMPILED PATTERNS |
| 559 | |
| 560 | The facilities described in this section are not available when the |
| 561 | POSIX inteface to PCRE is being used, that is, when the /P pattern mod- |
| 562 | ifier is specified. |
| 563 | |
| 564 | When the POSIX interface is not in use, you can cause pcretest to write |
| 565 | a compiled pattern to a file, by following the modifiers with > and a |
| 566 | file name. For example: |
| 567 | |
| 568 | /pattern/im >/some/file |
| 569 | |
| 570 | See the pcreprecompile documentation for a discussion about saving and |
| 571 | re-using compiled patterns. |
| 572 | |
| 573 | The data that is written is binary. The first eight bytes are the |
| 574 | length of the compiled pattern data followed by the length of the |
| 575 | optional study data, each written as four bytes in big-endian order |
| 576 | (most significant byte first). If there is no study data (either the |
| 577 | pattern was not studied, or studying did not return any data), the sec- |
| 578 | ond length is zero. The lengths are followed by an exact copy of the |
| 579 | compiled pattern. If there is additional study data, this follows imme- |
| 580 | diately after the compiled pattern. After writing the file, pcretest |
| 581 | expects to read a new pattern. |
| 582 | |
| 583 | A saved pattern can be reloaded into pcretest by specifing < and a file |
| 584 | name instead of a pattern. The name of the file must not contain a < |
| 585 | character, as otherwise pcretest will interpret the line as a pattern |
| 586 | delimited by < characters. For example: |
| 587 | |
| 588 | re> </some/file |
| 589 | Compiled regex loaded from /some/file |
| 590 | No study data |
| 591 | |
| 592 | When the pattern has been loaded, pcretest proceeds to read data lines |
| 593 | in the usual way. |
| 594 | |
| 595 | You can copy a file written by pcretest to a different host and reload |
| 596 | it there, even if the new host has opposite endianness to the one on |
| 597 | which the pattern was compiled. For example, you can compile on an i86 |
| 598 | machine and run on a SPARC machine. |
| 599 | |
| 600 | File names for saving and reloading can be absolute or relative, but |
| 601 | note that the shell facility of expanding a file name that starts with |
| 602 | a tilde (~) is not available. |
| 603 | |
| 604 | The ability to save and reload files in pcretest is intended for test- |
| 605 | ing and experimentation. It is not intended for production use because |
| 606 | only a single pattern can be written to a file. Furthermore, there is |
| 607 | no facility for supplying custom character tables for use with a |
| 608 | reloaded pattern. If the original pattern was compiled with custom |
| 609 | tables, an attempt to match a subject string using a reloaded pattern |
| 610 | is likely to cause pcretest to crash. Finally, if you attempt to load |
| 611 | a file that is not in the correct format, the result is undefined. |
| 612 | |
| 613 | |
| 614 | SEE ALSO |
| 615 | |
| 616 | pcre(3), pcreapi(3), pcrecallout(3), pcrematching(3), pcrepartial(d), |
| 617 | pcrepattern(3), pcreprecompile(3). |
| 618 | |
| 619 | |
| 620 | AUTHOR |
| 621 | |
| 622 | Philip Hazel |
| 623 | University Computing Service |
| 624 | Cambridge CB2 3QH, England. |
| 625 | |
| 626 | |
| 627 | REVISION |
| 628 | |
| 629 | Last updated: 24 April 2007 |
| 630 | Copyright (c) 1997-2007 University of Cambridge. |