Annotation of embedaddon/pcre/doc/html/pcretest.html, revision 1.1.1.1
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2: <head>
3: <title>pcretest specification</title>
4: </head>
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6: <h1>pcretest man page</h1>
7: <p>
8: Return to the <a href="index.html">PCRE index page</a>.
9: </p>
10: <p>
11: This page is part of the PCRE HTML documentation. It was generated automatically
12: from the original man page. If there is any nonsense in it, please consult the
13: man page, in case the conversion went wrong.
14: <br>
15: <ul>
16: <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
17: <li><a name="TOC2" href="#SEC2">COMMAND LINE OPTIONS</a>
18: <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
19: <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
20: <li><a name="TOC5" href="#SEC5">DATA LINES</a>
21: <li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
22: <li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
23: <li><a name="TOC8" href="#SEC8">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a>
24: <li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
25: <li><a name="TOC10" href="#SEC10">CALLOUTS</a>
26: <li><a name="TOC11" href="#SEC11">NON-PRINTING CHARACTERS</a>
27: <li><a name="TOC12" href="#SEC12">SAVING AND RELOADING COMPILED PATTERNS</a>
28: <li><a name="TOC13" href="#SEC13">SEE ALSO</a>
29: <li><a name="TOC14" href="#SEC14">AUTHOR</a>
30: <li><a name="TOC15" href="#SEC15">REVISION</a>
31: </ul>
32: <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
33: <P>
34: <b>pcretest [options] [input file [output file]]</b>
35: <br>
36: <br>
37: <b>pcretest</b> was written as a test program for the PCRE regular expression
38: library itself, but it can also be used for experimenting with regular
39: expressions. This document describes the features of the test program; for
40: details of the regular expressions themselves, see the
41: <a href="pcrepattern.html"><b>pcrepattern</b></a>
42: documentation. For details of the PCRE library function calls and their
43: options, see the
44: <a href="pcreapi.html"><b>pcreapi</b></a>
45: documentation. The input for <b>pcretest</b> is a sequence of regular expression
46: patterns and strings to be matched, as described below. The output shows the
47: result of each match. Options on the command line and the patterns control PCRE
48: options and exactly what is output.
49: </P>
50: <br><a name="SEC2" href="#TOC1">COMMAND LINE OPTIONS</a><br>
51: <P>
52: <b>-b</b>
53: Behave as if each pattern has the <b>/B</b> (show byte code) modifier; the
54: internal form is output after compilation.
55: </P>
56: <P>
57: <b>-C</b>
58: Output the version number of the PCRE library, and all available information
59: about the optional features that are included, and then exit.
60: </P>
61: <P>
62: <b>-d</b>
63: Behave as if each pattern has the <b>/D</b> (debug) modifier; the internal
64: form and information about the compiled pattern is output after compilation;
65: <b>-d</b> is equivalent to <b>-b -i</b>.
66: </P>
67: <P>
68: <b>-dfa</b>
69: Behave as if each data line contains the \D escape sequence; this causes the
70: alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
71: standard <b>pcre_exec()</b> function (more detail is given below).
72: </P>
73: <P>
74: <b>-help</b>
75: Output a brief summary these options and then exit.
76: </P>
77: <P>
78: <b>-i</b>
79: Behave as if each pattern has the <b>/I</b> modifier; information about the
80: compiled pattern is given after compilation.
81: </P>
82: <P>
83: <b>-M</b>
84: Behave as if each data line contains the \M escape sequence; this causes
85: PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by
86: calling <b>pcre_exec()</b> repeatedly with different limits.
87: </P>
88: <P>
89: <b>-m</b>
90: Output the size of each compiled pattern after it has been compiled. This is
91: equivalent to adding <b>/M</b> to each regular expression.
92: </P>
93: <P>
94: <b>-o</b> <i>osize</i>
95: Set the number of elements in the output vector that is used when calling
96: <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b> to be <i>osize</i>. The default value
97: is 45, which is enough for 14 capturing subexpressions for <b>pcre_exec()</b> or
98: 22 different matches for <b>pcre_dfa_exec()</b>. The vector size can be
99: changed for individual matching calls by including \O in the data line (see
100: below).
101: </P>
102: <P>
103: <b>-p</b>
104: Behave as if each pattern has the <b>/P</b> modifier; the POSIX wrapper API is
105: used to call PCRE. None of the other options has any effect when <b>-p</b> is
106: set.
107: </P>
108: <P>
109: <b>-q</b>
110: Do not output the version number of <b>pcretest</b> at the start of execution.
111: </P>
112: <P>
113: <b>-S</b> <i>size</i>
114: On Unix-like systems, set the size of the run-time stack to <i>size</i>
115: megabytes.
116: </P>
117: <P>
118: <b>-s</b> or <b>-s+</b>
119: Behave as if each pattern has the <b>/S</b> modifier; in other words, force each
120: pattern to be studied. If <b>-s+</b> is used, the PCRE_STUDY_JIT_COMPILE flag is
121: passed to <b>pcre_study()</b>, causing just-in-time optimization to be set up if
122: it is available. If the <b>/I</b> or <b>/D</b> option is present on a pattern
123: (requesting output about the compiled pattern), information about the result of
124: studying is not included when studying is caused only by <b>-s</b> and neither
125: <b>-i</b> nor <b>-d</b> is present on the command line. This behaviour means that
126: the output from tests that are run with and without <b>-s</b> should be
127: identical, except when options that output information about the actual running
128: of a match are set. The <b>-M</b>, <b>-t</b>, and <b>-tm</b> options, which give
129: information about resources used, are likely to produce different output with
130: and without <b>-s</b>. Output may also differ if the <b>/C</b> option is present
131: on an individual pattern. This uses callouts to trace the the matching process,
132: and this may be different between studied and non-studied patterns. If the
133: pattern contains (*MARK) items there may also be differences, for the same
134: reason. The <b>-s</b> command line option can be overridden for specific
135: patterns that should never be studied (see the <b>/S</b> pattern modifier
136: below).
137: </P>
138: <P>
139: <b>-t</b>
140: Run each compile, study, and match many times with a timer, and output
141: resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
142: <b>-t</b>, because you will then get the size output a zillion times, and the
143: timing will be distorted. You can control the number of iterations that are
144: used for timing by following <b>-t</b> with a number (as a separate item on the
145: command line). For example, "-t 1000" would iterate 1000 times. The default is
146: to iterate 500000 times.
147: </P>
148: <P>
149: <b>-tm</b>
150: This is like <b>-t</b> except that it times only the matching phase, not the
151: compile or study phases.
152: </P>
153: <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
154: <P>
155: If <b>pcretest</b> is given two filename arguments, it reads from the first and
156: writes to the second. If it is given only one filename argument, it reads from
157: that file and writes to stdout. Otherwise, it reads from stdin and writes to
158: stdout, and prompts for each line of input, using "re>" to prompt for regular
159: expressions, and "data>" to prompt for data lines.
160: </P>
161: <P>
162: When <b>pcretest</b> is built, a configuration option can specify that it should
163: be linked with the <b>libreadline</b> library. When this is done, if the input
164: is from a terminal, it is read using the <b>readline()</b> function. This
165: provides line-editing and history facilities. The output from the <b>-help</b>
166: option states whether or not <b>readline()</b> will be used.
167: </P>
168: <P>
169: The program handles any number of sets of input on a single input file. Each
170: set starts with a regular expression, and continues with any number of data
171: lines to be matched against the pattern.
172: </P>
173: <P>
174: Each data line is matched separately and independently. If you want to do
175: multi-line matches, you have to use the \n escape sequence (or \r or \r\n,
176: etc., depending on the newline setting) in a single line of input to encode the
177: newline sequences. There is no limit on the length of data lines; the input
178: buffer is automatically extended if it is too small.
179: </P>
180: <P>
181: An empty line signals the end of the data lines, at which point a new regular
182: expression is read. The regular expressions are given enclosed in any
183: non-alphanumeric delimiters other than backslash, for example:
184: <pre>
185: /(a|bc)x+yz/
186: </pre>
187: White space before the initial delimiter is ignored. A regular expression may
188: be continued over several input lines, in which case the newline characters are
189: included within it. It is possible to include the delimiter within the pattern
190: by escaping it, for example
191: <pre>
192: /abc\/def/
193: </pre>
194: If you do so, the escape and the delimiter form part of the pattern, but since
195: delimiters are always non-alphanumeric, this does not affect its interpretation.
196: If the terminating delimiter is immediately followed by a backslash, for
197: example,
198: <pre>
199: /abc/\
200: </pre>
201: then a backslash is added to the end of the pattern. This is done to provide a
202: way of testing the error condition that arises if a pattern finishes with a
203: backslash, because
204: <pre>
205: /abc\/
206: </pre>
207: is interpreted as the first line of a pattern that starts with "abc/", causing
208: pcretest to read the next line as a continuation of the regular expression.
209: </P>
210: <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
211: <P>
212: A pattern may be followed by any number of modifiers, which are mostly single
213: characters. Following Perl usage, these are referred to below as, for example,
214: "the <b>/i</b> modifier", even though the delimiter of the pattern need not
215: always be a slash, and no slash is used when writing modifiers. White space may
216: appear between the final pattern delimiter and the first modifier, and between
217: the modifiers themselves.
218: </P>
219: <P>
220: The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
221: PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
222: <b>pcre_compile()</b> is called. These four modifier letters have the same
223: effect as they do in Perl. For example:
224: <pre>
225: /caseless/i
226: </pre>
227: The following table shows additional modifiers for setting PCRE compile-time
228: options that do not correspond to anything in Perl:
229: <pre>
230: <b>/8</b> PCRE_UTF8
231: <b>/?</b> PCRE_NO_UTF8_CHECK
232: <b>/A</b> PCRE_ANCHORED
233: <b>/C</b> PCRE_AUTO_CALLOUT
234: <b>/E</b> PCRE_DOLLAR_ENDONLY
235: <b>/f</b> PCRE_FIRSTLINE
236: <b>/J</b> PCRE_DUPNAMES
237: <b>/N</b> PCRE_NO_AUTO_CAPTURE
238: <b>/U</b> PCRE_UNGREEDY
239: <b>/W</b> PCRE_UCP
240: <b>/X</b> PCRE_EXTRA
241: <b>/Y</b> PCRE_NO_START_OPTIMIZE
242: <b>/<JS></b> PCRE_JAVASCRIPT_COMPAT
243: <b>/<cr></b> PCRE_NEWLINE_CR
244: <b>/<lf></b> PCRE_NEWLINE_LF
245: <b>/<crlf></b> PCRE_NEWLINE_CRLF
246: <b>/<anycrlf></b> PCRE_NEWLINE_ANYCRLF
247: <b>/<any></b> PCRE_NEWLINE_ANY
248: <b>/<bsr_anycrlf></b> PCRE_BSR_ANYCRLF
249: <b>/<bsr_unicode></b> PCRE_BSR_UNICODE
250: </pre>
251: The modifiers that are enclosed in angle brackets are literal strings as shown,
252: including the angle brackets, but the letters within can be in either case.
253: This example sets multiline matching with CRLF as the line ending sequence:
254: <pre>
255: /^abc/m<CRLF>
256: </pre>
257: As well as turning on the PCRE_UTF8 option, the <b>/8</b> modifier also causes
258: any non-printing characters in output strings to be printed using the
259: \x{hh...} notation if they are valid UTF-8 sequences. Full details of the PCRE
260: options are given in the
261: <a href="pcreapi.html"><b>pcreapi</b></a>
262: documentation.
263: </P>
264: <br><b>
265: Finding all matches in a string
266: </b><br>
267: <P>
268: Searching for all possible matches within each subject string can be requested
269: by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
270: again to search the remainder of the subject string. The difference between
271: <b>/g</b> and <b>/G</b> is that the former uses the <i>startoffset</i> argument to
272: <b>pcre_exec()</b> to start searching at a new point within the entire string
273: (which is in effect what Perl does), whereas the latter passes over a shortened
274: substring. This makes a difference to the matching process if the pattern
275: begins with a lookbehind assertion (including \b or \B).
276: </P>
277: <P>
278: If any call to <b>pcre_exec()</b> in a <b>/g</b> or <b>/G</b> sequence matches an
279: empty 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, match at the
281: same point. If this second match fails, the start offset is advanced, and the
282: normal match is retried. This imitates the way Perl handles such cases when
283: using the <b>/g</b> modifier or the <b>split()</b> function. Normally, the start
284: offset is advanced by one character, but if the newline convention recognizes
285: CRLF as a newline, and the current character is CR followed by LF, an advance
286: of two is used.
287: </P>
288: <br><b>
289: Other modifiers
290: </b><br>
291: <P>
292: There are yet more modifiers for controlling the way <b>pcretest</b>
293: operates.
294: </P>
295: <P>
296: The <b>/+</b> modifier requests that as well as outputting the substring that
297: matched the entire pattern, <b>pcretest</b> should in addition output the
298: remainder of the subject string. This is useful for tests where the subject
299: contains multiple copies of the same substring. If the <b>+</b> modifier appears
300: twice, the same action is taken for captured substrings. In each case the
301: remainder is output on the following line with a plus character following the
302: capture number. Note that this modifier must not immediately follow the /S
303: modifier because /S+ has another meaning.
304: </P>
305: <P>
306: The <b>/=</b> modifier requests that the values of all potential captured
307: parentheses be output after a match by <b>pcre_exec()</b>. By default, only
308: those up to the highest one actually used in the match are output
309: (corresponding to the return code from <b>pcre_exec()</b>). Values in the
310: offsets vector corresponding to higher numbers should be set to -1, and these
311: are output as "<unset>". This modifier gives a way of checking that this is
312: happening.
313: </P>
314: <P>
315: The <b>/B</b> modifier is a debugging feature. It requests that <b>pcretest</b>
316: output a representation of the compiled byte code after compilation. Normally
317: this information contains length and offset values; however, if <b>/Z</b> is
318: also present, this data is replaced by spaces. This is a special feature for
319: use in the automatic test scripts; it ensures that the same output is generated
320: for different internal link sizes.
321: </P>
322: <P>
323: The <b>/D</b> modifier is a PCRE debugging feature, and is equivalent to
324: <b>/BI</b>, that is, both the <b>/B</b> and the <b>/I</b> modifiers.
325: </P>
326: <P>
327: The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
328: fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
329: facility is for testing the feature in PCRE that allows it to execute patterns
330: that were compiled on a host with a different endianness. This feature is not
331: available when the POSIX interface to PCRE is being used, that is, when the
332: <b>/P</b> pattern modifier is specified. See also the section about saving and
333: reloading compiled patterns below.
334: </P>
335: <P>
336: The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
337: compiled pattern (whether it is anchored, has a fixed first character, and
338: so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
339: pattern. If the pattern is studied, the results of that are also output.
340: </P>
341: <P>
342: The <b>/K</b> modifier requests <b>pcretest</b> to show names from backtracking
343: control verbs that are returned from calls to <b>pcre_exec()</b>. It causes
344: <b>pcretest</b> to create a <b>pcre_extra</b> block if one has not already been
345: created by a call to <b>pcre_study()</b>, and to set the PCRE_EXTRA_MARK flag
346: and the <b>mark</b> field within it, every time that <b>pcre_exec()</b> is
347: called. If the variable that the <b>mark</b> field points to is non-NULL for a
348: match, non-match, or partial match, <b>pcretest</b> prints the string to which
349: it points. For a match, this is shown on a line by itself, tagged with "MK:".
350: For a non-match it is added to the message.
351: </P>
352: <P>
353: The <b>/L</b> modifier must be followed directly by the name of a locale, for
354: example,
355: <pre>
356: /pattern/Lfr_FR
357: </pre>
358: For this reason, it must be the last modifier. The given locale is set,
359: <b>pcre_maketables()</b> is called to build a set of character tables for the
360: locale, and this is then passed to <b>pcre_compile()</b> when compiling the
361: regular expression. Without an <b>/L</b> (or <b>/T</b>) modifier, NULL is passed
362: as the tables pointer; that is, <b>/L</b> applies only to the expression on
363: which it appears.
364: </P>
365: <P>
366: The <b>/M</b> modifier causes the size of memory block used to hold the compiled
367: pattern to be output. This does not include the size of the <b>pcre</b> block;
368: it is just the actual compiled data. If the pattern is successfully studied
369: with the PCRE_STUDY_JIT_COMPILE option, the size of the JIT compiled code is
370: also output.
371: </P>
372: <P>
373: If the <b>/S</b> modifier appears once, it causes <b>pcre_study()</b> to be
374: called after the expression has been compiled, and the results used when the
375: expression is matched. If <b>/S</b> appears twice, it suppresses studying, even
376: if it was requested externally by the <b>-s</b> command line option. This makes
377: it possible to specify that certain patterns are always studied, and others are
378: never studied, independently of <b>-s</b>. This feature is used in the test
379: files in a few cases where the output is different when the pattern is studied.
380: </P>
381: <P>
382: If the <b>/S</b> modifier is immediately followed by a + character, the call to
383: <b>pcre_study()</b> is made with the PCRE_STUDY_JIT_COMPILE option, requesting
384: just-in-time optimization support if it is available. Note that there is also a
385: <b>/+</b> modifier; it must not be given immediately after <b>/S</b> because this
386: will be misinterpreted. If JIT studying is successful, it will automatically be
387: used when <b>pcre_exec()</b> is run, except when incompatible run-time options
388: are specified. These include the partial matching options; a complete list is
389: given in the
390: <a href="pcrejit.html"><b>pcrejit</b></a>
391: documentation. See also the <b>\J</b> escape sequence below for a way of
392: setting the size of the JIT stack.
393: </P>
394: <P>
395: The <b>/T</b> modifier must be followed by a single digit. It causes a specific
396: set of built-in character tables to be passed to <b>pcre_compile()</b>. It is
397: used in the standard PCRE tests to check behaviour with different character
398: tables. The digit specifies the tables as follows:
399: <pre>
400: 0 the default ASCII tables, as distributed in
401: pcre_chartables.c.dist
402: 1 a set of tables defining ISO 8859 characters
403: </pre>
404: In table 1, some characters whose codes are greater than 128 are identified as
405: letters, digits, spaces, etc.
406: </P>
407: <br><b>
408: Using the POSIX wrapper API
409: </b><br>
410: <P>
411: The <b>/P</b> modifier causes <b>pcretest</b> to call PCRE via the POSIX wrapper
412: API rather than its native API. When <b>/P</b> is set, the following modifiers
413: set options for the <b>regcomp()</b> function:
414: <pre>
415: /i REG_ICASE
416: /m REG_NEWLINE
417: /N REG_NOSUB
418: /s REG_DOTALL )
419: /U REG_UNGREEDY ) These options are not part of
420: /W REG_UCP ) the POSIX standard
421: /8 REG_UTF8 )
422: </pre>
423: The <b>/+</b> modifier works as described above. All other modifiers are
424: ignored.
425: </P>
426: <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
427: <P>
428: Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
429: white space is removed, and it is then scanned for \ escapes. Some of these
430: are pretty esoteric features, intended for checking out some of the more
431: complicated features of PCRE. If you are just testing "ordinary" regular
432: expressions, you probably don't need any of these. The following escapes are
433: recognized:
434: <pre>
435: \a alarm (BEL, \x07)
436: \b backspace (\x08)
437: \e escape (\x27)
438: \f form feed (\x0c)
439: \n newline (\x0a)
440: \qdd set the PCRE_MATCH_LIMIT limit to dd (any number of digits)
441: \r carriage return (\x0d)
442: \t tab (\x09)
443: \v vertical tab (\x0b)
444: \nnn octal character (up to 3 octal digits)
445: always a byte unless > 255 in UTF-8 mode
446: \xhh hexadecimal byte (up to 2 hex digits)
447: \x{hh...} hexadecimal character, any number of digits in UTF-8 mode
448: \A pass the PCRE_ANCHORED option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
449: \B pass the PCRE_NOTBOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
450: \Cdd call pcre_copy_substring() for substring dd after a successful match (number less than 32)
451: \Cname call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
452: ated by next non alphanumeric character)
453: \C+ show the current captured substrings at callout time
454: \C- do not supply a callout function
455: \C!n return 1 instead of 0 when callout number n is reached
456: \C!n!m return 1 instead of 0 when callout number n is reached for the nth time
457: \C*n pass the number n (may be negative) as callout data; this is used as the callout return value
458: \D use the <b>pcre_dfa_exec()</b> match function
459: \F only shortest match for <b>pcre_dfa_exec()</b>
460: \Gdd call pcre_get_substring() for substring dd after a successful match (number less than 32)
461: \Gname call pcre_get_named_substring() for substring "name" after a successful match (name termin-
462: ated by next non-alphanumeric character)
463: \Jdd set up a JIT stack of dd kilobytes maximum (any number of digits)
464: \L call pcre_get_substringlist() after a successful match
465: \M discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings
466: \N pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
467: PCRE_NOTEMPTY_ATSTART option
468: \Odd set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
469: \P pass the PCRE_PARTIAL_SOFT option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>; if used twice, pass the
470: PCRE_PARTIAL_HARD option
471: \Qdd set the PCRE_MATCH_LIMIT_RECURSION limit to dd (any number of digits)
472: \R pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
473: \S output details of memory get/free calls during matching
474: \Y pass the PCRE_NO_START_OPTIMIZE option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
475: \Z pass the PCRE_NOTEOL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
476: \? pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
477: \>dd start the match at offset dd (optional "-"; then any number of digits); this sets the <i>startoffset</i>
478: argument for <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
479: \<cr> pass the PCRE_NEWLINE_CR option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
480: \<lf> pass the PCRE_NEWLINE_LF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
481: \<crlf> pass the PCRE_NEWLINE_CRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
482: \<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
483: \<any> pass the PCRE_NEWLINE_ANY option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
484: </pre>
485: Note that \xhh always specifies one byte, even in UTF-8 mode; this makes it
486: possible to construct invalid UTF-8 sequences for testing purposes. On the
487: other hand, \x{hh} is interpreted as a UTF-8 character in UTF-8 mode,
488: generating more than one byte if the value is greater than 127. When not in
489: UTF-8 mode, it generates one byte for values less than 256, and causes an error
490: for greater values.
491: </P>
492: <P>
493: The escapes that specify line ending sequences are literal strings, exactly as
494: shown. No more than one newline setting should be present in any data line.
495: </P>
496: <P>
497: A backslash followed by anything else just escapes the anything else. If
498: the very last character is a backslash, it is ignored. This gives a way of
499: passing an empty line as data, since a real empty line terminates the data
500: input.
501: </P>
502: <P>
503: The <b>\J</b> escape provides a way of setting the maximum stack size that is
504: used by the just-in-time optimization code. It is ignored if JIT optimization
505: is not being used. Providing a stack that is larger than the default 32K is
506: necessary only for very complicated patterns.
507: </P>
508: <P>
509: If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
510: different values in the <i>match_limit</i> and <i>match_limit_recursion</i>
511: fields of the <b>pcre_extra</b> data structure, until it finds the minimum
512: numbers for each parameter that allow <b>pcre_exec()</b> to complete without
513: error. Because this is testing a specific feature of the normal interpretive
514: <b>pcre_exec()</b> execution, the use of any JIT optimization that might have
515: been set up by the <b>/S+</b> qualifier of <b>-s+</b> option is disabled.
516: </P>
517: <P>
518: The <i>match_limit</i> number is a measure of the amount of backtracking
519: that takes place, and checking it out can be instructive. For most simple
520: matches, the number is quite small, but for patterns with very large numbers of
521: matching possibilities, it can become large very quickly with increasing length
522: of subject string. The <i>match_limit_recursion</i> number is a measure of how
523: much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is
524: needed to complete the match attempt.
525: </P>
526: <P>
527: When \O is used, the value specified may be higher or lower than the size set
528: by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
529: the call of <b>pcre_exec()</b> for the line in which it appears.
530: </P>
531: <P>
532: If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
533: API to be used, the only option-setting sequences that have any effect are \B,
534: \N, and \Z, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,
535: to be passed to <b>regexec()</b>.
536: </P>
537: <P>
538: The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
539: of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
540: any number of hexadecimal digits inside the braces. The result is from one to
541: six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
542: allows for values in the range 0 to 0x7FFFFFFF. Note that not all of those are
543: valid Unicode code points, or indeed valid UTF-8 characters according to the
544: later rules in RFC 3629.
545: </P>
546: <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
547: <P>
548: By default, <b>pcretest</b> uses the standard PCRE matching function,
549: <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
550: alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
551: different way, and has some restrictions. The differences between the two
552: functions are described in the
553: <a href="pcrematching.html"><b>pcrematching</b></a>
554: documentation.
555: </P>
556: <P>
557: If a data line contains the \D escape sequence, or if the command line
558: contains the <b>-dfa</b> option, the alternative matching function is called.
559: This function finds all possible matches at a given point. If, however, the \F
560: escape sequence is present in the data line, it stops after the first match is
561: found. This is always the shortest possible match.
562: </P>
563: <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
564: <P>
565: This section describes the output when the normal matching function,
566: <b>pcre_exec()</b>, is being used.
567: </P>
568: <P>
569: When a match succeeds, <b>pcretest</b> outputs the list of captured substrings
570: that <b>pcre_exec()</b> returns, starting with number 0 for the string that
571: matched the whole pattern. Otherwise, it outputs "No match" when the return is
572: PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching
573: substring when <b>pcre_exec()</b> returns PCRE_ERROR_PARTIAL. (Note that this is
574: the entire substring that was inspected during the partial match; it may
575: include characters before the actual match start if a lookbehind assertion,
576: \K, \b, or \B was involved.) For any other return, <b>pcretest</b> outputs
577: the PCRE negative error number and a short descriptive phrase. If the error is
578: a failed UTF-8 string check, the byte offset of the start of the failing
579: character and the reason code are also output, provided that the size of the
580: output vector is at least two. Here is an example of an interactive
581: <b>pcretest</b> run.
582: <pre>
583: $ pcretest
584: PCRE version 8.13 2011-04-30
585:
586: re> /^abc(\d+)/
587: data> abc123
588: 0: abc123
589: 1: 123
590: data> xyz
591: No match
592: </pre>
593: Unset capturing substrings that are not followed by one that is set are not
594: returned by <b>pcre_exec()</b>, and are not shown by <b>pcretest</b>. In the
595: following example, there are two capturing substrings, but when the first data
596: line is matched, the second, unset substring is not shown. An "internal" unset
597: substring is shown as "<unset>", as for the second data line.
598: <pre>
599: re> /(a)|(b)/
600: data> a
601: 0: a
602: 1: a
603: data> b
604: 0: b
605: 1: <unset>
606: 2: b
607: </pre>
608: If the strings contain any non-printing characters, they are output as \0x
609: escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
610: pattern. See below for the definition of non-printing characters. If the
611: pattern has the <b>/+</b> modifier, the output for substring 0 is followed by
612: the the rest of the subject string, identified by "0+" like this:
613: <pre>
614: re> /cat/+
615: data> cataract
616: 0: cat
617: 0+ aract
618: </pre>
619: If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
620: matching attempts are output in sequence, like this:
621: <pre>
622: re> /\Bi(\w\w)/g
623: data> Mississippi
624: 0: iss
625: 1: ss
626: 0: iss
627: 1: ss
628: 0: ipp
629: 1: pp
630: </pre>
631: "No match" is output only if the first match attempt fails. Here is an example
632: of a failure message (the offset 4 that is specified by \>4 is past the end of
633: the subject string):
634: <pre>
635: re> /xyz/
636: data> xyz\>4
637: Error -24 (bad offset value)
638: </PRE>
639: </P>
640: <P>
641: If any of the sequences <b>\C</b>, <b>\G</b>, or <b>\L</b> are present in a
642: data line that is successfully matched, the substrings extracted by the
643: convenience functions are output with C, G, or L after the string number
644: instead of a colon. This is in addition to the normal full list. The string
645: length (that is, the return from the extraction function) is given in
646: parentheses after each string for <b>\C</b> and <b>\G</b>.
647: </P>
648: <P>
649: Note that whereas patterns can be continued over several lines (a plain ">"
650: prompt is used for continuations), data lines may not. However newlines can be
651: included in data by means of the \n escape (or \r, \r\n, etc., depending on
652: the newline sequence setting).
653: </P>
654: <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
655: <P>
656: When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
657: means of the \D escape sequence or the <b>-dfa</b> command line option), the
658: output consists of a list of all the matches that start at the first point in
659: the subject where there is at least one match. For example:
660: <pre>
661: re> /(tang|tangerine|tan)/
662: data> yellow tangerine\D
663: 0: tangerine
664: 1: tang
665: 2: tan
666: </pre>
667: (Using the normal matching function on this data finds only "tang".) The
668: longest matching string is always given first (and numbered zero). After a
669: PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the
670: partially matching substring. (Note that this is the entire substring that was
671: inspected during the partial match; it may include characters before the actual
672: match start if a lookbehind assertion, \K, \b, or \B was involved.)
673: </P>
674: <P>
675: If <b>/g</b> is present on the pattern, the search for further matches resumes
676: at the end of the longest match. For example:
677: <pre>
678: re> /(tang|tangerine|tan)/g
679: data> yellow tangerine and tangy sultana\D
680: 0: tangerine
681: 1: tang
682: 2: tan
683: 0: tang
684: 1: tan
685: 0: tan
686: </pre>
687: Since the matching function does not support substring capture, the escape
688: sequences that are concerned with captured substrings are not relevant.
689: </P>
690: <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
691: <P>
692: When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
693: indicating that the subject partially matched the pattern, you can restart the
694: match with additional subject data by means of the \R escape sequence. For
695: example:
696: <pre>
697: re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
698: data> 23ja\P\D
699: Partial match: 23ja
700: data> n05\R\D
701: 0: n05
702: </pre>
703: For further information about partial matching, see the
704: <a href="pcrepartial.html"><b>pcrepartial</b></a>
705: documentation.
706: </P>
707: <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
708: <P>
709: If the pattern contains any callout requests, <b>pcretest</b>'s callout function
710: is called during matching. This works with both matching functions. By default,
711: the called function displays the callout number, the start and current
712: positions in the text at the callout time, and the next pattern item to be
713: tested. For example, the output
714: <pre>
715: --->pqrabcdef
716: 0 ^ ^ \d
717: </pre>
718: indicates that callout number 0 occurred for a match attempt starting at the
719: fourth character of the subject string, when the pointer was at the seventh
720: character of the data, and when the next pattern item was \d. Just one
721: circumflex is output if the start and current positions are the same.
722: </P>
723: <P>
724: Callouts numbered 255 are assumed to be automatic callouts, inserted as a
725: result of the <b>/C</b> pattern modifier. In this case, instead of showing the
726: callout number, the offset in the pattern, preceded by a plus, is output. For
727: example:
728: <pre>
729: re> /\d?[A-E]\*/C
730: data> E*
731: --->E*
732: +0 ^ \d?
733: +3 ^ [A-E]
734: +8 ^^ \*
735: +10 ^ ^
736: 0: E*
737: </pre>
738: If a pattern contains (*MARK) items, an additional line is output whenever
739: a change of latest mark is passed to the callout function. For example:
740: <pre>
741: re> /a(*MARK:X)bc/C
742: data> abc
743: --->abc
744: +0 ^ a
745: +1 ^^ (*MARK:X)
746: +10 ^^ b
747: Latest Mark: X
748: +11 ^ ^ c
749: +12 ^ ^
750: 0: abc
751: </pre>
752: The mark changes between matching "a" and "b", but stays the same for the rest
753: of the match, so nothing more is output. If, as a result of backtracking, the
754: mark reverts to being unset, the text "<unset>" is output.
755: </P>
756: <P>
757: The callout function in <b>pcretest</b> returns zero (carry on matching) by
758: default, but you can use a \C item in a data line (as described above) to
759: change this and other parameters of the callout.
760: </P>
761: <P>
762: Inserting callouts can be helpful when using <b>pcretest</b> to check
763: complicated regular expressions. For further information about callouts, see
764: the
765: <a href="pcrecallout.html"><b>pcrecallout</b></a>
766: documentation.
767: </P>
768: <br><a name="SEC11" href="#TOC1">NON-PRINTING CHARACTERS</a><br>
769: <P>
770: When <b>pcretest</b> is outputting text in the compiled version of a pattern,
771: bytes other than 32-126 are always treated as non-printing characters are are
772: therefore shown as hex escapes.
773: </P>
774: <P>
775: When <b>pcretest</b> is outputting text that is a matched part of a subject
776: string, it behaves in the same way, unless a different locale has been set for
777: the pattern (using the <b>/L</b> modifier). In this case, the <b>isprint()</b>
778: function to distinguish printing and non-printing characters.
779: </P>
780: <br><a name="SEC12" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
781: <P>
782: The facilities described in this section are not available when the POSIX
783: interface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
784: specified.
785: </P>
786: <P>
787: When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
788: compiled pattern to a file, by following the modifiers with > and a file name.
789: For example:
790: <pre>
791: /pattern/im >/some/file
792: </pre>
793: See the
794: <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
795: documentation for a discussion about saving and re-using compiled patterns.
796: Note that if the pattern was successfully studied with JIT optimization, the
797: JIT data cannot be saved.
798: </P>
799: <P>
800: The data that is written is binary. The first eight bytes are the length of the
801: compiled pattern data followed by the length of the optional study data, each
802: written as four bytes in big-endian order (most significant byte first). If
803: there is no study data (either the pattern was not studied, or studying did not
804: return any data), the second length is zero. The lengths are followed by an
805: exact copy of the compiled pattern. If there is additional study data, this
806: (excluding any JIT data) follows immediately after the compiled pattern. After
807: writing the file, <b>pcretest</b> expects to read a new pattern.
808: </P>
809: <P>
810: A saved pattern can be reloaded into <b>pcretest</b> by specifying < and a file
811: name instead of a pattern. The name of the file must not contain a < character,
812: as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by <
813: characters.
814: For example:
815: <pre>
816: re> </some/file
817: Compiled pattern loaded from /some/file
818: No study data
819: </pre>
820: If the pattern was previously studied with the JIT optimization, the JIT
821: information cannot be saved and restored, and so is lost. When the pattern has
822: been loaded, <b>pcretest</b> proceeds to read data lines in the usual way.
823: </P>
824: <P>
825: You can copy a file written by <b>pcretest</b> to a different host and reload it
826: there, even if the new host has opposite endianness to the one on which the
827: pattern was compiled. For example, you can compile on an i86 machine and run on
828: a SPARC machine.
829: </P>
830: <P>
831: File names for saving and reloading can be absolute or relative, but note that
832: the shell facility of expanding a file name that starts with a tilde (~) is not
833: available.
834: </P>
835: <P>
836: The ability to save and reload files in <b>pcretest</b> is intended for testing
837: and experimentation. It is not intended for production use because only a
838: single pattern can be written to a file. Furthermore, there is no facility for
839: supplying custom character tables for use with a reloaded pattern. If the
840: original pattern was compiled with custom tables, an attempt to match a subject
841: string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
842: Finally, if you attempt to load a file that is not in the correct format, the
843: result is undefined.
844: </P>
845: <br><a name="SEC13" href="#TOC1">SEE ALSO</a><br>
846: <P>
847: <b>pcre</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3), <b>pcrejit</b>,
848: <b>pcrematching</b>(3), <b>pcrepartial</b>(d), <b>pcrepattern</b>(3),
849: <b>pcreprecompile</b>(3).
850: </P>
851: <br><a name="SEC14" href="#TOC1">AUTHOR</a><br>
852: <P>
853: Philip Hazel
854: <br>
855: University Computing Service
856: <br>
857: Cambridge CB2 3QH, England.
858: <br>
859: </P>
860: <br><a name="SEC15" href="#TOC1">REVISION</a><br>
861: <P>
862: Last updated: 02 December 2011
863: <br>
864: Copyright © 1997-2011 University of Cambridge.
865: <br>
866: <p>
867: Return to the <a href="index.html">PCRE index page</a>.
868: </p>
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