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revision 53 by nigel, Sat Feb 24 21:39:42 2007 UTC revision 87 by nigel, Sat Feb 24 21:41:21 2007 UTC
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2  .SH NAME  .SH NAME
3  pcretest - a program for testing Perl-compatible regular expressions.  pcretest - a program for testing Perl-compatible regular expressions.
4  .SH SYNOPSIS  .SH SYNOPSIS
5  .B pcretest "[-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]"  .rs
6    .sp
7  \fBpcretest\fR was written as a test program for the PCRE regular expression  .B pcretest "[-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]"
8    .ti +5n
9    .B "[destination]"
10    .P
11    \fBpcretest\fP was written as a test program for the PCRE regular expression
12  library itself, but it can also be used for experimenting with regular  library itself, but it can also be used for experimenting with regular
13  expressions. This man page describes the features of the test program; for  expressions. This document describes the features of the test program; for
14  details of the regular expressions themselves, see the \fBpcre\fR man page.  details of the regular expressions themselves, see the
15    .\" HREF
16    \fBpcrepattern\fP
17    .\"
18    documentation. For details of the PCRE library function calls and their
19    options, see the
20    .\" HREF
21    \fBpcreapi\fP
22    .\"
23    documentation.
24    .
25    .
26  .SH OPTIONS  .SH OPTIONS
27    .rs
28  .TP 10  .TP 10
29  \fB-d\fR  \fB-C\fP
30  Behave as if each regex had the \fB/D\fR modifier (see below); the internal  Output the version number of the PCRE library, and all available information
31    about the optional features that are included, and then exit.
32    .TP 10
33    \fB-d\fP
34    Behave as if each regex has the \fB/D\fP (debug) modifier; the internal
35  form is output after compilation.  form is output after compilation.
36  .TP 10  .TP 10
37  \fB-i\fR  \fB-dfa\fP
38  Behave as if each regex had the \fB/I\fR modifier; information about the  Behave as if each data line contains the \eD escape sequence; this causes the
39    alternative matching function, \fBpcre_dfa_exec()\fP, to be used instead of the
40    standard \fBpcre_exec()\fP function (more detail is given below).
41    .TP 10
42    \fB-i\fP
43    Behave as if each regex has the \fB/I\fP modifier; information about the
44  compiled pattern is given after compilation.  compiled pattern is given after compilation.
45  .TP 10  .TP 10
46  \fB-m\fR  \fB-m\fP
47  Output the size of each compiled pattern after it has been compiled. This is  Output the size of each compiled pattern after it has been compiled. This is
48  equivalent to adding /M to each regular expression. For compatibility with  equivalent to adding \fB/M\fP to each regular expression. For compatibility
49  earlier versions of pcretest, \fB-s\fR is a synonym for \fB-m\fR.  with earlier versions of pcretest, \fB-s\fP is a synonym for \fB-m\fP.
50    .TP 10
51    \fB-o\fP \fIosize\fP
52    Set the number of elements in the output vector that is used when calling
53    \fBpcre_exec()\fP to be \fIosize\fP. The default value is 45, which is enough
54    for 14 capturing subexpressions. The vector size can be changed for individual
55    matching calls by including \eO in the data line (see below).
56  .TP 10  .TP 10
57  \fB-o\fR \fIosize\fR  \fB-p\fP
58  Set the number of elements in the output vector that is used when calling PCRE  Behave as if each regex has the \fB/P\fP modifier; the POSIX wrapper API is
59  to be \fIosize\fR. The default value is 45, which is enough for 14 capturing  used to call PCRE. None of the other options has any effect when \fB-p\fP is
60  subexpressions. The vector size can be changed for individual matching calls by  set.
 including \\O in the data line (see below).  
61  .TP 10  .TP 10
62  \fB-p\fR  \fP-q\fP
63  Behave as if each regex has \fB/P\fR modifier; the POSIX wrapper API is used  Do not output the version number of \fBpcretest\fP at the start of execution.
 to call PCRE. None of the other options has any effect when \fB-p\fR is set.  
64  .TP 10  .TP 10
65  \fB-t\fR  \fB-t\fP
66  Run each compile, study, and match 20000 times with a timer, and output  Run each compile, study, and match many times with a timer, and output
67  resulting time per compile or match (in milliseconds). Do not set \fB-t\fR with  resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with
68  \fB-m\fR, because you will then get the size output 20000 times and the timing  \fB-t\fP, because you will then get the size output a zillion times, and the
69  will be distorted.  timing will be distorted.
70    .
71    .
72  .SH DESCRIPTION  .SH DESCRIPTION
73    .rs
74  If \fBpcretest\fR is given two filename arguments, it reads from the first and  .sp
75    If \fBpcretest\fP is given two filename arguments, it reads from the first and
76  writes to the second. If it is given only one filename argument, it reads from  writes to the second. If it is given only one filename argument, it reads from
77  that file and writes to stdout. Otherwise, it reads from stdin and writes to  that file and writes to stdout. Otherwise, it reads from stdin and writes to
78  stdout, and prompts for each line of input, using "re>" to prompt for regular  stdout, and prompts for each line of input, using "re>" to prompt for regular
79  expressions, and "data>" to prompt for data lines.  expressions, and "data>" to prompt for data lines.
80    .P
81  The program handles any number of sets of input on a single input file. Each  The program handles any number of sets of input on a single input file. Each
82  set starts with a regular expression, and continues with any number of data  set starts with a regular expression, and continues with any number of data
83  lines to be matched against the pattern. An empty line signals the end of the  lines to be matched against the pattern.
84  data lines, at which point a new regular expression is read. The regular  .P
85  expressions are given enclosed in any non-alphameric delimiters other than  Each data line is matched separately and independently. If you want to do
86  backslash, for example  multiple-line matches, you have to use the \en escape sequence in a single line
87    of input to encode the newline characters. The maximum length of data line is
88    30,000 characters.
89    .P
90    An empty line signals the end of the data lines, at which point a new regular
91    expression is read. The regular expressions are given enclosed in any
92    non-alphanumeric delimiters other than backslash, for example
93    .sp
94    /(a|bc)x+yz/    /(a|bc)x+yz/
95    .sp
96  White space before the initial delimiter is ignored. A regular expression may  White space before the initial delimiter is ignored. A regular expression may
97  be continued over several input lines, in which case the newline characters are  be continued over several input lines, in which case the newline characters are
98  included within it. It is possible to include the delimiter within the pattern  included within it. It is possible to include the delimiter within the pattern
99  by escaping it, for example  by escaping it, for example
100    .sp
101    /abc\\/def/    /abc\e/def/
102    .sp
103  If you do so, the escape and the delimiter form part of the pattern, but since  If you do so, the escape and the delimiter form part of the pattern, but since
104  delimiters are always non-alphameric, this does not affect its interpretation.  delimiters are always non-alphanumeric, this does not affect its interpretation.
105  If the terminating delimiter is immediately followed by a backslash, for  If the terminating delimiter is immediately followed by a backslash, for
106  example,  example,
107    .sp
108    /abc/\\    /abc/\e
109    .sp
110  then a backslash is added to the end of the pattern. This is done to provide a  then a backslash is added to the end of the pattern. This is done to provide a
111  way of testing the error condition that arises if a pattern finishes with a  way of testing the error condition that arises if a pattern finishes with a
112  backslash, because  backslash, because
113    .sp
114    /abc\\/    /abc\e/
115    .sp
116  is interpreted as the first line of a pattern that starts with "abc/", causing  is interpreted as the first line of a pattern that starts with "abc/", causing
117  pcretest to read the next line as a continuation of the regular expression.  pcretest to read the next line as a continuation of the regular expression.
118    .
119    .
120  .SH PATTERN MODIFIERS  .SH "PATTERN MODIFIERS"
121    .rs
122  The pattern may be followed by \fBi\fR, \fBm\fR, \fBs\fR, or \fBx\fR to set the  .sp
123  PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,  A pattern may be followed by any number of modifiers, which are mostly single
124  respectively. For example:  characters. Following Perl usage, these are referred to below as, for example,
125    "the \fB/i\fP modifier", even though the delimiter of the pattern need not
126    always be a slash, and no slash is used when writing modifiers. Whitespace may
127    appear between the final pattern delimiter and the first modifier, and between
128    the modifiers themselves.
129    .P
130    The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,
131    PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
132    \fBpcre_compile()\fP is called. These four modifier letters have the same
133    effect as they do in Perl. For example:
134    .sp
135    /caseless/i    /caseless/i
136    .sp
137  These modifier letters have the same effect as they do in Perl. There are  The following table shows additional modifiers for setting PCRE options that do
138  others which set PCRE options that do not correspond to anything in Perl:  not correspond to anything in Perl:
139  \fB/A\fR, \fB/E\fR, and \fB/X\fR set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and  .sp
140  PCRE_EXTRA respectively.    \fB/A\fP    PCRE_ANCHORED
141      \fB/C\fP    PCRE_AUTO_CALLOUT
142      \fB/E\fP    PCRE_DOLLAR_ENDONLY
143      \fB/f\fP    PCRE_FIRSTLINE
144      \fB/N\fP    PCRE_NO_AUTO_CAPTURE
145      \fB/U\fP    PCRE_UNGREEDY
146      \fB/X\fP    PCRE_EXTRA
147    .sp
148  Searching for all possible matches within each subject string can be requested  Searching for all possible matches within each subject string can be requested
149  by the \fB/g\fR or \fB/G\fR modifier. After finding a match, PCRE is called  by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called
150  again to search the remainder of the subject string. The difference between  again to search the remainder of the subject string. The difference between
151  \fB/g\fR and \fB/G\fR is that the former uses the \fIstartoffset\fR argument to  \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to
152  \fBpcre_exec()\fR to start searching at a new point within the entire string  \fBpcre_exec()\fP to start searching at a new point within the entire string
153  (which is in effect what Perl does), whereas the latter passes over a shortened  (which is in effect what Perl does), whereas the latter passes over a shortened
154  substring. This makes a difference to the matching process if the pattern  substring. This makes a difference to the matching process if the pattern
155  begins with a lookbehind assertion (including \\b or \\B).  begins with a lookbehind assertion (including \eb or \eB).
156    .P
157  If any call to \fBpcre_exec()\fR in a \fB/g\fR or \fB/G\fR sequence matches an  If any call to \fBpcre_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches an
158  empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED  empty string, the next call is done with the PCRE_NOTEMPTY and PCRE_ANCHORED
159  flags set in order to search for another, non-empty, match at the same point.  flags set in order to search for another, non-empty, match at the same point.
160  If this second match fails, the start offset is advanced by one, and the normal  If this second match fails, the start offset is advanced by one, and the normal
161  match is retried. This imitates the way Perl handles such cases when using the  match is retried. This imitates the way Perl handles such cases when using the
162  \fB/g\fR modifier or the \fBsplit()\fR function.  \fB/g\fP modifier or the \fBsplit()\fP function.
163    .P
164  There are a number of other modifiers for controlling the way \fBpcretest\fR  There are yet more modifiers for controlling the way \fBpcretest\fP
165  operates.  operates.
166    .P
167  The \fB/+\fR modifier requests that as well as outputting the substring that  The \fB/+\fP modifier requests that as well as outputting the substring that
168  matched the entire pattern, pcretest should in addition output the remainder of  matched the entire pattern, pcretest should in addition output the remainder of
169  the subject string. This is useful for tests where the subject contains  the subject string. This is useful for tests where the subject contains
170  multiple copies of the same substring.  multiple copies of the same substring.
171    .P
172  The \fB/L\fR modifier must be followed directly by the name of a locale, for  The \fB/L\fP modifier must be followed directly by the name of a locale, for
173  example,  example,
174    .sp
175    /pattern/Lfr    /pattern/Lfr_FR
176    .sp
177  For this reason, it must be the last modifier letter. The given locale is set,  For this reason, it must be the last modifier. The given locale is set,
178  \fBpcre_maketables()\fR is called to build a set of character tables for the  \fBpcre_maketables()\fP is called to build a set of character tables for the
179  locale, and this is then passed to \fBpcre_compile()\fR when compiling the  locale, and this is then passed to \fBpcre_compile()\fP when compiling the
180  regular expression. Without an \fB/L\fR modifier, NULL is passed as the tables  regular expression. Without an \fB/L\fP modifier, NULL is passed as the tables
181  pointer; that is, \fB/L\fR applies only to the expression on which it appears.  pointer; that is, \fB/L\fP applies only to the expression on which it appears.
182    .P
183  The \fB/I\fR modifier requests that \fBpcretest\fR output information about the  The \fB/I\fP modifier requests that \fBpcretest\fP output information about the
184  compiled expression (whether it is anchored, has a fixed first character, and  compiled pattern (whether it is anchored, has a fixed first character, and
185  so on). It does this by calling \fBpcre_fullinfo()\fR after compiling an  so on). It does this by calling \fBpcre_fullinfo()\fP after compiling a
186  expression, and outputting the information it gets back. If the pattern is  pattern. If the pattern is studied, the results of that are also output.
187  studied, the results of that are also output.  .P
188    The \fB/D\fP modifier is a PCRE debugging feature, which also assumes \fB/I\fP.
 The \fB/D\fR modifier is a PCRE debugging feature, which also assumes \fB/I\fR.  
189  It causes the internal form of compiled regular expressions to be output after  It causes the internal form of compiled regular expressions to be output after
190  compilation.  compilation. If the pattern was studied, the information returned is also
191    output.
192  The \fB/S\fR modifier causes \fBpcre_study()\fR to be called after the  .P
193    The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the
194    fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
195    facility is for testing the feature in PCRE that allows it to execute patterns
196    that were compiled on a host with a different endianness. This feature is not
197    available when the POSIX interface to PCRE is being used, that is, when the
198    \fB/P\fP pattern modifier is specified. See also the section about saving and
199    reloading compiled patterns below.
200    .P
201    The \fB/S\fP modifier causes \fBpcre_study()\fP to be called after the
202  expression has been compiled, and the results used when the expression is  expression has been compiled, and the results used when the expression is
203  matched.  matched.
204    .P
205  The \fB/M\fR modifier causes the size of memory block used to hold the compiled  The \fB/M\fP modifier causes the size of memory block used to hold the compiled
206  pattern to be output.  pattern to be output.
207    .P
208  The \fB/P\fR modifier causes \fBpcretest\fR to call PCRE via the POSIX wrapper  The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper
209  API rather than its native API. When this is done, all other modifiers except  API rather than its native API. When this is done, all other modifiers except
210  \fB/i\fR, \fB/m\fR, and \fB/+\fR are ignored. REG_ICASE is set if \fB/i\fR is  \fB/i\fP, \fB/m\fP, and \fB/+\fP are ignored. REG_ICASE is set if \fB/i\fP is
211  present, and REG_NEWLINE is set if \fB/m\fR is present. The wrapper functions  present, and REG_NEWLINE is set if \fB/m\fP is present. The wrapper functions
212  force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.  force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
213    .P
214  The \fB/8\fR modifier causes \fBpcretest\fR to call PCRE with the PCRE_UTF8  The \fB/8\fP modifier causes \fBpcretest\fP to call PCRE with the PCRE_UTF8
215  option set. This turns on the (currently incomplete) support for UTF-8  option set. This turns on support for UTF-8 character handling in PCRE,
216  character handling in PCRE, provided that it was compiled with this support  provided that it was compiled with this support enabled. This modifier also
217  enabled. This modifier also causes any non-printing characters in output  causes any non-printing characters in output strings to be printed using the
218  strings to be printed using the \\x{hh...} notation if they are valid UTF-8  \ex{hh...} notation if they are valid UTF-8 sequences.
219  sequences.  .P
220    If the \fB/?\fP modifier is used with \fB/8\fP, it causes \fBpcretest\fP to
221    call \fBpcre_compile()\fP with the PCRE_NO_UTF8_CHECK option, to suppress the
222  .SH DATA LINES  checking of the string for UTF-8 validity.
223    .
224  Before each data line is passed to \fBpcre_exec()\fR, leading and trailing  .
225  whitespace is removed, and it is then scanned for \\ escapes. The following are  .SH "DATA LINES"
226    .rs
227    .sp
228    Before each data line is passed to \fBpcre_exec()\fP, leading and trailing
229    whitespace is removed, and it is then scanned for \e escapes. Some of these are
230    pretty esoteric features, intended for checking out some of the more
231    complicated features of PCRE. If you are just testing "ordinary" regular
232    expressions, you probably don't need any of these. The following escapes are
233  recognized:  recognized:
234    .sp
235    \\a         alarm (= BEL)    \ea         alarm (= BEL)
236    \\b         backspace    \eb         backspace
237    \\e         escape    \ee         escape
238    \\f         formfeed    \ef         formfeed
239    \\n         newline    \en         newline
240    \\r         carriage return    \er         carriage return
241    \\t         tab    \et         tab
242    \\v         vertical tab    \ev         vertical tab
243    \\nnn       octal character (up to 3 octal digits)    \ennn       octal character (up to 3 octal digits)
244    \\xhh       hexadecimal character (up to 2 hex digits)    \exhh       hexadecimal character (up to 2 hex digits)
245    \\x{hh...}  hexadecimal UTF-8 character  .\" JOIN
246      \ex{hh...}  hexadecimal character, any number of digits
247    \\A         pass the PCRE_ANCHORED option to \fBpcre_exec()\fR                 in UTF-8 mode
248    \\B         pass the PCRE_NOTBOL option to \fBpcre_exec()\fR    \eA         pass the PCRE_ANCHORED option to \fBpcre_exec()\fP
249    \\Cdd       call pcre_copy_substring() for substring dd    \eB         pass the PCRE_NOTBOL option to \fBpcre_exec()\fP
250                  after a successful match (any decimal number  .\" JOIN
251                  less than 32)    \eCdd       call pcre_copy_substring() for substring dd
252    \\Gdd       call pcre_get_substring() for substring dd                 after a successful match (number less than 32)
253                  after a successful match (any decimal number  .\" JOIN
254                  less than 32)    \eCname     call pcre_copy_named_substring() for substring
255    \\L         call pcre_get_substringlist() after a                 "name" after a successful match (name termin-
256                  successful match                 ated by next non alphanumeric character)
257    \\N         pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fR  .\" JOIN
258    \\Odd       set the size of the output vector passed to    \eC+        show the current captured substrings at callout
259                  \fBpcre_exec()\fR to dd (any number of decimal                 time
260                  digits)    \eC-        do not supply a callout function
261    \\Z         pass the PCRE_NOTEOL option to \fBpcre_exec()\fR  .\" JOIN
262      \eC!n       return 1 instead of 0 when callout number n is
263  When \\O is used, it may be higher or lower than the size set by the \fB-O\fR                 reached
264  option (or defaulted to 45); \\O applies only to the call of \fBpcre_exec()\fR  .\" JOIN
265  for the line in which it appears.    \eC!n!m     return 1 instead of 0 when callout number n is
266                   reached for the nth time
267    .\" JOIN
268      \eC*n       pass the number n (may be negative) as callout
269                   data; this is used as the callout return value
270      \eD         use the \fBpcre_dfa_exec()\fP match function
271      \eF         only shortest match for \fBpcre_dfa_exec()\fP
272    .\" JOIN
273      \eGdd       call pcre_get_substring() for substring dd
274                   after a successful match (number less than 32)
275    .\" JOIN
276      \eGname     call pcre_get_named_substring() for substring
277                   "name" after a successful match (name termin-
278                   ated by next non-alphanumeric character)
279    .\" JOIN
280      \eL         call pcre_get_substringlist() after a
281                   successful match
282      \eM         discover the minimum MATCH_LIMIT and
283                   MATCH_LIMIT_RECURSION settings
284      \eN         pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fP
285    .\" JOIN
286      \eOdd       set the size of the output vector passed to
287                   \fBpcre_exec()\fP to dd (any number of digits)
288    .\" JOIN
289      \eP         pass the PCRE_PARTIAL option to \fBpcre_exec()\fP
290                   or \fBpcre_dfa_exec()\fP
291      \eR         pass the PCRE_DFA_RESTART option to \fBpcre_dfa_exec()\fP
292      \eS         output details of memory get/free calls during matching
293      \eZ         pass the PCRE_NOTEOL option to \fBpcre_exec()\fP
294    .\" JOIN
295      \e?         pass the PCRE_NO_UTF8_CHECK option to
296                   \fBpcre_exec()\fP
297      \e>dd       start the match at offset dd (any number of digits);
298                   this sets the \fIstartoffset\fP argument for \fBpcre_exec()\fP
299    .sp
300  A backslash followed by anything else just escapes the anything else. If the  A backslash followed by anything else just escapes the anything else. If the
301  very last character is a backslash, it is ignored. This gives a way of passing  very last character is a backslash, it is ignored. This gives a way of passing
302  an empty line as data, since a real empty line terminates the data input.  an empty line as data, since a real empty line terminates the data input.
303    .P
304  If \fB/P\fR was present on the regex, causing the POSIX wrapper API to be used,  If \eM is present, \fBpcretest\fP calls \fBpcre_exec()\fP several times, with
305  only \fB\B\fR, and \fB\Z\fR have any effect, causing REG_NOTBOL and REG_NOTEOL  different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP
306  to be passed to \fBregexec()\fR respectively.  fields of the \fBpcre_extra\fP data structure, until it finds the minimum
307    numbers for each parameter that allow \fBpcre_exec()\fP to complete. The
308  The use of \\x{hh...} to represent UTF-8 characters is not dependent on the use  \fImatch_limit\fP number is a measure of the amount of backtracking that takes
309  of the \fB/8\fR modifier on the pattern. It is recognized always. There may be  place, and checking it out can be instructive. For most simple matches, the
310    number is quite small, but for patterns with very large numbers of matching
311    possibilities, it can become large very quickly with increasing length of
312    subject string. The \fImatch_limit_recursion\fP number is a measure of how much
313    stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is needed
314    to complete the match attempt.
315    .P
316    When \eO is used, the value specified may be higher or lower than the size set
317    by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to
318    the call of \fBpcre_exec()\fP for the line in which it appears.
319    .P
320    If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper
321    API to be used, the only option-setting sequences that have any effect are \eB
322    and \eZ, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
323    \fBregexec()\fP.
324    .P
325    The use of \ex{hh...} to represent UTF-8 characters is not dependent on the use
326    of the \fB/8\fP modifier on the pattern. It is recognized always. There may be
327  any number of hexadecimal digits inside the braces. The result is from one to  any number of hexadecimal digits inside the braces. The result is from one to
328  six bytes, encoded according to the UTF-8 rules.  six bytes, encoded according to the UTF-8 rules.
329    .
330    .
331  .SH OUTPUT FROM PCRETEST  .SH "THE ALTERNATIVE MATCHING FUNCTION"
332    .rs
333    .sp
334    By default, \fBpcretest\fP uses the standard PCRE matching function,
335    \fBpcre_exec()\fP to match each data line. From release 6.0, PCRE supports an
336    alternative matching function, \fBpcre_dfa_test()\fP, which operates in a
337    different way, and has some restrictions. The differences between the two
338    functions are described in the
339    .\" HREF
340    \fBpcrematching\fP
341    .\"
342    documentation.
343    .P
344    If a data line contains the \eD escape sequence, or if the command line
345    contains the \fB-dfa\fP option, the alternative matching function is called.
346    This function finds all possible matches at a given point. If, however, the \eF
347    escape sequence is present in the data line, it stops after the first match is
348    found. This is always the shortest possible match.
349    .
350    .
351    .SH "DEFAULT OUTPUT FROM PCRETEST"
352    .rs
353    .sp
354    This section describes the output when the normal matching function,
355    \fBpcre_exec()\fP, is being used.
356    .P
357  When a match succeeds, pcretest outputs the list of captured substrings that  When a match succeeds, pcretest outputs the list of captured substrings that
358  \fBpcre_exec()\fR returns, starting with number 0 for the string that matched  \fBpcre_exec()\fP returns, starting with number 0 for the string that matched
359  the whole pattern. Here is an example of an interactive pcretest run.  the whole pattern. Otherwise, it outputs "No match" or "Partial match"
360    when \fBpcre_exec()\fP returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
361    respectively, and otherwise the PCRE negative error number. Here is an example
362    of an interactive \fBpcretest\fP run.
363    .sp
364    $ pcretest    $ pcretest
365    PCRE version 2.06 08-Jun-1999    PCRE version 5.00 07-Sep-2004
366    .sp
367      re> /^abc(\\d+)/      re> /^abc(\ed+)/
368    data> abc123    data> abc123
369     0: abc123     0: abc123
370     1: 123     1: 123
371    data> xyz    data> xyz
372    No match    No match
373    .sp
374  If the strings contain any non-printing characters, they are output as \\0x  If the strings contain any non-printing characters, they are output as \e0x
375  escapes, or as \\x{...} escapes if the \fB/8\fR modifier was present on the  escapes, or as \ex{...} escapes if the \fB/8\fP modifier was present on the
376  pattern. If the pattern has the \fB/+\fR modifier, then the output for  pattern. If the pattern has the \fB/+\fP modifier, the output for substring 0
377  substring 0 is followed by the the rest of the subject string, identified by  is followed by the the rest of the subject string, identified by "0+" like
378  "0+" like this:  this:
379    .sp
380      re> /cat/+      re> /cat/+
381    data> cataract    data> cataract
382     0: cat     0: cat
383     0+ aract     0+ aract
384    .sp
385  If the pattern has the \fB/g\fR or \fB/G\fR modifier, the results of successive  If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive
386  matching attempts are output in sequence, like this:  matching attempts are output in sequence, like this:
387    .sp
388      re> /\\Bi(\\w\\w)/g      re> /\eBi(\ew\ew)/g
389    data> Mississippi    data> Mississippi
390     0: iss     0: iss
391     1: ss     1: ss
# Line 251  matching attempts are output in sequence Line 393  matching attempts are output in sequence
393     1: ss     1: ss
394     0: ipp     0: ipp
395     1: pp     1: pp
396    .sp
397  "No match" is output only if the first match attempt fails.  "No match" is output only if the first match attempt fails.
398    .P
399  If any of the sequences \fB\\C\fR, \fB\\G\fR, or \fB\\L\fR are present in a  If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a
400  data line that is successfully matched, the substrings extracted by the  data line that is successfully matched, the substrings extracted by the
401  convenience functions are output with C, G, or L after the string number  convenience functions are output with C, G, or L after the string number
402  instead of a colon. This is in addition to the normal full list. The string  instead of a colon. This is in addition to the normal full list. The string
403  length (that is, the return from the extraction function) is given in  length (that is, the return from the extraction function) is given in
404  parentheses after each string for \fB\\C\fR and \fB\\G\fR.  parentheses after each string for \fB\eC\fP and \fB\eG\fP.
405    .P
406  Note that while patterns can be continued over several lines (a plain ">"  Note that while patterns can be continued over several lines (a plain ">"
407  prompt is used for continuations), data lines may not. However newlines can be  prompt is used for continuations), data lines may not. However newlines can be
408  included in data by means of the \\n escape.  included in data by means of the \en escape.
409    .
410    .
411    .SH "OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION"
412    .rs
413    .sp
414    When the alternative matching function, \fBpcre_dfa_exec()\fP, is used (by
415    means of the \eD escape sequence or the \fB-dfa\fP command line option), the
416    output consists of a list of all the matches that start at the first point in
417    the subject where there is at least one match. For example:
418    .sp
419        re> /(tang|tangerine|tan)/
420      data> yellow tangerine\eD
421       0: tangerine
422       1: tang
423       2: tan
424    .sp
425    (Using the normal matching function on this data finds only "tang".) The
426    longest matching string is always given first (and numbered zero).
427    .P
428    If \fB/g\P is present on the pattern, the search for further matches resumes
429    at the end of the longest match. For example:
430    .sp
431        re> /(tang|tangerine|tan)/g
432      data> yellow tangerine and tangy sultana\eD
433       0: tangerine
434       1: tang
435       2: tan
436       0: tang
437       1: tan
438       0: tan
439    .sp
440    Since the matching function does not support substring capture, the escape
441    sequences that are concerned with captured substrings are not relevant.
442    .
443    .
444    .SH "RESTARTING AFTER A PARTIAL MATCH"
445    .rs
446    .sp
447    When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
448    indicating that the subject partially matched the pattern, you can restart the
449    match with additional subject data by means of the \eR escape sequence. For
450    example:
451    .sp
452        re> /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
453      data> 23ja\eP\eD
454      Partial match: 23ja
455      data> n05\eR\eD
456       0: n05
457    .sp
458    For further information about partial matching, see the
459    .\" HREF
460    \fBpcrepartial\fP
461    .\"
462    documentation.
463    .
464    .
465    .SH CALLOUTS
466    .rs
467    .sp
468    If the pattern contains any callout requests, \fBpcretest\fP's callout function
469    is called during matching. This works with both matching functions. By default,
470    the called function displays the callout number, the start and current
471    positions in the text at the callout time, and the next pattern item to be
472    tested. For example, the output
473    .sp
474      --->pqrabcdef
475        0    ^  ^     \ed
476    .sp
477    indicates that callout number 0 occurred for a match attempt starting at the
478    fourth character of the subject string, when the pointer was at the seventh
479    character of the data, and when the next pattern item was \ed. Just one
480    circumflex is output if the start and current positions are the same.
481    .P
482    Callouts numbered 255 are assumed to be automatic callouts, inserted as a
483    result of the \fB/C\fP pattern modifier. In this case, instead of showing the
484    callout number, the offset in the pattern, preceded by a plus, is output. For
485    example:
486    .sp
487        re> /\ed?[A-E]\e*/C
488      data> E*
489      --->E*
490       +0 ^      \ed?
491       +3 ^      [A-E]
492       +8 ^^     \e*
493      +10 ^ ^
494       0: E*
495    .sp
496    The callout function in \fBpcretest\fP returns zero (carry on matching) by
497    default, but you can use a \eC item in a data line (as described above) to
498    change this.
499    .P
500    Inserting callouts can be helpful when using \fBpcretest\fP to check
501    complicated regular expressions. For further information about callouts, see
502    the
503    .\" HREF
504    \fBpcrecallout\fP
505    .\"
506    documentation.
507    .
508    .
509    .SH "SAVING AND RELOADING COMPILED PATTERNS"
510    .rs
511    .sp
512    The facilities described in this section are not available when the POSIX
513    inteface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is
514    specified.
515    .P
516    When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a
517    compiled pattern to a file, by following the modifiers with > and a file name.
518    For example:
519    .sp
520      /pattern/im >/some/file
521    .sp
522    See the
523    .\" HREF
524    \fBpcreprecompile\fP
525    .\"
526    documentation for a discussion about saving and re-using compiled patterns.
527    .P
528    The data that is written is binary. The first eight bytes are the length of the
529    compiled pattern data followed by the length of the optional study data, each
530    written as four bytes in big-endian order (most significant byte first). If
531    there is no study data (either the pattern was not studied, or studying did not
532    return any data), the second length is zero. The lengths are followed by an
533    exact copy of the compiled pattern. If there is additional study data, this
534    follows immediately after the compiled pattern. After writing the file,
535    \fBpcretest\fP expects to read a new pattern.
536    .P
537    A saved pattern can be reloaded into \fBpcretest\fP by specifing < and a file
538    name instead of a pattern. The name of the file must not contain a < character,
539    as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <
540    characters.
541    For example:
542    .sp
543       re> </some/file
544      Compiled regex loaded from /some/file
545      No study data
546    .sp
547    When the pattern has been loaded, \fBpcretest\fP proceeds to read data lines in
548    the usual way.
549    .P
550    You can copy a file written by \fBpcretest\fP to a different host and reload it
551    there, even if the new host has opposite endianness to the one on which the
552    pattern was compiled. For example, you can compile on an i86 machine and run on
553    a SPARC machine.
554    .P
555    File names for saving and reloading can be absolute or relative, but note that
556    the shell facility of expanding a file name that starts with a tilde (~) is not
557    available.
558    .P
559    The ability to save and reload files in \fBpcretest\fP is intended for testing
560    and experimentation. It is not intended for production use because only a
561    single pattern can be written to a file. Furthermore, there is no facility for
562    supplying custom character tables for use with a reloaded pattern. If the
563    original pattern was compiled with custom tables, an attempt to match a subject
564    string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.
565    Finally, if you attempt to load a file that is not in the correct format, the
566    result is undefined.
567    .
568    .
569  .SH AUTHOR  .SH AUTHOR
570  Philip Hazel <ph10@cam.ac.uk>  .rs
571    .sp
572    Philip Hazel
573  .br  .br
574  University Computing Service,  University Computing Service,
575  .br  .br
 New Museums Site,  
 .br  
576  Cambridge CB2 3QG, England.  Cambridge CB2 3QG, England.
577    .P
578    .in 0
579    Last updated: 18 January 2006
580  .br  .br
581  Phone: +44 1223 334714  Copyright (c) 1997-2006 University of Cambridge.
   
 Last updated: 15 August 2001  
 .br  
 Copyright (c) 1997-2001 University of Cambridge.  

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