/[pcre]/code/trunk/doc/pcretest.1

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-revision 53 by nigel,
Sat Feb 24 21:39:42 2007 UTC
+revision 63 by nigel,
Sat Feb 24 21:40:03 2007 UTC
 Line 6 
 pcretest - a program for testing Perl-co
  \fBpcretest\fR was written as a test program for the PCRE regular expression
  library itself, but it can also be used for experimenting with regular
- expressions. This man page describes the features of the test program; for
+ expressions. This document describes the features of the test program; for
- details of the regular expressions themselves, see the \fBpcre\fR man page.
+ details of the regular expressions themselves, see the
+ .\" HREF
+ \fBpcrepattern\fR
+ .\"
+ documentation. For details of PCRE and its options, see the
+ .\" HREF
+ \fBpcreapi\fR
+ .\"
+ documentation.
  .SH OPTIONS
+ .rs
+ .sp
+ .TP 10
+ \fB-C\fR
+ Output the version number of the PCRE library, and all available information
+ about the optional features that are included, and then exit.
  .TP 10
  \fB-d\fR
  Behave as if each regex had the \fB/D\fR modifier (see below); the internal
-Line 35 
 Behave as if each regex has \fB/P\fR mod
+Line 49 
 Behave as if each regex has \fB/P\fR mod
  to call PCRE. None of the other options has any effect when \fB-p\fR is set.
  .TP 10
  \fB-t\fR
- 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
  resulting time per compile or match (in milliseconds). Do not set \fB-t\fR with
  \fB-m\fR, because you will then get the size output 20000 times and the timing
  will be distorted.
  .SH DESCRIPTION
+ .rs
+ .sp
  If \fBpcretest\fR is given two filename arguments, it reads from the first and
  writes to the second. If it is given only one filename argument, it reads from
  that file and writes to stdout. Otherwise, it reads from stdin and writes to
-Line 51 
 expressions, and "data>" to prompt for d
+Line 65 
 expressions, and "data>" to prompt for d
  The program handles any number of sets of input on a single input file. Each
  set starts with a regular expression, and continues with any number of data
- lines to be matched against the pattern. An empty line signals the end of the
+ lines to be matched against the pattern.
- data lines, at which point a new regular expression is read. The regular
- expressions are given enclosed in any non-alphameric delimiters other than
+ Each line is matched separately and independently. If you want to do
- backslash, for example
+ multiple-line matches, you have to use the \\n escape sequence in a single line
+ of input to encode the newline characters. The maximum length of data line is
+,000 characters.
+ An empty line signals the end of the data lines, at which point a new regular
+ expression is read. The regular expressions are given enclosed in any
+ non-alphameric delimiters other than backslash, for example
    /(a|bc)x+yz/
-Line 81 
 backslash, because
+Line 101 
 backslash, because
  is interpreted as the first line of a pattern that starts with "abc/", causing
  pcretest to read the next line as a continuation of the regular expression.
  .SH PATTERN MODIFIERS
+ .rs
+ .sp
  The pattern may be followed by \fBi\fR, \fBm\fR, \fBs\fR, or \fBx\fR to set the
  PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,
  respectively. For example:
-Line 138 
 studied, the results of that are also ou
+Line 158 
 studied, the results of that are also ou
  The \fB/D\fR modifier is a PCRE debugging feature, which also assumes \fB/I\fR.
  It causes the internal form of compiled regular expressions to be output after
- compilation.
+ compilation. If the pattern was studied, the information returned is also
+ output.
  The \fB/S\fR modifier causes \fBpcre_study()\fR to be called after the
  expression has been compiled, and the results used when the expression is
-Line 154 
 present, and REG_NEWLINE is set if \fB/m
+Line 175 
 present, and REG_NEWLINE is set if \fB/m
  force PCRE_DOLLAR_ENDONLY always, and PCRE_DOTALL unless REG_NEWLINE is set.
  The \fB/8\fR modifier causes \fBpcretest\fR to call PCRE with the PCRE_UTF8
- 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,
- character handling in PCRE, provided that it was compiled with this support
+ provided that it was compiled with this support enabled. This modifier also
- enabled. This modifier also causes any non-printing characters in output
+ causes any non-printing characters in output strings to be printed using the
- strings to be printed using the \\x{hh...} notation if they are valid UTF-8
+ \\x{hh...} notation if they are valid UTF-8 sequences.
- sequences.
+ .SH CALLOUTS
+ .rs
+ .sp
+ If the pattern contains any callout requests, \fBpcretest\fR's callout function
+ will be called. By default, it displays the callout number, and the start and
+ current positions in the text at the callout time. For example, the output
+   --->pqrabcdef
+   ^  ^
+ indicates that callout number 0 occurred for a match attempt starting at the
+ fourth character of the subject string, when the pointer was at the seventh
+ character. The callout function returns zero (carry on matching) by default.
+ Inserting callouts may be helpful when using \fBpcretest\fR to check
+ complicated regular expressions. For further information about callouts, see
+ the
+ .\" HREF
+ \fBpcrecallout\fR
+ .\"
+ documentation.
+ For testing the PCRE library, additional control of callout behaviour is
+ available via escape sequences in the data, as described in the following
+ section. In particular, it is possible to pass in a number as callout data (the
+ default is zero). If the callout function receives a non-zero number, it
+ returns that value instead of zero.
  .SH DATA LINES
+ .rs
+ .sp
  Before each data line is passed to \fBpcre_exec()\fR, leading and trailing
- whitespace is removed, and it is then scanned for \\ escapes. The following are
+ whitespace is removed, and it is then scanned for \\ escapes. Some of these are
+ pretty esoteric features, intended for checking out some of the more
+ complicated features of PCRE. If you are just testing "ordinary" regular
+ expressions, you probably don't need any of these. The following escapes are
  recognized:
    \\a         alarm (= BEL)
-Line 177 
 recognized:
+Line 228 
 recognized:
    \\v         vertical tab
    \\nnn       octal character (up to 3 octal digits)
    \\xhh       hexadecimal character (up to 2 hex digits)
-   \\x{hh...}  hexadecimal UTF-8 character
+   \\x{hh...}  hexadecimal character, any number of digits
+                in UTF-8 mode
    \\A         pass the PCRE_ANCHORED option to \fBpcre_exec()\fR
    \\B         pass the PCRE_NOTBOL option to \fBpcre_exec()\fR
    \\Cdd       call pcre_copy_substring() for substring dd
-                 after a successful match (any decimal number
+                after a successful match (any decimal number
-                 less than 32)
+                less than 32)
+   \\Cname     call pcre_copy_named_substring() for substring
+                "name" after a successful match (name termin-
+                ated by next non alphanumeric character)
+   \\C+        show the current captured substrings at callout
+                time
+   \\C-        do not supply a callout function
+   \\C!n       return 1 instead of 0 when callout number n is
+                reached
+   \\C!n!m     return 1 instead of 0 when callout number n is
+                reached for the nth time
+   \\C*n       pass the number n (may be negative) as callout
+                data
    \\Gdd       call pcre_get_substring() for substring dd
-                 after a successful match (any decimal number
+                after a successful match (any decimal number
-                 less than 32)
+                less than 32)
+   \\Gname     call pcre_get_named_substring() for substring
+                "name" after a successful match (name termin-
+                ated by next non-alphanumeric character)
    \\L         call pcre_get_substringlist() after a
-                 successful match
+                successful match
+   \\M         discover the minimum MATCH_LIMIT setting
    \\N         pass the PCRE_NOTEMPTY option to \fBpcre_exec()\fR
    \\Odd       set the size of the output vector passed to
-                 \fBpcre_exec()\fR to dd (any number of decimal
+                \fBpcre_exec()\fR to dd (any number of decimal
-                 digits)
+                digits)
    \\Z         pass the PCRE_NOTEOL option to \fBpcre_exec()\fR
+ If \\M is present, \fBpcretest\fR calls \fBpcre_exec()\fR several times, with
+ different values in the \fImatch_limit\fR field of the \fBpcre_extra\fR data
+ structure, until it finds the minimum number that is needed for
+ \fBpcre_exec()\fR to complete. This number is a measure of the amount of
+ recursion and backtracking that takes place, and checking it out can be
+ instructive. For most simple matches, the number is quite small, but for
+ patterns with very large numbers of matching possibilities, it can become large
+ very quickly with increasing length of subject string.
  When \\O is used, it may be higher or lower than the size set by the \fB-O\fR
  option (or defaulted to 45); \\O applies only to the call of \fBpcre_exec()\fR
  for the line in which it appears.
-Line 212 
 of the \fB/8\fR modifier on the pattern.
+Line 288 
 of the \fB/8\fR modifier on the pattern.
  any number of hexadecimal digits inside the braces. The result is from one to
  six bytes, encoded according to the UTF-8 rules.
  .SH OUTPUT FROM PCRETEST
+ .rs
+ .sp
  When a match succeeds, pcretest outputs the list of captured substrings that
  \fBpcre_exec()\fR returns, starting with number 0 for the string that matched
  the whole pattern. Here is an example of an interactive pcretest run.
    $ pcretest
-   PCRE version 2.06 08-Jun-1999
+   PCRE version 4.00 08-Jan-2003
      re> /^abc(\\d+)/
    data> abc123
-Line 265 
 Note that while patterns can be continue
+Line 341 
 Note that while patterns can be continue
  prompt is used for continuations), data lines may not. However newlines can be
  included in data by means of the \\n escape.
  .SH AUTHOR
+ .rs
+ .sp
  Philip Hazel <ph10@cam.ac.uk>
  .br
  University Computing Service,
  .br
- New Museums Site,
- .br
  Cambridge CB2 3QG, England.
- .br
- Phone: +44 1223 334714
- Last updated: 15 August 2001
+ .in 0
+ Last updated: 03 February 2003
  .br
- Copyright (c) 1997-2001 University of Cambridge.
+ Copyright (c) 1997-2003 University of Cambridge.

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