/[pcre]/code/trunk/doc/html/pcrepattern.html

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-revision 512 by ph10,
Tue Mar 30 11:11:52 2010 UTC
+revision 518 by ph10,
Tue May 18 15:47:01 2010 UTC
 Line 18 
 man page, in case the conversion went wr
  <li><a name="TOC3" href="#SEC3">CHARACTERS AND METACHARACTERS</a>
  <li><a name="TOC4" href="#SEC4">BACKSLASH</a>
  <li><a name="TOC5" href="#SEC5">CIRCUMFLEX AND DOLLAR</a>
- <li><a name="TOC6" href="#SEC6">FULL STOP (PERIOD, DOT)</a>
+ <li><a name="TOC6" href="#SEC6">FULL STOP (PERIOD, DOT) AND \N</a>
  <li><a name="TOC7" href="#SEC7">MATCHING A SINGLE BYTE</a>
  <li><a name="TOC8" href="#SEC8">SQUARE BRACKETS AND CHARACTER CLASSES</a>
  <li><a name="TOC9" href="#SEC9">POSIX CHARACTER CLASSES</a>
 Line 124 
 they must be in upper case. If more than
  is used.
  </P>
  <P>
- The newline convention does not affect what the \R escape sequence matches. By
+ The newline convention affects the interpretation of the dot metacharacter when
- default, this is any Unicode newline sequence, for Perl compatibility. However,
+ PCRE_DOTALL is not set, and also the behaviour of \N. However, it does not
- this can be changed; see the description of \R in the section entitled
+ affect what the \R escape sequence matches. By default, this is any Unicode
+ newline sequence, for Perl compatibility. However, this can be changed; see the
+ description of \R in the section entitled
  <a href="#newlineseq">"Newline sequences"</a>
  below. A change of \R setting can be combined with a change of newline
  convention.
-Line 308 
 zero, because no more than three octal d
+Line 310 
 zero, because no more than three octal d
  <P>
  All the sequences that define a single character value can be used both inside
  and outside character classes. In addition, inside a character class, the
- sequence \b is interpreted as the backspace character (hex 08), and the
+ sequence \b is interpreted as the backspace character (hex 08). The sequences
- sequences \R and \X are interpreted as the characters "R" and "X",
+ \B, \N, \R, and \X are not special inside a character class. Like any other
- respectively. Outside a character class, these sequences have different
+ unrecognized escape sequences, they are treated as the literal characters "B",
- meanings
+ "N", "R", and "X" by default, but cause an error if the PCRE_EXTRA option is
- <a href="#uniextseq">(see below).</a>
+ set. Outside a character class, these sequences have different meanings.
  </P>
  <br><b>
  Absolute and relative back references
-Line 337 
 Note that \g{...} (Perl syntax) and \g&#
+Line 339 
 Note that \g{...} (Perl syntax) and \g&#
  synonymous. The former is a back reference; the latter is a
  <a href="#subpatternsassubroutines">subroutine</a>
  call.
- </P>
+ <a name="genericchartypes"></a></P>
  <br><b>
  Generic character types
  </b><br>
  <P>
- Another use of backslash is for specifying generic character types. The
+ Another use of backslash is for specifying generic character types:
- following are always recognized:
  <pre>
    \d     any decimal digit
    \D     any character that is not a decimal digit
-Line 356 
 following are always recognized:
+Line 357 
 following are always recognized:
    \w     any "word" character
    \W     any "non-word" character
  </pre>
- Each pair of escape sequences partitions the complete set of characters into
+ There is also the single sequence \N, which matches a non-newline character.
- two disjoint sets. Any given character matches one, and only one, of each pair.
+ This is the same as
+ <a href="#fullstopdot">the "." metacharacter</a>
+ when PCRE_DOTALL is not set.
+ </P>
+ <P>
+ Each pair of lower and upper case escape sequences partitions the complete set
+ of characters into two disjoint sets. Any given character matches one, and only
+ one, of each pair.
  </P>
  <P>
  These character type sequences can appear both inside and outside character
-Line 475 
 convention, for example, a pattern can s
+Line 483 
 convention, for example, a pattern can s
  <pre>
    (*ANY)(*BSR_ANYCRLF)
  </pre>
- Inside a character class, \R matches the letter "R".
+ Inside a character class, \R is treated as an unrecognized escape sequence,
+ and so matches the letter "R" by default, but causes an error if PCRE_EXTRA is
+ set.
  <a name="uniextseq"></a></P>
  <br><b>
  Unicode character properties
-Line 492 
 The extra escape sequences are:
+Line 502 
 The extra escape sequences are:
    \X       an extended Unicode sequence
  </pre>
  The property names represented by <i>xx</i> above are limited to the Unicode
- script names, the general category properties, and "Any", which matches any
+ script names, the general category properties, "Any", which matches any
- character (including newline). Other properties such as "InMusicalSymbols" are
+ character (including newline), and some special PCRE properties (described
- not currently supported by PCRE. Note that \P{Any} does not match any
+ in the
- characters, so always causes a match failure.
+ <a href="#extraprops">next section).</a>
+ Other Perl properties such as "InMusicalSymbols" are not currently supported by
+ PCRE. Note that \P{Any} does not match any characters, so always causes a
+ match failure.
  </P>
  <P>
  Sets of Unicode characters are defined as belonging to certain scripts. A
-Line 603 
 Vai,
+Line 616 
 Vai,
  Yi.
  </P>
  <P>
- Each character has exactly one general category property, specified by a
+ Each character has exactly one Unicode general category property, specified by
- two-letter abbreviation. For compatibility with Perl, negation can be specified
+ a two-letter abbreviation. For compatibility with Perl, negation can be
- by including a circumflex between the opening brace and the property name. For
+ specified by including a circumflex between the opening brace and the property
- example, \p{^Lu} is the same as \P{Lu}.
+ name. For example, \p{^Lu} is the same as \P{Lu}.
  </P>
  <P>
  If only one letter is specified with \p or \P, it includes all the general
-Line 708 
 Matching characters by Unicode property
+Line 721 
 Matching characters by Unicode property
  a structure that contains data for over fifteen thousand characters. That is
  why the traditional escape sequences such as \d and \w do not use Unicode
  properties in PCRE.
+ <a name="extraprops"></a></P>
+ <br><b>
+ PCRE's additional properties
+ </b><br>
+ <P>
+ As well as the standard Unicode properties described in the previous
+ section, PCRE supports four more that make it possible to convert traditional
+ escape sequences such as \w and \s and POSIX character classes to use Unicode
+ properties. These are:
+ <pre>
+   Xan   Any alphanumeric character
+   Xps   Any POSIX space character
+   Xsp   Any Perl space character
+   Xwd   Any Perl "word" character
+ </pre>
+ Xan matches characters that have either the L (letter) or the N (number)
+ property. Xps matches the characters tab, linefeed, vertical tab, formfeed, or
+ carriage return, and any other character that has the Z (separator) property.
+ Xsp is the same as Xps, except that vertical tab is excluded. Xwd matches the
+ same characters as Xan, plus underscore.
  <a name="resetmatchstart"></a></P>
  <br><b>
  Resetting the match start
-Line 756 
 The backslashed assertions are:
+Line 789 
 The backslashed assertions are:
    \z     matches only at the end of the subject
    \G     matches at the first matching position in the subject
  </pre>
- These assertions may not appear in character classes (but note that \b has a
+ Inside a character class, \b has a different meaning; it matches the backspace
- different meaning, namely the backspace character, inside a character class).
+ character. If any other of these assertions appears in a character class, by
+ default it matches the corresponding literal character (for example, \B
+ matches the letter B). However, if the PCRE_EXTRA option is set, an "invalid
+ escape sequence" error is generated instead.
  </P>
  <P>
  A word boundary is a position in the subject string where the current character
-Line 853 
 PCRE_DOLLAR_ENDONLY option is ignored if
+Line 889 
 PCRE_DOLLAR_ENDONLY option is ignored if
  Note that the sequences \A, \Z, and \z can be used to match the start and
  end of the subject in both modes, and if all branches of a pattern start with
  \A it is always anchored, whether or not PCRE_MULTILINE is set.
- </P>
+ <a name="fullstopdot"></a></P>
- <br><a name="SEC6" href="#TOC1">FULL STOP (PERIOD, DOT)</a><br>
+ <br><a name="SEC6" href="#TOC1">FULL STOP (PERIOD, DOT) AND \N</a><br>
  <P>
  Outside a character class, a dot in the pattern matches any one character in
  the subject string except (by default) a character that signifies the end of a
-Line 879 
 The handling of dot is entirely independ
+Line 915 
 The handling of dot is entirely independ
  dollar, the only relationship being that they both involve newlines. Dot has no
  special meaning in a character class.
  </P>
+ <P>
+ The escape sequence \N always behaves as a dot does when PCRE_DOTALL is not
+ set. In other words, it matches any one character except one that signifies the
+ end of a line.
+ </P>
  <br><a name="SEC7" href="#TOC1">MATCHING A SINGLE BYTE</a><br>
  <P>
  Outside a character class, the escape sequence \C matches any one byte, both
-Line 2548 
 Cambridge CB2 3QH, England.
+Line 2589 
 Cambridge CB2 3QH, England.
  </P>
  <br><a name="SEC28" href="#TOC1">REVISION</a><br>
  <P>
- Last updated: 27 March 2010
+ Last updated: 05 May 2010
  <br>
  Copyright &copy; 1997-2010 University of Cambridge.
  <br>

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