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revision 517 by ph10, Wed May 5 10:44:20 2010 UTC revision 518 by ph10, Tue May 18 15:47:01 2010 UTC
# Line 42  in the main Line 42  in the main
42  .\"  .\"
43  page.  page.
44  .P  .P
45    Another special sequence that may appear at the start of a pattern or in
46    combination with (*UTF8) is:
47    .sp
48      (*UCP)
49    .sp
50    This has the same effect as setting the PCRE_UCP option: it causes sequences
51    such as \ed and \ew to use Unicode properties to determine character types,
52    instead of recognizing only characters with codes less than 128 via a lookup
53    table.
54    .P
55  The remainder of this document discusses the patterns that are supported by  The remainder of this document discusses the patterns that are supported by
56  PCRE when its main matching function, \fBpcre_exec()\fP, is used.  PCRE when its main matching function, \fBpcre_exec()\fP, is used.
57  From release 6.0, PCRE offers a second matching function,  From release 6.0, PCRE offers a second matching function,
# Line 340  subroutine Line 350  subroutine
350  call.  call.
351  .  .
352  .  .
353    .\" HTML <a name="genericchartypes"></a>
354  .SS "Generic character types"  .SS "Generic character types"
355  .rs  .rs
356  .sp  .sp
# Line 366  when PCRE_DOTALL is not set. Line 377  when PCRE_DOTALL is not set.
377  .P  .P
378  Each pair of lower and upper case escape sequences partitions the complete set  Each pair of lower and upper case escape sequences partitions the complete set
379  of characters into two disjoint sets. Any given character matches one, and only  of characters into two disjoint sets. Any given character matches one, and only
380  one, of each pair.  one, of each pair. The sequences can appear both inside and outside character
 .P  
 These character type sequences can appear both inside and outside character  
381  classes. They each match one character of the appropriate type. If the current  classes. They each match one character of the appropriate type. If the current
382  matching point is at the end of the subject string, all of them fail, since  matching point is at the end of the subject string, all of them fail, because
383  there is no character to match.  there is no character to match.
384  .P  .P
385  For compatibility with Perl, \es does not match the VT character (code 11).  For compatibility with Perl, \es does not match the VT character (code 11).
# Line 379  are HT (9), LF (10), FF (12), CR (13), a Line 388  are HT (9), LF (10), FF (12), CR (13), a
388  included in a Perl script, \es may match the VT character. In PCRE, it never  included in a Perl script, \es may match the VT character. In PCRE, it never
389  does.  does.
390  .P  .P
391  In UTF-8 mode, characters with values greater than 128 never match \ed, \es, or  A "word" character is an underscore or any character that is a letter or digit.
392  \ew, and always match \eD, \eS, and \eW. This is true even when Unicode  By default, the definition of letters and digits is controlled by PCRE's
393  character property support is available. These sequences retain their original  low-valued character tables, and may vary if locale-specific matching is taking
394  meanings from before UTF-8 support was available, mainly for efficiency  place (see
395  reasons. Note that this also affects \eb, because it is defined in terms of \ew  .\" HTML <a href="pcreapi.html#localesupport">
396  and \eW.  .\" </a>
397    "Locale support"
398    .\"
399    in the
400    .\" HREF
401    \fBpcreapi\fP
402    .\"
403    page). For example, in a French locale such as "fr_FR" in Unix-like systems,
404    or "french" in Windows, some character codes greater than 128 are used for
405    accented letters, and these are then matched by \ew. The use of locales with
406    Unicode is discouraged.
407    .P
408    By default, in UTF-8 mode, characters with values greater than 128 never match
409    \ed, \es, or \ew, and always match \eD, \eS, and \eW. These sequences retain
410    their original meanings from before UTF-8 support was available, mainly for
411    efficiency reasons. However, if PCRE is compiled with Unicode property support,
412    and the PCRE_UCP option is set, the behaviour is changed so that Unicode
413    properties are used to determine character types, as follows:
414    .sp
415      \ed  any character that \ep{Nd} matches (decimal digit)
416      \es  any character that \ep{Z} matches, plus HT, LF, FF, CR
417      \ew  any character that \ep{L} or \ep{N} matches, plus underscore
418    .sp
419    The upper case escapes match the inverse sets of characters. Note that \ed
420    matches only decimal digits, whereas \ew matches any Unicode digit, as well as
421    any Unicode letter, and underscore. Note also that PCRE_UCP affects \eb, and
422    \eB because they are defined in terms of \ew and \eW. Matching these sequences
423    is noticeably slower when PCRE_UCP is set.
424  .P  .P
425  The sequences \eh, \eH, \ev, and \eV are Perl 5.10 features. In contrast to the  The sequences \eh, \eH, \ev, and \eV are Perl 5.10 features. In contrast to the
426  other sequences, these do match certain high-valued codepoints in UTF-8 mode.  other sequences, which match only ASCII characters by default, these always
427  The horizontal space characters are:  match certain high-valued codepoints in UTF-8 mode, whether or not PCRE_UCP is
428    set. The horizontal space characters are:
429  .sp  .sp
430    U+0009     Horizontal tab    U+0009     Horizontal tab
431    U+0020     Space    U+0020     Space
# Line 419  The vertical space characters are: Line 456  The vertical space characters are:
456    U+0085     Next line    U+0085     Next line
457    U+2028     Line separator    U+2028     Line separator
458    U+2029     Paragraph separator    U+2029     Paragraph separator
 .P  
 A "word" character is an underscore or any character less than 256 that is a  
 letter or digit. The definition of letters and digits is controlled by PCRE's  
 low-valued character tables, and may vary if locale-specific matching is taking  
 place (see  
 .\" HTML <a href="pcreapi.html#localesupport">  
 .\" </a>  
 "Locale support"  
 .\"  
 in the  
 .\" HREF  
 \fBpcreapi\fP  
 .\"  
 page). For example, in a French locale such as "fr_FR" in Unix-like systems,  
 or "french" in Windows, some character codes greater than 128 are used for  
 accented letters, and these are matched by \ew. The use of locales with Unicode  
 is discouraged.  
459  .  .
460  .  .
461  .\" HTML <a name="newlineseq"></a>  .\" HTML <a name="newlineseq"></a>
# Line 481  These override the default and the optio Line 501  These override the default and the optio
501  which are not Perl-compatible, are recognized only at the very start of a  which are not Perl-compatible, are recognized only at the very start of a
502  pattern, and that they must be in upper case. If more than one of them is  pattern, and that they must be in upper case. If more than one of them is
503  present, the last one is used. They can be combined with a change of newline  present, the last one is used. They can be combined with a change of newline
504  convention, for example, a pattern can start with:  convention; for example, a pattern can start with:
505  .sp  .sp
506    (*ANY)(*BSR_ANYCRLF)    (*ANY)(*BSR_ANYCRLF)
507  .sp  .sp
508  Inside a character class, \eR is treated as an unrecognized escape sequence,  They can also be combined with the (*UTF8) or (*UCP) special sequences. Inside
509  and so matches the letter "R" by default, but causes an error if PCRE_EXTRA is  a character class, \eR is treated as an unrecognized escape sequence, and so
510  set.  matches the letter "R" by default, but causes an error if PCRE_EXTRA is set.
511  .  .
512  .  .
513  .\" HTML <a name="uniextseq"></a>  .\" HTML <a name="uniextseq"></a>
# Line 721  non-UTF-8 mode \eX matches any one chara Line 741  non-UTF-8 mode \eX matches any one chara
741  Matching characters by Unicode property is not fast, because PCRE has to search  Matching characters by Unicode property is not fast, because PCRE has to search
742  a structure that contains data for over fifteen thousand characters. That is  a structure that contains data for over fifteen thousand characters. That is
743  why the traditional escape sequences such as \ed and \ew do not use Unicode  why the traditional escape sequences such as \ed and \ew do not use Unicode
744  properties in PCRE.  properties in PCRE by default, though you can make them do so by setting the
745    PCRE_UCP option for \fBpcre_compile()\fP or by starting the pattern with
746    (*UCP).
747  .  .
748  .  .
749  .\" HTML <a name="extraprops"></a>  .\" HTML <a name="extraprops"></a>
# Line 731  properties in PCRE. Line 753  properties in PCRE.
753  As well as the standard Unicode properties described in the previous  As well as the standard Unicode properties described in the previous
754  section, PCRE supports four more that make it possible to convert traditional  section, PCRE supports four more that make it possible to convert traditional
755  escape sequences such as \ew and \es and POSIX character classes to use Unicode  escape sequences such as \ew and \es and POSIX character classes to use Unicode
756  properties. These are:  properties. PCRE uses these non-standard, non-Perl properties internally when
757    PCRE_UCP is set. They are:
758  .sp  .sp
759    Xan   Any alphanumeric character    Xan   Any alphanumeric character
760    Xps   Any POSIX space character    Xps   Any POSIX space character
# Line 810  escape sequence" error is generated inst Line 833  escape sequence" error is generated inst
833  A word boundary is a position in the subject string where the current character  A word boundary is a position in the subject string where the current character
834  and the previous character do not both match \ew or \eW (i.e. one matches  and the previous character do not both match \ew or \eW (i.e. one matches
835  \ew and the other matches \eW), or the start or end of the string if the  \ew and the other matches \eW), or the start or end of the string if the
836  first or last character matches \ew, respectively. Neither PCRE nor Perl has a  first or last character matches \ew, respectively. In UTF-8 mode, the meanings
837  separte "start of word" or "end of word" metasequence. However, whatever  of \ew and \eW can be changed by setting the PCRE_UCP option. When this is
838  follows \eb normally determines which it is. For example, the fragment  done, it also affects \eb and \eB. Neither PCRE nor Perl has a separate "start
839  \eba matches "a" at the start of a word.  of word" or "end of word" metasequence. However, whatever follows \eb normally
840    determines which it is. For example, the fragment \eba matches "a" at the start
841    of a word.
842  .P  .P
843  The \eA, \eZ, and \ez assertions differ from the traditional circumflex and  The \eA, \eZ, and \ez assertions differ from the traditional circumflex and
844  dollar (described in the next section) in that they only ever match at the very  dollar (described in the next section) in that they only ever match at the very
# Line 1018  characters in both cases. In UTF-8 mode, Line 1043  characters in both cases. In UTF-8 mode,
1043  characters with values greater than 128 only when it is compiled with Unicode  characters with values greater than 128 only when it is compiled with Unicode
1044  property support.  property support.
1045  .P  .P
1046  The character types \ed, \eD, \ep, \eP, \es, \eS, \ew, and \eW may also appear  The character types \ed, \eD, \eh, \eH, \ep, \eP, \es, \eS, \ev, \eV, \ew, and
1047  in a character class, and add the characters that they match to the class. For  \eW may also appear in a character class, and add the characters that they
1048  example, [\edABCDEF] matches any hexadecimal digit. A circumflex can  match to the class. For example, [\edABCDEF] matches any hexadecimal digit. A
1049  conveniently be used with the upper case character types to specify a more  circumflex can conveniently be used with the upper case character types to
1050  restricted set of characters than the matching lower case type. For example,  specify a more restricted set of characters than the matching lower case type.
1051  the class [^\eW_] matches any letter or digit, but not underscore.  For example, the class [^\eW_] matches any letter or digit, but not underscore.
1052  .P  .P
1053  The only metacharacters that are recognized in character classes are backslash,  The only metacharacters that are recognized in character classes are backslash,
1054  hyphen (only where it can be interpreted as specifying a range), circumflex  hyphen (only where it can be interpreted as specifying a range), circumflex
# Line 1043  this notation. For example, Line 1068  this notation. For example,
1068    [01[:alpha:]%]    [01[:alpha:]%]
1069  .sp  .sp
1070  matches "0", "1", any alphabetic character, or "%". The supported class names  matches "0", "1", any alphabetic character, or "%". The supported class names
1071  are  are:
1072  .sp  .sp
1073    alnum    letters and digits    alnum    letters and digits
1074    alpha    letters    alpha    letters
# Line 1054  are Line 1079  are
1079    graph    printing characters, excluding space    graph    printing characters, excluding space
1080    lower    lower case letters    lower    lower case letters
1081    print    printing characters, including space    print    printing characters, including space
1082    punct    printing characters, excluding letters and digits    punct    printing characters, excluding letters and digits and space
1083    space    white space (not quite the same as \es)    space    white space (not quite the same as \es)
1084    upper    upper case letters    upper    upper case letters
1085    word     "word" characters (same as \ew)    word     "word" characters (same as \ew)
# Line 1075  matches "1", "2", or any non-digit. PCRE Line 1100  matches "1", "2", or any non-digit. PCRE
1100  syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not  syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not
1101  supported, and an error is given if they are encountered.  supported, and an error is given if they are encountered.
1102  .P  .P
1103  In UTF-8 mode, characters with values greater than 128 do not match any of  By default, in UTF-8 mode, characters with values greater than 128 do not match
1104  the POSIX character classes.  any of the POSIX character classes. However, if the PCRE_UCP option is passed
1105    to \fBpcre_compile()\fP, some of the classes are changed so that Unicode
1106    character properties are used. This is achieved by replacing the POSIX classes
1107    by other sequences, as follows:
1108    .sp
1109      [:alnum:]  becomes  \ep{Xan}
1110      [:alpha:]  becomes  \ep{L}
1111      [:blank:]  becomes  \eh
1112      [:digit:]  becomes  \ep{Nd}
1113      [:lower:]  becomes  \ep{Ll}
1114      [:space:]  becomes  \ep{Xps}
1115      [:upper:]  becomes  \ep{Lu}
1116      [:word:]   becomes  \ep{Xwd}
1117    .sp
1118    Negated versions, such as [:^alpha:] use \eP instead of \ep. The other POSIX
1119    classes are unchanged, and match only characters with code points less than
1120    128.
1121  .  .
1122  .  .
1123  .SH "VERTICAL BAR"  .SH "VERTICAL BAR"
# Line 1155  section entitled Line 1196  section entitled
1196  .\" </a>  .\" </a>
1197  "Newline sequences"  "Newline sequences"
1198  .\"  .\"
1199  above. There is also the (*UTF8) leading sequence that can be used to set UTF-8  above. There are also the (*UTF8) and (*UCP) leading sequences that can be used
1200  mode; this is equivalent to setting the PCRE_UTF8 option.  to set UTF-8 and Unicode property modes; they are equivalent to setting the
1201    PCRE_UTF8 and the PCRE_UCP options, respectively.
1202  .  .
1203  .  .
1204  .\" HTML <a name="subpattern"></a>  .\" HTML <a name="subpattern"></a>
# Line 2624  Cambridge CB2 3QH, England. Line 2666  Cambridge CB2 3QH, England.
2666  .rs  .rs
2667  .sp  .sp
2668  .nf  .nf
2669  Last updated: 05 May 2010  Last updated: 18 May 2010
2670  Copyright (c) 1997-2010 University of Cambridge.  Copyright (c) 1997-2010 University of Cambridge.
2671  .fi  .fi
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