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Diffstat (limited to 'doc/pcre2pattern.3')
| -rw-r--r-- | doc/pcre2pattern.3 | 44 |
1 files changed, 30 insertions, 14 deletions
diff --git a/doc/pcre2pattern.3 b/doc/pcre2pattern.3 index c88ce03..47c0f31 100644 --- a/doc/pcre2pattern.3 +++ b/doc/pcre2pattern.3 @@ -1,4 +1,4 @@ -.TH PCRE2PATTERN 3 "24 February 2020" "PCRE2 10.35" +.TH PCRE2PATTERN 3 "05 October 2020" "PCRE2 10.35" .SH NAME PCRE2 - Perl-compatible regular expressions (revised API) .SH "PCRE2 REGULAR EXPRESSION DETAILS" @@ -263,8 +263,11 @@ corresponding characters in the subject. As a trivial example, the pattern The quick brown fox .sp matches a portion of a subject string that is identical to itself. When -caseless matching is specified (the PCRE2_CASELESS option), letters are matched -independently of case. +caseless matching is specified (the PCRE2_CASELESS option or (?i) within the +pattern), letters are matched independently of case. Note that there are two +ASCII characters, K and S, that, in addition to their lower case ASCII +equivalents, are case-equivalent with Unicode U+212A (Kelvin sign) and U+017F +(long S) respectively when either PCRE2_UTF or PCRE2_UCP is set. .P The power of regular expressions comes from the ability to include wild cards, character classes, alternatives, and repetitions in the pattern. These are @@ -298,6 +301,22 @@ a character class the only metacharacters are: [ POSIX character class (if followed by POSIX syntax) ] terminates the character class .sp +If a pattern is compiled with the PCRE2_EXTENDED option, most white space in +the pattern, other than in a character class, and characters between a # +outside a character class and the next newline, inclusive, are ignored. An +escaping backslash can be used to include a white space or a # character as +part of the pattern. If the PCRE2_EXTENDED_MORE option is set, the same +applies, but in addition unescaped space and horizontal tab characters are +ignored inside a character class. Note: only these two characters are ignored, +not the full set of pattern white space characters that are ignored outside a +character class. Option settings can be changed within a pattern; see the +section entitled +.\" HTML <a href="#internaloptions"> +.\" </a> +"Internal Option Setting" +.\" +below. +.P The following sections describe the use of each of the metacharacters. . . @@ -315,15 +334,9 @@ would otherwise be interpreted as a metacharacter, so it is always safe to precede a non-alphanumeric with backslash to specify that it stands for itself. In particular, if you want to match a backslash, you write \e\e. .P -In a UTF mode, only ASCII digits and letters have any special meaning after a -backslash. All other characters (in particular, those whose code points are -greater than 127) are treated as literals. -.P -If a pattern is compiled with the PCRE2_EXTENDED option, most white space in -the pattern (other than in a character class), and characters between a # -outside a character class and the next newline, inclusive, are ignored. An -escaping backslash can be used to include a white space or # character as part -of the pattern. +Only ASCII digits and letters have any special meaning after a backslash. All +other characters (in particular, those whose code points are greater than 127) +are treated as literals. .P If you want to treat all characters in a sequence as literals, you can do so by putting them between \eQ and \eE. This is different from Perl in that $ and @ @@ -1436,7 +1449,10 @@ Characters in a class may be specified by their code points using \eo, \ex, or \eN{U+hh..} in the usual way. When caseless matching is set, any letters in a class represent both their upper case and lower case versions, so for example, a caseless [aeiou] matches "A" as well as "a", and a caseless [^aeiou] does not -match "A", whereas a caseful version would. +match "A", whereas a caseful version would. Note that there are two ASCII +characters, K and S, that, in addition to their lower case ASCII equivalents, +are case-equivalent with Unicode U+212A (Kelvin sign) and U+017F (long S) +respectively when either PCRE2_UTF or PCRE2_UCP is set. .P Characters that might indicate line breaks are never treated in any special way when matching character classes, whatever line-ending sequence is in use, and @@ -3881,6 +3897,6 @@ Cambridge, England. .rs .sp .nf -Last updated: 24 February 2020 +Last updated: 05 October 2020 Copyright (c) 1997-2020 University of Cambridge. .fi |