diff options
author | afresh1 <afresh1@cvs.openbsd.org> | 2014-03-24 14:59:14 +0000 |
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committer | afresh1 <afresh1@cvs.openbsd.org> | 2014-03-24 14:59:14 +0000 |
commit | c080cf55b5ad88c4056e6e9a4f858e0dfbf642b1 (patch) | |
tree | 90e52b9a68c9bf2fe8cd12484950cdc93821c2c4 /gnu/usr.bin/perl/pod/perlrebackslash.pod | |
parent | 2fae50d18aceff793a4705626eb1156e0070870a (diff) |
Import perl-5.18.2
OK espie@ sthen@ deraadt@
Diffstat (limited to 'gnu/usr.bin/perl/pod/perlrebackslash.pod')
-rw-r--r-- | gnu/usr.bin/perl/pod/perlrebackslash.pod | 25 |
1 files changed, 14 insertions, 11 deletions
diff --git a/gnu/usr.bin/perl/pod/perlrebackslash.pod b/gnu/usr.bin/perl/pod/perlrebackslash.pod index f81af0c6dd7..44b0e7db06e 100644 --- a/gnu/usr.bin/perl/pod/perlrebackslash.pod +++ b/gnu/usr.bin/perl/pod/perlrebackslash.pod @@ -68,7 +68,7 @@ as C<Not in [].> \A Beginning of string. Not in []. \b Word/non-word boundary. (Backspace in []). \B Not a word/non-word boundary. Not in []. - \cX Control-X + \cX Control-X. \C Single octet, even under UTF-8. Not in []. \d Character class for digits. \D Character class for non-digits. @@ -76,7 +76,8 @@ as C<Not in [].> \E Turn off \Q, \L and \U processing. Not in []. \f Form feed. \F Foldcase till \E. Not in []. - \g{}, \g1 Named, absolute or relative backreference. Not in [] + \g{}, \g1 Named, absolute or relative backreference. + Not in []. \G Pos assertion. Not in []. \h Character class for horizontal whitespace. \H Character class for non horizontal whitespace. @@ -85,7 +86,7 @@ as C<Not in [].> \l Lowercase next character. Not in []. \L Lowercase till \E. Not in []. \n (Logical) newline character. - \N Any character but newline. Experimental. Not in []. + \N Any character but newline. Not in []. \N{} Named or numbered (Unicode) character or sequence. \o{} Octal escape sequence. \p{}, \pP Character with the given Unicode property. @@ -246,16 +247,17 @@ Mnemonic: I<0>ctal or I<o>ctal. $str = "Perl"; $str =~ /\o{120}/; # Match, "\120" is "P". $str =~ /\120/; # Same. - $str =~ /\o{120}+/; # Match, "\120" is "P", it's repeated at least once + $str =~ /\o{120}+/; # Match, "\120" is "P", + # it's repeated at least once. $str =~ /\120+/; # Same. $str =~ /P\053/; # No match, "\053" is "+" and taken literally. /\o{23073}/ # Black foreground, white background smiling face. - /\o{4801234567}/ # Raises a warning, and yields chr(4) + /\o{4801234567}/ # Raises a warning, and yields chr(4). =head4 Disambiguation rules between old-style octal escapes and backreferences Octal escapes of the C<\000> form outside of bracketed character classes -potentially clash with old-style backreferences. (see L</Absolute referencing> +potentially clash with old-style backreferences (see L</Absolute referencing> below). They both consist of a backslash followed by numbers. So Perl has to use heuristics to determine whether it is a backreference or an octal escape. Perl uses the following rules to disambiguate: @@ -282,7 +284,7 @@ takes only the first three for the octal escape; the rest are matched as is. $pat .= ")" x 999; /^($pat)\1000$/; # Matches 'aa'; there are 1000 capture groups. /^$pat\1000$/; # Matches 'a@0'; there are 999 capture groups - # and \1000 is seen as \100 (a '@') and a '0' + # and \1000 is seen as \100 (a '@') and a '0'. =back @@ -430,7 +432,7 @@ Mnemonic: I<g>roup. =head4 Examples /(\w+) \g1/; # Finds a duplicated word, (e.g. "cat cat"). - /(\w+) \1/; # Same thing; written old-style + /(\w+) \1/; # Same thing; written old-style. /(.)(.)\g2\g1/; # Match a four letter palindrome (e.g. "ABBA"). @@ -575,7 +577,7 @@ categories above. These are: C<\C> always matches a single octet, even if the source string is encoded in UTF-8 format, and the character to be matched is a multi-octet character. -C<\C> was introduced in perl 5.6. This is very dangerous, because it violates +This is very dangerous, because it violates the logical character abstraction and can cause UTF-8 sequences to become malformed. Mnemonic: oI<C>tet. @@ -591,7 +593,7 @@ Mnemonic: I<K>eep. =item \N -This is an experimental feature new to perl 5.12.0. It matches any character +This feature, available starting in v5.12, matches any character that is B<not> a newline. It is a short-hand for writing C<[^\n]>, and is identical to the C<.> metasymbol, except under the C</s> flag, which changes the meaning of C<.>, but not C<\N>. @@ -647,7 +649,8 @@ Mnemonic: eI<X>tended Unicode character. =head4 Examples - "\x{256}" =~ /^\C\C$/; # Match as chr (0x256) takes 2 octets in UTF-8. + "\x{256}" =~ /^\C\C$/; # Match as chr (0x256) takes + # 2 octets in UTF-8. $str =~ s/foo\Kbar/baz/g; # Change any 'bar' following a 'foo' to 'baz' $str =~ s/(.)\K\g1//g; # Delete duplicated characters. |