diff options
| -rw-r--r-- | pod/perlre.pod | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/pod/perlre.pod b/pod/perlre.pod index f24e97157b..32a7e6fcf7 100644 --- a/pod/perlre.pod +++ b/pod/perlre.pod @@ -224,8 +224,17 @@ X<character class> [:class:] -is also available. The available classes and their backslash -equivalents (if available) are as follows: +is also available. Note that the C<[> and C<]> braces are I<literal>; +they must always be used within a character class expression. + + # this is correct: + $string =~ /[[:alpha:]]/; + + # this is not, and will generate a warning: + $string =~ /[:alpha:]/; + +The available classes and their backslash equivalents (if available) are +as follows: X<character class> X<alpha> X<alnum> X<ascii> X<blank> X<cntrl> X<digit> X<graph> X<lower> X<print> X<punct> X<space> X<upper> X<word> X<xdigit> @@ -274,7 +283,7 @@ The following equivalences to Unicode \p{} constructs and equivalent backslash character classes (if available), will hold: X<character class> X<\p> X<\p{}> - [:...:] \p{...} backslash + [[:...:]] \p{...} backslash alpha IsAlpha alnum IsAlnum @@ -292,7 +301,7 @@ X<character class> X<\p> X<\p{}> word IsWord xdigit IsXDigit -For example C<[:lower:]> and C<\p{IsLower}> are equivalent. +For example C<[[:lower:]]> and C<\p{IsLower}> are equivalent. If the C<utf8> pragma is not used but the C<locale> pragma is, the classes correlate with the usual isalpha(3) interface (except for @@ -339,11 +348,11 @@ You can negate the [::] character classes by prefixing the class name with a '^'. This is a Perl extension. For example: X<character class, negation> - POSIX traditional Unicode + POSIX traditional Unicode - [:^digit:] \D \P{IsDigit} - [:^space:] \S \P{IsSpace} - [:^word:] \W \P{IsWord} + [[:^digit:]] \D \P{IsDigit} + [[:^space:]] \S \P{IsSpace} + [[:^word:]] \W \P{IsWord} Perl respects the POSIX standard in that POSIX character classes are only supported within a character class. The POSIX character classes |