alpha
alnum
ascii
+ blank [1]
cntrl
digit \d
graph
lower
print
punct
- space \s
+ space \s [2]
upper
- word \w
+ word \w [3]
xdigit
+ [1] A GNU extension equivalent to C<[ \t]>, `all horizontal whitespace'.
+ [2] Not I<exactly equivalent> to C<\s> since the C<[[:space:]]> includes
+ also the (very rare) `vertical tabulator', "\ck", chr(11).
+ [3] A Perl extension.
+
For example use C<[:upper:]> to match all the uppercase characters.
-Note that the C<[]> are part of the C<[::]> construct, not part of the whole
-character class. For example:
+Note that the C<[]> are part of the C<[::]> construct, not part of the
+whole character class. For example:
[01[:alpha:]%]
-matches one, zero, any alphabetic character, and the percentage sign.
+matches zero, one, any alphabetic character, and the percentage sign.
If the C<utf8> pragma is used, the following equivalences to Unicode
\p{} constructs hold:
alpha IsAlpha
alnum IsAlnum
ascii IsASCII
+ blank IsSpace
cntrl IsCntrl
digit IsDigit
graph IsGraph
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 isalpha(3) interface (except for `word',
-which is a Perl extension, mirroring C<\w>).
+classes correlate with the usual isalpha(3) interface (except for
+`word' and `blank').
The assumedly non-obviously named classes are:
Any control character. Usually characters that don't produce output as
such but instead control the terminal somehow: for example newline and
backspace are control characters. All characters with ord() less than
-32 are most often classified as control characters.
+32 are most often classified as control characters (assuming ASCII,
+the ISO Latin character sets, and Unicode).
=item graph
=item xdigit
-Any hexadecimal digit. Though this may feel silly (/0-9a-f/i would
+Any hexadecimal digit. Though this may feel silly ([0-9A-Fa-f] would
work just fine) it is included for completeness.
=back
after the matched string.
The numbered variables ($1, $2, $3, etc.) and the related punctuation
-set (C<<$+>, C<$&>, C<$`>, and C<$'>) are all dynamically scoped
+set (C<$+>, C<$&>, C<$`>, and C<$'>) are all dynamically scoped
until the end of the enclosing block or until the next successful
match, whichever comes first. (See L<perlsyn/"Compound Statements">.)