it is a sequence of characters, not bytes. See L<perlunitut> for a
tutorial about that.
-Let us now discuss Unicode character classes. Just as with Unicode
-characters, there are named Unicode character classes represented by the
+Let us now discuss Unicode character classes, most usually called
+"character properties". These are represented by the
C<\p{name}> escape sequence. Closely associated is the C<\P{name}>
-character class, which is the negation of the C<\p{name}> class. For
+property, which is the negation of the C<\p{name}> one. For
example, to match lower and uppercase characters,
$x = "BOB";
(The "Is" is optional.)
-Here is the association between some Perl named classes and the
-traditional Unicode classes:
-
- Perl class Unicode class name or regular expression
- name
-
- IsAlpha /^[LM]/
- IsAlnum /^[LMN]/
- IsASCII $code <= 127
- IsCntrl /^C/
- IsBlank $code =~ /^(0020|0009)$/ || /^Z[^lp]/
- IsDigit Nd
- IsGraph /^([LMNPS]|Co)/
- IsLower Ll
- IsPrint /^([LMNPS]|Co|Zs)/
- IsPunct /^P/
- IsSpace /^Z/ || ($code =~ /^(0009|000A|000B|000C|000D)$/
- IsSpacePerl /^Z/ || ($code =~ /^(0009|000A|000C|000D|0085|2028|2029)$/
- IsUpper /^L[ut]/
- IsWord /^[LMN]/ || $code eq "005F"
- IsXDigit $code =~ /^00(3[0-9]|[46][1-6])$/
-
-You can also use the official Unicode class names with C<\p> and
-C<\P>, like C<\p{L}> for Unicode 'letters', C<\p{Lu}> for uppercase
-letters, or C<\P{Nd}> for non-digits. If a C<name> is just one
-letter, the braces can be dropped. For instance, C<\pM> is the
-character class of Unicode 'marks', for example accent marks.
-For the full list see L<perlunicode>.
-
-Unicode has also been separated into various sets of characters
-which you can test with C<\p{...}> (in) and C<\P{...}> (not in).
-To test whether a character is (or is not) an element of a script
-you would use the script name, for example C<\p{Latin}>, C<\p{Greek}>,
-or C<\P{Katakana}>.
+There are many, many Unicode character properties. For the full list
+see L<perluniprops>. Most of them have synonyms with shorter names,
+also listed there. Some synonyms are a single character. For these,
+you can drop the braces. For instance, C<\pM> is the same thing as
+C<\p{Mark}>, meaning things like accent marks.
+
+The Unicode C<\p{Script}> property is used to categorize every Unicode
+character into the language script it is written in. For example,
+English, French, and a bunch of other European languages are written in
+the Latin script. But there is also the Greek script, the Thai script,
+the Katakana script, etc. You can test whether a character is in a
+particular script with, for example C<\p{Latin}>, C<\p{Greek}>,
+or C<\p{Katakana}>. To test if it isn't in the Balinese script, you
+would use C<\P{Balinese}>.
What we have described so far is the single form of the C<\p{...}> character
classes. There is also a compound form which you may run into. These
can be used interchangeably). These are more general than the single form,
and in fact most of the single forms are just Perl-defined shortcuts for common
compound forms. For example, the script examples in the previous paragraph
-could be written equivalently as C<\p{Script=Latin}>, C<\p{Script:Greek}>, and
-C<\P{script=katakana}> (case is irrelevant between the C<{}> braces). You may
+could be written equivalently as C<\p{Script=Latin}>, C<\p{Script:Greek}>,
+C<\p{script=katakana}>, and C<\P{script=balinese}> (case is irrelevant
+between the C<{}> braces). You may
never have to use the compound forms, but sometimes it is necessary, and their
use can make your code easier to understand.
https://perl5.git.perl.org / perl5.git / blobdiff