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from cover to cover, Perl does support many Unicode features.
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People who want to learn to use Unicode in Perl, should probably read
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L<the Perl Unicode tutorial, perlunitut|perlunitut>, before reading
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the L<Perl Unicode tutorial, perlunitut|perlunitut>, before reading
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this reference document.
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Also, the use of Unicode may present security issues that aren't obvious.
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Read L<Unicode Security Considerations|http://www.unicode.org/reports/tr36>.
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=item Input and Output Layers
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semantics in a particular lexical scope. See L<bytes>.
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The C<use feature 'unicode_strings'> pragma is intended to always, regardless
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of platform, force Unicode semantics in a particular lexical scope. In
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release 5.12, it is partially implemented, applying only to case changes.
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of platform, force character (Unicode) semantics in a particular lexical scope.
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In release 5.12, it is partially implemented, applying only to case changes.
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See L</The "Unicode Bug"> below.
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The C<utf8> pragma is primarily a compatibility device that enables
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Character classes in regular expressions match characters instead of
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Bracketed character classes in regular expressions match characters instead of
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bytes and match against the character properties specified in the
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Unicode properties database. C<\w> can be used to match a Japanese
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ideograph, for instance.
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Named Unicode properties, scripts, and block ranges may be used like
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character classes via the C<\p{}> "matches property" construct and
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Named Unicode properties, scripts, and block ranges may be used (like bracketed
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character classes) by using the C<\p{}> "matches property" construct and
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the C<\P{}> negation, "doesn't match property".
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See L</"Unicode Character Properties"> for more details.
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You can define your own mappings to be used in lc(),
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lcfirst(), uc(), and ucfirst() (or their string-inlined versions).
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You can define your own mappings to be used in C<lc()>,
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C<lcfirst()>, C<uc()>, and C<ucfirst()> (or their double-quoted string inlined
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versions such as C<\U>).
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See L</"User-Defined Case Mappings"> for more details.
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=head2 Unicode Character Properties
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Most Unicode character properties are accessible by using regular expressions.
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They are used like character classes via the C<\p{}> "matches property"
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construct and the C<\P{}> negation, "doesn't match property".
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For instance, C<\p{Uppercase}> matches any character with the Unicode
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They are used (like bracketed character classes) by using the C<\p{}> "matches
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property" construct and the C<\P{}> negation, "doesn't match property".
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Note that the only time that Perl considers a sequence of individual code
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points as a single logical character is in the C<\X> construct, already
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mentioned above. Therefore "character" in this discussion means a single
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For instance, C<\p{Uppercase}> matches any single character with the Unicode
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"Uppercase" property, while C<\p{L}> matches any character with a
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General_Category of "L" (letter) property. Brackets are not
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required for single letter properties, so C<\p{L}> is equivalent to C<\pL>.
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required for single letter property names, so C<\p{L}> is equivalent to C<\pL>.
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More formally, C<\p{Uppercase}> matches any character whose Unicode Uppercase
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property value is True, and C<\P{Uppercase}> matches any character whose
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Uppercase property value is False, and they could have been written as
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C<\p{Uppercase=True}> and C<\p{Uppercase=False}>, respectively
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More formally, C<\p{Uppercase}> matches any single character whose Unicode
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Uppercase property value is True, and C<\P{Uppercase}> matches any character
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whose Uppercase property value is False, and they could have been written as
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C<\p{Uppercase=True}> and C<\p{Uppercase=False}>, respectively.
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This formality is needed when properties are not binary, that is if they can
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take on more values than just True and False. For example, the Bidi_Class (see
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L</"Bidirectional Character Types"> below), can take on a number of different
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values, such as Left, Right, Whitespace, and others. To match these, one needs
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to specify the property name (Bidi_Class), and the value being matched against
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(Left, Right, I<etc.>). This is done, as in the examples above, by having the
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(Left, Right, etc.). This is done, as in the examples above, by having the
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two components separated by an equal sign (or interchangeably, a colon), like
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C<\p{Bidi_Class: Left}>.
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Single-letter properties match all characters in any of the
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two-letter sub-properties starting with the same letter.
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C<LC> and C<L&> are special cases, which are aliases for the set of
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C<Ll>, C<Lu>, and C<Lt>.
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C<LC> and C<L&> are special cases, which are both aliases for the set consisting of everything matched by C<Ll>, C<Lu>, and C<Lt>.
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Because Perl hides the need for the user to understand the internal
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representation of Unicode characters, there is no need to implement
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Hiragana or Katakana. There are many more.
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The Unicode Script property gives what script a given character is in,
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and can be matched with the compound form like C<\p{Script=Hebrew}> (short:
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C<\p{sc=hebr}>). Perl furnishes shortcuts for all script names. You can omit
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everything up through the equals (or colon), and simply write C<\p{Latin}> or
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and the property can be specified with the compound form like
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C<\p{Script=Hebrew}> (short: C<\p{sc=hebr}>). Perl furnishes shortcuts for all
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script names. You can omit everything up through the equals (or colon), and
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simply write C<\p{Latin}> or C<\P{Cyrillic}>.
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A complete list of scripts and their shortcuts is in L<perluniprops>.
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block is all characters whose ordinals are between 0 and 127, inclusive, in
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other words, the ASCII characters. The "Latin" script contains some letters
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from this block as well as several more, like "Latin-1 Supplement",
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"Latin Extended-A", I<etc.>, but it does not contain all the characters from
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"Latin Extended-A", etc., but it does not contain all the characters from
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those blocks. It does not, for example, contain digits, because digits are
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shared across many scripts. Digits and similar groups, like punctuation, are in
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the script called C<Common>. There is also a script called C<Inherited> for
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necessary to know some basics about decomposition.
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Consider a character, say H. It could appear with various marks around it,
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such as an acute accent, or a circumflex, or various hooks, circles, arrows,
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I<etc.>, above, below, to one side and/or the other, I<etc.> There are many
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I<etc.>, above, below, to one side and/or the other, etc. There are many
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possibilities among the world's languages. The number of combinations is
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astronomical, and if there were a character for each combination, it would
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soon exhaust Unicode's more than a million possible characters. So Unicode
added
removed
pod/perlunicode.pod
