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Unicode::UCD

Perl 5 version 8.8 documentation
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Unicode::UCD

NAME

Unicode::UCD - Unicode character database

SYNOPSIS

  1. use Unicode::UCD 'charinfo';
  2. my $charinfo = charinfo($codepoint);
  3. use Unicode::UCD 'charblock';
  4. my $charblock = charblock($codepoint);
  5. use Unicode::UCD 'charscript';
  6. my $charscript = charscript($codepoint);
  7. use Unicode::UCD 'charblocks';
  8. my $charblocks = charblocks();
  9. use Unicode::UCD 'charscripts';
  10. my %charscripts = charscripts();
  11. use Unicode::UCD qw(charscript charinrange);
  12. my $range = charscript($script);
  13. print "looks like $script\n" if charinrange($range, $codepoint);
  14. use Unicode::UCD 'compexcl';
  15. my $compexcl = compexcl($codepoint);
  16. use Unicode::UCD 'namedseq';
  17. my $namedseq = namedseq($named_sequence_name);
  18. my $unicode_version = Unicode::UCD::UnicodeVersion();

DESCRIPTION

The Unicode::UCD module offers a simple interface to the Unicode Character Database.

charinfo

  1. use Unicode::UCD 'charinfo';
  2. my $charinfo = charinfo(0x41);

charinfo() returns a reference to a hash that has the following fields as defined by the Unicode standard:

  1. key
  2. code code point with at least four hexdigits
  3. name name of the character IN UPPER CASE
  4. category general category of the character
  5. combining classes used in the Canonical Ordering Algorithm
  6. bidi bidirectional category
  7. decomposition character decomposition mapping
  8. decimal if decimal digit this is the integer numeric value
  9. digit if digit this is the numeric value
  10. numeric if numeric is the integer or rational numeric value
  11. mirrored if mirrored in bidirectional text
  12. unicode10 Unicode 1.0 name if existed and different
  13. comment ISO 10646 comment field
  14. upper uppercase equivalent mapping
  15. lower lowercase equivalent mapping
  16. title titlecase equivalent mapping
  17. block block the character belongs to (used in \p{In...})
  18. script script the character belongs to

If no match is found, a reference to an empty hash is returned.

The block property is the same as returned by charinfo(). It is not defined in the Unicode Character Database proper (Chapter 4 of the Unicode 3.0 Standard, aka TUS3) but instead in an auxiliary database (Chapter 14 of TUS3). Similarly for the script property.

Note that you cannot do (de)composition and casing based solely on the above decomposition and lower , upper , title , properties, you will need also the compexcl(), casefold(), and casespec() functions.

charblock

  1. use Unicode::UCD 'charblock';
  2. my $charblock = charblock(0x41);
  3. my $charblock = charblock(1234);
  4. my $charblock = charblock("0x263a");
  5. my $charblock = charblock("U+263a");
  6. my $range = charblock('Armenian');

With a code point argument charblock() returns the block the character belongs to, e.g. Basic Latin . Note that not all the character positions within all blocks are defined.

See also Blocks versus Scripts.

If supplied with an argument that can't be a code point, charblock() tries to do the opposite and interpret the argument as a character block. The return value is a range: an anonymous list of lists that contain start-of-range, end-of-range code point pairs. You can test whether a code point is in a range using the charinrange function. If the argument is not a known character block, undef is returned.

charscript

  1. use Unicode::UCD 'charscript';
  2. my $charscript = charscript(0x41);
  3. my $charscript = charscript(1234);
  4. my $charscript = charscript("U+263a");
  5. my $range = charscript('Thai');

With a code point argument charscript() returns the script the character belongs to, e.g. Latin , Greek , Han .

See also Blocks versus Scripts.

If supplied with an argument that can't be a code point, charscript() tries to do the opposite and interpret the argument as a character script. The return value is a range: an anonymous list of lists that contain start-of-range, end-of-range code point pairs. You can test whether a code point is in a range using the charinrange function. If the argument is not a known character script, undef is returned.

charblocks

  1. use Unicode::UCD 'charblocks';
  2. my $charblocks = charblocks();

charblocks() returns a reference to a hash with the known block names as the keys, and the code point ranges (see charblock) as the values.

See also Blocks versus Scripts.

charscripts

  1. use Unicode::UCD 'charscripts';
  2. my %charscripts = charscripts();

charscripts() returns a hash with the known script names as the keys, and the code point ranges (see charscript) as the values.

See also Blocks versus Scripts.

Blocks versus Scripts

The difference between a block and a script is that scripts are closer to the linguistic notion of a set of characters required to present languages, while block is more of an artifact of the Unicode character numbering and separation into blocks of (mostly) 256 characters.

For example the Latin script is spread over several blocks, such as Basic Latin , Latin 1 Supplement, Latin Extended-A , and Latin Extended-B . On the other hand, the Latin script does not contain all the characters of the Basic Latin block (also known as the ASCII): it includes only the letters, and not, for example, the digits or the punctuation.

For blocks see http://www.unicode.org/Public/UNIDATA/Blocks.txt

For scripts see UTR #24: http://www.unicode.org/unicode/reports/tr24/

Matching Scripts and Blocks

Scripts are matched with the regular-expression construct \p{...} (e.g. \p{Tibetan} matches characters of the Tibetan script), while \p{In...} is used for blocks (e.g. \p{InTibetan} matches any of the 256 code points in the Tibetan block).

Code Point Arguments

A code point argument is either a decimal or a hexadecimal scalar designating a Unicode character, or U+ followed by hexadecimals designating a Unicode character. In other words, if you want a code point to be interpreted as a hexadecimal number, you must prefix it with either 0x or U+ , because a string like e.g. 123 will be interpreted as a decimal code point. Also note that Unicode is not limited to 16 bits (the number of Unicode characters is open-ended, in theory unlimited): you may have more than 4 hexdigits.

charinrange

In addition to using the \p{In...} and \P{In...} constructs, you can also test whether a code point is in the range as returned by charblock and charscript or as the values of the hash returned by charblocks and charscripts by using charinrange():

  1. use Unicode::UCD qw(charscript charinrange);
  2. $range = charscript('Hiragana');
  3. print "looks like hiragana\n" if charinrange($range, $codepoint);

compexcl

  1. use Unicode::UCD 'compexcl';
  2. my $compexcl = compexcl("09dc");

The compexcl() returns the composition exclusion (that is, if the character should not be produced during a precomposition) of the character specified by a code point argument.

If there is a composition exclusion for the character, true is returned. Otherwise, false is returned.

casefold

  1. use Unicode::UCD 'casefold';
  2. my $casefold = casefold("00DF");

The casefold() returns the locale-independent case folding of the character specified by a code point argument.

If there is a case folding for that character, a reference to a hash with the following fields is returned:

  1. key
  2. code code point with at least four hexdigits
  3. status "C", "F", "S", or "I"
  4. mapping one or more codes separated by spaces

The meaning of the status is as follows:

  1. C common case folding, common mappings shared
  2. by both simple and full mappings
  3. F full case folding, mappings that cause strings
  4. to grow in length. Multiple characters are separated
  5. by spaces
  6. S simple case folding, mappings to single characters
  7. where different from F
  8. I special case for dotted uppercase I and
  9. dotless lowercase i
  10. - If this mapping is included, the result is
  11. case-insensitive, but dotless and dotted I's
  12. are not distinguished
  13. - If this mapping is excluded, the result is not
  14. fully case-insensitive, but dotless and dotted
  15. I's are distinguished

If there is no case folding for that character, undef is returned.

For more information about case mappings see http://www.unicode.org/unicode/reports/tr21/

casespec

  1. use Unicode::UCD 'casespec';
  2. my $casespec = casespec("FB00");

The casespec() returns the potentially locale-dependent case mapping of the character specified by a code point argument. The mapping may change the length of the string (which the basic Unicode case mappings as returned by charinfo() never do).

If there is a case folding for that character, a reference to a hash with the following fields is returned:

  1. key
  2. code code point with at least four hexdigits
  3. lower lowercase
  4. title titlecase
  5. upper uppercase
  6. condition condition list (may be undef)

The condition is optional. Where present, it consists of one or more locales or contexts, separated by spaces (other than as used to separate elements, spaces are to be ignored). A condition list overrides the normal behavior if all of the listed conditions are true. Case distinctions in the condition list are not significant. Conditions preceded by "NON_" represent the negation of the condition.

Note that when there are multiple case folding definitions for a single code point because of different locales, the value returned by casespec() is a hash reference which has the locales as the keys and hash references as described above as the values.

A locale is defined as a 2-letter ISO 3166 country code, possibly followed by a "_" and a 2-letter ISO language code (possibly followed by a "_" and a variant code). You can find the lists of those codes, see Locale::Country and Locale::Language.

A context is one of the following choices:

  1. FINAL The letter is not followed by a letter of
  2. general category L (e.g. Ll, Lt, Lu, Lm, or Lo)
  3. MODERN The mapping is only used for modern text
  4. AFTER_i The last base character was "i" (U+0069)

For more information about case mappings see http://www.unicode.org/unicode/reports/tr21/

namedseq()

  1. use Unicode::UCD 'namedseq';
  2. my $namedseq = namedseq("KATAKANA LETTER AINU P");
  3. my @namedseq = namedseq("KATAKANA LETTER AINU P");
  4. my %namedseq = namedseq();

If used with a single argument in a scalar context, returns the string consisting of the code points of the named sequence, or undef if no named sequence by that name exists. If used with a single argument in a list context, returns list of the code points. If used with no arguments in a list context, returns a hash with the names of the named sequences as the keys and the named sequences as strings as the values. Otherwise, returns undef or empty list depending on the context.

(New from Unicode 4.1.0)

Unicode::UCD::UnicodeVersion

Unicode::UCD::UnicodeVersion() returns the version of the Unicode Character Database, in other words, the version of the Unicode standard the database implements. The version is a string of numbers delimited by dots ('.' ).

Implementation Note

The first use of charinfo() opens a read-only filehandle to the Unicode Character Database (the database is included in the Perl distribution). The filehandle is then kept open for further queries. In other words, if you are wondering where one of your filehandles went, that's where.

BUGS

Does not yet support EBCDIC platforms.

AUTHOR

Jarkko Hietaniemi