Unicode::UCD - Unicode character database

- NAME
- SYNOPSIS
- DESCRIPTION

- charinfo
- charblock
- charscript
- charblocks
- charscripts
- Blocks versus Scripts
- Matching Scripts and Blocks
- Code Point Arguments
- charinrange
- compexcl
- casefold
- casespec
- Unicode::UCD::UnicodeVersion
- Implementation Note

- BUGS
- AUTHOR

# NAME

Unicode::UCD - Unicode character database

# SYNOPSIS

        use Unicode::UCD 'charinfo';
        my $charinfo   = charinfo($codepoint);

        use Unicode::UCD 'charblock';
        my $charblock  = charblock($codepoint);

        use Unicode::UCD 'charscript';
        my $charscript = charscript($codepoint);

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

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

        use Unicode::UCD qw(charscript charinrange);
        my $range = charscript($script);
        print "looks like $script\n" if charinrange($range, $codepoint);

        use Unicode::UCD 'compexcl';
        my $compexcl = compexcl($codepoint);

        my $unicode_version = Unicode::UCD::UnicodeVersion();

# DESCRIPTION

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

## charinfo

        use Unicode::UCD 'charinfo';

        my $charinfo = charinfo(0x41);

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

        key

        code             code point with at least four hexdigits
        name             name of the character IN UPPER CASE
        category         general category of the character
        combining        classes used in the Canonical Ordering Algorithm
        bidi             bidirectional category
        decomposition    character decomposition mapping
        decimal          if decimal digit this is the integer numeric value
        digit            if digit this is the numeric value
        numeric          if numeric is the integer or rational numeric value
        mirrored         if mirrored in bidirectional text
        unicode10        Unicode 1.0 name if existed and different
        comment          ISO 10646 comment field
        upper            uppercase equivalent mapping
        lower            lowercase equivalent mapping
        title            titlecase equivalent mapping

        block            block the character belongs to (used in \p{In...})
        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

        use Unicode::UCD 'charblock';

        my $charblock = charblock(0x41);
        my $charblock = charblock(1234);
        my $charblock = charblock("0x263a");
        my $charblock = charblock("U+263a");

        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 charater block, `undef` is returned.

## charscript

        use Unicode::UCD 'charscript';

        my $charscript = charscript(0x41);
        my $charscript = charscript(1234);
        my $charscript = charscript("U+263a");

        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 charater script, `undef` is returned.

## charblocks

        use Unicode::UCD 'charblocks';

        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

        use Unicode::UCD 'charscripts';

        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():

        use Unicode::UCD qw(charscript charinrange);

        $range = charscript('Hiragana');
        print "looks like hiragana\n" if charinrange($range, $codepoint);

## compexcl

        use Unicode::UCD 'compexcl';

        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

        use Unicode::UCD 'casefold';

        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:

        key

        code             code point with at least four hexdigits
        status           "C", "F", "S", or "I"
        mapping          one or more codes separated by spaces

The meaning of the status is as follows:

       C                 common case folding, common mappings shared
                         by both simple and full mappings
       F                 full case folding, mappings that cause strings
                         to grow in length. Multiple characters are separated
                         by spaces
       S                 simple case folding, mappings to single characters
                         where different from F
       I                 special case for dotted uppercase I and
                         dotless lowercase i
                         - If this mapping is included, the result is
                           case-insensitive, but dotless and dotted I's
                           are not distinguished
                         - If this mapping is excluded, the result is not
                           fully case-insensitive, but dotless and dotted
                           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

        use Unicode::UCD 'casespec';

        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:

        key

        code             code point with at least four hexdigits
        lower            lowercase
        title            titlecase
        upper            uppercase
        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 the Locale::Country manpage and the Locale::Language manpage.

A context is one of the following choices:

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

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

## 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

Unicode::UCD - Unicode character database