Unicode::UCD(3perl) - man - phpMan

 


Unicode::UCD(3perl)
NAME SYNOPSIS DESCRIPTION AUTHOR
NAME
    Unicode::UCD - Unicode character database

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

        use Unicode::UCD 'charprop';
        my $value  = charprop($codepoint, $property);

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

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

        use Unicode::UCD 'all_casefolds';
        my $all_casefolds_ref = all_casefolds();

        use Unicode::UCD 'casespec';
        my $casespec = casespec($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 qw(general_categories bidi_types);
        my $categories = general_categories();
        my $types = bidi_types();

        use Unicode::UCD 'prop_aliases';
        my @space_names = prop_aliases("space");

        use Unicode::UCD 'prop_value_aliases';
        my @gc_punct_names = prop_value_aliases("Gc", "Punct");

        use Unicode::UCD 'prop_values';
        my @all_EA_short_names = prop_values("East_Asian_Width");

        use Unicode::UCD 'prop_invlist';
        my @puncts = prop_invlist("gc=punctuation");

        use Unicode::UCD 'prop_invmap';
        my ($list_ref, $map_ref, $format, $missing)
                                          = prop_invmap("General Category");

        use Unicode::UCD 'search_invlist';
        my $index = search_invlist(\@invlist, $code_point);

        # The following function should be used only internally in
        # implementations of the Unicode Normalization Algorithm, and there
        # are better choices than it.
        use Unicode::UCD 'compexcl';
        my $compexcl = compexcl($codepoint);

        use Unicode::UCD 'namedseq';
        my $namedseq = namedseq($named_sequence_name);

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

        my $convert_to_numeric =
                  Unicode::UCD::num("\N{RUMI DIGIT ONE}\N{RUMI DIGIT TWO}");

DESCRIPTION
    The Unicode::UCD module offers a series of functions that provide a
    simple interface to the Unicode Character Database.

  code point argument
    Some of the functions are called with a *code point argument*, which is
    either a decimal or a hexadecimal scalar designating a code point in the
    platform's native character set (extended to Unicode), or a string
    containing "U+" followed by hexadecimals designating a Unicode code
    point. A leading 0 will force a hexadecimal interpretation, as will a
    hexadecimal digit that isn't a decimal digit.

    Examples:

        223     # Decimal 223 in native character set
        0223    # Hexadecimal 223, native (= 547 decimal)
        0xDF    # Hexadecimal DF, native (= 223 decimal)
        '0xDF'  # String form of hexadecimal (= 223 decimal)
        'U+DF'  # Hexadecimal DF, in Unicode's character set
                                  (= LATIN SMALL LETTER SHARP S)

    Note that the largest code point in Unicode is U+10FFFF.

  charinfo()
        use Unicode::UCD 'charinfo';

        my $charinfo = charinfo(0x41);

    This returns information about the input "code point argument" as a
    reference to a hash of fields as defined by the Unicode standard. If the
    "code point argument" is not assigned in the standard (i.e., has the
    general category "Cn" meaning "Unassigned") or is a non-character
    (meaning it is guaranteed to never be assigned in the standard), "undef"
    is returned.

    Fields that aren't applicable to the particular code point argument
    exist in the returned hash, and are empty.

    For results that are less "raw" than this function returns, or to get
    the values for any property, not just the few covered by this function,
    use the "charprop()" function.

    The keys in the hash with the meanings of their values are:

    code
        the input native "code point argument" expressed in hexadecimal,
        with leading zeros added if necessary to make it contain at least
        four hexdigits

    name
        name of *code*, all IN UPPER CASE. Some control-type code points do
        not have names. This field will be empty for "Surrogate" and
        "Private Use" code points, and for the others without a name, it
        will contain a description enclosed in angle brackets, like
        "<control>".

    category
        The short name of the general category of *code*. This will match
        one of the keys in the hash returned by "general_categories()".

        The "prop_value_aliases()" function can be used to get all the
        synonyms of the category name.

    combining
        the combining class number for *code* used in the Canonical Ordering
        Algorithm. For Unicode 5.1, this is described in Section 3.11
        "Canonical Ordering Behavior" available at
        <http://www.unicode.org/versions/Unicode5.1.0/>

        The "prop_value_aliases()" function can be used to get all the
        synonyms of the combining class number.

    bidi
        bidirectional type of *code*. This will match one of the keys in the
        hash returned by "bidi_types()".

        The "prop_value_aliases()" function can be used to get all the
        synonyms of the bidi type name.

    decomposition
        is empty if *code* has no decomposition; or is one or more codes
        (separated by spaces) that, taken in order, represent a
        decomposition for *code*. Each has at least four hexdigits. The
        codes may be preceded by a word enclosed in angle brackets, then a
        space, like "<compat> ", giving the type of decomposition

        This decomposition may be an intermediate one whose components are
        also decomposable. Use Unicode::Normalize to get the final
        decomposition in one step.

    decimal
        if *code* represents a decimal digit this is its integer numeric
        value

    digit
        if *code* represents some other digit-like number, this is its
        integer numeric value

    numeric
        if *code* represents a whole or rational number, this is its numeric
        value. Rational values are expressed as a string like "1/4".

    mirrored
        "Y" or "N" designating if *code* is mirrored in bidirectional text

    unicode10
        name of *code* in the Unicode 1.0 standard if one existed for this
        code point and is different from the current name

    comment
        As of Unicode 6.0, this is always empty.

    upper
        is, if non-empty, the uppercase mapping for *code* expressed as at
        least four hexdigits. This indicates that the full uppercase mapping
        is a single character, and is identical to the simple
        (single-character only) mapping. When this field is empty, it means
        that the simple uppercase mapping is *code* itself; you'll need some
        other means, (like "charprop()" or "casespec()" to get the full
        mapping.

    lower
        is, if non-empty, the lowercase mapping for *code* expressed as at
        least four hexdigits. This indicates that the full lowercase mapping
        is a single character, and is identical to the simple
        (single-character only) mapping. When this field is empty, it means
        that the simple lowercase mapping is *code* itself; you'll need some
        other means, (like "charprop()" or "casespec()" to get the full
        mapping.

    title
        is, if non-empty, the titlecase mapping for *code* expressed as at
        least four hexdigits. This indicates that the full titlecase mapping
        is a single character, and is identical to the simple
        (single-character only) mapping. When this field is empty, it means
        that the simple titlecase mapping is *code* itself; you'll need some
        other means, (like "charprop()" or "casespec()" to get the full
        mapping.

    block
        the block *code* belongs to (used in "\p{Blk=...}"). The
        "prop_value_aliases()" function can be used to get all the synonyms
        of the block name.

        See "Blocks versus Scripts".

    script
        the script *code* belongs to. The "prop_value_aliases()" function
        can be used to get all the synonyms of the script name. Note that
        this is the older "Script" property value, and not the improved
        "Script_Extensions" value.

        See "Blocks versus Scripts".

    Note that you cannot do (de)composition and casing based solely on the
    *decomposition*, *combining*, *lower*, *upper*, and *title* fields; you
    will need also the "casespec()" function and the "Composition_Exclusion"
    property. (Or you could just use the lc(), uc(), and ucfirst()
    functions, and the Unicode::Normalize module.)

  charprop()
        use Unicode::UCD 'charprop';

        print charprop(0x41, "Gc"), "\n";
        print charprop(0x61, "General_Category"), "\n";

      prints
        Lu
        Ll

    This returns the value of the Unicode property given by the second
    parameter for the "code point argument" given by the first.

    The passed-in property may be specified as any of the synonyms returned
    by "prop_aliases()".

    The return value is always a scalar, either a string or a number. For
    properties where there are synonyms for the values, the synonym returned
    by this function is the longest, most descriptive form, the one returned
    by "prop_value_aliases()" when called in a scalar context. Of course,
    you can call "prop_value_aliases()" on the result to get other synonyms.

    The return values are more "cooked" than the "charinfo()" ones. For
    example, the "uc" property value is the actual string containing the
    full uppercase mapping of the input code point. You have to go to extra
    trouble with "charinfo" to get this value from its "upper" hash element
    when the full mapping differs from the simple one.

    Special note should be made of the return values for a few properties:

    Block
        The value returned is the new-style (see "Old-style versus new-style
        block names").

    Decomposition_Mapping
        Like "charinfo()", the result may be an intermediate decomposition
        whose components are also decomposable. Use Unicode::Normalize to
        get the final decomposition in one step.

        Unlike "charinfo()", this does not include the decomposition type.
        Use the "Decomposition_Type" property to get that.

    Name_Alias
        If the input code point's name has more than one synonym, they are
        returned joined into a single comma-separated string.

    Numeric_Value
        If the result is a fraction, it is converted into a floating point
        number to the accuracy of your platform.

    Script_Extensions
        If the result is multiple script names, they are returned joined
        into a single comma-separated string.

    When called with a property that is a Perl extension that isn't
    expressible in a compound form, this function currently returns "undef",
    as the only two possible values are *true* or *false* (1 or 0 I
    suppose). This behavior may change in the future, so don't write code
    that relies on it. "Present_In" is a Perl extension that is expressible
    in a bipartite or compound form (for example, "\p{Present_In=4.0}"), so
    "charprop" accepts it. But "Any" is a Perl extension that isn't
    expressible that way, so "charprop" returns "undef" for it. Also
    "charprop" returns "undef" for all Perl extensions that are
    internal-only.

  charprops_all()
        use Unicode::UCD 'charprops_all';

        my $%properties_of_A_hash_ref = charprops_all("U+41");

    This returns a reference to a hash whose keys are all the distinct
    Unicode (no Perl extension) properties, and whose values are the
    respective values for those properties for the input "code point
    argument".

    Each key is the property name in its longest, most descriptive form. The
    values are what "charprop()" would return.

    This function is expensive in time and memory.

  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 code
    point belongs to, e.g. "Basic Latin". The old-style block name is
    returned (see "Old-style versus new-style block names"). The
    "prop_value_aliases()" function can be used to get all the synonyms of
    the block name.

    If the code point is unassigned, this returns the block it would belong
    to if it were assigned. (If the Unicode version being used is so early
    as to not have blocks, all code points are considered to be in
    "No_Block".)

    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 an old-style
    block name. On an ASCII platform, the return value is a *range set* with
    one range: an anonymous array with a single element that consists of
    another anonymous array whose first element is the first code point in
    the block, and whose second element is the final code point in the
    block. On an EBCDIC platform, the first two Unicode blocks are not
    contiguous. Their range sets are lists containing *start-of-range*,
    *end-of-range* code point pairs. You can test whether a code point is in
    a range set using the "charinrange()" function. (To be precise, each
    *range set* contains a third array element, after the range boundary
    ones: the old_style block name.)

    If the argument to "charblock()" is not a known 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
    code point belongs to, e.g., "Latin", "Greek", "Han". If the code point
    is unassigned or the Unicode version being used is so early that it
    doesn't have scripts, this function returns "Unknown". The
    "prop_value_aliases()" function can be used to get all the synonyms of
    the script name.

    Note that the Script_Extensions property is an improved version of the
    Script property, and you should probably be using that instead, with the
    "charprop()" function.

    If supplied with an argument that can't be a code point, charscript()
    tries to do the opposite and interpret the argument as a script name.
    The return value is a *range set*: an anonymous array of arrays that
    contain *start-of-range*, *end-of-range* code point pairs. You can test
    whether a code point is in a range set using the "charinrange()"
    function. (To be precise, each *range set* contains a third array
    element, after the range boundary ones: the script name.)

    If the "charscript()" argument is not a known script, "undef" is
    returned.

    See also "Blocks versus Scripts".

  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.

    The names are in the old-style (see "Old-style versus new-style block
    names").

    prop_invmap("block") can be used to get this same data in a different
    type of data structure.

    prop_values("Block") can be used to get all the known new-style block
    names as a list, without the code point ranges.

    See also "Blocks versus Scripts".

  charscripts()
        use Unicode::UCD 'charscripts';

        my $charscripts = charscripts();

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

    prop_invmap("script") can be used to get this same data in a different
    type of data structure. Since the Script_Extensions property is an
    improved version of the Script property, you should instead use
    prop_invmap("scx").

    "prop_values("Script")" can be used to get all the known script names as
    a list, without the code point ranges.

    See also "Blocks versus Scripts".

  charinrange()
    In addition to using the "\p{Blk=...}" and "\P{Blk=...}" 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);

  general_categories()
        use Unicode::UCD 'general_categories';

        my $categories = general_categories();

    This returns a reference to a hash which has short general category
    names (such as "Lu", "Nd", "Zs", "S") as keys and long names (such as
    "UppercaseLetter", "DecimalNumber", "SpaceSeparator", "Symbol") as
    values. The hash is reversible in case you need to go from the long
    names to the short names. The general category is the one returned from
    "charinfo()" under the "category" key.

    The "prop_values()" and "prop_value_aliases()" functions can be used as
    an alternative to this function; the first returning a simple list of
    the short category names; and the second gets all the synonyms of a
    given category name.

  bidi_types()
        use Unicode::UCD 'bidi_types';

        my $categories = bidi_types();

    This returns a reference to a hash which has the short bidi
    (bidirectional) type names (such as "L", "R") as keys and long names
    (such as "Left-to-Right", "Right-to-Left") as values. The hash is
    reversible in case you need to go from the long names to the short
    names. The bidi type is the one returned from "charinfo()" under the
    "bidi" key. For the exact meaning of the various bidi classes the
    Unicode TR9 is recommended reading:
    <http://www.unicode.org/reports/tr9/> (as of Unicode 5.0.0)

    The "prop_values()" and "prop_value_aliases()" functions can be used as
    an alternative to this function; the first returning a simple list of
    the short bidi type names; and the second gets all the synonyms of a
    given bidi type name.

  compexcl()
    WARNING: Unicode discourages the use of this function or any of the
    alternative mechanisms listed in this section (the documentation of
    "compexcl()"), except internally in implementations of the Unicode
    Normalization Algorithm. You should be using Unicode::Normalize directly
    instead of these. Using these will likely lead to half-baked results.

        use Unicode::UCD 'compexcl';

        my $compexcl = compexcl(0x09dc);

    This routine returns "undef" if the Unicode version being used is so
    early that it doesn't have this property.

    "compexcl()" is included for backwards compatibility, but as of Perl
    5.12 and more modern Unicode versions, for most purposes it is probably
    more convenient to use one of the following instead:

        my $compexcl = chr(0x09dc) =~ /\p{Comp_Ex};
        my $compexcl = chr(0x09dc) =~ /\p{Full_Composition_Exclusion};

    or even

        my $compexcl = chr(0x09dc) =~ /\p{CE};
        my $compexcl = chr(0x09dc) =~ /\p{Composition_Exclusion};

    The first two forms return true if the "code point argument" should not
    be produced by composition normalization. For the final two forms to
    return true, it is additionally required that this fact not otherwise be
    determinable from the Unicode data base.

    This routine behaves identically to the final two forms. That is, it
    does not return true if the code point has a decomposition consisting of
    another single code point, nor if its decomposition starts with a code
    point whose combining class is non-zero. Code points that meet either of
    these conditions should also not be produced by composition
    normalization, which is probably why you should use the
    "Full_Composition_Exclusion" property instead, as shown above.

    The routine returns false otherwise.

  casefold()
        use Unicode::UCD 'casefold';

        my $casefold = casefold(0xDF);
        if (defined $casefold) {
            my @full_fold_hex = split / /, $casefold->{'full'};
            my $full_fold_string =
                        join "", map {chr(hex($_))} @full_fold_hex;
            my @turkic_fold_hex =
                            split / /, ($casefold->{'turkic'} ne "")
                                            ? $casefold->{'turkic'}
                                            : $casefold->{'full'};
            my $turkic_fold_string =
                            join "", map {chr(hex($_))} @turkic_fold_hex;
        }
        if (defined $casefold && $casefold->{'simple'} ne "") {
            my $simple_fold_hex = $casefold->{'simple'};
            my $simple_fold_string = chr(hex($simple_fold_hex));
        }

    This returns the (almost) locale-independent case folding of the
    character specified by the "code point argument". (Starting in Perl
    v5.16, the core function "fc()" returns the "full" mapping (described
    below) faster than this does, and for entire strings.)

    If there is no case folding for the input code point, "undef" is
    returned.

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

    code
        the input native "code point argument" expressed in hexadecimal,
        with leading zeros added if necessary to make it contain at least
        four hexdigits

    full
        one or more codes (separated by spaces) that, taken in order, give
        the code points for the case folding for *code*. Each has at least
        four hexdigits.

    simple
        is empty, or is exactly one code with at least four hexdigits which
        can be used as an alternative case folding when the calling program
        cannot cope with the fold being a sequence of multiple code points.
        If *full* is just one code point, then *simple* equals *full*. If
        there is no single code point folding defined for *code*, then
        *simple* is the empty string. Otherwise, it is an inferior, but
        still better-than-nothing alternative folding to *full*.

    mapping
        is the same as *simple* if *simple* is not empty, and it is the same
        as *full* otherwise. It can be considered to be the simplest
        possible folding for *code*. It is defined primarily for backwards
        compatibility.

    status
        is "C" (for "common") if the best possible fold is a single code
        point (*simple* equals *full* equals *mapping*). It is "S" if there
        are distinct folds, *simple* and *full* (*mapping* equals *simple*).
        And it is "F" if there is only a *full* fold (*mapping* equals
        *full*; *simple* is empty). Note that this describes the contents of
        *mapping*. It is defined primarily for backwards compatibility.

        For Unicode versions between 3.1 and 3.1.1 inclusive, *status* can
        also be "I" which is the same as "C" but is a special case for
        dotted uppercase I and dotless lowercase i:

        * If you use this "I" mapping
            the result is case-insensitive, but dotless and dotted I's are
            not distinguished

        * If you exclude this "I" mapping
            the result is not fully case-insensitive, but dotless and dotted
            I's are distinguished

    turkic
        contains any special folding for Turkic languages. For versions of
        Unicode starting with 3.2, this field is empty unless *code* has a
        different folding in Turkic languages, in which case it is one or
        more codes (separated by spaces) that, taken in order, give the code
        points for the case folding for *code* in those languages. Each code
        has at least four hexdigits. Note that this folding does not
        maintain canonical equivalence without additional processing.

        For Unicode versions between 3.1 and 3.1.1 inclusive, this field is
        empty unless there is a special folding for Turkic languages, in
        which case *status* is "I", and *mapping*, *full*, *simple*, and
        *turkic* are all equal.

    Programs that want complete generality and the best folding results
    should use the folding contained in the *full* field. But note that the
    fold for some code points will be a sequence of multiple code points.

    Programs that can't cope with the fold mapping being multiple code
    points can use the folding contained in the *simple* field, with the
    loss of some generality. In Unicode 5.1, about 7% of the defined
    foldings have no single code point folding.

    The *mapping* and *status* fields are provided for backwards
    compatibility for existing programs. They contain the same values as in
    previous versions of this function.

    Locale is not completely independent. The *turkic* field contains
    results to use when the locale is a Turkic language.

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

  all_casefolds()
        use Unicode::UCD 'all_casefolds';

        my $all_folds_ref = all_casefolds();
        foreach my $char_with_casefold (sort { $a <=> $b }
                                        keys %$all_folds_ref)
        {
            printf "%04X:", $char_with_casefold;
            my $casefold = $all_folds_ref->{$char_with_casefold};

            # Get folds for $char_with_casefold

            my @full_fold_hex = split / /, $casefold->{'full'};
            my $full_fold_string =
                        join "", map {chr(hex($_))} @full_fold_hex;
            print " full=", join " ", @full_fold_hex;
            my @turkic_fold_hex =
                            split / /, ($casefold->{'turkic'} ne "")
                                            ? $casefold->{'turkic'}
                                            : $casefold->{'full'};
            my $turkic_fold_string =
                            join "", map {chr(hex($_))} @turkic_fold_hex;
            print "; turkic=", join " ", @turkic_fold_hex;
            if (defined $casefold && $casefold->{'simple'} ne "") {
                my $simple_fold_hex = $casefold->{'simple'};
                my $simple_fold_string = chr(hex($simple_fold_hex));
                print "; simple=$simple_fold_hex";
            }
            print "\n";
        }

    This returns all the case foldings in the current version of Unicode in
    the form of a reference to a hash. Each key to the hash is the decimal
    representation of a Unicode character that has a casefold to other than
    itself. The casefold of a semi-colon is itself, so it isn't in the hash;
    likewise for a lowercase "a", but there is an entry for a capital "A".
    The hash value for each key is another hash, identical to what is
    returned by "casefold()" if called with that code point as its argument.
    So the value "all_casefolds()->{ord("A")}'" is equivalent to
    "casefold(ord("A"))";

  casespec()
        use Unicode::UCD 'casespec';

        my $casespec = casespec(0xFB00);

    This returns the potentially locale-dependent case mappings of the "code
    point argument". The mappings may be longer than a single code point
    (which the basic Unicode case mappings as returned by "charinfo()" never
    are).

    If there are no case mappings for the "code point argument", or if all
    three possible mappings (*lower*, *title* and *upper*) result in single
    code points and are locale independent and unconditional, "undef" is
    returned (which means that the case mappings, if any, for the code point
    are those returned by "charinfo()").

    Otherwise, a reference to a hash giving the mappings (or a reference to
    a hash of such hashes, explained below) is returned with the following
    keys and their meanings:

    The keys in the bottom layer hash with the meanings of their values are:

    code
        the input native "code point argument" expressed in hexadecimal,
        with leading zeros added if necessary to make it contain at least
        four hexdigits

    lower
        one or more codes (separated by spaces) that, taken in order, give
        the code points for the lower case of *code*. Each has at least four
        hexdigits.

    title
        one or more codes (separated by spaces) that, taken in order, give
        the code points for the title case of *code*. Each has at least four
        hexdigits.

    upper
        one or more codes (separated by spaces) that, taken in order, give
        the code points for the upper case of *code*. Each has at least four
        hexdigits.

    condition
        the conditions for the mappings to be valid. If "undef", the
        mappings are always valid. When defined, this field is a list of
        conditions, all of which must be true for the mappings to be valid.
        The list consists of one or more *locales* (see below) and/or
        *contexts* (explained in the next paragraph), separated by spaces.
        (Other than as used to separate elements, spaces are to be ignored.)
        Case distinctions in the condition list are not significant.
        Conditions preceded by "NON_" represent the negation of the
        condition.

        A *context* is one of those defined in the Unicode standard. For
        Unicode 5.1, they are defined in Section 3.13 "Default Case
        Operations" available at
        <http://www.unicode.org/versions/Unicode5.1.0/>. These are for
        context-sensitive casing.

    The hash described above is returned for locale-independent casing,
    where at least one of the mappings has length longer than one. If
    "undef" is returned, the code point may have mappings, but if so, all
    are length one, and are returned by "charinfo()". Note that when this
    function does return a value, it will be for the complete set of
    mappings for a code point, even those whose length is one.

    If there are additional casing rules that apply only in certain locales,
    an additional key for each will be defined in the returned hash. Each
    such key will be its locale name, 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 all possible locales, see Locale::Country and Locale::Language. (In
    Unicode 6.0, the only locales returned by this function are "lt", "tr",
    and "az".)

    Each locale key is a reference to a hash that has the form above, and
    gives the casing rules for that particular locale, which take precedence
    over the locale-independent ones when in that locale.

    If the only casing for a code point is locale-dependent, then the
    returned hash will not have any of the base keys, like "code", "upper",
    etc., but will contain only locale keys.

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

  namedseq()
        use Unicode::UCD 'namedseq';

        my $namedseq = namedseq("KATAKANA LETTER AINU P");
        my @namedseq = namedseq("KATAKANA LETTER AINU P");
        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, it returns the list of the ordinals of the code points.

    If used with no arguments in a list context, it returns a hash with the
    names of all the named sequences as the keys and their sequences as
    strings as the values. Otherwise, it returns "undef" or an empty list
    depending on the context.

    This function only operates on officially approved (not provisional)
    named sequences.

    Note that as of Perl 5.14, "\N{KATAKANA LETTER AINU P}" will insert the
    named sequence into double-quoted strings, and
    "charnames::string_vianame("KATAKANA LETTER AINU P")" will return the
    same string this function does, but will also operate on character names
    that aren't named sequences, without you having to know which are which.
    See charnames.

  num()
        use Unicode::UCD 'num';

        my $val = num("123");
        my $one_quarter = num("\N{VULGAR FRACTION 1/4}");
        my $val = num("12a", \$valid_length);  # $valid_length contains 2

    "num()" returns the numeric value of the input Unicode string; or
    "undef" if it doesn't think the entire string has a completely valid,
    safe numeric value. If called with an optional second parameter, a
    reference to a scalar, "num()" will set the scalar to the length of any
    valid initial substring; or to 0 if none.

    If the string is just one character in length, the Unicode numeric value
    is returned if it has one, or "undef" otherwise. If the optional scalar
    ref is passed, it would be set to 1 if the return is valid; or 0 if the
    return is "undef". Note that the numeric value returned need not be a
    whole number. "num("\N{TIBETAN DIGIT HALF ZERO}")", for example returns
    -0.5.

    If the string is more than one character, "undef" is returned unless all
    its characters are decimal digits (that is, they would match "\d+"),
    from the same script. For example if you have an ASCII '0' and a Bengali
    '3', mixed together, they aren't considered a valid number, and "undef"
    is returned. A further restriction is that the digits all have to be of
    the same form. A half-width digit mixed with a full-width one will
    return "undef". The Arabic script has two sets of digits; "num" will
    return "undef" unless all the digits in the string come from the same
    set. In all cases, the optional scalar ref parameter is set to how long
    any valid initial substring of digits is; hence it will be set to the
    entire string length if the main return value is not "undef".

    "num" errs on the side of safety, and there may be valid strings of
    decimal digits that it doesn't recognize. Note that Unicode defines a
    number of "digit" characters that aren't "decimal digit" characters.
    "Decimal digits" have the property that they have a positional value,
    i.e., there is a units position, a 10's position, a 100's, etc, AND they
    are arranged in Unicode in blocks of 10 contiguous code points. The
    Chinese digits, for example, are not in such a contiguous block, and so
    Unicode doesn't view them as decimal digits, but merely digits, and so
    "\d" will not match them. A single-character string containing one of
    these digits will have its decimal value returned by "num", but any
    longer string containing only these digits will return "undef".

    Strings of multiple sub- and superscripts are not recognized as numbers.
    You can use either of the compatibility decompositions in
    Unicode::Normalize to change these into digits, and then call "num" on
    the result.

  prop_aliases()
        use Unicode::UCD 'prop_aliases';

        my ($short_name, $full_name, @other_names) = prop_aliases("space");
        my $same_full_name = prop_aliases("Space");     # Scalar context
        my ($same_short_name) = prop_aliases("Space");  # gets 0th element
        print "The full name is $full_name\n";
        print "The short name is $short_name\n";
        print "The other aliases are: ", join(", ", @other_names), "\n";

        prints:
        The full name is White_Space
        The short name is WSpace
        The other aliases are: Space

    Most Unicode properties have several synonymous names. Typically, there
    is at least a short name, convenient to type, and a long name that more
    fully describes the property, and hence is more easily understood.

    If you know one name for a Unicode property, you can use "prop_aliases"
    to find either the long name (when called in scalar context), or a list
    of all of the names, somewhat ordered so that the short name is in the
    0th element, the long name in the next element, and any other synonyms
    are in the remaining elements, in no particular order.

    The long name is returned in a form nicely capitalized, suitable for
    printing.

    The input parameter name is loosely matched, which means that white
    space, hyphens, and underscores are ignored (except for the trailing
    underscore in the old_form grandfathered-in "L_", which is better
    written as "LC", and both of which mean "General_Category=Cased
    Letter").

    If the name is unknown, "undef" is returned (or an empty list in list
    context). Note that Perl typically recognizes property names in regular
    expressions with an optional ""Is_"" (with or without the underscore)
    prefixed to them, such as "\p{isgc=punct}". This function does not
    recognize those in the input, returning "undef". Nor are they included
    in the output as possible synonyms.

    "prop_aliases" does know about the Perl extensions to Unicode
    properties, such as "Any" and "XPosixAlpha", and the single form
    equivalents to Unicode properties such as "XDigit", "Greek", "In_Greek",
    and "Is_Greek". The final example demonstrates that the "Is_" prefix is
    recognized for these extensions; it is needed to resolve ambiguities.
    For example, "prop_aliases('lc')" returns the list "(lc,
    Lowercase_Mapping)", but "prop_aliases('islc')" returns "(Is_LC,
    Cased_Letter)". This is because "islc" is a Perl extension which is
    short for "General_Category=Cased Letter". The lists returned for the
    Perl extensions will not include the "Is_" prefix (whether or not the
    input had it) unless needed to resolve ambiguities, as shown in the
    "islc" example, where the returned list had one element containing
    "Is_", and the other without.

    It is also possible for the reverse to happen: "prop_aliases('isc')"
    returns the list "(isc, ISO_Comment)"; whereas "prop_aliases('c')"
    returns "(C, Other)" (the latter being a Perl extension meaning
    "General_Category=Other". "Properties accessible through Unicode::UCD"
    in perluniprops lists the available forms, including which ones are
    discouraged from use.

    Those discouraged forms are accepted as input to "prop_aliases", but are
    not returned in the lists. "prop_aliases('isL&')" and
    "prop_aliases('isL_')", which are old synonyms for "Is_LC" and should
    not be used in new code, are examples of this. These both return
    "(Is_LC, Cased_Letter)". Thus this function allows you to take a
    discouraged form, and find its acceptable alternatives. The same goes
    with single-form Block property equivalences. Only the forms that begin
    with "In_" are not discouraged; if you pass "prop_aliases" a discouraged
    form, you will get back the equivalent ones that begin with "In_". It
    will otherwise look like a new-style block name (see. "Old-style versus
    new-style block names").

    "prop_aliases" does not know about any user-defined properties, and will
    return "undef" if called with one of those. Likewise for Perl internal
    properties, with the exception of "Perl_Decimal_Digit" which it does
    know about (and which is documented below in "prop_invmap()").

  prop_values()
        use Unicode::UCD 'prop_values';

        print "AHex values are: ", join(", ", prop_values("AHex")),
                                   "\n";
      prints:
        AHex values are: N, Y

    Some Unicode properties have a restricted set of legal values. For
    example, all binary properties are restricted to just "true" or "false";
    and there are only a few dozen possible General Categories. Use
    "prop_values" to find out if a given property is one such, and if so, to
    get a list of the values:

        print join ", ", prop_values("NFC_Quick_Check");
      prints:
        M, N, Y

    If the property doesn't have such a restricted set, "undef" is returned.

    There are usually several synonyms for each possible value. Use
    "prop_value_aliases()" to access those.

    Case, white space, hyphens, and underscores are ignored in the input
    property name (except for the trailing underscore in the old-form
    grandfathered-in general category property value "L_", which is better
    written as "LC").

    If the property name is unknown, "undef" is returned. Note that Perl
    typically recognizes property names in regular expressions with an
    optional ""Is_"" (with or without the underscore) prefixed to them, such
    as "\p{isgc=punct}". This function does not recognize those in the
    property parameter, returning "undef".

    For the block property, new-style block names are returned (see
    "Old-style versus new-style block names").

    "prop_values" does not know about any user-defined properties, and will
    return "undef" if called with one of those.

  prop_value_aliases()
        use Unicode::UCD 'prop_value_aliases';

        my ($short_name, $full_name, @other_names)
                                       = prop_value_aliases("Gc", "Punct");
        my $same_full_name = prop_value_aliases("Gc", "P");   # Scalar cntxt
        my ($same_short_name) = prop_value_aliases("Gc", "P"); # gets 0th
                                                               # element
        print "The full name is $full_name\n";
        print "The short name is $short_name\n";
        print "The other aliases are: ", join(", ", @other_names), "\n";

      prints:
        The full name is Punctuation
        The short name is P
        The other aliases are: Punct

    Some Unicode properties have a restricted set of legal values. For
    example, all binary properties are restricted to just "true" or "false";
    and there are only a few dozen possible General Categories.

    You can use "prop_values()" to find out if a given property is one which
    has a restricted set of values, and if so, what those values are. But
    usually each value actually has several synonyms. For example, in
    Unicode binary properties, *truth* can be represented by any of the
    strings "Y", "Yes", "T", or "True"; and the General Category
    "Punctuation" by that string, or "Punct", or simply "P".

    Like property names, there is typically at least a short name for each
    such property-value, and a long name. If you know any name of the
    property-value (which you can get by "prop_values()", you can use
    "prop_value_aliases"() to get the long name (when called in scalar
    context), or a list of all the names, with the short name in the 0th
    element, the long name in the next element, and any other synonyms in
    the remaining elements, in no particular order, except that any
    all-numeric synonyms will be last.

    The long name is returned in a form nicely capitalized, suitable for
    printing.

    Case, white space, hyphens, and underscores are ignored in the input
    parameters (except for the trailing underscore in the old-form
    grandfathered-in general category property value "L_", which is better
    written as "LC").

    If either name is unknown, "undef" is returned. Note that Perl typically
    recognizes property names in regular expressions with an optional
    ""Is_"" (with or without the underscore) prefixed to them, such as
    "\p{isgc=punct}". This function does not recognize those in the property
    parameter, returning "undef".

    If called with a property that doesn't have synonyms for its values, it
    returns the input value, possibly normalized with capitalization and
    underscores, but not necessarily checking that the input value is valid.

    For the block property, new-style block names are returned (see
    "Old-style versus new-style block names").

    To find the synonyms for single-forms, such as "\p{Any}", use
    "prop_aliases()" instead.

    "prop_value_aliases" does not know about any user-defined properties,
    and will return "undef" if called with one of those.

  prop_invlist()
    "prop_invlist" returns an inversion list (described below) that defines
    all the code points for the binary Unicode property (or "property=value"
    pair) given by the input parameter string:

     use feature 'say';
     use Unicode::UCD 'prop_invlist';
     say join ", ", prop_invlist("Any");

     prints:
     0, 1114112

    If the input is unknown "undef" is returned in scalar context; an
    empty-list in list context. If the input is known, the number of
    elements in the list is returned if called in scalar context.

    perluniprops gives the list of properties that this function accepts, as
    well as all the possible forms for them (including with the optional
    "Is_" prefixes). (Except this function doesn't accept any Perl-internal
    properties, some of which are listed there.) This function uses the same
    loose or tighter matching rules for resolving the input property's name
    as is done for regular expressions. These are also specified in
    perluniprops. Examples of using the "property=value" form are:

     say join ", ", prop_invlist("Script_Extensions=Shavian");

     prints:
     66640, 66688

     say join ", ", prop_invlist("ASCII_Hex_Digit=No");

     prints:
     0, 48, 58, 65, 71, 97, 103

     say join ", ", prop_invlist("ASCII_Hex_Digit=Yes");

     prints:
     48, 58, 65, 71, 97, 103

    Inversion lists are a compact way of specifying Unicode property-value
    definitions. The 0th item in the list is the lowest code point that has
    the property-value. The next item (item [1]) is the lowest code point
    beyond that one that does NOT have the property-value. And the next item
    beyond that ([2]) is the lowest code point beyond that one that does
    have the property-value, and so on. Put another way, each element in the
    list gives the beginning of a range that has the property-value (for
    even numbered elements), or doesn't have the property-value (for odd
    numbered elements). The name for this data structure stems from the fact
    that each element in the list toggles (or inverts) whether the
    corresponding range is or isn't on the list.

    In the final example above, the first ASCII Hex digit is code point 48,
    the character "0", and all code points from it through 57 (a "9") are
    ASCII hex digits. Code points 58 through 64 aren't, but 65 (an "A")
    through 70 (an "F") are, as are 97 ("a") through 102 ("f"). 103 starts a
    range of code points that aren't ASCII hex digits. That range extends to
    infinity, which on your computer can be found in the variable
    $Unicode::UCD::MAX_CP. (This variable is as close to infinity as Perl
    can get on your platform, and may be too high for some operations to
    work; you may wish to use a smaller number for your purposes.)

    Note that the inversion lists returned by this function can possibly
    include non-Unicode code points, that is anything above 0x10FFFF.
    Unicode properties are not defined on such code points. You might wish
    to change the output to not include these. Simply add 0x110000 at the
    end of the non-empty returned list if it isn't already that value; and
    pop that value if it is; like:

     my @list = prop_invlist("foo");
     if (@list) {
         if ($list[-1] == 0x110000) {
             pop @list;  # Defeat the turning on for above Unicode
         }
         else {
             push @list, 0x110000; # Turn off for above Unicode
         }
     }

    It is a simple matter to expand out an inversion list to a full list of
    all code points that have the property-value:

     my @invlist = prop_invlist($property_name);
     die "empty" unless @invlist;
     my @full_list;
     for (my $i = 0; $i < @invlist; $i += 2) {
        my $upper = ($i + 1) < @invlist
                    ? $invlist[$i+1] - 1      # In range
                    : $Unicode::UCD::MAX_CP;  # To infinity.
        for my $j ($invlist[$i] .. $upper) {
            push @full_list, $j;
        }
     }

    "prop_invlist" does not know about any user-defined nor Perl
    internal-only properties, and will return "undef" if called with one of
    those.

    The "search_invlist()" function is provided for finding a code point
    within an inversion list.

  prop_invmap()
     use Unicode::UCD 'prop_invmap';
     my ($list_ref, $map_ref, $format, $default)
                                          = prop_invmap("General Category");

    "prop_invmap" is used to get the complete mapping definition for a
    property, in the form of an inversion map. An inversion map consists of
    two parallel arrays. One is an ordered list of code points that mark
    range beginnings, and the other gives the value (or mapping) that all
    code points in the corresponding range have.

    "prop_invmap" is called with the name of the desired property. The name
    is loosely matched, meaning that differences in case, white-space,
    hyphens, and underscores are not meaningful (except for the trailing
    underscore in the old-form grandfathered-in property "L_", which is
    better written as "LC", or even better, "Gc=LC").

    Many Unicode properties have more than one name (or alias).
    "prop_invmap" understands all of these, including Perl extensions to
    them. Ambiguities are resolved as described above for "prop_aliases()"
    (except if a property has both a complete mapping, and a binary "Y"/"N"
    mapping, then specifying the property name prefixed by "is" causes the
    binary one to be returned). The Perl internal property
    "Perl_Decimal_Digit, described below, is also accepted. An empty list is
    returned if the property name is unknown. See "Properties accessible
    through Unicode::UCD" in perluniprops for the properties acceptable as
    inputs to this function.

    It is a fatal error to call this function except in list context.

    In addition to the two arrays that form the inversion map, "prop_invmap"
    returns two other values; one is a scalar that gives some details as to
    the format of the entries of the map array; the other is a default
    value, useful in maps whose format name begins with the letter "a", as
    described below in its subsection; and for specialized purposes, such as
    converting to another data structure, described at the end of this main
    section.

    This means that "prop_invmap" returns a 4 element list. For example,

     my ($blocks_ranges_ref, $blocks_maps_ref, $format, $default)
                                                     = prop_invmap("Block");

    In this call, the two arrays will be populated as shown below (for
    Unicode 6.0):

     Index  @blocks_ranges  @blocks_maps
       0        0x0000      Basic Latin
       1        0x0080      Latin-1 Supplement
       2        0x0100      Latin Extended-A
       3        0x0180      Latin Extended-B
       4        0x0250      IPA Extensions
       5        0x02B0      Spacing Modifier Letters
       6        0x0300      Combining Diacritical Marks
       7        0x0370      Greek and Coptic
       8        0x0400      Cyrillic
      ...
     233        0x2B820     No_Block
     234        0x2F800     CJK Compatibility Ideographs Supplement
     235        0x2FA20     No_Block
     236        0xE0000     Tags
     237        0xE0080     No_Block
     238        0xE0100     Variation Selectors Supplement
     239        0xE01F0     No_Block
     240        0xF0000     Supplementary Private Use Area-A
     241        0x100000    Supplementary Private Use Area-B
     242        0x110000    No_Block

    The first line (with Index [0]) means that the value for code point 0 is
    "Basic Latin". The entry "0x0080" in the @blocks_ranges column in the
    second line means that the value from the first line, "Basic Latin",
    extends to all code points in the range from 0 up to but not including
    0x0080, that is, through 127. In other words, the code points from 0 to
    127 are all in the "Basic Latin" block. Similarly, all code points in
    the range from 0x0080 up to (but not including) 0x0100 are in the block
    named "Latin-1 Supplement", etc. (Notice that the return is the
    old-style block names; see "Old-style versus new-style block names").

    The final line (with Index [242]) means that the value for all code
    points above the legal Unicode maximum code point have the value
    "No_Block", which is the term Unicode uses for a non-existing block.

    The arrays completely specify the mappings for all possible code points.
    The final element in an inversion map returned by this function will
    always be for the range that consists of all the code points that aren't
    legal Unicode, but that are expressible on the platform. (That is, it
    starts with code point 0x110000, the first code point above the legal
    Unicode maximum, and extends to infinity.) The value for that range will
    be the same that any typical unassigned code point has for the specified
    property. (Certain unassigned code points are not "typical"; for example
    the non-character code points, or those in blocks that are to be written
    right-to-left. The above-Unicode range's value is not based on these
    atypical code points.) It could be argued that, instead of treating
    these as unassigned Unicode code points, the value for this range should
    be "undef". If you wish, you can change the returned arrays accordingly.

    The maps for almost all properties are simple scalars that should be
    interpreted as-is. These values are those given in the Unicode-supplied
    data files, which may be inconsistent as to capitalization and as to
    which synonym for a property-value is given. The results may be
    normalized by using the "prop_value_aliases()" function.

    There are exceptions to the simple scalar maps. Some properties have
    some elements in their map list that are themselves lists of scalars;
    and some special strings are returned that are not to be interpreted
    as-is. Element [2] (placed into $format in the example above) of the
    returned four element list tells you if the map has any of these special
    elements or not, as follows:

    "s" means all the elements of the map array are simple scalars, with no
        special elements. Almost all properties are like this, like the
        "block" example above.

    "sl"
        means that some of the map array elements have the form given by
        "s", and the rest are lists of scalars. For example, here is a
        portion of the output of calling "prop_invmap"() with the "Script
        Extensions" property:

         @scripts_ranges  @scripts_maps
              ...
              0x0953      Devanagari
              0x0964      [ Bengali, Devanagari, Gurumukhi, Oriya ]
              0x0966      Devanagari
              0x0970      Common

        Here, the code points 0x964 and 0x965 are both used in Bengali,
        Devanagari, Gurmukhi, and Oriya, but no other scripts.

        The Name_Alias property is also of this form. But each scalar
        consists of two components: 1) the name, and 2) the type of alias
        this is. They are separated by a colon and a space. In Unicode 6.1,
        there are several alias types:

        "correction"
            indicates that the name is a corrected form for the original
            name (which remains valid) for the same code point.

        "control"
            adds a new name for a control character.

        "alternate"
            is an alternate name for a character

        "figment"
            is a name for a character that has been documented but was never
            in any actual standard.

        "abbreviation"
            is a common abbreviation for a character

        The lists are ordered (roughly) so the most preferred names come
        before less preferred ones.

        For example,

         @aliases_ranges        @alias_maps
            ...
            0x009E        [ 'PRIVACY MESSAGE: control', 'PM: abbreviation' ]
            0x009F        [ 'APPLICATION PROGRAM COMMAND: control',
                            'APC: abbreviation'
                          ]
            0x00A0        'NBSP: abbreviation'
            0x00A1        ""
            0x00AD        'SHY: abbreviation'
            0x00AE        ""
            0x01A2        'LATIN CAPITAL LETTER GHA: correction'
            0x01A3        'LATIN SMALL LETTER GHA: correction'
            0x01A4        ""
            ...

        A map to the empty string means that there is no alias defined for
        the code point.

    "a" is like "s" in that all the map array elements are scalars, but here
        they are restricted to all being integers, and some have to be
        adjusted (hence the name "a") to get the correct result. For
        example, in:

         my ($uppers_ranges_ref, $uppers_maps_ref, $format, $default)
                                  = prop_invmap("Simple_Uppercase_Mapping");

        the returned arrays look like this:

         @$uppers_ranges_ref    @$uppers_maps_ref   Note
               0                      0
              97                     65          'a' maps to 'A', b => B ...
             123                      0
             181                    924          MICRO SIGN => Greek Cap MU
             182                      0
             ...

        and $default is 0.

        Let's start with the second line. It says that the uppercase of code
        point 97 is 65; or "uc("a")" == "A". But the line is for the entire
        range of code points 97 through 122. To get the mapping for any code
        point in this range, you take the offset it has from the beginning
        code point of the range, and add that to the mapping for that first
        code point. So, the mapping for 122 ("z") is derived by taking the
        offset of 122 from 97 (=25) and adding that to 65, yielding 90
        ("z"). Likewise for everything in between.

        Requiring this simple adjustment allows the returned arrays to be
        significantly smaller than otherwise, up to a factor of 10, speeding
        up searching through them.

        Ranges that map to $default, "0", behave somewhat differently. For
        these, each code point maps to itself. So, in the first line in the
        example, "ord(uc(chr(0)))" is 0, "ord(uc(chr(1)))" is 1, ..
        "ord(uc(chr(96)))" is 96.

    "al"
        means that some of the map array elements have the form given by
        "a", and the rest are ordered lists of code points. For example, in:

         my ($uppers_ranges_ref, $uppers_maps_ref, $format, $default)
                                         = prop_invmap("Uppercase_Mapping");

        the returned arrays look like this:

         @$uppers_ranges_ref    @$uppers_maps_ref
               0                      0
              97                     65
             123                      0
             181                    924
             182                      0
             ...
            0x0149              [ 0x02BC 0x004E ]
            0x014A                    0
            0x014B                  330
             ...

        This is the full Uppercase_Mapping property (as opposed to the
        Simple_Uppercase_Mapping given in the example for format "a"). The
        only difference between the two in the ranges shown is that the code
        point at 0x0149 (LATIN SMALL LETTER N PRECEDED BY APOSTROPHE) maps
        to a string of two characters, 0x02BC (MODIFIER LETTER APOSTROPHE)
        followed by 0x004E (LATIN CAPITAL LETTER N).

        No adjustments are needed to entries that are references to arrays;
        each such entry will have exactly one element in its range, so the
        offset is always 0.

        The fourth (index [3]) element ($default) in the list returned for
        this format is 0.

    "ae"
        This is like "a", but some elements are the empty string, and should
        not be adjusted. The one internal Perl property accessible by
        "prop_invmap" is of this type: "Perl_Decimal_Digit" returns an
        inversion map which gives the numeric values that are represented by
        the Unicode decimal digit characters. Characters that don't
        represent decimal digits map to the empty string, like so:

         @digits    @values
         0x0000       ""
         0x0030        0
         0x003A:      ""
         0x0660:       0
         0x066A:      ""
         0x06F0:       0
         0x06FA:      ""
         0x07C0:       0
         0x07CA:      ""
         0x0966:       0
         ...

        This means that the code points from 0 to 0x2F do not represent
        decimal digits; the code point 0x30 (DIGIT ZERO) represents 0; code
        point 0x31, (DIGIT ONE), represents 0+1-0 = 1; ... code point 0x39,
        (DIGIT NINE), represents 0+9-0 = 9; ... code points 0x3A through
        0x65F do not represent decimal digits; 0x660 (ARABIC-INDIC DIGIT
        ZERO), represents 0; ... 0x07C1 (NKO DIGIT ONE), represents 0+1-0 =
        1 ...

        The fourth (index [3]) element ($default) in the list returned for
        this format is the empty string.

    "ale"
        is a combination of the "al" type and the "ae" type. Some of the map
        array elements have the forms given by "al", and the rest are the
        empty string. The property "NFKC_Casefold" has this form. An example
        slice is:

         @$ranges_ref  @$maps_ref         Note
            ...
           0x00AA       97                FEMININE ORDINAL INDICATOR => 'a'
           0x00AB        0
           0x00AD                         SOFT HYPHEN => ""
           0x00AE        0
           0x00AF     [ 0x0020, 0x0304 ]  MACRON => SPACE . COMBINING MACRON
           0x00B0        0
           ...

        The fourth (index [3]) element ($default) in the list returned for
        this format is 0.

    "ar"
        means that all the elements of the map array are either rational
        numbers or the string "NaN", meaning "Not a Number". A rational
        number is either an integer, or two integers separated by a solidus
        ("/"). The second integer represents the denominator of the division
        implied by the solidus, and is actually always positive, so it is
        guaranteed not to be 0 and to not be signed. When the element is a
        plain integer (without the solidus), it may need to be adjusted to
        get the correct value by adding the offset, just as other "a"
        properties. No adjustment is needed for fractions, as the range is
        guaranteed to have just a single element, and so the offset is
        always 0.

        If you want to convert the returned map to entirely scalar numbers,
        you can use something like this:

         my ($invlist_ref, $invmap_ref, $format) = prop_invmap($property);
         if ($format && $format eq "ar") {
             map { $_ = eval $_ if $_ ne 'NaN' } @$map_ref;
         }

        Here's some entries from the output of the property "Nv", which has
        format "ar".

         @numerics_ranges  @numerics_maps       Note
                0x00           "NaN"
                0x30             0           DIGIT 0 .. DIGIT 9
                0x3A           "NaN"
                0xB2             2           SUPERSCRIPTs 2 and 3
                0xB4           "NaN"
                0xB9             1           SUPERSCRIPT 1
                0xBA           "NaN"
                0xBC            1/4          VULGAR FRACTION 1/4
                0xBD            1/2          VULGAR FRACTION 1/2
                0xBE            3/4          VULGAR FRACTION 3/4
                0xBF           "NaN"
                0x660            0           ARABIC-INDIC DIGIT ZERO .. NINE
                0x66A          "NaN"

        The fourth (index [3]) element ($default) in the list returned for
        this format is "NaN".

    "n" means the Name property. All the elements of the map array are
        simple scalars, but some of them contain special strings that
        require more work to get the actual name.

        Entries such as:

         CJK UNIFIED IDEOGRAPH-<code point>

        mean that the name for the code point is "CJK UNIFIED IDEOGRAPH-"
        with the code point (expressed in hexadecimal) appended to it, like
        "CJK UNIFIED IDEOGRAPH-3403" (similarly for
        "CJK COMPATIBILITY IDEOGRAPH-<code point>").

        Also, entries like

         <hangul syllable>

        means that the name is algorithmically calculated. This is easily
        done by the function "charnames::viacode(code)" in charnames.

        Note that for control characters ("Gc=cc"), Unicode's data files
        have the string ""<control>"", but the real name of each of these
        characters is the empty string. This function returns that real
        name, the empty string. (There are names for these characters, but
        they are considered aliases, not the Name property name, and are
        contained in the "Name_Alias" property.)

    "ad"
        means the Decomposition_Mapping property. This property is like "al"
        properties, except that one of the scalar elements is of the form:

         <hangul syllable>

        This signifies that this entry should be replaced by the
        decompositions for all the code points whose decomposition is
        algorithmically calculated. (All of them are currently in one range
        and no others outside the range are likely to ever be added to
        Unicode; the "n" format has this same entry.) These can be generated
        via the function Unicode::Normalize::NFD().

        Note that the mapping is the one that is specified in the Unicode
        data files, and to get the final decomposition, it may need to be
        applied recursively. Unicode in fact discourages use of this
        property except internally in implementations of the Unicode
        Normalization Algorithm.

        The fourth (index [3]) element ($default) in the list returned for
        this format is 0.

    Note that a format begins with the letter "a" if and only the property
    it is for requires adjustments by adding the offsets in multi-element
    ranges. For all these properties, an entry should be adjusted only if
    the map is a scalar which is an integer. That is, it must match the
    regular expression:

        / ^ -? \d+ $ /xa

    Further, the first element in a range never needs adjustment, as the
    adjustment would be just adding 0.

    A binary search such as that provided by "search_invlist()", can be used
    to quickly find a code point in the inversion list, and hence its
    corresponding mapping.

    The final, fourth element (index [3], assigned to $default in the
    "block" example) in the four element list returned by this function is
    used with the "a" format types; it may also be useful for applications
    that wish to convert the returned inversion map data structure into some
    other, such as a hash. It gives the mapping that most code points map to
    under the property. If you establish the convention that any code point
    not explicitly listed in your data structure maps to this value, you can
    potentially make your data structure much smaller. As you construct your
    data structure from the one returned by this function, simply ignore
    those ranges that map to this value. For example, to convert to the data
    structure searchable by "charinrange()", you can follow this recipe for
    properties that don't require adjustments:

     my ($list_ref, $map_ref, $format, $default) = prop_invmap($property);
     my @range_list;

     # Look at each element in the list, but the -2 is needed because we
     # look at $i+1 in the loop, and the final element is guaranteed to map
     # to $default by prop_invmap(), so we would skip it anyway.
     for my $i (0 .. @$list_ref - 2) {
        next if $map_ref->[$i] eq $default;
        push @range_list, [ $list_ref->[$i],
                            $list_ref->[$i+1],
                            $map_ref->[$i]
                          ];
     }

     print charinrange(\@range_list, $code_point), "\n";

    With this, "charinrange()" will return "undef" if its input code point
    maps to $default. You can avoid this by omitting the "next" statement,
    and adding a line after the loop to handle the final element of the
    inversion map.

    Similarly, this recipe can be used for properties that do require
    adjustments:

     for my $i (0 .. @$list_ref - 2) {
        next if $map_ref->[$i] eq $default;

        # prop_invmap() guarantees that if the mapping is to an array, the
        # range has just one element, so no need to worry about adjustments.
        if (ref $map_ref->[$i]) {
            push @range_list,
                       [ $list_ref->[$i], $list_ref->[$i], $map_ref->[$i] ];
        }
        else {  # Otherwise each element is actually mapped to a separate
                # value, so the range has to be split into single code point
                # ranges.

            my $adjustment = 0;

            # For each code point that gets mapped to something...
            for my $j ($list_ref->[$i] .. $list_ref->[$i+1] -1 ) {

                # ... add a range consisting of just it mapping to the
                # original plus the adjustment, which is incremented for the
                # next time through the loop, as the offset increases by 1
                # for each element in the range
                push @range_list,
                                 [ $j, $j, $map_ref->[$i] + $adjustment++ ];
            }
        }
     }

    Note that the inversion maps returned for the "Case_Folding" and
    "Simple_Case_Folding" properties do not include the Turkic-locale
    mappings. Use "casefold()" for these.

    "prop_invmap" does not know about any user-defined properties, and will
    return "undef" if called with one of those.

    The returned values for the Perl extension properties, such as "Any" and
    "Greek" are somewhat misleading. The values are either "Y" or ""N"". All
    Unicode properties are bipartite, so you can actually use the "Y" or
    ""N"" in a Perl regular expression for these, like "qr/\p{ID_Start=Y/}"
    or "qr/\p{Upper=N/}". But the Perl extensions aren't specified this way,
    only like "/qr/\p{Any}", *etc*. You can't actually use the "Y" and ""N""
    in them.

   Getting every available name
    Instead of reading the Unicode Database directly from files, as you were
    able to do for a long time, you are encouraged to use the supplied
    functions. So, instead of reading "Name.pl" directly, which changed
    formats in 5.32, and may do so again without notice in the future or
    even disappear, you ought to use "prop_invmap()" like this:

      my (%name, %cp, %cps, $n);
      # All codepoints
      foreach my $cat (qw( Name Name_Alias )) {
          my ($codepoints, $names, $format, $default) = prop_invmap($cat);
          # $format => "n", $default => ""
          foreach my $i (0 .. @$codepoints - 2) {
              my ($cp, $n) = ($codepoints->[$i], $names->[$i]);
              # If $n is a ref, the same codepoint has multiple names
              foreach my $name (ref $n ? @$n : $n) {
                  $name{$cp} //= $name;
                  $cp{$name} //= $cp;
              }
          }
      }
      # Named sequences
      {   my %ns = namedseq();
          foreach my $name (sort { $ns{$a} cmp $ns{$b} } keys %ns) {
              $cp{$name} //= [ map { ord } split "" => $ns{$name} ];
          }
      }

  search_invlist()
     use Unicode::UCD qw(prop_invmap prop_invlist);
     use Unicode::UCD 'search_invlist';

     my @invlist = prop_invlist($property_name);
     print $code_point, ((search_invlist(\@invlist, $code_point) // -1) % 2)
                         ? " isn't"
                         : " is",
         " in $property_name\n";

     my ($blocks_ranges_ref, $blocks_map_ref) = prop_invmap("Block");
     my $index = search_invlist($blocks_ranges_ref, $code_point);
     print "$code_point is in block ", $blocks_map_ref->[$index], "\n";

    "search_invlist" is used to search an inversion list returned by
    "prop_invlist" or "prop_invmap" for a particular "code point argument".
    "undef" is returned if the code point is not found in the inversion list
    (this happens only when it is not a legal "code point argument", or is
    less than the list's first element). A warning is raised in the first
    instance.

    Otherwise, it returns the index into the list of the range that contains
    the code point.; that is, find "i" such that

        list[i]<= code_point < list[i+1].

    As explained in "prop_invlist()", whether a code point is in the list or
    not depends on if the index is even (in) or odd (not in). And as
    explained in "prop_invmap()", the index is used with the returned
    parallel array to find the mapping.

  Unicode::UCD::UnicodeVersion
    This 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 ('.').

  Blocks versus Scripts
    The difference between a block and a script is that scripts are closer
    to the linguistic notion of a set of code points required to represent
    languages, while block is more of an artifact of the Unicode code point
    numbering and separation into blocks of consecutive code points (so far
    the size of a block is some multiple of 16, like 128 or 256).

    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 ASCII): it
    includes only the letters, and not, for example, the digits nor 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{Blk=...}" is used for blocks (e.g. "\p{Blk=Tibetan}" matches any of
    the 256 code points in the Tibetan block).

  Old-style versus new-style block names
    Unicode publishes the names of blocks in two different styles, though
    the two are equivalent under Unicode's loose matching rules.

    The original style uses blanks and hyphens in the block names (except
    for "No_Block"), like so:

     Miscellaneous Mathematical Symbols-B

    The newer style replaces these with underscores, like this:

     Miscellaneous_Mathematical_Symbols_B

    This newer style is consistent with the values of other Unicode
    properties. To preserve backward compatibility, all the functions in
    Unicode::UCD that return block names (except as noted) return the
    old-style ones. "prop_value_aliases()" returns the new-style and can be
    used to convert from old-style to new-style:

     my $new_style = prop_values_aliases("block", $old_style);

    Perl also has single-form extensions that refer to blocks,
    "In_Cyrillic", meaning "Block=Cyrillic". These have always been written
    in the new style.

    To convert from new-style to old-style, follow this recipe:

     $old_style = charblock((prop_invlist("block=$new_style"))[0]);

    (which finds the range of code points in the block using "prop_invlist",
    gets the lower end of the range (0th element) and then looks up the old
    name for its block using "charblock").

    Note that starting in Unicode 6.1, many of the block names have shorter
    synonyms. These are always given in the new style.

  Use with older Unicode versions
    The functions in this module work as well as can be expected when used
    on earlier Unicode versions. But, obviously, they use the available data
    from that Unicode version. For example, if the Unicode version predates
    the definition of the script property (Unicode 3.1), then any function
    that deals with scripts is going to return "undef" for the script
    portion of the return value.

AUTHOR
    Jarkko Hietaniemi. Now maintained by perl5 porters.


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