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Unicode::UCD(3pm)      Perl Programmers Reference Guide      Unicode::UCD(3pm)




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);

           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
           '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.

           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.

       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.

       "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()
           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}");

       "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 the string is just one character in length, the Unicode numeric
       value is returned if it has one, or "undef" otherwise.  Note that this
       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.

       "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=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.  You may want
                                                 # to stop much much earlier;
                                                 # going this high may expose
                                                 # perl deficiencies with very
                                                 # large numbers.
           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.

           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 rexpression 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.

   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.



perl v5.24.0                      2016-03-01                 Unicode::UCD(3pm)

perl 5.24 - Generated Sat Nov 26 09:36:05 CST 2016
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