NAME¶
Unicode::UCD - Unicode character database
SYNOPSIS¶
use Unicode::UCD 'charinfo';
my $charinfo = charinfo($codepoint);
use Unicode::UCD 'casefold';
my $casefold = casefold(0xFB00);
use Unicode::UCD 'all_casefolds';
my $all_casefolds_ref = all_casefolds();
use Unicode::UCD 'casespec';
my $casespec = casespec(0xFB00);
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 $types = bidi_types();
use Unicode::UCD 'prop_aliases';
my @space_names = prop_aliases("space");
use Unicode::UCD 'prop_value_aliases';
my @gc_punct_names = prop_value_aliases("Gc", "Punct");
use Unicode::UCD 'prop_invlist';
my @puncts = prop_invlist("gc=punctuation");
use Unicode::UCD 'prop_invmap';
my ($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 "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.
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.
- 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 empty if there is no single code point uppercase mapping for
code (its uppercase mapping is itself); otherwise it is that
mapping expressed as at least four hexdigits. ("
casespec()" should be used in addition to
charinfo() for case mappings when the calling
program can cope with multiple code point mappings.)
- lower
- is empty if there is no single code point lowercase mapping for
code (its lowercase mapping is itself); otherwise it is that
mapping expressed as at least four hexdigits. ("
casespec()" should be used in addition to
charinfo() for case mappings when the calling
program can cope with multiple code point mappings.)
- title
- is empty if there is no single code point titlecase mapping for
code (its titlecase mapping is itself); otherwise it is that
mapping expressed as at least four hexdigits. ("
casespec()" should be used in addition to
charinfo() for case mappings when the calling
program can cope with multiple code point mappings.)
- block
- the block code belongs to (used in "\p{Blk=...}"). See
"Blocks versus Scripts".
- script
- the script code belongs to. 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 "
compexcl()",
and "
casespec()" functions.
charblock()¶
use Unicode::UCD 'charblock';
my $charblock = charblock(0x41);
my $charblock = charblock(1234);
my $charblock = charblock(0x263a);
my $charblock = charblock("U+263a");
my $range = charblock('Armenian');
With a "code point argument" "charblock()" returns the
block the code point belongs to, e.g. "Basic Latin". The
old-style block name is returned (see "Old-style versus new-style block
names"). 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 list with a single element that consists of another
anonymous list 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".
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 list of lists that contain
start-of-range,
end-of-range code point pairs. You can test
whether a code point is in a range 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.
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.
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_value_aliases()" function can be used to get all the
synonyms of the 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_value_aliases()" function can be used to get all the
synonyms of the 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_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.
For such properties, there are usually several synonyms for each possible value.
For example, in 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,
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.
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, $default)
= prop_invmap("General Category");
"prop_invmap" is used to get the complete mapping definition for a
property, in the form of an inversion map. An inversion map consists of two
parallel arrays. One is an ordered list of code points that mark range
beginnings, and the other gives the value (or mapping) that all code points in
the corresponding range have.
"prop_invmap" is called with the name of the desired property. The
name is loosely matched, meaning that differences in case, white-space,
hyphens, and underscores are not meaningful (except for the trailing
underscore in the old-form grandfathered-in property "L_", which is
better written as "LC", or even better, "Gc=LC").
Many Unicode properties have more than one name (or alias).
"prop_invmap" understands all of these, including Perl extensions to
them. Ambiguities are resolved as described above for "
prop_aliases()". The Perl internal property
"Perl_Decimal_Digit, described below, is also accepted. An empty list is
returned if the property name is unknown. See "Properties accessible
through Unicode::UCD" in perluniprops for the properties acceptable as
inputs to this function.
It is a fatal error to call this function except in list context.
In addition to the two arrays that form the inversion map,
"prop_invmap" returns two other values; one is a scalar that gives
some details as to the format of the entries of the map array; the other is a
default value, useful in maps whose format name begins with the letter
"a", as described below in its subsection; and for specialized
purposes, such as converting to another data structure, described at the end
of this main section.
This means that "prop_invmap" returns a 4 element list. For example,
my ($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] + $adjustment++ ];
}
}
}
Note that the inversion maps returned for the "Case_Folding" and
"Simple_Case_Folding" properties do not include the Turkic-locale
mappings. Use "
casefold()" for these.
"prop_invmap" does not know about any user-defined properties, and
will return "undef" if called with one of those.
search_invlist()¶
use Unicode::UCD qw(prop_invmap prop_invlist);
use Unicode::UCD 'search_invlist';
my @invlist = prop_invlist($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 present 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 or the punctuation.
For blocks see <
http://www.unicode.org/Public/UNIDATA/Blocks.txt>
For scripts see UTR #24: <
http://www.unicode.org/unicode/reports/tr24/>
Matching Scripts and Blocks¶
Scripts are matched with the regular-expression construct "\p{...}"
(e.g. "\p{Tibetan}" matches characters of the Tibetan script), while
"\p{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 one) return the old-style ones. That one function, "
prop_value_aliases()" 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.
AUTHOR¶
Jarkko Hietaniemi. Now maintained by perl5 porters.