New API available to access Unicode DB, and RFC on changes to it.
[email protected] (Karl Williamson) Mon, 21 Nov 2011 13:42:22 -0700
| Newsgroups | perl.unicode |
|---|---|
| Message-ID | <[email protected]> |
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Perl 5.15.5, now available, has additions to Unicode::UCD in it to allow
unfettered programmatic access to the Unicode character data base. The
API is quite similar to what was sent out for comment on this list
several months ago; several changes were required as a result of lessons
learned during implementation. This email has an attachment that is an
html file giving (with a yellow background) the additions since 5.14 to
the pod.
As a result of this API, it is deprecated to read the files in
lib/unicore directly. These may change, and the API will be stable as
of 5.16. In the meantime, I'd be happy to have people use this, and
give me get feedback on any problems with the API or bugs in the code.
And, I do wish to change the API already for certain of the outputs in
prop_invmap() in order to make them more compact. For example, take the
uc() property. What it currently returns is this (taken from the
attached pod):
@$uppers_ranges_ref @$uppers_maps_ref Note
0 "<code point>"
97 65 'a' maps to 'A'
98 66 'b' => 'B'
99 67 'c' => 'C'
...
120 88 'x' => 'X'
121 89 'y' => 'Y'
122 90 'z' => 'Z'
123 "<code point>"
181 924 MICRO SIGN => Greek Cap MU
182 "<code point>"
...
0x0149 [ 0x02BC 0x004E ]
0x014A "<code point>"
0x014B 0x014A
...
That could be more compactly represented as:
@$uppers_ranges_ref @$uppers_maps_ref Note
0 0
97 -32 'a-z' maps to 'A'-'Z'
123 0
181 743 MICRO SIGN => Greek Cap MU
182 0
...
0x0149 [ 0x02BC 0x004E ]
0x014A 0
0x014B -1
...
where the map is to be added to the code point to get the final result.
Thus only one entry is needed to represent all 26 ASCII lower case
character mappings, instead of 26 entries. This makes such tables
significantly smaller. The Perl core currently does a linear search
through them looking for mappings. Using the more compact versions
would speed that up significantly. The percentage gain is 30-40%, and
with the mapping for decimal digits the result is a full order of
magnitude smaller, making the search much much faster.
Returning the delta only makes sense on a few tables, ones that whose
map is code points, or the decimal digits.
As you can see in the example for 0x0149, I wouldn't propose to make
deltas of the lists, even though that is inconsistent. They generally
require special handling.
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NAME <#___top>
Unicode::UCD - Unicode character database
SYNOPSIS <#___top>
use Unicode::UCD 'charinfo';
my $charinfo = charinfo($codepoint);
use Unicode::UCD 'casefold';
my $casefold = casefold(0xFB00);
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 '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 <#___top>
The Unicode::UCD module offers a series of functions that provide a
simple interface to the Unicode Character Database.
code point argument <#___top>
Some of the functions are called with a /code point argument/, which is
either a decimal or a hexadecimal scalar designating a Unicode code
point, or |U+| followed by hexadecimals designating a Unicode code
point. In other words, if you want a code point to be interpreted as a
hexadecimal number, you must prefix it with either |0x| or |U+|, because
a string like e.g. |123| will be interpreted as a decimal code point.
Note that the largest code point in Unicode is U+10FFFF.
*charinfo()* <#___top>
use Unicode::UCD 'charinfo';
my $charinfo = charinfo(0x41);
This returns information about the input "code point argument"
<#code_point_argument> as a reference to a hash of fields as defined by
the Unicode standard. If the "code point argument"
<#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 "code point argument" <#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()"
<#general_categories()>.
The "prop_value_aliases()" <#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()" <#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()" <#bidi_types()>.
The "prop_value_aliases()" <#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 |<compa<> |, giving the type of decomposition
This decomposition may be an intermediate one whose components are
also decomposable. Use Unicode::Normalize
<http://search.cpan.org/perldoc?Unicode%3A%3ANormalize> to get the
final decomposition.
*decimal*
if /code/ is 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()"
<#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()"
<#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()"
<#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" <#Blocks_versus_Scripts>.
*script*
the script /code/ belongs to. See "Blocks versus Scripts"
<#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()" <#compexcl()>, and "casespec()"
<#casespec()> functions.
*charblock()* <#___top>
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" <#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"
<#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.
See also "Blocks versus Scripts" <#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
blockname. 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 (and final) element is the final code point in the block. (The
extra list consisting of just one element is so that the same program
logic can be used to handle both this return, and the return from
"charscript()" <#charscript()> which can have multiple ranges.) You can
test whether a code point is in a range using the "charinrange()"
<#charinrange()> function. If the argument is not a known block, |undef|
is returned.
*charscript()* <#___top>
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" <#code_point_argument> charscript() returns
the /script/ the code point belongs to, e.g. |Latin|, |Greek|, |Han|. If
the code point is unassigned, it 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 scriptname. 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()"
<#charinrange()> function. If the argument is not a known script,
|undef| is returned.
See also "Blocks versus Scripts" <#Blocks_versus_Scripts>.
*charblocks()* <#___top>
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()" <#charblock()>)
as the values.
The names are in the old-style (see "Old-style versus new-style block
names" <#Old-style_versus_new-style_block_names>).
prop_invmap("block") <#prop_invmap()> can be used to get this same data
in a different type of data structure.
See also "Blocks versus Scripts" <#Blocks_versus_Scripts>.
*charscripts()* <#___top>
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()"
<#charscript()>) as the values.
prop_invmap("script") <#prop_invmap()> can be used to get this same data
in a different type of data structure.
See also "Blocks versus Scripts" <#Blocks_versus_Scripts>.
*charinrange()* <#___top>
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()" <#charblock()> and "charscript()" <#charscript()> or as
the values of the hash returned by "charblocks()" <#charblocks()> and
"charscripts()" <#charscripts()> by using charinrange():
use Unicode::UCD qw(charscript charinrange);
$range = charscript('Hiragana');
print "looks like hiragana\n" if charinrange($range, $codepoint);
*general_categories()* <#___top>
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()" <#charinfo()> under the |category| key.
The "prop_value_aliases()" <#prop_value_aliases()> function can be used
to get all the synonyms of the category name.
*bidi_types()* <#___top>
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()" <#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()" <#prop_value_aliases()> function can be used
to get all the synonyms of the bidi type name.
*compexcl()* <#___top>
use Unicode::UCD 'compexcl';
my $compexcl = compexcl(0x09dc);
This routine is included for backwards compatibility, but as of Perl
5.12, 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"
<#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()* <#___top>
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" <#code_point_argument>.
If there is no case folding for that 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 "code point argument" <#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.
On versions 3.1 and earlier of Unicode, /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 versions of Unicode 3.1 and earlier, 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
*casespec()* <#___top>
use Unicode::UCD 'casespec';
my $casespec = casespec(0xFB00);
This returns the potentially locale-dependent case mappings of the "code
point argument" <#code_point_argument>. The mappings may be longer than
a single code point (which the basic Unicode case mappings as returned
by "charinfo()" <#charinfo()> never are).
If there are no case mappings for the "code point argument"
<#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()" <#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 "code point argument" <#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()" <#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
<http://search.cpan.org/perldoc?Locale%3A%3ACountry> and
Locale::Language <http://search.cpan.org/perldoc?Locale%3A%3ALanguage>.
(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()* <#___top>
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, returns a hash with the names
of the named sequences as the keys and the named 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 <http://search.cpan.org/perldoc?charnames>.
*num()* <#___top>
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()* <#___top>
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
<http://search.cpan.org/perldoc?perluniprops#Properties_accessible_through_Unicode%3A%3AUCD>
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
discourarged 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"
<#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_invmap()>).
*prop_value_aliases()* <#___top>
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"
<#Old-style_versus_new-style_block_names>).
To find the synonyms for single-forms, such as |\p{Any}|, use
"prop_aliases()" <#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()* <#___top>
|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
An empty list is returned if the input is unknown; the number of
elements in the list is returned if called in scalar context.
perluniprops
<http://search.cpan.org/perldoc?perluniprops#Properties_accessible_through_%5Cp%7B%7D_and_%5CP%7B%7D>
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
<http://search.cpan.org/perldoc?perluniprops#Properties_accessible_through_%5Cp%7B%7D_and_%5CP%7B%7D>.
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. This
is in contrast to Perl regular expression matches on those code points,
in which a non-Unicode code point always fails to match. For example,
both of these have the same result:
chr(0x110000) =~ \p{ASCII_Hex_Digit=True} # Fails.
chr(0x110000) =~ \p{ASCII_Hex_Digit=False} # Fails!
And both raise a warning that a Unicode property is being used on a
non-Unicode code point. It is arguable as to which is the correct thing
to do here. This function has chosen the way opposite to the Perl
regular expression behavior. This allows you to easily flip to to the
Perl regular expression way (for you to go in the other direction would
be far harder). 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, $j;
}
}
|prop_invlist| does not know about any user-defined nor Perl
internal-only properties, and will return |undef| if called with one of
those.
*prop_invmap()* <#___top>
use Unicode::UCD 'prop_invmap';
my ($list_ref, $map_ref, $format, $missing)
= prop_invmap("General Category");
|prop_invmap| is used to get the complete mapping definition for a
property, in the form of an inversion map. An inversion map consists of
two parallel arrays. One is an ordered list of code points that mark
range beginnings, and the other gives the value (or mapping) that all
code points in the corresponding range have.
|prop_invmap| is called with the name of the desired property. The name
is loosely matched, meaning that differences in case, white-space,
hyphens, and underscores are not meaningful (except for the trailing
underscore in the old-form grandfathered-in property |"L_"|, which is
better written as |"LC"|, or even better, |"Gc=LC"|).
Many Unicode properties have more than one name (or alias).
|prop_invmap| understands all of these, including Perl extensions to
them. Ambiguities are resolved as described above for "prop_aliases()"
<#prop_aliases()>. The Perl internal property "Perl_Decimal_Digit,
described below, is also accepted. |undef| is returned if the property
name is unknown. See "Properties accessible through Unicode::UCD" in
perluniprops
<http://search.cpan.org/perldoc?perluniprops#Properties_accessible_through_Unicode%3A%3AUCD>
for the properties acceptable as inputs to this function.
It is a fatal error to call this function except in list context.
In addition to the the two arrays that form the inversion map,
|prop_invmap| returns two other values; one is a scalar that gives some
details as to the format of the entries of the map array; the other is
used for specialized purposes, described at the end of this section.
This means that |prop_invmap| returns a 4 element list. For example,
my ($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 255. In other words, the code points from 0 to
255 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"
<#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 are almost always 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()" <#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, 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 Deva
0x0964 [ Beng Deva Guru Orya ]
0x0966 Deva
0x0970 Common
Here, the code points 0x964 and 0x965 are used in the Bengali,
Devanagari, Gurmukhi, and Oriya scripts.
|r|
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 guaranteed not to be 0. If
you want to convert them to scalar numbers, you can use something
like this:
my ($invlist_ref, $invmap_ref, $format) = prop_invmap($property);
if ($format && $format eq "r") {
map { $_ = eval $_ } @$invmap_ref;
}
Here's some entries from the output of the property "Nv", which has
format |"r"|.
@numerics_ranges @numerics_maps Note
0x00 "NaN"
0x30 0 DIGIT 0
0x31 1
0x32 2
...
0x37 7
0x38 8
0x39 9 DIGIT 9
0x3A "NaN"
0xB2 2 SUPERSCRIPT 2
0xB3 3 SUPERSCRIPT 2
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
|c|
is like |s| in that all the map array elements are scalars, but some
of them are the special string |"<code point>"|, meaning that the
map of each code point in the corresponding range in the inversion
list is the code point itself. For example, in:
my ($uppers_ranges_ref, $uppers_maps_ref, $format)
= prop_invmap("Simple_Uppercase_Mapping");
the returned arrays look like this:
@$uppers_ranges_ref @$uppers_maps_ref Note
0 "<code point>"
97 65 'a' maps to 'A'
98 66 'b' => 'B'
99 67 'c' => 'C'
...
120 88 'x' => 'X'
121 89 'y' => 'Y'
122 90 'z' => 'Z'
123 "<code point>"
181 924 MICRO SIGN => Greek Cap MU
182 "<code point>"
...
The first line means that the uppercase of code point 0 is 0; the
uppercase of code point 1 is 1; ... of code point 96 is 96. Without
the |"<code_point>"| notation, every code point would have to have
an entry. This would mean that the arrays would each have more than
a million entries to list just the legal Unicode code points!
|cl|
means that some of the map array elements have the form given by
|c|, and the rest are ordered lists of code points. For example, in:
my ($uppers_ranges_ref, $uppers_maps_ref, $format)
= prop_invmap("Uppercase_Mapping");
the returned arrays look like this:
@$uppers_ranges_ref @$uppers_maps_ref
0 "<code point>"
97 65
...
122 90
123 "<code point>"
181 924
182 "<code point>"
...
0x0149 [ 0x02BC 0x004E ]
0x014A "<code point>"
0x014B 0x014A
...
This is the full Uppercase_Mapping property (as opposed to the
Simple_Uppercase_Mapping given in the example for format |"c"|). The
only difference between the two in the ranges shown is that the code
point at 0x0149 (LATIN SMALL LETTER N PRECEDED BY APOSTROPHE) maps
to a string of two characters, 0x02BC (MODIFIER LETTER APOSTROPHE)
followed by 0x004E (LATIN CAPITAL LETTER N).
|cle|
means that some of the map array elements have the forms given by
|cl|, and the rest are the empty string. The property
|NFKC_Casefold| has this form. An example slice is:
@$ranges_ref @$maps_ref Note
...
0x00AA 0x0061 FEMININE ORDINAL INDICATOR => 'a'
0x00AB <code point>
0x00AD SOFT HYPHEN => ""
0x00AE <code point>
0x00AF [ 0x0020, 0x0304 ] MACRON => SPACE . COMBINING MACRON
0x00B0 <code point>
...
|n|
means the Name property. All the elements of the map array are
simple scalars, but some of them contain special strings that
require more work to get the actual name.
Entries such as:
CJK UNIFIED IDEOGRAPH-<code point>
mean that the name for the code point is "CJK UNIFIED IDEOGRAPH-"
with the code point (expressed in hexadecimal) appended to it, like
"CJK UNIFIED IDEOGRAPH-3403" (similarly for |CJK COMPATIBILITY
IDEOGRAPH-<code point>|).
Also, entries like
<hangul syllable>
means that the name is algorithmically calculated. This is easily
done by the function "charnames::viacode(code)" in charnames
<http://search.cpan.org/perldoc?charnames#charnames%3A%3Aviacode(code)>.
Note that for control characters (|Gc=cc|), Unicode's data files
have the string "|<control>|", but the real name of each of these
characters is the empty string. This function returns that real
name, the empty string.
|d|
means the Decomposition_Mapping property. This property is like |cl|
properties, except it has an additional entry type:
<hangul syllable>
for those code points whose decomposition is algorithmically
calculated. (The |n| format has this same entry.) These can be
generated via the function Unicode::Normalize::NFD()
<http://search.cpan.org/perldoc?Unicode%3A%3ANormalize>.
Note that the mapping is the one that is specified in the Unicode
data files, and to get the final decomposition, it may need to be
applied recursively.
A binary search can be used to quickly find a code point in the
inversion list, and hence its corresponding mapping.
The final element (index [3], assigned to |$default| in the "block"
example) in the four element list returned by this function may 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, generally called the "default" value. For example, to
convert to the data structure searchable by "charinrange()"
<#charinrange()>, you can follow this recipe:
my ($list_ref, $map_ref, $format, $missing) = prop_invmap($property);
my @range_list;
for my $i (0 .. @$list_ref - 2) {
next if $map_ref->[$i] eq $missing;
push @range_list, [ $list_ref->[$i],
$list_ref->[$i+1],
$map_ref->[$i]
];
}
print charinrange(\@range_list, $code_point), "\n";
With this, |charinrange()| will return |undef| if its input code point
maps to |$missing|. 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.
One internal Perl property is accessible by this function.
"Perl_Decimal_Digit" returns an inversion map in which all the Unicode
decimal digits map to their numeric values, and everything else to the
empty string, like so:
@digits @values
0x0000 ""
0x0030 0
0x0031 1
0x0032 2
0x0033 3
0x0034 4
0x0035 5
0x0036 6
0x0037 7
0x0038 8
0x0039 9
0x003A ""
0x0660 0
0x0661 1
...
Note that the inversion maps returned for the |Case_Folding| and
|Simple_Case_Folding| properties do not include the Turkic-locale
mappings. Use "casefold()" <#casefold()> for these.
The |Name_Alias| property is potentially undergoing signficant revision
by Unicode at the time of this writing. The format of the values
returned for it may change substantially in future Unicode versions.
|prop_invmap| does not know about any user-defined properties, and will
return |undef| if called with one of those.
Unicode::UCD::UnicodeVersion <#___top>
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* <#___top>
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 (mostly) 256 code points.
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* <#___top>
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 <#___top>
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()" <#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|).
BUGS <#___top>
Does not yet support EBCDIC platforms.
AUTHOR <#___top>
Jarkko Hietaniemi. Now maintained by perl5 porters.
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