Unicode/Normalize/Normalize.pm

package Unicode::Normalize;

BEGIN {
    unless ("A" eq pack('U', 0x41)) {
        die "Unicode::Normalize cannot stringify a Unicode code point\n";
    }
}

use 5.006;
use strict;
use warnings;
use Carp;

no warnings 'utf8';

our $VERSION = '0.32';
our $PACKAGE = __PACKAGE__;

require Exporter;
require DynaLoader;

our @ISA = qw(Exporter DynaLoader);
our @EXPORT = qw( NFC NFD NFKC NFKD );
our @EXPORT_OK = qw(
    normalize decompose reorder compose
    checkNFD checkNFKD checkNFC checkNFKC check
    getCanon getCompat getComposite getCombinClass
    isExclusion isSingleton isNonStDecomp isComp2nd isComp_Ex
    isNFD_NO isNFC_NO isNFC_MAYBE isNFKD_NO isNFKC_NO isNFKC_MAYBE
    FCD checkFCD FCC checkFCC composeContiguous
    splitOnLastStarter
);
our %EXPORT_TAGS = (
    all       => [ @EXPORT, @EXPORT_OK ],
    normalize => [ @EXPORT, qw/normalize decompose reorder compose/ ],
    check     => [ qw/checkNFD checkNFKD checkNFC checkNFKC check/ ],
    fast      => [ qw/FCD checkFCD FCC checkFCC composeContiguous/ ],
);

######

bootstrap Unicode::Normalize $VERSION;

######

sub pack_U {
    return pack('U*', @_);
}

sub unpack_U {
    return unpack('U*', pack('U*').shift);
}


##
## normalization forms
##

use constant COMPAT => 1;

sub NFD  ($) { reorder(decompose($_[0])) }
sub NFKD ($) { reorder(decompose($_[0], COMPAT)) }
sub NFC  ($) { compose(reorder(decompose($_[0]))) }
sub NFKC ($) { compose(reorder(decompose($_[0], COMPAT))) }

sub FCD ($) {
    my $str = shift;
    return checkFCD($str) ? $str : NFD($str);
}
sub FCC ($) { composeContiguous(reorder(decompose($_[0]))) }

our %formNorm = (
    NFC  => \&NFC,      C  => \&NFC,
    NFD  => \&NFD,      D  => \&NFD,
    NFKC => \&NFKC,     KC => \&NFKC,
    NFKD => \&NFKD,     KD => \&NFKD,
    FCD  => \&FCD,      FCC => \&FCC,
);

sub normalize($$)
{
    my $form = shift;
    my $str = shift;
    return exists $formNorm{$form}
        ? $formNorm{$form}->($str)
        : croak $PACKAGE."::normalize: invalid form name: $form";
}


##
## quick check
##

our %formCheck = (
    NFC  => \&checkNFC,         C  => \&checkNFC,
    NFD  => \&checkNFD,         D  => \&checkNFD,
    NFKC => \&checkNFKC,        KC => \&checkNFKC,
    NFKD => \&checkNFKD,        KD => \&checkNFKD,
    FCD  => \&checkFCD,         FCC => \&checkFCC,
);

sub check($$)
{
    my $form = shift;
    my $str = shift;
    return exists $formCheck{$form}
        ? $formCheck{$form}->($str)
        : croak $PACKAGE."::check: invalid form name: $form";
}

1;
__END__

=head1 NAME

Unicode::Normalize - Unicode Normalization Forms

=head1 SYNOPSIS

(1) using function names exported by default:

  use Unicode::Normalize;

  $NFD_string  = NFD($string);  # Normalization Form D
  $NFC_string  = NFC($string);  # Normalization Form C
  $NFKD_string = NFKD($string); # Normalization Form KD
  $NFKC_string = NFKC($string); # Normalization Form KC

(2) using function names exported on request:

  use Unicode::Normalize 'normalize';

  $NFD_string  = normalize('D',  $string);  # Normalization Form D
  $NFC_string  = normalize('C',  $string);  # Normalization Form C
  $NFKD_string = normalize('KD', $string);  # Normalization Form KD
  $NFKC_string = normalize('KC', $string);  # Normalization Form KC

=head1 DESCRIPTION

Parameters:

C<$string> is used as a string under character semantics
(see F<perlunicode>).

C<$codepoint> should be an unsigned integer
representing a Unicode code point.

Note: Between XSUB and pure Perl, there is an incompatibility
about the interpretation of C<$codepoint> as a decimal number.
XSUB converts C<$codepoint> to an unsigned integer, but pure Perl does not.
Do not use a floating point nor a negative sign in C<$codepoint>.

=head2 Normalization Forms

=over 4

=item C<$NFD_string = NFD($string)>

returns the Normalization Form D (formed by canonical decomposition).

=item C<$NFC_string = NFC($string)>

returns the Normalization Form C (formed by canonical decomposition
followed by canonical composition).

=item C<$NFKD_string = NFKD($string)>

returns the Normalization Form KD (formed by compatibility decomposition).

=item C<$NFKC_string = NFKC($string)>

returns the Normalization Form KC (formed by compatibility decomposition
followed by B<canonical> composition).

=item C<$FCD_string = FCD($string)>

If the given string is in FCD ("Fast C or D" form; cf. UTN #5),
returns it without modification; otherwise returns an FCD string.

Note: FCD is not always unique, then plural forms may be equivalent
each other. C<FCD()> will return one of these equivalent forms.

=item C<$FCC_string = FCC($string)>

returns the FCC form ("Fast C Contiguous"; cf. UTN #5).

Note: FCC is unique, as well as four normalization forms (NF*).

=item C<$normalized_string = normalize($form_name, $string)>

As C<$form_name>, one of the following names must be given.

  'C'  or 'NFC'  for Normalization Form C  (UAX #15)
  'D'  or 'NFD'  for Normalization Form D  (UAX #15)
  'KC' or 'NFKC' for Normalization Form KC (UAX #15)
  'KD' or 'NFKD' for Normalization Form KD (UAX #15)

  'FCD'          for "Fast C or D" Form  (UTN #5)
  'FCC'          for "Fast C Contiguous" (UTN #5)

=back

=head2 Decomposition and Composition

=over 4

=item C<$decomposed_string = decompose($string)>

=item C<$decomposed_string = decompose($string, $useCompatMapping)>

Decomposes the specified string and returns the result.

If the second parameter (a boolean) is omitted or false, decomposes it
using the Canonical Decomposition Mapping.
If true, decomposes it using the Compatibility Decomposition Mapping.

The string returned is not always in NFD/NFKD.
Reordering may be required.

    $NFD_string  = reorder(decompose($string));       # eq. to NFD()
    $NFKD_string = reorder(decompose($string, TRUE)); # eq. to NFKD()

=item C<$reordered_string  = reorder($string)>

Reorders the combining characters and the like in the canonical ordering
and returns the result.

E.g., when you have a list of NFD/NFKD strings,
you can get the concatenated NFD/NFKD string from them, saying

    $concat_NFD  = reorder(join '', @NFD_strings);
    $concat_NFKD = reorder(join '', @NFKD_strings);

=item C<$composed_string   = compose($string)>

Returns the string where composable pairs are composed.

E.g., when you have a NFD/NFKD string,
you can get its NFC/NFKC string, saying

    $NFC_string  = compose($NFD_string);
    $NFKC_string = compose($NFKD_string);

=back

=head2 Quick Check

(see Annex 8, UAX #15; and F<DerivedNormalizationProps.txt>)

The following functions check whether the string is in that normalization form.

The result returned will be:

    YES     The string is in that normalization form.
    NO      The string is not in that normalization form.
    MAYBE   Dubious. Maybe yes, maybe no.

=over 4

=item C<$result = checkNFD($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.

=item C<$result = checkNFC($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
C<undef> if C<MAYBE>.

=item C<$result = checkNFKD($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.

=item C<$result = checkNFKC($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
C<undef> if C<MAYBE>.

=item C<$result = checkFCD($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.

=item C<$result = checkFCC($string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
C<undef> if C<MAYBE>.

If a string is not in FCD, it must not be in FCC.
So C<checkFCC($not_FCD_string)> should return C<NO>.

=item C<$result = check($form_name, $string)>

returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
C<undef> if C<MAYBE>.

As C<$form_name>, one of the following names must be given.

  'C'  or 'NFC'  for Normalization Form C  (UAX #15)
  'D'  or 'NFD'  for Normalization Form D  (UAX #15)
  'KC' or 'NFKC' for Normalization Form KC (UAX #15)
  'KD' or 'NFKD' for Normalization Form KD (UAX #15)

  'FCD'          for "Fast C or D" Form  (UTN #5)
  'FCC'          for "Fast C Contiguous" (UTN #5)

=back

B<Note>

In the cases of NFD, NFKD, and FCD, the answer must be
either C<YES> or C<NO>. The answer C<MAYBE> may be returned
in the cases of NFC, NFKC, and FCC.

A C<MAYBE> string should contain at least one combining character
or the like. For example, C<COMBINING ACUTE ACCENT> has
the MAYBE_NFC/MAYBE_NFKC property.

Both C<checkNFC("A\N{COMBINING ACUTE ACCENT}")>
and C<checkNFC("B\N{COMBINING ACUTE ACCENT}")> will return C<MAYBE>.
C<"A\N{COMBINING ACUTE ACCENT}"> is not in NFC
(its NFC is C<"\N{LATIN CAPITAL LETTER A WITH ACUTE}">),
while C<"B\N{COMBINING ACUTE ACCENT}"> is in NFC.

If you want to check exactly, compare the string with its NFC/NFKC/FCC.

    if ($string eq NFC($string)) {
        # $string is exactly normalized in NFC;
    } else {
        # $string is not normalized in NFC;
    }

    if ($string eq NFKC($string)) {
        # $string is exactly normalized in NFKC;
    } else {
        # $string is not normalized in NFKC;
    }

=head2 Character Data

These functions are interface of character data used internally.
If you want only to get Unicode normalization forms, you don't need
call them yourself.

=over 4

=item C<$canonical_decomposed = getCanon($codepoint)>

If the character of the specified codepoint is canonically
decomposable (including Hangul Syllables),
returns the B<completely decomposed> string canonically equivalent to it.

If it is not decomposable, returns C<undef>.

=item C<$compatibility_decomposed = getCompat($codepoint)>

If the character of the specified codepoint is compatibility
decomposable (including Hangul Syllables),
returns the B<completely decomposed> string compatibility equivalent to it.

If it is not decomposable, returns C<undef>.

=item C<$codepoint_composite = getComposite($codepoint_here, $codepoint_next)>

If two characters here and next (as codepoints) are composable
(including Hangul Jamo/Syllables and Composition Exclusions),
returns the codepoint of the composite.

If they are not composable, returns C<undef>.

=item C<$combining_class = getCombinClass($codepoint)>

Returns the combining class of the character as an integer.

=item C<$is_exclusion = isExclusion($codepoint)>

Returns a boolean whether the character of the specified codepoint
is a composition exclusion.

=item C<$is_singleton = isSingleton($codepoint)>

Returns a boolean whether the character of the specified codepoint is
a singleton.

=item C<$is_non_starter_decomposition = isNonStDecomp($codepoint)>

Returns a boolean whether the canonical decomposition
of the character of the specified codepoint
is a Non-Starter Decomposition.

=item C<$may_be_composed_with_prev_char = isComp2nd($codepoint)>

Returns a boolean whether the character of the specified codepoint
may be composed with the previous one in a certain composition
(including Hangul Compositions, but excluding
Composition Exclusions and Non-Starter Decompositions).

=back

=head1 EXPORT

C<NFC>, C<NFD>, C<NFKC>, C<NFKD>: by default.

C<normalize> and other some functions: on request.

=head1 CAVEATS

=over 4

=item Perl's version vs. Unicode version

Since this module refers to perl core's Unicode database in the directory
F</lib/unicore> (or formerly F</lib/unicode>), the Unicode version of
normalization implemented by this module depends on your perl's version.

    perl's version         implemented Unicode version
       5.6.1                  3.0.1
       5.7.2                  3.1.0
       5.7.3                  3.1.1 (same normalized form as that of 3.1.0)
       5.8.0                  3.2.0
     5.8.1-5.8.3              4.0.0
     5.8.4-5.8.6 (latest)     4.0.1 (same normalized form as that of 4.0.0)

=item Correction of decomposition mapping

In older Unicode versions, a small number of characters (all of which are
CJK compatibility ideographs as far as they have been found) may have
an erroneous decomposition mapping (see F<NormalizationCorrections.txt>).
Anyhow, this module will neither refer to F<NormalizationCorrections.txt>
nor provide any specific version of normalization. Therefore this module
running on an older perl with an older Unicode database may use
the erroneous decomposition mapping blindly conforming to the Unicode database.

=item Revised definition of canonical composition

In Unicode 4.1.0, the definition D2 of canonical composition (which
affects NFC and NFKC) has been changed (see Public Review Issue #29
and recent UAX #15). This module has used the newer definition
since the version 0.07 (Oct 31, 2001).
This module does not support normalization according to the older
definition, even if the Unicode version implemented by perl is
lower than 4.1.0.

=back

=head1 AUTHOR

SADAHIRO Tomoyuki <SADAHIRO@cpan.org>

Copyright(C) 2001-2005, SADAHIRO Tomoyuki. Japan. All rights reserved.

This module is free software; you can redistribute it
and/or modify it under the same terms as Perl itself.

=head1 SEE ALSO

=over 4

=item http://www.unicode.org/reports/tr15/

Unicode Normalization Forms - UAX #15

=item http://www.unicode.org/Public/UNIDATA/DerivedNormalizationProps.txt

Derived Normalization Properties

=item http://www.unicode.org/Public/UNIDATA/NormalizationCorrections.txt

Normalization Corrections

=item http://www.unicode.org/review/pr-29.html

Public Review Issue #29: Normalization Issue

=item http://www.unicode.org/notes/tn5/

Canonical Equivalence in Applications - UTN #5

=back

=cut
Revision:	1.1
Committed:	Thu Jun 30 14:27:06 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	package Unicode::Normalize;
2
3			BEGIN {
4			unless ("A" eq pack('U', 0x41)) {
5			die "Unicode::Normalize cannot stringify a Unicode code point\n";
6			}
7			}
8
9			use 5.006;
10			use strict;
11			use warnings;
12			use Carp;
13
14			no warnings 'utf8';
15
16			our $VERSION = '0.32';
17			our $PACKAGE = __PACKAGE__;
18
19			require Exporter;
20			require DynaLoader;
21
22			our @ISA = qw(Exporter DynaLoader);
23			our @EXPORT = qw( NFC NFD NFKC NFKD );
24			our @EXPORT_OK = qw(
25			normalize decompose reorder compose
26			checkNFD checkNFKD checkNFC checkNFKC check
27			getCanon getCompat getComposite getCombinClass
28			isExclusion isSingleton isNonStDecomp isComp2nd isComp_Ex
29			isNFD_NO isNFC_NO isNFC_MAYBE isNFKD_NO isNFKC_NO isNFKC_MAYBE
30			FCD checkFCD FCC checkFCC composeContiguous
31			splitOnLastStarter
32			);
33			our %EXPORT_TAGS = (
34			all => [ @EXPORT, @EXPORT_OK ],
35			normalize => [ @EXPORT, qw/normalize decompose reorder compose/ ],
36			check => [ qw/checkNFD checkNFKD checkNFC checkNFKC check/ ],
37			fast => [ qw/FCD checkFCD FCC checkFCC composeContiguous/ ],
38			);
39
40			######
41
42			bootstrap Unicode::Normalize $VERSION;
43
44			######
45
46			sub pack_U {
47			return pack('U*', @_);
48			}
49
50			sub unpack_U {
51			return unpack('U', pack('U').shift);
52			}
53
54
55			##
56			## normalization forms
57			##
58
59			use constant COMPAT => 1;
60
61			sub NFD ($) { reorder(decompose($_[0])) }
62			sub NFKD ($) { reorder(decompose($_[0], COMPAT)) }
63			sub NFC ($) { compose(reorder(decompose($_[0]))) }
64			sub NFKC ($) { compose(reorder(decompose($_[0], COMPAT))) }
65
66			sub FCD ($) {
67			my $str = shift;
68			return checkFCD($str) ? $str : NFD($str);
69			}
70			sub FCC ($) { composeContiguous(reorder(decompose($_[0]))) }
71
72			our %formNorm = (
73			NFC => \&NFC, C => \&NFC,
74			NFD => \&NFD, D => \&NFD,
75			NFKC => \&NFKC, KC => \&NFKC,
76			NFKD => \&NFKD, KD => \&NFKD,
77			FCD => \&FCD, FCC => \&FCC,
78			);
79
80			sub normalize($$)
81			{
82			my $form = shift;
83			my $str = shift;
84			return exists $formNorm{$form}
85			? $formNorm{$form}->($str)
86			: croak $PACKAGE."::normalize: invalid form name: $form";
87			}
88
89
90			##
91			## quick check
92			##
93
94			our %formCheck = (
95			NFC => \&checkNFC, C => \&checkNFC,
96			NFD => \&checkNFD, D => \&checkNFD,
97			NFKC => \&checkNFKC, KC => \&checkNFKC,
98			NFKD => \&checkNFKD, KD => \&checkNFKD,
99			FCD => \&checkFCD, FCC => \&checkFCC,
100			);
101
102			sub check($$)
103			{
104			my $form = shift;
105			my $str = shift;
106			return exists $formCheck{$form}
107			? $formCheck{$form}->($str)
108			: croak $PACKAGE."::check: invalid form name: $form";
109			}
110
111			1;
112			__END__
113
114			=head1 NAME
115
116			Unicode::Normalize - Unicode Normalization Forms
117
118			=head1 SYNOPSIS
119
120			(1) using function names exported by default:
121
122			use Unicode::Normalize;
123
124			$NFD_string = NFD($string); # Normalization Form D
125			$NFC_string = NFC($string); # Normalization Form C
126			$NFKD_string = NFKD($string); # Normalization Form KD
127			$NFKC_string = NFKC($string); # Normalization Form KC
128
129			(2) using function names exported on request:
130
131			use Unicode::Normalize 'normalize';
132
133			$NFD_string = normalize('D', $string); # Normalization Form D
134			$NFC_string = normalize('C', $string); # Normalization Form C
135			$NFKD_string = normalize('KD', $string); # Normalization Form KD
136			$NFKC_string = normalize('KC', $string); # Normalization Form KC
137
138			=head1 DESCRIPTION
139
140			Parameters:
141
142			C<$string> is used as a string under character semantics
143			(see F<perlunicode>).
144
145			C<$codepoint> should be an unsigned integer
146			representing a Unicode code point.
147
148			Note: Between XSUB and pure Perl, there is an incompatibility
149			about the interpretation of C<$codepoint> as a decimal number.
150			XSUB converts C<$codepoint> to an unsigned integer, but pure Perl does not.
151			Do not use a floating point nor a negative sign in C<$codepoint>.
152
153			=head2 Normalization Forms
154
155			=over 4
156
157			=item C<$NFD_string = NFD($string)>
158
159			returns the Normalization Form D (formed by canonical decomposition).
160
161			=item C<$NFC_string = NFC($string)>
162
163			returns the Normalization Form C (formed by canonical decomposition
164			followed by canonical composition).
165
166			=item C<$NFKD_string = NFKD($string)>
167
168			returns the Normalization Form KD (formed by compatibility decomposition).
169
170			=item C<$NFKC_string = NFKC($string)>
171
172			returns the Normalization Form KC (formed by compatibility decomposition
173			followed by B<canonical> composition).
174
175			=item C<$FCD_string = FCD($string)>
176
177			If the given string is in FCD ("Fast C or D" form; cf. UTN #5),
178			returns it without modification; otherwise returns an FCD string.
179
180			Note: FCD is not always unique, then plural forms may be equivalent
181			each other. C<FCD()> will return one of these equivalent forms.
182
183			=item C<$FCC_string = FCC($string)>
184
185			returns the FCC form ("Fast C Contiguous"; cf. UTN #5).
186
187			Note: FCC is unique, as well as four normalization forms (NF*).
188
189			=item C<$normalized_string = normalize($form_name, $string)>
190
191			As C<$form_name>, one of the following names must be given.
192
193			'C' or 'NFC' for Normalization Form C (UAX #15)
194			'D' or 'NFD' for Normalization Form D (UAX #15)
195			'KC' or 'NFKC' for Normalization Form KC (UAX #15)
196			'KD' or 'NFKD' for Normalization Form KD (UAX #15)
197
198			'FCD' for "Fast C or D" Form (UTN #5)
199			'FCC' for "Fast C Contiguous" (UTN #5)
200
201			=back
202
203			=head2 Decomposition and Composition
204
205			=over 4
206
207			=item C<$decomposed_string = decompose($string)>
208
209			=item C<$decomposed_string = decompose($string, $useCompatMapping)>
210
211			Decomposes the specified string and returns the result.
212
213			If the second parameter (a boolean) is omitted or false, decomposes it
214			using the Canonical Decomposition Mapping.
215			If true, decomposes it using the Compatibility Decomposition Mapping.
216
217			The string returned is not always in NFD/NFKD.
218			Reordering may be required.
219
220			$NFD_string = reorder(decompose($string)); # eq. to NFD()
221			$NFKD_string = reorder(decompose($string, TRUE)); # eq. to NFKD()
222
223			=item C<$reordered_string = reorder($string)>
224
225			Reorders the combining characters and the like in the canonical ordering
226			and returns the result.
227
228			E.g., when you have a list of NFD/NFKD strings,
229			you can get the concatenated NFD/NFKD string from them, saying
230
231			$concat_NFD = reorder(join '', @NFD_strings);
232			$concat_NFKD = reorder(join '', @NFKD_strings);
233
234			=item C<$composed_string = compose($string)>
235
236			Returns the string where composable pairs are composed.
237
238			E.g., when you have a NFD/NFKD string,
239			you can get its NFC/NFKC string, saying
240
241			$NFC_string = compose($NFD_string);
242			$NFKC_string = compose($NFKD_string);
243
244			=back
245
246			=head2 Quick Check
247
248			(see Annex 8, UAX #15; and F<DerivedNormalizationProps.txt>)
249
250			The following functions check whether the string is in that normalization form.
251
252			The result returned will be:
253
254			YES The string is in that normalization form.
255			NO The string is not in that normalization form.
256			MAYBE Dubious. Maybe yes, maybe no.
257
258			=over 4
259
260			=item C<$result = checkNFD($string)>
261
262			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.
263
264			=item C<$result = checkNFC($string)>
265
266			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
267			C<undef> if C<MAYBE>.
268
269			=item C<$result = checkNFKD($string)>
270
271			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.
272
273			=item C<$result = checkNFKC($string)>
274
275			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
276			C<undef> if C<MAYBE>.
277
278			=item C<$result = checkFCD($string)>
279
280			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>.
281
282			=item C<$result = checkFCC($string)>
283
284			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
285			C<undef> if C<MAYBE>.
286
287			If a string is not in FCD, it must not be in FCC.
288			So C<checkFCC($not_FCD_string)> should return C<NO>.
289
290			=item C<$result = check($form_name, $string)>
291
292			returns true (C<1>) if C<YES>; false (C<empty string>) if C<NO>;
293			C<undef> if C<MAYBE>.
294
295			As C<$form_name>, one of the following names must be given.
296
297			'C' or 'NFC' for Normalization Form C (UAX #15)
298			'D' or 'NFD' for Normalization Form D (UAX #15)
299			'KC' or 'NFKC' for Normalization Form KC (UAX #15)
300			'KD' or 'NFKD' for Normalization Form KD (UAX #15)
301
302			'FCD' for "Fast C or D" Form (UTN #5)
303			'FCC' for "Fast C Contiguous" (UTN #5)
304
305			=back
306
307			B<Note>
308
309			In the cases of NFD, NFKD, and FCD, the answer must be
310			either C<YES> or C<NO>. The answer C<MAYBE> may be returned
311			in the cases of NFC, NFKC, and FCC.
312
313			A C<MAYBE> string should contain at least one combining character
314			or the like. For example, C<COMBINING ACUTE ACCENT> has
315			the MAYBE_NFC/MAYBE_NFKC property.
316
317			Both C<checkNFC("A\N{COMBINING ACUTE ACCENT}")>
318			and C<checkNFC("B\N{COMBINING ACUTE ACCENT}")> will return C<MAYBE>.
319			C<"A\N{COMBINING ACUTE ACCENT}"> is not in NFC
320			(its NFC is C<"\N{LATIN CAPITAL LETTER A WITH ACUTE}">),
321			while C<"B\N{COMBINING ACUTE ACCENT}"> is in NFC.
322
323			If you want to check exactly, compare the string with its NFC/NFKC/FCC.
324
325			if ($string eq NFC($string)) {
326			# $string is exactly normalized in NFC;
327			} else {
328			# $string is not normalized in NFC;
329			}
330
331			if ($string eq NFKC($string)) {
332			# $string is exactly normalized in NFKC;
333			} else {
334			# $string is not normalized in NFKC;
335			}
336
337			=head2 Character Data
338
339			These functions are interface of character data used internally.
340			If you want only to get Unicode normalization forms, you don't need
341			call them yourself.
342
343			=over 4
344
345			=item C<$canonical_decomposed = getCanon($codepoint)>
346
347			If the character of the specified codepoint is canonically
348			decomposable (including Hangul Syllables),
349			returns the B<completely decomposed> string canonically equivalent to it.
350
351			If it is not decomposable, returns C<undef>.
352
353			=item C<$compatibility_decomposed = getCompat($codepoint)>
354
355			If the character of the specified codepoint is compatibility
356			decomposable (including Hangul Syllables),
357			returns the B<completely decomposed> string compatibility equivalent to it.
358
359			If it is not decomposable, returns C<undef>.
360
361			=item C<$codepoint_composite = getComposite($codepoint_here, $codepoint_next)>
362
363			If two characters here and next (as codepoints) are composable
364			(including Hangul Jamo/Syllables and Composition Exclusions),
365			returns the codepoint of the composite.
366
367			If they are not composable, returns C<undef>.
368
369			=item C<$combining_class = getCombinClass($codepoint)>
370
371			Returns the combining class of the character as an integer.
372
373			=item C<$is_exclusion = isExclusion($codepoint)>
374
375			Returns a boolean whether the character of the specified codepoint
376			is a composition exclusion.
377
378			=item C<$is_singleton = isSingleton($codepoint)>
379
380			Returns a boolean whether the character of the specified codepoint is
381			a singleton.
382
383			=item C<$is_non_starter_decomposition = isNonStDecomp($codepoint)>
384
385			Returns a boolean whether the canonical decomposition
386			of the character of the specified codepoint
387			is a Non-Starter Decomposition.
388
389			=item C<$may_be_composed_with_prev_char = isComp2nd($codepoint)>
390
391			Returns a boolean whether the character of the specified codepoint
392			may be composed with the previous one in a certain composition
393			(including Hangul Compositions, but excluding
394			Composition Exclusions and Non-Starter Decompositions).
395
396			=back
397
398			=head1 EXPORT
399
400			C<NFC>, C<NFD>, C<NFKC>, C<NFKD>: by default.
401
402			C<normalize> and other some functions: on request.
403
404			=head1 CAVEATS
405
406			=over 4
407
408			=item Perl's version vs. Unicode version
409
410			Since this module refers to perl core's Unicode database in the directory
411			F</lib/unicore> (or formerly F</lib/unicode>), the Unicode version of
412			normalization implemented by this module depends on your perl's version.
413
414			perl's version implemented Unicode version
415			5.6.1 3.0.1
416			5.7.2 3.1.0
417			5.7.3 3.1.1 (same normalized form as that of 3.1.0)
418			5.8.0 3.2.0
419			5.8.1-5.8.3 4.0.0
420			5.8.4-5.8.6 (latest) 4.0.1 (same normalized form as that of 4.0.0)
421
422			=item Correction of decomposition mapping
423
424			In older Unicode versions, a small number of characters (all of which are
425			CJK compatibility ideographs as far as they have been found) may have
426			an erroneous decomposition mapping (see F<NormalizationCorrections.txt>).
427			Anyhow, this module will neither refer to F<NormalizationCorrections.txt>
428			nor provide any specific version of normalization. Therefore this module
429			running on an older perl with an older Unicode database may use
430			the erroneous decomposition mapping blindly conforming to the Unicode database.
431
432			=item Revised definition of canonical composition
433
434			In Unicode 4.1.0, the definition D2 of canonical composition (which
435			affects NFC and NFKC) has been changed (see Public Review Issue #29
436			and recent UAX #15). This module has used the newer definition
437			since the version 0.07 (Oct 31, 2001).
438			This module does not support normalization according to the older
439			definition, even if the Unicode version implemented by perl is
440			lower than 4.1.0.
441
442			=back
443
444			=head1 AUTHOR
445
446			SADAHIRO Tomoyuki <SADAHIRO@cpan.org>
447
448			Copyright(C) 2001-2005, SADAHIRO Tomoyuki. Japan. All rights reserved.
449
450			This module is free software; you can redistribute it
451			and/or modify it under the same terms as Perl itself.
452
453			=head1 SEE ALSO
454
455			=over 4
456
457			=item http://www.unicode.org/reports/tr15/
458
459			Unicode Normalization Forms - UAX #15
460
461			=item http://www.unicode.org/Public/UNIDATA/DerivedNormalizationProps.txt
462
463			Derived Normalization Properties
464
465			=item http://www.unicode.org/Public/UNIDATA/NormalizationCorrections.txt
466
467			Normalization Corrections
468
469			=item http://www.unicode.org/review/pr-29.html
470
471			Public Review Issue #29: Normalization Issue
472
473			=item http://www.unicode.org/notes/tn5/
474
475			Canonical Equivalence in Applications - UTN #5
476
477			=back
478
479			=cut