PC Professionell 2006 December/PCpro_2006_12.ISO/ossdvd/server/Perl2/lib/Unicode/Normalize.pm

Perl POD Document | 2002-06-19 | 8.9 KB | 326 lines

package Unicode::Normalize;

BEGIN {
    if (ord("A") == 193) {
    die "Unicode::Normalize not ported to EBCDIC\n";
    }
}

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

our $VERSION = '0.17';
our $PACKAGE = __PACKAGE__;

require Exporter;
require DynaLoader;
require AutoLoader;

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
);
our %EXPORT_TAGS = (
    all       => [ @EXPORT, @EXPORT_OK ],
    normalize => [ @EXPORT, qw/normalize decompose reorder compose/ ],
    check     => [ qw/checkNFD checkNFKD checkNFC checkNFKC check/ ],
);

bootstrap Unicode::Normalize $VERSION;

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 normalize($$)
{
    my $form = shift;
    my $str = shift;
    $form =~ s/^NF//;
    return
    $form eq 'D'  ? NFD ($str) :
    $form eq 'C'  ? NFC ($str) :
    $form eq 'KD' ? NFKD($str) :
    $form eq 'KC' ? NFKC($str) :
      croak $PACKAGE."::normalize: invalid form name: $form";
}

sub check($$)
{
    my $form = shift;
    my $str = shift;
    $form =~ s/^NF//;
    return
    $form eq 'D'  ? checkNFD ($str) :
    $form eq 'C'  ? checkNFC ($str) :
    $form eq 'KD' ? checkNFKD($str) :
    $form eq 'KC' ? checkNFKC($str) :
      croak $PACKAGE."::check: invalid form name: $form";
}

1;
__END__

=head1 NAME

Unicode::Normalize - Unicode Normalization Forms

=head1 SYNOPSIS

  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

   or

  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

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

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

  'C'  or 'NFC'  for Normalization Form C
  'D'  or 'NFD'  for Normalization Form D
  'KC' or 'NFKC' for Normalization Form KC
  'KD' or 'NFKD' for Normalization Form KD

=back

=head2 Decomposition and Composition

=over 4

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

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

Decompose 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)>

Reorder 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; 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 C<YES> (C<1>) or C<NO> (C<empty string>).

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

returns C<YES> (C<1>), C<NO> (C<empty string>), or C<MAYBE> (C<undef>).

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

returns C<YES> (C<1>) or C<NO> (C<empty string>).

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

returns C<YES> (C<1>), C<NO> (C<empty string>), or C<MAYBE> (C<undef>).

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

returns C<YES> (C<1>), C<NO> (C<empty string>), or C<MAYBE> (C<undef>).

C<$form_name> is alike to that for C<normalize()>.

=back

B<Note>

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

A MAYBE-NFC/NFKC 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; i.e.,

    $string eq NFC($string)    # more thorough than checkNFC($string)
    $string eq NFKC($string)   # more thorough than checkNFKC($string)

=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<$is_non_startar_decomposition = isNonStDecomp($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

=head2 EXPORT

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

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

=head1 AUTHOR

SADAHIRO Tomoyuki, E<lt>[e-mail]<gt>

  http://homepage1.nifty.com/nomenclator/perl/

  Copyright(C) 2001-2002, SADAHIRO Tomoyuki. Japan. All rights reserved.

  This program 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/unicode/reports/tr15/

Unicode Normalization Forms - UAX #15

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

Derived Normalization Properties

=back

=cut