ext::Unicode::NorPerlzProgrext::Unicode::Normalize::Normalize(3p)NAMEUnicode::Normalize - Unicode Normalization Forms
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
DESCRIPTION
Parameters:
$string is used as a string under character semantics (see
perlunicode).
$codepoint should be an unsigned integer representing a
Unicode code point.
Note: Between XSUB and pure Perl, there is an incompatibil-
ity about the interpretation of $codepoint as a decimal
number. XSUB converts $codepoint to an unsigned integer, but
pure Perl does not. Do not use a floating point nor a nega-
tive sign in $codepoint.
Normalization Forms
"$NFD_string = NFD($string)"
returns the Normalization Form D (formed by canonical
decomposition).
"$NFC_string = NFC($string)"
returns the Normalization Form C (formed by canonical
decomposition followed by canonical composition).
"$NFKD_string = NFKD($string)"
returns the Normalization Form KD (formed by compatibil-
ity decomposition).
"$NFKC_string = NFKC($string)"
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returns the Normalization Form KC (formed by compatibil-
ity decomposition followed by canonical composition).
"$FCD_string = FCD($string)"
If the given string is in FCD ("Fast C or D" form; cf.
UTN #5), returns it without modification; otherwise
returns an FCD string.
Note: FCD is not always unique, then plural forms may be
equivalent each other. "FCD()" will return one of these
equivalent forms.
"$FCC_string = FCC($string)"
returns the FCC form ("Fast C Contiguous"; cf. UTN #5).
Note: FCC is unique, as well as four normalization forms
(NF*).
"$normalized_string = normalize($form_name, $string)"
As $form_name, one of the following names must be given.
'C' or 'NFC' for Normalization Form C (UAX #15)
'D' or 'NFD' for Normalization Form D (UAX #15)
'KC' or 'NFKC' for Normalization Form KC (UAX #15)
'KD' or 'NFKD' for Normalization Form KD (UAX #15)
'FCD' for "Fast C or D" Form (UTN #5)
'FCC' for "Fast C Contiguous" (UTN #5)
Decomposition and Composition
"$decomposed_string = decompose($string)"
"$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 Decompo-
sition Mapping.
The string returned is not always in NFD/NFKD. Reorder-
ing may be required.
$NFD_string = reorder(decompose($string)); # eq. to NFD()
$NFKD_string = reorder(decompose($string, TRUE)); # eq. to NFKD()
"$reordered_string = reorder($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
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$concat_NFD = reorder(join '', @NFD_strings);
$concat_NFKD = reorder(join '', @NFKD_strings);
"$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);
Quick Check
(see Annex 8, UAX #15; and 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.
"$result = checkNFD($string)"
returns true (1) if "YES"; false ("empty string") if
"NO".
"$result = checkNFC($string)"
returns true (1) if "YES"; false ("empty string") if
"NO"; "undef" if "MAYBE".
"$result = checkNFKD($string)"
returns true (1) if "YES"; false ("empty string") if
"NO".
"$result = checkNFKC($string)"
returns true (1) if "YES"; false ("empty string") if
"NO"; "undef" if "MAYBE".
"$result = checkFCD($string)"
returns true (1) if "YES"; false ("empty string") if
"NO".
"$result = checkFCC($string)"
returns true (1) if "YES"; false ("empty string") if
"NO"; "undef" if "MAYBE".
If a string is not in FCD, it must not be in FCC. So
"checkFCC($not_FCD_string)" should return "NO".
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"$result = check($form_name, $string)"
returns true (1) if "YES"; false ("empty string") if
"NO"; "undef" if "MAYBE".
As $form_name, one of the following names must be given.
'C' or 'NFC' for Normalization Form C (UAX #15)
'D' or 'NFD' for Normalization Form D (UAX #15)
'KC' or 'NFKC' for Normalization Form KC (UAX #15)
'KD' or 'NFKD' for Normalization Form KD (UAX #15)
'FCD' for "Fast C or D" Form (UTN #5)
'FCC' for "Fast C Contiguous" (UTN #5)
Note
In the cases of NFD, NFKD, and FCD, the answer must be
either "YES" or "NO". The answer "MAYBE" may be returned in
the cases of NFC, NFKC, and FCC.
A "MAYBE" string should contain at least one combining char-
acter or the like. For example, "COMBINING ACUTE ACCENT" has
the MAYBE_NFC/MAYBE_NFKC property.
Both "checkNFC("A\N{COMBINING ACUTE ACCENT}")" and
"checkNFC("B\N{COMBINING ACUTE ACCENT}")" will return
"MAYBE". "A\N{COMBINING ACUTE ACCENT}" is not in NFC (its
NFC is "\N{LATIN CAPITAL LETTER A WITH ACUTE}"), while
"B\N{COMBINING ACUTE ACCENT}" is in NFC.
If you want to check exactly, compare the string with its
NFC/NFKC/FCC.
if ($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 {
# $string is not normalized in NFKC;
}
Character Data
These functions are interface of character data used inter-
nally. If you want only to get Unicode normalization forms,
you don't need call them yourself.
"$canonical_decomposed = getCanon($codepoint)"
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If the character of the specified codepoint is canoni-
cally decomposable (including Hangul Syllables), returns
the completely decomposed string canonically equivalent
to it.
If it is not decomposable, returns "undef".
"$compatibility_decomposed = getCompat($codepoint)"
If the character of the specified codepoint is compati-
bility decomposable (including Hangul Syllables),
returns the completely decomposed string compatibility
equivalent to it.
If it is not decomposable, returns "undef".
$codepoint_next)"
"$codepoint_composite = getComposite($codepoint_here,
If two characters here and next (as codepoints) are com-
posable (including Hangul Jamo/Syllables and Composition
Exclusions), returns the codepoint of the composite.
If they are not composable, returns "undef".
"$combining_class = getCombinClass($codepoint)"
Returns the combining class of the character as an
integer.
"$is_exclusion = isExclusion($codepoint)"
Returns a boolean whether the character of the specified
codepoint is a composition exclusion.
"$is_singleton = isSingleton($codepoint)"
Returns a boolean whether the character of the specified
codepoint is a singleton.
"$is_non_starter_decomposition = isNonStDecomp($codepoint)"
Returns a boolean whether the canonical decomposition of
the character of the specified codepoint is a Non-
Starter Decomposition.
"$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 Decom-
positions).
EXPORT
"NFC", "NFD", "NFKC", "NFKD": by default.
"normalize" and other some functions: on request.
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ext::Unicode::NorPerlzProgrext::Unicode::Normalize::Normalize(3p)CAVEATS
Perl's version vs. Unicode version
Since this module refers to perl core's Unicode database
in the directory /lib/unicore (or formerly
/lib/unicode), the Unicode version of normalization
implemented by this module depends on your perl's ver-
sion.
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)
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 decomposi-
tion mapping (see NormalizationCorrections.txt). Anyhow,
this module will neither refer to
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.
Revised definition of canonical composition
In Unicode 4.1.0, the definition D2 of canonical compo-
sition (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 nor-
malization according to the older definition, even if
the Unicode version implemented by perl is lower than
4.1.0.
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.
SEE ALSO
http://www.unicode.org/reports/tr15/
Unicode Normalization Forms - UAX #15
http://www.unicode.org/Public/UNIDATA/DerivedNormalizationProps.txt
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Derived Normalization Properties
http://www.unicode.org/Public/UNIDATA/NormalizationCorrections.txt
Normalization Corrections
http://www.unicode.org/review/pr-29.html
Public Review Issue #29: Normalization Issue
http://www.unicode.org/notes/tn5/
Canonical Equivalence in Applications - UTN #5
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