


ext::Unicode-NormPerlePrograext::Unicode-Normalize::Normalize(3p)


NAME
       Unicode::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).

       $code_point should be an unsigned integer representing a
       Unicode code point.

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

   Normalization Forms
       "$NFD_string = NFD($string)"
           It returns the Normalization Form D (formed by
           canonical decomposition).

       "$NFC_string = NFC($string)"
           It returns the Normalization Form C (formed by
           canonical decomposition followed by canonical
           composition).

       "$NFKD_string = NFKD($string)"
           It returns the Normalization Form KD (formed by
           compatibility decomposition).

       "$NFKC_string = NFKC($string)"
           It returns the Normalization Form KC (formed by
           compatibility decomposition followed by canonical



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           composition).

       "$FCD_string = FCD($string)"
           If the given string is in FCD ("Fast C or D" form; cf.
           UTN #5), it returns the string without modification;
           otherwise it 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)"
           It 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)"
           It returns the normalization form of $form_name.

           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 [,
       $useCompatMapping])"
           It returns the concatenation of the decomposition of
           each character in the string.

           If the second parameter (a boolean) is omitted or
           false, the decomposition is canonical decomposition;
           if the second parameter (a boolean) is true, the
           decomposition is compatibility decomposition.

           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()

       "$reordered_string = reorder($string)"
           It returns the result of reordering the combining
           characters according to Canonical Ordering Behavior.

           For example, when you have a list of NFD/NFKD strings,



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           you can get the concatenated NFD/NFKD string from
           them, by saying

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

       "$composed_string = compose($string)"
           It returns the result of canonical composition without
           applying any decomposition.

           For example, when you have a NFD/NFKD string, you can
           get its NFC/NFKC string, by 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 one of the following:

           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)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO".

       "$result = checkNFC($string)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO"; "undef" if "MAYBE".

       "$result = checkNFKD($string)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO".

       "$result = checkNFKC($string)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO"; "undef" if "MAYBE".

       "$result = checkFCD($string)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO".

       "$result = checkFCC($string)"
           It returns true (1) if "YES"; false ("empty string")
           if "NO"; "undef" if "MAYBE".

           Note: If a string is not in FCD, it must not be in
           FCC.  So "checkFCC($not_FCD_string)" should return



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           "NO".

       "$result = check($form_name, $string)"
           It 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
       character 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
       internally.  If you want only to get Unicode normalization
       forms, you don't need call them yourself.





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       "$canonical_decomposition = getCanon($code_point)"
           If the character is canonically decomposable
           (including Hangul Syllables), it returns the (full)
           canonical decomposition as a string.  Otherwise it
           returns "undef".

           Note: According to the Unicode standard, the canonical
           decomposition of the character that is not canonically
           decomposable is same as the character itself.

       "$compatibility_decomposition = getCompat($code_point)"
           If the character is compatibility decomposable
           (including Hangul Syllables), it returns the (full)
           compatibility decomposition as a string.  Otherwise it
           returns "undef".

           Note: According to the Unicode standard, the
           compatibility decomposition of the character that is
           not compatibility decomposable is same as the
           character itself.

       "$code_point_composite = getComposite($code_point_here,
       $code_point_next)"
           If two characters here and next (as code points) are
           composable (including Hangul Jamo/Syllables and
           Composition Exclusions), it returns the code point of
           the composite.

           If they are not composable, it returns "undef".

       "$combining_class = getCombinClass($code_point)"
           It returns the combining class (as an integer) of the
           character.

       "$may_be_composed_with_prev_char = isComp2nd($code_point)"
           It 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).

       "$is_exclusion = isExclusion($code_point)"
           It returns a boolean whether the code point is a
           composition exclusion.

       "$is_singleton = isSingleton($code_point)"
           It returns a boolean whether the code point is a
           singleton

       "$is_non_starter_decomposition =
       isNonStDecomp($code_point)"
           It returns a boolean whether the code point has Non-
           Starter Decomposition.




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       "$is_Full_Composition_Exclusion = isComp_Ex($code_point)"
           It returns a boolean of the derived property Comp_Ex
           (Full_Composition_Exclusion). This property is
           generated from Composition Exclusions + Singletons +
           Non-Starter Decompositions.

       "$NFD_is_NO = isNFD_NO($code_point)"
           It returns a boolean of the derived property NFD_NO
           (NFD_Quick_Check=No).

       "$NFC_is_NO = isNFC_NO($code_point)"
           It returns a boolean of the derived property NFC_NO
           (NFC_Quick_Check=No).

       "$NFC_is_MAYBE = isNFC_MAYBE($code_point)"
           It returns a boolean of the derived property NFC_MAYBE
           (NFC_Quick_Check=Maybe).

       "$NFKD_is_NO = isNFKD_NO($code_point)"
           It returns a boolean of the derived property NFKD_NO
           (NFKD_Quick_Check=No).

       "$NFKC_is_NO = isNFKC_NO($code_point)"
           It returns a boolean of the derived property NFKC_NO
           (NFKC_Quick_Check=No).

       "$NFKC_is_MAYBE = isNFKC_MAYBE($code_point)"
           It returns a boolean of the derived property
           NFKC_MAYBE (NFKC_Quick_Check=Maybe).

EXPORT
       "NFC", "NFD", "NFKC", "NFKD": by default.

       "normalize" and other some functions: on request.

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
           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 (normalization is same as 3.1.0)
                  5.8.0              3.2.0
                5.8.1-5.8.3          4.0.0
                5.8.4-5.8.6          4.0.1 (normalization is same as 4.0.0)
                5.8.7-5.8.8          4.1.0
                  5.10.0             5.0.0
                  5.8.9              5.1.0




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       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
           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
           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 will not
           support the normalization 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) 2001-2007, 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/CompositionExclusions.txt
           Composition Exclusion Table

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