Unicode::Normalize(3p) Perl Programmers Reference Guide

Unicode::Normalize(3p) Perl Programmers Reference Guide #

Unicode::Normalize(3p) Perl Programmers Reference Guide

NNAAMMEE #

 Unicode::Normalize - Unicode Normalization Forms

SSYYNNOOPPSSIISS #

 (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

DDEESSCCRRIIPPTTIIOONN #

 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.

NNoorrmmaalliizzaattiioonn FFoorrmmss “$NFD_string = NFD($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 ccaannoonniiccaall 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)

DDeeccoommppoossiittiioonn aanndd CCoommppoossiittiioonn “$decomposed_string = decompose($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, 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);

 "($processed, $unprocessed) = splitOnLastStarter($normalized)"
     It returns two strings: the first one, $processed, is a part before
     the last starter, and the second one, $unprocessed is another part
     after the first part. A starter is a character having a combining
     class of zero (see UAX #15).

     Note that $processed may be empty (when $normalized contains no
     starter or starts with the last starter), and then $unprocessed
     should be equal to the entire $normalized.

     When you have a $normalized string and an $unnormalized string
     following it, a simple concatenation is wrong:

      $concat = $normalized . normalize($form, $unnormalized); # wrong!

     Instead of it, do like this:

      ($processed, $unprocessed) = splitOnLastStarter($normalized);
      $concat = $processed . normalize($form,$unprocessed.$unnormalized);

     "splitOnLastStarter()" should be called with a pre-normalized
     parameter $normalized, that is in the same form as $form you want.

     If you have an array of @string that should be concatenated and then
     normalized, you can do like this:

         my $result = "";
         my $unproc = "";
         foreach my $str (@string) {
             $unproc .= $str;
             my $n = normalize($form, $unproc);
             my($p, $u) = splitOnLastStarter($n);
             $result .= $p;
             $unproc  = $u;
         }
         $result .= $unproc;
         # instead of normalize($form, join('', @string))

 "$processed = normalize_partial($form, $unprocessed)"
     A wrapper for the combination of "normalize()" and
     "splitOnLastStarter()".  Note that $unprocessed will be modified as a
     side-effect.

     If you have an array of @string that should be concatenated and then
     normalized, you can do like this:

         my $result = "";
         my $unproc = "";
         foreach my $str (@string) {
             $unproc .= $str;
             $result .= normalize_partial($form, $unproc);
         }
         $result .= $unproc;
         # instead of normalize($form, join('', @string))

 "$processed = NFD_partial($unprocessed)"
     It does like "normalize_partial('NFD', $unprocessed)".  Note that
     $unprocessed will be modified as a side-effect.

 "$processed = NFC_partial($unprocessed)"
     It does like "normalize_partial('NFC', $unprocessed)".  Note that
     $unprocessed will be modified as a side-effect.

 "$processed = NFKD_partial($unprocessed)"
     It does like "normalize_partial('NFKD', $unprocessed)".  Note that
     $unprocessed will be modified as a side-effect.

 "$processed = NFKC_partial($unprocessed)"
     It does like "normalize_partial('NFKC', $unprocessed)".  Note that
     $unprocessed will be modified as a side-effect.

QQuuiicckk CChheecckk (see Annex 8, UAX #15; and _D_e_r_i_v_e_d_N_o_r_m_a_l_i_z_a_t_i_o_n_P_r_o_p_s_._t_x_t)

 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 "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)

 NNoottee

 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;
     }

CChhaarraacctteerr DDaattaa 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.

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

     NNoottee:: 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".

     NNoottee:: 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.

 "$is_Full_Composition_Exclusion = isComp_Ex($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).

EEXXPPOORRTT #

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

 "normalize" and other some functions: on request.

CCAAVVEEAATTSS #

 Perl's version vs. Unicode version
     Since this module refers to perl core's Unicode database in the
     directory _/_l_i_b_/_u_n_i_c_o_r_e (or formerly _/_l_i_b_/_u_n_i_c_o_d_e), the Unicode
     version of normalization implemented by this module depends on what
     has been compiled into your perl.  The following table lists the
     default Unicode version that comes with various perl versions.  (It
     is possible to change the Unicode version in any perl version to be
     any earlier Unicode version, so one could cause Unicode 3.2 to be
     used in any perl version starting with 5.8.0.  Read
     _$_C_o_n_f_i_g_{_p_r_i_v_l_i_b_}_/_u_n_i_c_o_r_e_/_R_E_A_D_M_E_._p_e_r_l for details.

         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, 5.10.1     5.1.0
            5.12.x             5.2.0
            5.14.x             6.0.0
            5.16.x             6.1.0
            5.18.x             6.2.0
            5.20.x             6.3.0
            5.22.x             7.0.0

 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 decomposition mapping (see
     _N_o_r_m_a_l_i_z_a_t_i_o_n_C_o_r_r_e_c_t_i_o_n_s_._t_x_t).  Anyhow, this module will neither
     refer to _N_o_r_m_a_l_i_z_a_t_i_o_n_C_o_r_r_e_c_t_i_o_n_s_._t_x_t 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.

AAUUTTHHOORR #

 SADAHIRO Tomoyuki <SADAHIRO@cpan.org>

 Currently maintained by <perl5-porters@perl.org>

 Copyright(C) 2001-2012, SADAHIRO Tomoyuki. Japan. All rights reserved.

LLIICCEENNSSEE #

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

SSEEEE AALLSSOO #

 <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

perl v5.36.3 2023-02-15 Unicode::Normalize(3p)