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Unicode::Normalize(3)


NAME

  Unicode::Normalize - Unicode Normalization Forms


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


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 XS edition and pure Perl edition, interpretation of
  $codepoint as a decimal number has incompatibility.  XS converts $codepoint
  to an unsigned integer, but pure Perl does not.  Do not use a floating
  point nor a negative 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 compatibility
      decomposition).

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

  "$reordered_string  = reorder($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);

  "$composed_string   = compose($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 "YES" (1) or "NO" ("empty string").

  "$result = checkNFC($string)"
      returns "YES" (1), "NO" ("empty string"), or "MAYBE" ("undef").

  "$result = checkNFKD($string)"
      returns "YES" (1) or "NO" ("empty string").

  "$result = checkNFKC($string)"
      returns "YES" (1), "NO" ("empty string"), or "MAYBE" ("undef").

  "$result = checkFCD($string)"
      returns "YES" (1) or "NO" ("empty string").

  "$result = checkFCC($string)"
      returns "YES" (1), "NO" ("empty string"), or "MAYBE" ("undef").

      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)"
      returns "YES" (1), "NO" ("empty string"), or "MAYBE" ("undef").

      $form_name is alike to that for "normalize()".

  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;
  i.e.,

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

  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.

  "$canonical_decomposed = getCanon($codepoint)"
      If the character of the specified codepoint is canonically 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 compatibility
      decomposable (including Hangul Syllables), returns the completely
      decomposed string compatibility equivalent to it.

      If it is not decomposable, returns "undef".

  "$codepoint_composite = getComposite($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 "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 Decompositions).

  EXPORT

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

  "normalize" and other some functions: on request.


AUTHOR

  SADAHIRO Tomoyuki, <SADAHIRO@cpan.org>

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

    Copyright(C) 2001-2003, 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
      Derived Normalization Properties

  http://www.unicode.org/notes/tn5/
      Canonical Equivalence in Applications - UTN #5

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