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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

  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).

  "$normalized_string = normalize($form_name, $string)"
      As $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

  Decomposition and Composition

  "$decomposed_string = decompose($string)"
  "$decomposed_string = decompose($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()

  "$reordered_string  = reorder($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);

  "$composed_string   = compose($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; 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").

  "$result = check($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 and NFKD, the answer must be either "YES" or "NO".  The
  answer "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, "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; i.e.,

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

  "$is_non_startar_decomposition = isNonStDecomp($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) 2001-2002, 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.


SEE ALSO

  http://www.unicode.org/unicode/reports/tr15/
      Unicode Normalization Forms - UAX #15

  http://www.unicode.org/Public/UNIDATA/DerivedNormalizationProps.txt
      Derived Normalization Properties

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