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