Unicode::Collate::Locale - Linguistic tailoring for DUCET via Unicode::Collate


  use Unicode::Collate::Locale;

  $Collator = Unicode::Collate::Locale->
      new(locale => $locale_name, %tailoring);

  @sorted = $Collator->sort(@not_sorted);

  $result = $Collator->cmp($a, $b); # returns 1, 0, or -1.

Note: Strings in @not_sorted, $a and $b are interpreted according to Perl's Unicode support. See perlunicode, perluniintro, perlunitut, perlunifaq, utf8. Otherwise you can use preprocess (cf. Unicode::Collate) or should decode them before.


This module provides linguistic tailoring for it taking advantage of Unicode::Collate.


The new method returns a collator object.

A parameter list for the constructor is a hash, which can include a special key locale and its value (case-insensitive) standing for a two-letter language code (ISO-639) like 'en' for English. For example, Unicode::Collate::Locale->new(locale => 'FR') returns a collator tailored for French.

$locale_name may be suffixed with a territory(country) code or a variant code, which are separated with '_'. E.g. en_US for English in USA, es_ES_traditional for Spanish in Spain (Traditional),

If $localename is not defined, fallback is selected in the following order:

    1. language_territory_variant
    2. language_territory
    3. language__variant
    4. language
    5. default

Tailoring tags provided by Unicode::Collate are allowed as long as they are not used for locale support. Esp. the table tag is always untailorable since it is reserved for DUCET.

E.g. a collator for French, which ignores diacritics and case difference (i.e. level 1), with reversed case ordering and no normalization.

        level => 1,
        locale => 'fr',
        upper_before_lower => 1,
        normalization => undef

Overriding a behavior already tailored by locale is disallowed if such a tailoring is passed to new().

        locale => 'da',
        upper_before_lower => 0, # causes error as reserved by 'da'

However change() inherited from Unicode::Collate allows such a tailoring that is reserved by locale. Examples:

    new(locale => 'ca')->change(backwards => undef)
    new(locale => 'da')->change(upper_before_lower => 0)
    new(locale => 'ja')->change(overrideCJK => undef)


Unicode::Collate::Locale is a subclass of Unicode::Collate and methods other than new are inherited from Unicode::Collate.

Here is a list of additional methods:


Returns a language code accepted and used actually on collation. If linguistic tailoring is not provided for a language code you passed (intensionally for some languages, or due to the incomplete implementation), this method returns a string 'default' meaning no special tailoring.

A list of tailorable locales

      locale name       description
      af                Afrikaans
      ar                Arabic
      az                Azerbaijani (Azeri)
      be                Belarusian
      bg                Bulgarian
      ca                Catalan
      cs                Czech
      cy                Welsh
      da                Danish
      de__phonebook     German (umlaut as 'ae', 'oe', 'ue')
      eo                Esperanto
      es                Spanish
      es__traditional   Spanish ('ch' and 'll' as a grapheme)
      et                Estonian
      fi                Finnish
      fil               Filipino
      fo                Faroese
      fr                French
      ha                Hausa
      haw               Hawaiian
      hr                Croatian
      hu                Hungarian
      hy                Armenian
      ig                Igbo
      is                Icelandic
      ja                Japanese [1]
      kk                Kazakh
      kl                Kalaallisut
      ko                Korean [2]
      lt                Lithuanian
      lv                Latvian
      mk                Macedonian
      mt                Maltese
      nb                Norwegian Bokmal
      nn                Norwegian Nynorsk
      nso               Northern Sotho
      om                Oromo
      pl                Polish
      ro                Romanian
      ru                Russian
      se                Northern Sami
      sk                Slovak
      sl                Slovenian
      sq                Albanian
      sr                Serbian
      sv                Swedish
      tn                Tswana
      to                Tonga
      tr                Turkish
      uk                Ukrainian
      vi                Vietnamese
      wo                Wolof
      yo                Yoruba
      zh                Chinese
      zh__big5han       Chinese (ideographs: big5 order)
      zh__gb2312han     Chinese (ideographs: GB-2312 order)
      zh__pinyin        Chinese (ideographs: pinyin order)
      zh__stroke        Chinese (ideographs: stroke order)

Locales according to the default UCA rules include de (German), en (English), ga (Irish), id (Indonesian), it (Italian), ka (Georgian), ln (Lingala), ms (Malay), nl (Dutch), pt (Portuguese), st (Southern Sotho), sw (Swahili), xh (Xhosa), zu (Zulu).


[1] ja: Ideographs are sorted in JIS X 0208 order. Fullwidth and halfwidth forms are identical to their normal form. The difference between hiragana and katakana is at the 4th level, the comparison also requires (variable => 'Non-ignorable'), and then katakana_before_hiragana has no effect.

[2] ko: Plenty of ideographs are sorted by their reading. Such an ideograph is primary (level 1) equal to, and secondary (level 2) greater than, the corresponding hangul syllable.


Installation of Unicode::Collate::Locale requires Collate/, Collate/Locale/*.pm, Collate/CJK/*.pm and Collate/allkeys.txt. On building, Unicode::Collate::Locale doesn't require any of data/*.txt, gendata/*, and mklocale. Tests for Unicode::Collate::Locale are named t/loc_*.t.


tailoring is not maximum

Even if a certain letter is tailored, its equivalent would not always tailored as well as it. For example, even though W is tailored, fullwidth W (U+FF37), W with acute (U+1E82), etc. are not tailored. The result may depend on whether source strings are normalized or not, and whether decomposed or composed. Thus (normalization => undef) is less preferred.


The Unicode::Collate::Locale module for perl was written by SADAHIRO Tomoyuki, <>. This module is Copyright(C) 2004-2011, 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.


Unicode Collation Algorithm - UTS #10

The Default Unicode Collation Element Table (DUCET)

Unicode Locale Data Markup Language (LDML) - UTS #35

CLDR - Unicode Common Locale Data Repository