You are viewing the version of this documentation from Perl 5.14.2. View the latest version



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
  sw                Swahili
  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), 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