Perl 5 version 14.3 documentation



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


  1. use Unicode::Collate::Locale;
  2. #construct
  3. $Collator = Unicode::Collate::Locale->
  4. new(locale => $locale_name, %tailoring);
  5. #sort
  6. @sorted = $Collator->sort(@not_sorted);
  7. #compare
  8. $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. 1. language_territory_variant
  2. 2. language_territory
  3. 3. language__variant
  4. 4. language
  5. 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.

  1. Unicode::Collate::Locale->new(
  2. level => 1,
  3. locale => 'fr',
  4. upper_before_lower => 1,
  5. normalization => undef
  6. )

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

  1. Unicode::Collate::Locale->new(
  2. locale => 'da',
  3. upper_before_lower => 0, # causes error as reserved by 'da'
  4. )

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

  1. new(locale => 'ca')->change(backwards => undef)
  2. new(locale => 'da')->change(upper_before_lower => 0)
  3. 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:

  • $Collator->getlocale

    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

  1. locale name description
  2. ----------------------------------------------------------
  3. af Afrikaans
  4. ar Arabic
  5. az Azerbaijani (Azeri)
  6. be Belarusian
  7. bg Bulgarian
  8. ca Catalan
  9. cs Czech
  10. cy Welsh
  11. da Danish
  12. de__phonebook German (umlaut as 'ae', 'oe', 'ue')
  13. eo Esperanto
  14. es Spanish
  15. es__traditional Spanish ('ch' and 'll' as a grapheme)
  16. et Estonian
  17. fi Finnish
  18. fil Filipino
  19. fo Faroese
  20. fr French
  21. ha Hausa
  22. haw Hawaiian
  23. hr Croatian
  24. hu Hungarian
  25. hy Armenian
  26. ig Igbo
  27. is Icelandic
  28. ja Japanese [1]
  29. kk Kazakh
  30. kl Kalaallisut
  31. ko Korean [2]
  32. lt Lithuanian
  33. lv Latvian
  34. mk Macedonian
  35. mt Maltese
  36. nb Norwegian Bokmal
  37. nn Norwegian Nynorsk
  38. nso Northern Sotho
  39. om Oromo
  40. pl Polish
  41. ro Romanian
  42. ru Russian
  43. se Northern Sami
  44. sk Slovak
  45. sl Slovenian
  46. sq Albanian
  47. sr Serbian
  48. sv Swedish
  49. sw Swahili
  50. tn Tswana
  51. to Tonga
  52. tr Turkish
  53. uk Ukrainian
  54. vi Vietnamese
  55. wo Wolof
  56. yo Yoruba
  57. zh Chinese
  58. zh__big5han Chinese (ideographs: big5 order)
  59. zh__gb2312han Chinese (ideographs: GB-2312 order)
  60. zh__pinyin Chinese (ideographs: pinyin order)
  61. zh__stroke Chinese (ideographs: stroke order)
  62. ----------------------------------------------------------

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.