Lingua::JA::Sort::ReadableKey - Sorting and Romanizing Japanese


  use Lingua::JA::Sort::ReadableKey;
  for ( map { $_->[0] }
       sort { $a->[1] cmp $b->[1] }
        map { [ $_, japanese_sortorder($_) ] } @utf8 ) {


First, does Lingua::JA::Sort::JIS do what you want? Look at that first.

It may not do what you want if you want

  • Kanji phrases sorted in their reading order, rather than as a separate block.

  • A machine-readable or storable key so that comparisons and sorting can be done by a non-Japanese-aware system later.

This module uses Text::ChaSen to do kanji-kana conversion, and then produces a comparable ASCII key for sorting.

All text should be in "real" UTF-8 - that is, strings in Perl's internal format with the UTF-8 flag on.


The following methods are exported:


Use ChaSen to convert a kanji sequence into hiragana. You obviously need to install ChaSen, and its Perl interface Text::ChaSen to make this work. You can get ChaSen from and Text::ChaSen is bundled with it. If you have Debian, install the packages "chasen" and "libtext-chasen-perl". This code will work with both ChaSen1 and ChaSen2.


This turns a Japanese string into an ASCII representation of its reading. You can't sort on this, because Japanese don't sort according to the Latin alphabet, but you can use to label Japanese things for people who can't read Japanese. This will automatically call kanji_to_kana if necessary to get the reading of kanji strings.


This returns an ASCII string which represents, in some bizarre magic encoding, the sort order of the Japanese input string, such that comparing the japanese_sort_order of two UTF-8 strings will tell you how they should be sorted in a Japanese dictionary.

By "bizarre" and "magic", I mean that for each character, we find its order in the Japanese alphabet, and then replace that with chr(32+$order) so that it can be compared with cmp.

This also calls kanji_to_kana if there are any kanji strings.


Lingua::JA::Sort::JIS, Text::ChaSen.


Simon Cozens, <>


Copyright (C) 2004 by Simon Cozens

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.4 or, at your option, any later version of Perl 5 you may have available.